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Measurement, spatial spillover and influencing factors of agricultural carbon emissions efficiency in China
WU Haoyue, HUANG Hanjiao, HE Yu, CHEN Wenkuan
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Effects of tillage and straw returning method on the distribution of carbon and nitrogen in soil aggregates
ZHANG Yuming, HU Chunsheng, CHEN Suying, WANG Yuying, LI Xiaoxin, DONG Wenxu, LIU Xiuping, PEI Lin, ZHANG Hui
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Relationship between policy incentives, ecological cognition, and organic fertilizer application by farmers: Based on a moderated mediation model
SANG Xiance, LUO Xiaofeng, HUANG Yanzhong, TANG Lin
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Spatio-temporal evolution of carbon stocks in the Yellow River Basin based on InVEST and CA-Markov models
YANG Jie, XIE Baopeng, ZHANG Degang
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Effects of straw returning and fertilization on soil bacterial and fungal community structures and diversities in rice-wheat rotation soil
ZHANG Hanlin, BAI Naling, ZHENG Xianqing, LI Shuangxi, ZHANG Juanqin, ZHANG Haiyun, ZHOU Sheng, SUN Huifeng, LYU Weiguang
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2013 Vol. 21, No. 12
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2013, 21(12): 1441-1448.
doi: 10.3724/SP.J.1011.2013.30669
Abstract:
Although China had great harvest in recent nine years, food importation and scale of grain transfer from the north to the south increased and food security in fragile balance. Due to the huge importation of soybean coupled with high over-consumption of oil and protein food in China, this study suggested a synergy strategy for food industry and food consumption structure. In accordance with the trend of development of China's grain production and grain supply capacity, attention should be paid to agricultural produce export, setting up overseas food production and supply bases, maintaining foothold and speeding up exploitation of reserve and cultivated lands and cut down China's protein food production. With specific reference to the imbalance in water resources distribution between the south and north, frequent droughts and flood disasters in recent years, we suggested that China's food security should be constructed on the basis of water resources security. Based on existing problems and development potential of China's major grain production areas like the middle and lower reaches of the Yangtze River, the North China Plain, the Northeast Plain and the Northwest Region, we suggested taking synergy strategies for water and food security in China. We emphasized that water security should be the basis for food security. Under the decreasing agricultural acreage condition, China total grain output mainly depended on per-unit-area grain yield. If only water conservation, increased water resource use efficiency, south-to-north water diversion, the synergy of north-to-south grain transfer, and exploration of western region grain bank were strengthened, the full grain yield potential of China could be realized in the near future.
Although China had great harvest in recent nine years, food importation and scale of grain transfer from the north to the south increased and food security in fragile balance. Due to the huge importation of soybean coupled with high over-consumption of oil and protein food in China, this study suggested a synergy strategy for food industry and food consumption structure. In accordance with the trend of development of China's grain production and grain supply capacity, attention should be paid to agricultural produce export, setting up overseas food production and supply bases, maintaining foothold and speeding up exploitation of reserve and cultivated lands and cut down China's protein food production. With specific reference to the imbalance in water resources distribution between the south and north, frequent droughts and flood disasters in recent years, we suggested that China's food security should be constructed on the basis of water resources security. Based on existing problems and development potential of China's major grain production areas like the middle and lower reaches of the Yangtze River, the North China Plain, the Northeast Plain and the Northwest Region, we suggested taking synergy strategies for water and food security in China. We emphasized that water security should be the basis for food security. Under the decreasing agricultural acreage condition, China total grain output mainly depended on per-unit-area grain yield. If only water conservation, increased water resource use efficiency, south-to-north water diversion, the synergy of north-to-south grain transfer, and exploration of western region grain bank were strengthened, the full grain yield potential of China could be realized in the near future.
ZHANG Dong-Mei,
ZHANG Wei,
LIU En-Ke,
JIANG Chun-Xia,
CHEN Qiong,
HAN Yan-Long,
HUANG Xue-Fang,
LIU Hua-Tao,
ZHAO Cong,
CHI Bao-Liang
2013, 21(12): 1449-1458.
doi: 10.3724/SP.J.1011.2013.30581
Abstract:
In order to determine the response of dryland maize sown at different dates to fertilization rate and planting density in early-maturity regions, consecutive field experiments were carried out in 2010 and 2011. The experiment studied the effects of sowing dates [autumn plowing and early sowing (APES) and conventional sowing (control)], fertilization rates and planting densities on the indicators of dryland maize yield. The study aimed to improve yield through highly efficient and compact planting techniques. Results showed that maize grain yield (GY), harvest index (HI) and water use efficiency (WUE) under APES with a certain degree of summer drought in 2010 increased respectively by 9.0%, 7.1% and 6.4% over the control (P < 0.01). The 100-grain weight (HGW, P < 0.01) and kernel ratio (KR, P < 0.05) were also greater than those of the control. GY, HI and WUE under APES in the rainy year of 2011 significantly increased (P < 0.01) respectively by 13.1%, 8.8% and 8.5% over the control. Grain number per spike (P < 0.05) and HGW (P < 0.01) were significantly greater than those of the control. GY and shoot biomass (SB) increased with increasing fertilization rate. However, yield under APES in 2010 decreased with excessive fertilization rate. For the rainy year of 2011, GY under fertilization treatment was significantly greater than that under non-fertilization treatment, while no significant difference was noted in GY among different fertilization treatments. The results suggested that APES with low fertilization rate favored high yields. With increasing planting density, maize GY and SB dynamics in 2010 tracked a quadratic parabolic curve. Plant density of 75 000 plants·hm-2 gave the highest yield under APES. This suggested that while yields under APES increased at higher planting density in dry year, increasing planting density severely limited yield under the control. In wet year of 2011, GY and SB increased with increasing planting density. However, as planting density was above 75 000 plants·hm-2, GY no longer significantly increased. In dry year of 2010, the effect of planting density on yield under APES was weaker than that under the control, which generally favored high yield under APES. While fertilization rate and planting density had a significant interactive effect on yield in dry year, such interactive effect was insignificant in wet year. Thus compared with present maize cultivation practices, early sowing during optimum period, low fertilization rate and appropriate planting density was an efficient maize cultivation technique for high yield.
In order to determine the response of dryland maize sown at different dates to fertilization rate and planting density in early-maturity regions, consecutive field experiments were carried out in 2010 and 2011. The experiment studied the effects of sowing dates [autumn plowing and early sowing (APES) and conventional sowing (control)], fertilization rates and planting densities on the indicators of dryland maize yield. The study aimed to improve yield through highly efficient and compact planting techniques. Results showed that maize grain yield (GY), harvest index (HI) and water use efficiency (WUE) under APES with a certain degree of summer drought in 2010 increased respectively by 9.0%, 7.1% and 6.4% over the control (P < 0.01). The 100-grain weight (HGW, P < 0.01) and kernel ratio (KR, P < 0.05) were also greater than those of the control. GY, HI and WUE under APES in the rainy year of 2011 significantly increased (P < 0.01) respectively by 13.1%, 8.8% and 8.5% over the control. Grain number per spike (P < 0.05) and HGW (P < 0.01) were significantly greater than those of the control. GY and shoot biomass (SB) increased with increasing fertilization rate. However, yield under APES in 2010 decreased with excessive fertilization rate. For the rainy year of 2011, GY under fertilization treatment was significantly greater than that under non-fertilization treatment, while no significant difference was noted in GY among different fertilization treatments. The results suggested that APES with low fertilization rate favored high yields. With increasing planting density, maize GY and SB dynamics in 2010 tracked a quadratic parabolic curve. Plant density of 75 000 plants·hm-2 gave the highest yield under APES. This suggested that while yields under APES increased at higher planting density in dry year, increasing planting density severely limited yield under the control. In wet year of 2011, GY and SB increased with increasing planting density. However, as planting density was above 75 000 plants·hm-2, GY no longer significantly increased. In dry year of 2010, the effect of planting density on yield under APES was weaker than that under the control, which generally favored high yield under APES. While fertilization rate and planting density had a significant interactive effect on yield in dry year, such interactive effect was insignificant in wet year. Thus compared with present maize cultivation practices, early sowing during optimum period, low fertilization rate and appropriate planting density was an efficient maize cultivation technique for high yield.
2013, 21(12): 1459-1466.
doi: 10.3724/SP.J.1011.2013.30466
Abstract:
Experiments were conducted on early rice "Luliangyou 996" and late rice "Wufengyou T025" during the double cropping seasons of 2010-2011 to study the effects of different methods of straw incorporation into soil on yield and top-three leaf characteristics of rice. The results showed that compared to non-straw incorporation, incorporating straw into soils significantly increased grain yield of early rice under equal NPK fertilization. However, straw incorporation was not significantly different from non-straw incorporation in terms of grain yield of late rice. Rice yield in straw-incorporated soils was significantly higher than non-straw incorporated soil under non-fertilization treatments in both early and late rice seasons. Straw incorporation ameliorated the characteristics of top-three leaves of double cropped rice, with higher optimization effect on early rice than on late rice. A significant relationship (P < 0.05) was noted between straw incorporation and grain yield. The index of the top-three leaves of early rice under non-straw incorporation was optimum when yield was maximum, which was not so obvious for late rice. Straw incorporation strengthened the quality of the top-three leaves of double cropped rice with a parabolic relationship between leaf area and leaf area rate of the top-three leaves with grain yield. A highly significant linear relationship was also noted between the specific leaf area and grain yield. The results suggested that rice yield increase under straw incorporation was mainly driven by the perfect structure of top-three leaves of double cropping rice.
Experiments were conducted on early rice "Luliangyou 996" and late rice "Wufengyou T025" during the double cropping seasons of 2010-2011 to study the effects of different methods of straw incorporation into soil on yield and top-three leaf characteristics of rice. The results showed that compared to non-straw incorporation, incorporating straw into soils significantly increased grain yield of early rice under equal NPK fertilization. However, straw incorporation was not significantly different from non-straw incorporation in terms of grain yield of late rice. Rice yield in straw-incorporated soils was significantly higher than non-straw incorporated soil under non-fertilization treatments in both early and late rice seasons. Straw incorporation ameliorated the characteristics of top-three leaves of double cropped rice, with higher optimization effect on early rice than on late rice. A significant relationship (P < 0.05) was noted between straw incorporation and grain yield. The index of the top-three leaves of early rice under non-straw incorporation was optimum when yield was maximum, which was not so obvious for late rice. Straw incorporation strengthened the quality of the top-three leaves of double cropped rice with a parabolic relationship between leaf area and leaf area rate of the top-three leaves with grain yield. A highly significant linear relationship was also noted between the specific leaf area and grain yield. The results suggested that rice yield increase under straw incorporation was mainly driven by the perfect structure of top-three leaves of double cropping rice.
2013, 21(12): 1467-1476.
doi: 10.3724/SP.J.1011.2013.30621
Abstract:
With wide application of plastic mulching in cotton fields in the arid regions of China, residual plastic films have become a growing concern. Compared with plastic mulching, straw mulching has been noted to safely avoid the residual problem associated with plastic mulching. To explore the feasibility of replacing plastic mulching with straw mulching in a combined mulching and drip irrigation system, the effects of straw mulching on distributions of soil water and salt and cotton root system in drip-irrigated cotton fields were evaluated in this study. In addition, the effect of deep straw mulching (buried a layer of straw at 30 cm soil depth) coupled with drip irrigation was evaluated. Pit test experiments were carried out on two soil types (non-saline and saline-alkali soils) with three straw mulching treatments - surface mulching, deep mulching and non-mulching - coupled with drip irrigation. Samples were taken at cotton batt stage when the distribution of root systems was stable, followed by analyses of water, salt and root distribution characteristics. The results showed that surface mulching was fairly effective in soil moisture conservation and effectively prevented water loss via evaporation and salt accumulation in the plough layer. Deep mulching was generally better in effect regarding water conservation than non-mulching. Deep mulching was only advantageous over surface mulching in soil areas near irrigation lines under the straw layer. While deep mulching significantly improved soil moisture content below the plough layer, it had no apparently effect on salt at the cotton batt stage. Straw mulching significantly influenced the distribution of cotton root systems, especially in deep soil layers, by controlling the movements of water and salt. For non-saline soils, in the 0 28 cm soil layer, the highest root length density, root weight density and root length density proportion occurred under non-mulching. Although surface mulching had the smallest root length density, it also had the largest proportion of root weight density. Moreover, the lowest root weight density was under deep mulching. Deep mulching had the highest root length density in the 28 70 cm soil layer. Surface mulching had the smallest root length density but the largest root length density proportion. Then non-mulching had the lowest root length density proportion. In the 28 56 cm soil layer, deep mulching had both the highest root weight density and root weight density proportion. For saline-alkaline soil, in the 0 28 cm soil layer, both surface and deep mulching treatments had higher root length density and root length density proportion than non-mulching. Then surface mulching had the highest root weight density. The lowest root weight density and root weight density proportion occurred under deep mulching. On the contrary, deep mulching had the highest root weight density proportion and the lowest root weight density in the 28 70 cm soil layer. These findings suggested that surface mulching promoted root development in the plough layers of both saline-alkaline and non-saline soils. Deep mulching inhibited root system development in the upper soil layers but enhanced root system development in soil layers below the 30 cm soil depth. Also straw mulching caused the root system to be thinner and longer under unfavorable salt and alkali conditions. Therefore the combination of straw mulching and drip irrigation was highly promising for efficient cotton production in arid areas.
With wide application of plastic mulching in cotton fields in the arid regions of China, residual plastic films have become a growing concern. Compared with plastic mulching, straw mulching has been noted to safely avoid the residual problem associated with plastic mulching. To explore the feasibility of replacing plastic mulching with straw mulching in a combined mulching and drip irrigation system, the effects of straw mulching on distributions of soil water and salt and cotton root system in drip-irrigated cotton fields were evaluated in this study. In addition, the effect of deep straw mulching (buried a layer of straw at 30 cm soil depth) coupled with drip irrigation was evaluated. Pit test experiments were carried out on two soil types (non-saline and saline-alkali soils) with three straw mulching treatments - surface mulching, deep mulching and non-mulching - coupled with drip irrigation. Samples were taken at cotton batt stage when the distribution of root systems was stable, followed by analyses of water, salt and root distribution characteristics. The results showed that surface mulching was fairly effective in soil moisture conservation and effectively prevented water loss via evaporation and salt accumulation in the plough layer. Deep mulching was generally better in effect regarding water conservation than non-mulching. Deep mulching was only advantageous over surface mulching in soil areas near irrigation lines under the straw layer. While deep mulching significantly improved soil moisture content below the plough layer, it had no apparently effect on salt at the cotton batt stage. Straw mulching significantly influenced the distribution of cotton root systems, especially in deep soil layers, by controlling the movements of water and salt. For non-saline soils, in the 0 28 cm soil layer, the highest root length density, root weight density and root length density proportion occurred under non-mulching. Although surface mulching had the smallest root length density, it also had the largest proportion of root weight density. Moreover, the lowest root weight density was under deep mulching. Deep mulching had the highest root length density in the 28 70 cm soil layer. Surface mulching had the smallest root length density but the largest root length density proportion. Then non-mulching had the lowest root length density proportion. In the 28 56 cm soil layer, deep mulching had both the highest root weight density and root weight density proportion. For saline-alkaline soil, in the 0 28 cm soil layer, both surface and deep mulching treatments had higher root length density and root length density proportion than non-mulching. Then surface mulching had the highest root weight density. The lowest root weight density and root weight density proportion occurred under deep mulching. On the contrary, deep mulching had the highest root weight density proportion and the lowest root weight density in the 28 70 cm soil layer. These findings suggested that surface mulching promoted root development in the plough layers of both saline-alkaline and non-saline soils. Deep mulching inhibited root system development in the upper soil layers but enhanced root system development in soil layers below the 30 cm soil depth. Also straw mulching caused the root system to be thinner and longer under unfavorable salt and alkali conditions. Therefore the combination of straw mulching and drip irrigation was highly promising for efficient cotton production in arid areas.
DING Hong,
ZHANG Zhi-Meng,
DAI Liang-Xiang,
CI Dun-Wei,
QIN Fei-Fei,
MA Deng-Chao,
LI Mei,
SONG Wen-Wu,
KANG Tao
2013, 21(12): 1477-1483.
doi: 10.3724/SP.J.1011.2013.30447
Abstract:
Peanut (Arachis hypogaea L.) is an important economic and oil crop with high drought tolerance. Long-term rainlessness or seasonal drought has not only been a limiting factor of peanut production but also the main driving factor of aflatoxin infection before harvest. Root is the main organ for plant water uptake. Changes in environment could change root morphological, physiological and biochemical characteristics. Plant root configuration is significantly different under different soil moisture conditions, which affects root ability to absorb nutrients and water. It is therefore important to study the relationship between root morphological development and drought tolerance for better understanding peanut water absorption, transport, utilization and loss and for breeding drought-tolerant peanut varieties. The aim of the present experiment was to (1) clarify root morphology during the mid and late growth stages of two peanut varieties with different drought tolerance; and (2) determine peanut root response to drought stress. Thus drought-resistant variety "Huayu 22" and drought-sensitive variety "Huayu 23" were planted in anti-canopy tanks in soil columns with different soil water conditions. The soil water conditions included a well-watered (80% 85% field capacity) and medium drought (45% 50% field capacity). Roots were sampled at flower-pegging, pod-setting and pod-filling stages. Root length, surface area and volume were determined using a scanner and analyzed using WinRhizo Pro Vision 5.0a software. Pod yield was recorded at harvest and drought coefficient (DC) calculated as the ratio of yield under water stress treatment to that under well-watered condition. The results showed that "Huayu 22" had higher yield and drought coefficient than "Huayu 23", which had poorer adaptability to drought stress. Root biomass, total root length and total root surface area of "Huayu 22" were higher, as "Huayu 22" had a more developed root system than "Huayu 23". Total root length, total root surface area and total root volume of the two peanut varieties at flower-pegging stage were smaller under drought stress treatment than under well-watered condition, while root traits were not significantly different at pod-setting and pod-filling stages. Drought stress increased root length density distribution ratio, root surface area and volume of two peanut varieties in soil layer below 40 cm. The increase in root traits of "Huayu 23" was less than that of "Huayu 22". Root surface area and root volume in 20 40 cm soil layer and in layers below 40 cm were significantly positively correlated with total root length, total root surface area and root volume under drought stress. Also root surface area and root volume in 0 20 cm soil layer were significantly correlated with total root length, total root surface area and root volume under well-watered condition. In conclusion, the main root morphology of drought-resistant peanut variety was characterized as lager root system and high root distributions in deeper soil layers. Under water-deficit condition, peanut efficiently utilized water by increased root length, root surface area, root volume and other morphological characteristics in deeper soil layers.
Peanut (Arachis hypogaea L.) is an important economic and oil crop with high drought tolerance. Long-term rainlessness or seasonal drought has not only been a limiting factor of peanut production but also the main driving factor of aflatoxin infection before harvest. Root is the main organ for plant water uptake. Changes in environment could change root morphological, physiological and biochemical characteristics. Plant root configuration is significantly different under different soil moisture conditions, which affects root ability to absorb nutrients and water. It is therefore important to study the relationship between root morphological development and drought tolerance for better understanding peanut water absorption, transport, utilization and loss and for breeding drought-tolerant peanut varieties. The aim of the present experiment was to (1) clarify root morphology during the mid and late growth stages of two peanut varieties with different drought tolerance; and (2) determine peanut root response to drought stress. Thus drought-resistant variety "Huayu 22" and drought-sensitive variety "Huayu 23" were planted in anti-canopy tanks in soil columns with different soil water conditions. The soil water conditions included a well-watered (80% 85% field capacity) and medium drought (45% 50% field capacity). Roots were sampled at flower-pegging, pod-setting and pod-filling stages. Root length, surface area and volume were determined using a scanner and analyzed using WinRhizo Pro Vision 5.0a software. Pod yield was recorded at harvest and drought coefficient (DC) calculated as the ratio of yield under water stress treatment to that under well-watered condition. The results showed that "Huayu 22" had higher yield and drought coefficient than "Huayu 23", which had poorer adaptability to drought stress. Root biomass, total root length and total root surface area of "Huayu 22" were higher, as "Huayu 22" had a more developed root system than "Huayu 23". Total root length, total root surface area and total root volume of the two peanut varieties at flower-pegging stage were smaller under drought stress treatment than under well-watered condition, while root traits were not significantly different at pod-setting and pod-filling stages. Drought stress increased root length density distribution ratio, root surface area and volume of two peanut varieties in soil layer below 40 cm. The increase in root traits of "Huayu 23" was less than that of "Huayu 22". Root surface area and root volume in 20 40 cm soil layer and in layers below 40 cm were significantly positively correlated with total root length, total root surface area and root volume under drought stress. Also root surface area and root volume in 0 20 cm soil layer were significantly correlated with total root length, total root surface area and root volume under well-watered condition. In conclusion, the main root morphology of drought-resistant peanut variety was characterized as lager root system and high root distributions in deeper soil layers. Under water-deficit condition, peanut efficiently utilized water by increased root length, root surface area, root volume and other morphological characteristics in deeper soil layers.
2013, 21(12): 1484-1490.
doi: 10.3724/SP.J.1011.2013.30296
Abstract:
Drought and salinity have been the main abiotic stresses that adversely affect wheat prodcution. In this paper, four wheat varieties were used in a preliminary analysis of salt-tolerant characteristics and agronomic traits under a two-year drought condition. The investigated wheat varieties included "Xindong 26" (from Xinjiang Uygur Autonomous Region), and "Cangmai 6001", "Cangmai 6002" and "Cangmai 6003" (from Cangzhou City, Hebei Province). The results of the study provided the needed reference information on wheat varietal improvement and genetic breeding. The results showed that under 100 mmol·L-1 NaCl, the relative growth rates of roots and shoots of "Xindong 26" were higher than those of the other varieties. Then under 200 mmol·L-1 NaCl, "Cangmai 6003" performed better than the other varieties. After treatment with 100 mmol·L-1 NaCl, the ratios of root to shoot of the four varieties decreased. However, in 200 mmol·L-1 NaCl, root-to-shoot ratio of "Xindong 26" increased. Under drought stress, "Xindong 26" and "Cangmai 6001" showed the highest yield among the four wheat varieties. Furthermore, agronomic traits of salt-tolerant wheat varieties under drought conditions were analyzed. Correlation analysis on agronomic traits showed that grain yield per plant was extremely positively correlated with tillering number, spikelet number and kernels number per spike and biological yield per plant, and positively correlated with economic coefficient. Multivariate regression analysis showed that tillering number, spikelet number, kernels number per spike and biological yield per plant determined 75.9% of the yield variation. The results suggested that wheat varieties with higher tillering number, spikelet number, kernels number per spike and biological yield per plant were better picks for salt/drought-tolerant varieties.
Drought and salinity have been the main abiotic stresses that adversely affect wheat prodcution. In this paper, four wheat varieties were used in a preliminary analysis of salt-tolerant characteristics and agronomic traits under a two-year drought condition. The investigated wheat varieties included "Xindong 26" (from Xinjiang Uygur Autonomous Region), and "Cangmai 6001", "Cangmai 6002" and "Cangmai 6003" (from Cangzhou City, Hebei Province). The results of the study provided the needed reference information on wheat varietal improvement and genetic breeding. The results showed that under 100 mmol·L-1 NaCl, the relative growth rates of roots and shoots of "Xindong 26" were higher than those of the other varieties. Then under 200 mmol·L-1 NaCl, "Cangmai 6003" performed better than the other varieties. After treatment with 100 mmol·L-1 NaCl, the ratios of root to shoot of the four varieties decreased. However, in 200 mmol·L-1 NaCl, root-to-shoot ratio of "Xindong 26" increased. Under drought stress, "Xindong 26" and "Cangmai 6001" showed the highest yield among the four wheat varieties. Furthermore, agronomic traits of salt-tolerant wheat varieties under drought conditions were analyzed. Correlation analysis on agronomic traits showed that grain yield per plant was extremely positively correlated with tillering number, spikelet number and kernels number per spike and biological yield per plant, and positively correlated with economic coefficient. Multivariate regression analysis showed that tillering number, spikelet number, kernels number per spike and biological yield per plant determined 75.9% of the yield variation. The results suggested that wheat varieties with higher tillering number, spikelet number, kernels number per spike and biological yield per plant were better picks for salt/drought-tolerant varieties.
2013, 21(12): 1491-1499.
doi: 10.3724/SP.J.1011.2013.30474
Abstract:
As a new slope protection technique, net terrace biological bank combines biological measures with engineering practices for soil/water conservation. They significantly influence soil nutrient contents and distribution patterns along slope. The technique has made it possible to realize full uses of land resources and ensure maintenance of ecological and economic benefits under insufficient supply of arable land resources against vast slope of varying lengths. To study soil nutrients distributions in different slope positions and to provide theoretical basis to further promote net terrace biological bank and artificial regulation of slope-protection economic vegetation, this article analyzed the impact of net terrace biological bank on soil nutrient distribution patterns on slope. It also determined the soil nutrients contents in net terrace biological bank with different construction years using field investigation and indoor experimental methods. The results showed that: (1) net terrace biological bank significantly changed soil pH and organic matter content. Also while soil pH decreased with increasing construction years, organic matter content significantly increased. The distribution pattern of organic matter along slope changed significantly, with that of the upper part > middle part > lower part of slope in all construction period. However, the trend of organic matter content change under the control (bare slope) tracked the reverse pattern. (2) With the increasing construction years of net terrace biological bank, total nitrogen content increased after an initial period of decrease. The improvement in nitrogen content in the upper part of slope was stronger than that in the middle and lower parts of slope. Alkali-hydrolysis nitrogen content was significantly related to total nitrogen content. The differences among different construction years were more significant in the upper and lower parts of slope. (3) In the first three construction years, differences were noted in the distribution patterns of total phosphorus on different slope positions. In the fourth year of development, however, the distribution pattern of total phosphorus along slope were in the reverse order to the control. The distribution pattern of total phosphorus along slope followed the order of lower part > middle part > upper part, with significant (P=0.000) difference among different slope positions. Furthermore, soil available phosphorus exhibited some degree of volatility with construction years of net terrace biological bank. Although the coefficient of variation was reached 31.37%, the average content of available phosphorus increased to 1.15 3.30 times compared with the control, where no obvious distribution patterns were noted on the slopes. (4) Compared with the control, total potassium content increased by 9.7% 28.2%. With increasing construction years of net terrace biological bank, however, total potassium decreased. Net terrace biological bank also improved soil available potassium content. The differences in available potassium content in different slope positions were enhanced after an initial year of construction of net terrace biological bank.
As a new slope protection technique, net terrace biological bank combines biological measures with engineering practices for soil/water conservation. They significantly influence soil nutrient contents and distribution patterns along slope. The technique has made it possible to realize full uses of land resources and ensure maintenance of ecological and economic benefits under insufficient supply of arable land resources against vast slope of varying lengths. To study soil nutrients distributions in different slope positions and to provide theoretical basis to further promote net terrace biological bank and artificial regulation of slope-protection economic vegetation, this article analyzed the impact of net terrace biological bank on soil nutrient distribution patterns on slope. It also determined the soil nutrients contents in net terrace biological bank with different construction years using field investigation and indoor experimental methods. The results showed that: (1) net terrace biological bank significantly changed soil pH and organic matter content. Also while soil pH decreased with increasing construction years, organic matter content significantly increased. The distribution pattern of organic matter along slope changed significantly, with that of the upper part > middle part > lower part of slope in all construction period. However, the trend of organic matter content change under the control (bare slope) tracked the reverse pattern. (2) With the increasing construction years of net terrace biological bank, total nitrogen content increased after an initial period of decrease. The improvement in nitrogen content in the upper part of slope was stronger than that in the middle and lower parts of slope. Alkali-hydrolysis nitrogen content was significantly related to total nitrogen content. The differences among different construction years were more significant in the upper and lower parts of slope. (3) In the first three construction years, differences were noted in the distribution patterns of total phosphorus on different slope positions. In the fourth year of development, however, the distribution pattern of total phosphorus along slope were in the reverse order to the control. The distribution pattern of total phosphorus along slope followed the order of lower part > middle part > upper part, with significant (P=0.000) difference among different slope positions. Furthermore, soil available phosphorus exhibited some degree of volatility with construction years of net terrace biological bank. Although the coefficient of variation was reached 31.37%, the average content of available phosphorus increased to 1.15 3.30 times compared with the control, where no obvious distribution patterns were noted on the slopes. (4) Compared with the control, total potassium content increased by 9.7% 28.2%. With increasing construction years of net terrace biological bank, however, total potassium decreased. Net terrace biological bank also improved soil available potassium content. The differences in available potassium content in different slope positions were enhanced after an initial year of construction of net terrace biological bank.
2013, 21(12): 1500-1506.
doi: 10.3724/SP.J.1011.2013.30440
Abstract:
Although crop yields can be improved by engineered genetic modification of plants, ecological concerns remain about persistence of such crops in the wild in the event of dispersal from cultivated habitats with unintended effects, like adverse impacts on weed community composition and diversity in the fields. This study aimed to assess the effects of GMC (genetically modified crop) rice with CryIAb gene on the diversity, structure and composition of weed communities in rice fields and using conventional indica rice ("MH86") as the control. A total of 16 plots in semi-wild cultivation and conventional cultivation conditions were analyzed. The conventional cultivation treatment was in accordance with local farming practice, while in the semi-wild cultivation was non-farming practice with irrigation. All weed species and numbers collected from five sample spots per plot were investigated. An investigated sample spot was 0.25 m2 in the semi-wild plots and 1.0 m2 in the conventional cultivation plot. The results showed: no significant difference in weed species between transgenic CryIAb ("Mfb") rice and non-transgenic ("MH86") rice fields under the same cultivation pattern. While high weed frequency and density were observed in semi-wild plots compared to conventional cultivation plots, no differences in frequency and density were noted between two varieties. Statistical analysis suggested that species richness and Shannon-Wiener diversity index were greater in semi-wild plots than in conventional cultivation plots. All the applied multivariate methods of analysis revealed that weed community composition was significantly different between the two cultivation conditions. There was an unobvious difference between transgenic and non-transgenic rice communities in terms of the indices of weed species richness, evenness, dominance and diversity. The results suggested that the diversity and stability of weed community in transgenic rice fields did not significantly differ from those in traditional rice fields.
Although crop yields can be improved by engineered genetic modification of plants, ecological concerns remain about persistence of such crops in the wild in the event of dispersal from cultivated habitats with unintended effects, like adverse impacts on weed community composition and diversity in the fields. This study aimed to assess the effects of GMC (genetically modified crop) rice with CryIAb gene on the diversity, structure and composition of weed communities in rice fields and using conventional indica rice ("MH86") as the control. A total of 16 plots in semi-wild cultivation and conventional cultivation conditions were analyzed. The conventional cultivation treatment was in accordance with local farming practice, while in the semi-wild cultivation was non-farming practice with irrigation. All weed species and numbers collected from five sample spots per plot were investigated. An investigated sample spot was 0.25 m2 in the semi-wild plots and 1.0 m2 in the conventional cultivation plot. The results showed: no significant difference in weed species between transgenic CryIAb ("Mfb") rice and non-transgenic ("MH86") rice fields under the same cultivation pattern. While high weed frequency and density were observed in semi-wild plots compared to conventional cultivation plots, no differences in frequency and density were noted between two varieties. Statistical analysis suggested that species richness and Shannon-Wiener diversity index were greater in semi-wild plots than in conventional cultivation plots. All the applied multivariate methods of analysis revealed that weed community composition was significantly different between the two cultivation conditions. There was an unobvious difference between transgenic and non-transgenic rice communities in terms of the indices of weed species richness, evenness, dominance and diversity. The results suggested that the diversity and stability of weed community in transgenic rice fields did not significantly differ from those in traditional rice fields.
2013, 21(12): 1507-1514.
doi: 10.3724/SP.J.1011.2013.30385
Abstract:
Phalaris minor Retz. is considered as one of the world's most destructive weed species in farmlands and its control and management have attracted tremendous attention globally. Understanding the morphological plasticity and competitiveness of P. minor under different environmental conditions has been crucial for early warning and control of the weed. To study the morphological plasticity and competitiveness of the invasive P. minor plant, a greenhouse experiment was conducted with the de Wit replacement series method. In the experiment, P. minor was cultivated together with native crops of wheat (Triticum aestivum L.), broad bean (Vicia faba L.) and rape (Brassica campestris L.) in different mixed ratios (2∶1, 1∶1, 1∶2), respectively. Two-way ANOVA results indicated that the planting ratio of the native and invader species had no effect on P. minor branch number and main spike length (P ≥ 0.05), while plant species, mixed ratio and their interaction significantly affected P. minor plant height, seed number of main ear, flag leaf area and biomass (P ≤ 0.05 or 0.001). When planted with rape, P. minor plant height was significantly higher than when planted with wheat, broad bean or monoculture. The number of branches, length of main spike, seed number of main ear, flag leaf area and biomass significantly decreased when P. minor was planted with rape than when planted with wheat or broad bean at the same mixed ratio. When planted with P. minor, wheat, broad bean and rape had significantly decreased relative yields (RY) (below 1.0), indicating inter-specific competition between P. minor and native species was dominant. RY of P. minor was larger than 1.0 when planted with broad bean at all three mixed ratio, and with wheat with 1∶1 and 1∶2, indicating that intra-specific competition was dominant. RY of P. minor was below 1.0 when planted with rape, indicating competition between two species was dominant. Competitive balance index (CB) between P. minor and native species was significantly greater than 0, implying that P. minor had a stronger competitive ability than native crops. However, when P. minor was planted together with rape under mixed ratio greater than 1∶1, CB between P. minor and rape was less than 1, rape became stronger than P. minor. Consequently, rape had a higher competitive ability than P. minor. The branch number, length of main spike, seed number of main ear, flag leaf area and biomass of P. minor significantly dropped when planted with rape. This suggested that it was possible to use rape to inhibit the expansion and outbreak of P. minor.
Phalaris minor Retz. is considered as one of the world's most destructive weed species in farmlands and its control and management have attracted tremendous attention globally. Understanding the morphological plasticity and competitiveness of P. minor under different environmental conditions has been crucial for early warning and control of the weed. To study the morphological plasticity and competitiveness of the invasive P. minor plant, a greenhouse experiment was conducted with the de Wit replacement series method. In the experiment, P. minor was cultivated together with native crops of wheat (Triticum aestivum L.), broad bean (Vicia faba L.) and rape (Brassica campestris L.) in different mixed ratios (2∶1, 1∶1, 1∶2), respectively. Two-way ANOVA results indicated that the planting ratio of the native and invader species had no effect on P. minor branch number and main spike length (P ≥ 0.05), while plant species, mixed ratio and their interaction significantly affected P. minor plant height, seed number of main ear, flag leaf area and biomass (P ≤ 0.05 or 0.001). When planted with rape, P. minor plant height was significantly higher than when planted with wheat, broad bean or monoculture. The number of branches, length of main spike, seed number of main ear, flag leaf area and biomass significantly decreased when P. minor was planted with rape than when planted with wheat or broad bean at the same mixed ratio. When planted with P. minor, wheat, broad bean and rape had significantly decreased relative yields (RY) (below 1.0), indicating inter-specific competition between P. minor and native species was dominant. RY of P. minor was larger than 1.0 when planted with broad bean at all three mixed ratio, and with wheat with 1∶1 and 1∶2, indicating that intra-specific competition was dominant. RY of P. minor was below 1.0 when planted with rape, indicating competition between two species was dominant. Competitive balance index (CB) between P. minor and native species was significantly greater than 0, implying that P. minor had a stronger competitive ability than native crops. However, when P. minor was planted together with rape under mixed ratio greater than 1∶1, CB between P. minor and rape was less than 1, rape became stronger than P. minor. Consequently, rape had a higher competitive ability than P. minor. The branch number, length of main spike, seed number of main ear, flag leaf area and biomass of P. minor significantly dropped when planted with rape. This suggested that it was possible to use rape to inhibit the expansion and outbreak of P. minor.
2013, 21(12): 1515-1525.
doi: 10.3724/SP.J.1011.2013.30376
Abstract:
Accompanying the increasing consumption of industrial and city water, irrigation water has been reduced due to fast growing national economy and urbanization. This has led to a strong conflict between supply and demand of irrigation water. The fraction of irrigation water in society's total water consumption has reduced from 80% in the 1970s to 60% at the present state. Discussing the distribution of limited water resources among different crops and crop growth stages in an optimal way that maximizes yields or profits has been particularly critical for alleviating irrigation water resources shortage. In this paper, a decomposition and coordination model was set up based on maximum total yield of crops in irrigation areas. The aim of the model was to simultaneously attain optimal allocation of planting structures and irrigation amount in multi-crops system at different crop growth stages. The key related factors considered during the model setting up included irrigation amoung, planting area, water production function, productivity reactivity coefficient and water sensitivity index. The model was driven by an algorithm that combined improved real coding genetic algorithm with decomposing and coordinating iterative algorithm. The model algorithm was used to optimize the planting structures and irrigation amount of mixed planting of corn and wheat. This in turn optimized irrigation schemes for corn and wheat using multi-year experimental data from the Yanting Purple Soil Agro-Ecological Experimental Station of Chinese Academy of Sciences. The results showed that higher productivity reactivity coefficient meant faster yield increment with increased irrigation amount. The crops with higher high productivity reactivity coefficient shared greater irrigation amount and planting area. Higher water sensitivity index implied more irrigation amount of crops at different growth stages when potential evapotranspiration was close to available usable water. On the contrary, it was possible that crops with high water sensitivity index had insufficient irrigation amount. The results were consistent with the theories of geometric meaning of crop productivity reactivity coefficient, the law of diminishing marginal utility, and the notion of increased income from water saving. The results further illustrated that the model was strongly practical not only in optimation of multi-crop planting structures, but also in optimal distribution of limited water resources among different crops and at different growth stages. The improved real coding genetic algorithm overcame the shortfalls of the traditional real coding genetic algorithm such as low accuracy, easy early maturing, inconsistent equality constraint requirements, and it could find optimal solution within a short time. This proved that the improved real coding genetic algorithm had practical application value for solving problems of equality and inequality constraints due to its high optimum solution capability that fully satisfied equality constraint requirements. The decomposing and coordinating iterative algorithm attained model convergence within the allowable range of iterative error under different irrigation amounts. It attained optimal solution with a satisfactory overall effect of the model. The study showed that the decomposing and coordinating iterative algorithm had comparative advantage in solving complex large-scale optimization problems.
Accompanying the increasing consumption of industrial and city water, irrigation water has been reduced due to fast growing national economy and urbanization. This has led to a strong conflict between supply and demand of irrigation water. The fraction of irrigation water in society's total water consumption has reduced from 80% in the 1970s to 60% at the present state. Discussing the distribution of limited water resources among different crops and crop growth stages in an optimal way that maximizes yields or profits has been particularly critical for alleviating irrigation water resources shortage. In this paper, a decomposition and coordination model was set up based on maximum total yield of crops in irrigation areas. The aim of the model was to simultaneously attain optimal allocation of planting structures and irrigation amount in multi-crops system at different crop growth stages. The key related factors considered during the model setting up included irrigation amoung, planting area, water production function, productivity reactivity coefficient and water sensitivity index. The model was driven by an algorithm that combined improved real coding genetic algorithm with decomposing and coordinating iterative algorithm. The model algorithm was used to optimize the planting structures and irrigation amount of mixed planting of corn and wheat. This in turn optimized irrigation schemes for corn and wheat using multi-year experimental data from the Yanting Purple Soil Agro-Ecological Experimental Station of Chinese Academy of Sciences. The results showed that higher productivity reactivity coefficient meant faster yield increment with increased irrigation amount. The crops with higher high productivity reactivity coefficient shared greater irrigation amount and planting area. Higher water sensitivity index implied more irrigation amount of crops at different growth stages when potential evapotranspiration was close to available usable water. On the contrary, it was possible that crops with high water sensitivity index had insufficient irrigation amount. The results were consistent with the theories of geometric meaning of crop productivity reactivity coefficient, the law of diminishing marginal utility, and the notion of increased income from water saving. The results further illustrated that the model was strongly practical not only in optimation of multi-crop planting structures, but also in optimal distribution of limited water resources among different crops and at different growth stages. The improved real coding genetic algorithm overcame the shortfalls of the traditional real coding genetic algorithm such as low accuracy, easy early maturing, inconsistent equality constraint requirements, and it could find optimal solution within a short time. This proved that the improved real coding genetic algorithm had practical application value for solving problems of equality and inequality constraints due to its high optimum solution capability that fully satisfied equality constraint requirements. The decomposing and coordinating iterative algorithm attained model convergence within the allowable range of iterative error under different irrigation amounts. It attained optimal solution with a satisfactory overall effect of the model. The study showed that the decomposing and coordinating iterative algorithm had comparative advantage in solving complex large-scale optimization problems.
2013, 21(12): 1526-1536.
doi: 10.3724/SP.J.1011.2013.30562
Abstract:
Maize is a major cultivated grain crop in Sichuan and has contributed significantly to total grain production in the province. Sichuan Province has a complex topography and various landforms where climate change has caused temperature and precipitation anomalies, adversely affecting local maize production in the past 50 years. However, studies of future changes in agricultural climatic resources and corresponding impacts on maize production in Sichuan have rarely been reported. Predicting temporal and spatial changes in climatic resources and potential productivity during the entire growth period of maize under global climate change in the Sichuan Basin can lay key theoretical basis for developing response strategies of climate change and macroscopic policy decisions on maize production. Based on baseline climatic condition (1961 1990) and daily data for A2 and B2 climate scenarios (2071 2100) from the PRECIS regional climate model, the spatial and temporal characteristics of climatic resources (accumulated temperature ≥10 ℃ of daily average temperature, sunshine hours, precipitation, reference crop evapotranspiration and water deficient ratio) and potential productivity (photosynthetic potential productivity, photo-temperature potential productivity and climatic potential productivity) of maize in Sichuan Basin were analyzed. The results showed that accumulated temperature ≥10 ℃, sunshine hours and reference crop evapotranspiration during the entire growth period of maize increased in 2071 2100 under A2 and B2 climate scenarios compared with the 1961 1990 baseline climate conditions. Accumulated temperature ≥10 ℃ increased respectively by 460 641 ℃·d and 376 492 ℃·d under A2 and B2 climate scenarios with the highest increase in the western basin. Sunshine hours would increased respectively by 15 225 h and 33 202 h, with the highest increase in Ya'an. Reference crop evapotranspiration increased respectively by 76 144 mm and 73 123 mm with the highest increase in Ya'an. Precipitation decreased in most of the regions of Sichuan Basin with the highest decrease in Ya'an. For individual region, however, precipitation apparently respectively increased within 87 56 mm and 73 47 mm under the A2 and B2 climate scenarios. Water deficient ratio of maize respectively increased by 2% 18% and 5% 16% under the future A2 and B2 climate scenarios, suggesting increasing maize drought disaster risks in Sichuan Basin. Compared with the 1961 1990 baseline climate conditions, photosynthetic potential productivity of maize respectively increased by 228 3 277 kg·hm-2 and 485 2 960 kg·hm-2 during 2071 2100 under A2 and B2 climate scenarios with the highest increase in Ya'an and northern basin. Photo-temperature potential productivity respectively increased by 2 923 5 874 kg·hm-2 and 2 697 4 909 kg·hm-2 during 2071 2100 under A2 and B2 climate scenarios with the highest increase in Ya'an. Climatic potential productivity respectively increased by 984 2 975 kg·hm-2 and 293 2 090 kg·hm-2 during 2071 2100 under A2 and B2 climate scenarios with the highest increase in western basin. Future changes in climatic resources were apparently beneficial to maize yield in Sichuan Basin.
Maize is a major cultivated grain crop in Sichuan and has contributed significantly to total grain production in the province. Sichuan Province has a complex topography and various landforms where climate change has caused temperature and precipitation anomalies, adversely affecting local maize production in the past 50 years. However, studies of future changes in agricultural climatic resources and corresponding impacts on maize production in Sichuan have rarely been reported. Predicting temporal and spatial changes in climatic resources and potential productivity during the entire growth period of maize under global climate change in the Sichuan Basin can lay key theoretical basis for developing response strategies of climate change and macroscopic policy decisions on maize production. Based on baseline climatic condition (1961 1990) and daily data for A2 and B2 climate scenarios (2071 2100) from the PRECIS regional climate model, the spatial and temporal characteristics of climatic resources (accumulated temperature ≥10 ℃ of daily average temperature, sunshine hours, precipitation, reference crop evapotranspiration and water deficient ratio) and potential productivity (photosynthetic potential productivity, photo-temperature potential productivity and climatic potential productivity) of maize in Sichuan Basin were analyzed. The results showed that accumulated temperature ≥10 ℃, sunshine hours and reference crop evapotranspiration during the entire growth period of maize increased in 2071 2100 under A2 and B2 climate scenarios compared with the 1961 1990 baseline climate conditions. Accumulated temperature ≥10 ℃ increased respectively by 460 641 ℃·d and 376 492 ℃·d under A2 and B2 climate scenarios with the highest increase in the western basin. Sunshine hours would increased respectively by 15 225 h and 33 202 h, with the highest increase in Ya'an. Reference crop evapotranspiration increased respectively by 76 144 mm and 73 123 mm with the highest increase in Ya'an. Precipitation decreased in most of the regions of Sichuan Basin with the highest decrease in Ya'an. For individual region, however, precipitation apparently respectively increased within 87 56 mm and 73 47 mm under the A2 and B2 climate scenarios. Water deficient ratio of maize respectively increased by 2% 18% and 5% 16% under the future A2 and B2 climate scenarios, suggesting increasing maize drought disaster risks in Sichuan Basin. Compared with the 1961 1990 baseline climate conditions, photosynthetic potential productivity of maize respectively increased by 228 3 277 kg·hm-2 and 485 2 960 kg·hm-2 during 2071 2100 under A2 and B2 climate scenarios with the highest increase in Ya'an and northern basin. Photo-temperature potential productivity respectively increased by 2 923 5 874 kg·hm-2 and 2 697 4 909 kg·hm-2 during 2071 2100 under A2 and B2 climate scenarios with the highest increase in Ya'an. Climatic potential productivity respectively increased by 984 2 975 kg·hm-2 and 293 2 090 kg·hm-2 during 2071 2100 under A2 and B2 climate scenarios with the highest increase in western basin. Future changes in climatic resources were apparently beneficial to maize yield in Sichuan Basin.
2013, 21(12): 1537-1544.
doi: 10.3724/SP.J.1011.2013.30403
Abstract:
This study determined the risk of cold and freezing damage to Zizyphus mauritiana introduced to the complex terrains of Fujian Province from Taiwan Province in order to avoid planting the crop in high risk areas. Based on disaster risk system theory, the study used meteorological, agricultural and economic data to analyze potential hazards of cold and freezing damage and vulnerability of Z. mauritiana. The study also investigated the prevention measures of cold and freezing damage in the cultivated regions and developed a model-driven index system of evaluation based on the AHP, entropy-weight coefficient and comprehensive weighting methods. The study further determined the degree and region of risk of cold and freezing damage to Z. mauritiana in Fujian. In terms of risk factor composition, the results showed that potential hazard was the determinant factor of cold and freezing damage and prevention measures only mitigated this potential. For risk region, the areas of lighter risk of cold and freezing damage to Z. mauritiana were Hui'an County of Xiamen Region and the coastal counties to the south of Xiamen Region. The potential hazard of cold and freezing damage was low in these regions and frequency occurrence of moderate or severe damages were less or even non-existent. The regions with moderate risk were in the low elevation areas of Zhangzhou Inland Region, low elevation areas of the coastal counties of Fuzhou Region, and parts of Yongchun County, Tong'an District and Hui'an County. The occurrence frequency of moderate or severe damages was relatively low in the areas. Other cultivated regions of Z. mauritiana had severe risk of cold and freezing damage. Among the regions, cold and freezing damage risk was severe in Longyan City, the western mountain areas of Zhangzhou Region, the western and northern mountain areas of Fuzhou Region, Yongchun County, Ningde City and Xiapu County. Based on the risk evaluation results and Z. mauritiana cold and freezing damage, the morphological characterization of cold and freezing damage to Z. mauritiana was consistent with the risk evaluation results. The results of the study offered the basis for decisions on Z. mauritiana cultivation and arrangement in Fujian Province.
This study determined the risk of cold and freezing damage to Zizyphus mauritiana introduced to the complex terrains of Fujian Province from Taiwan Province in order to avoid planting the crop in high risk areas. Based on disaster risk system theory, the study used meteorological, agricultural and economic data to analyze potential hazards of cold and freezing damage and vulnerability of Z. mauritiana. The study also investigated the prevention measures of cold and freezing damage in the cultivated regions and developed a model-driven index system of evaluation based on the AHP, entropy-weight coefficient and comprehensive weighting methods. The study further determined the degree and region of risk of cold and freezing damage to Z. mauritiana in Fujian. In terms of risk factor composition, the results showed that potential hazard was the determinant factor of cold and freezing damage and prevention measures only mitigated this potential. For risk region, the areas of lighter risk of cold and freezing damage to Z. mauritiana were Hui'an County of Xiamen Region and the coastal counties to the south of Xiamen Region. The potential hazard of cold and freezing damage was low in these regions and frequency occurrence of moderate or severe damages were less or even non-existent. The regions with moderate risk were in the low elevation areas of Zhangzhou Inland Region, low elevation areas of the coastal counties of Fuzhou Region, and parts of Yongchun County, Tong'an District and Hui'an County. The occurrence frequency of moderate or severe damages was relatively low in the areas. Other cultivated regions of Z. mauritiana had severe risk of cold and freezing damage. Among the regions, cold and freezing damage risk was severe in Longyan City, the western mountain areas of Zhangzhou Region, the western and northern mountain areas of Fuzhou Region, Yongchun County, Ningde City and Xiapu County. Based on the risk evaluation results and Z. mauritiana cold and freezing damage, the morphological characterization of cold and freezing damage to Z. mauritiana was consistent with the risk evaluation results. The results of the study offered the basis for decisions on Z. mauritiana cultivation and arrangement in Fujian Province.
2013, 21(12): 1545-1553.
doi: 10.3724/SP.J.1011.2013.30142
Abstract:
The southwest karst area in China could be a key carbon sink after appropriate ecological engineering. Vegetation carbon pool has been noted to be more critical for carbon budgets of ecosystems than shallow soils which have limited carbon saving capacity. However, due to the unique nature of geological settings of karst regions, spatial distributions of vegetation in these regions usually follow three-dimensional characteristics of discontinuity and fragmentation. This has resulted in difficulties in obtaining the belowground portions of vegetation, which have in turn caused a general lack of attention to this issue. Thus vegetation carbon pool has become a limiting factor in the assessment of regional vegetation carbon savings. In this study, we attempted to reveal the spatial distribution characteristics and differentiations of vegetation carbon savings in typical karst regions by analyzing remote sensing images. The spatio-temporal variation of vegetation carbon storage and density in typical karst areas of Northwest Guangxi in China was analyzed using remote sensing images of 1990, 2000 and 2005 in combination with elevation and weather data in geographic information system (GIS) environment. The results showed that vegetation carbon storage and density in the study area increased for 1990-2005. Vegetation carbon storage increased from 1.03×108 t in 1990 to 1.41×108 t in 2000 and then to 1.63×108 t in 2005. The corresponding carbon density was 14.82 t·hm-2 in 1990, 20.38 t·hm-2 in 2000 and 23.49 t·hm-2 in 2005, consistent with vegetation carbon density in Sichuan (18.47 t·hm-2) and Jiangxi (25.38 t·hm-2) Provinces of China. With regards to spatial distribution of carbon storage and density, high values were noted for the west or high-elevation (elevation > 500 m) regions and low values in the east or low-elevation (elevation < 500 m) regions of the study area. The carbon density was 15 22 t·hm-2 in most of the western counties of the study area while it was 8 15 t·hm-2 in most of the eastern counties of the study area in 1990. While an explicit increase was noted in the trend of change in spatial distribution of carbon storage and density in low-value areas (the eastern part of the region), slight decrease or increase was noted in high-value areas (the western part of the region). Vegetation carbon density obviously increased in typical karst areas with carbon storage to vegetation ratios of 45.54% in 1990 and 51.99% in 2005. The study suggested that vegetation carbon storage and density in cluster and depression regions obviously increased. Also ecosystem conditions accordingly improved due to policy initiatives regarding prevention of rocky desertification such as ecological migration and returning farmlands to forests. This had clearly benefited by enhancing vegetation carbon storage. This paper showed that assessments based on remote sensing images could provide the scientific basis for reducing uncertainty in estimating carbon stocks in karst regions and carbon balance in terrestrial ecosystems. It provided the basis for scientific reference regarding beneficial evaluation and adaptive regulation of rocky desertification in karsts in a comprehensive manner.
The southwest karst area in China could be a key carbon sink after appropriate ecological engineering. Vegetation carbon pool has been noted to be more critical for carbon budgets of ecosystems than shallow soils which have limited carbon saving capacity. However, due to the unique nature of geological settings of karst regions, spatial distributions of vegetation in these regions usually follow three-dimensional characteristics of discontinuity and fragmentation. This has resulted in difficulties in obtaining the belowground portions of vegetation, which have in turn caused a general lack of attention to this issue. Thus vegetation carbon pool has become a limiting factor in the assessment of regional vegetation carbon savings. In this study, we attempted to reveal the spatial distribution characteristics and differentiations of vegetation carbon savings in typical karst regions by analyzing remote sensing images. The spatio-temporal variation of vegetation carbon storage and density in typical karst areas of Northwest Guangxi in China was analyzed using remote sensing images of 1990, 2000 and 2005 in combination with elevation and weather data in geographic information system (GIS) environment. The results showed that vegetation carbon storage and density in the study area increased for 1990-2005. Vegetation carbon storage increased from 1.03×108 t in 1990 to 1.41×108 t in 2000 and then to 1.63×108 t in 2005. The corresponding carbon density was 14.82 t·hm-2 in 1990, 20.38 t·hm-2 in 2000 and 23.49 t·hm-2 in 2005, consistent with vegetation carbon density in Sichuan (18.47 t·hm-2) and Jiangxi (25.38 t·hm-2) Provinces of China. With regards to spatial distribution of carbon storage and density, high values were noted for the west or high-elevation (elevation > 500 m) regions and low values in the east or low-elevation (elevation < 500 m) regions of the study area. The carbon density was 15 22 t·hm-2 in most of the western counties of the study area while it was 8 15 t·hm-2 in most of the eastern counties of the study area in 1990. While an explicit increase was noted in the trend of change in spatial distribution of carbon storage and density in low-value areas (the eastern part of the region), slight decrease or increase was noted in high-value areas (the western part of the region). Vegetation carbon density obviously increased in typical karst areas with carbon storage to vegetation ratios of 45.54% in 1990 and 51.99% in 2005. The study suggested that vegetation carbon storage and density in cluster and depression regions obviously increased. Also ecosystem conditions accordingly improved due to policy initiatives regarding prevention of rocky desertification such as ecological migration and returning farmlands to forests. This had clearly benefited by enhancing vegetation carbon storage. This paper showed that assessments based on remote sensing images could provide the scientific basis for reducing uncertainty in estimating carbon stocks in karst regions and carbon balance in terrestrial ecosystems. It provided the basis for scientific reference regarding beneficial evaluation and adaptive regulation of rocky desertification in karsts in a comprehensive manner.
2013, 21(12): 1554-1564.
doi: 10.3724/SP.J.1011.2013.30565
Abstract:
Strong demands for rural landscape development have taken into account of environmental issues related to sustainable development. The objective of this paper was to evaluate the main ecological effects of fine-scale rural landscape construction projects. Local landscapes boundaries, land uses and attributes were identified in a field survey with the help of high-resolution satellite images. Landscapes with least edge length over 2 m were classes as patches. These landscapes contained eight land use types, including farmlands, orchards, forests, grass, construction lands, roads, waters and others. Landscapes with least edge length between 0.5 m and 2 m were classed as linear landscapes. Such landscapes included vegetations, field roads, field ridges and ditches. All the field survey data were digitalized into a database in ArcGIS. Evaluation of landscape patterns and attributes was based on the rural landscape database composed of patches and linear landscapes. Landscape attributes contained land pavement and vegetation. Vegetation improvement potential was analyzed in three scenario conditions - basic, standard and optimal scenarios. Case studies were conducted in Daxing Region of Beijing City, Quzhou County of Hebei Province and Changshu City of Jiangsu Province. The study showed that current rural landscape construction projects seldom considered environment issues and had caused negative effects on landscape patterns and attributes. Simple block landscape patterns built in rural landscape construction projects eliminated landscape characteristics among different regions, forming similar landscapes in different areas. Field roads, ditches and field ridges were important linear landscapes with high densities in all three areas. Management patterns of shelterbelts were bad as interval distances between main shelterbelts were always larger than required optimal length for wind prevention. Over use of impervious surface pavements was a critical environmental risk in rural infrastructure construction. This risk was more serious in rural areas with strong economic support than in areas with weak economic investment. Excessive impervious surface pavements such as roads had reached 28.46% and 56.19% in Daxing Region and Changshu City, respectively, while it was only 5.6% in Quzhou County. Based on the evaluation of wood-cover and live vegetation volume, linear shelterbelt was nearly as importance as wood-plots at the local scale. Shelterbelts faced risks of simple vegetation structure, low tree species diversity and missing shelterbelt in range of 18% 38%. Simulation of the basic, standard and optimal scenarios showed a large potential for the improvement of wood-cover and live vegetation volume in rural areas through planting linear vegetation. Land use pressure was not simulated for linear vegetation distributions in marginal lands along roads, ditches and river banks. Through legitimate and appropriate planning and construction, wood-cover potentially increased by 0.58% 1.16% while live vegetation volume increased by 2.22% 19.59% under the standard scenario. Furthermore, the optimal scenario had higher growth of wood-cover and live vegetation volume. It was important to pay more attention to linear vegetation, including shelterbelt, in rural landscape planning for purpose of ecological improvement. The study revealed that evaluation at local scale was efficient in quantitatively identifying the shortcomings of current local landscape in terms of ecological conservation.
Strong demands for rural landscape development have taken into account of environmental issues related to sustainable development. The objective of this paper was to evaluate the main ecological effects of fine-scale rural landscape construction projects. Local landscapes boundaries, land uses and attributes were identified in a field survey with the help of high-resolution satellite images. Landscapes with least edge length over 2 m were classes as patches. These landscapes contained eight land use types, including farmlands, orchards, forests, grass, construction lands, roads, waters and others. Landscapes with least edge length between 0.5 m and 2 m were classed as linear landscapes. Such landscapes included vegetations, field roads, field ridges and ditches. All the field survey data were digitalized into a database in ArcGIS. Evaluation of landscape patterns and attributes was based on the rural landscape database composed of patches and linear landscapes. Landscape attributes contained land pavement and vegetation. Vegetation improvement potential was analyzed in three scenario conditions - basic, standard and optimal scenarios. Case studies were conducted in Daxing Region of Beijing City, Quzhou County of Hebei Province and Changshu City of Jiangsu Province. The study showed that current rural landscape construction projects seldom considered environment issues and had caused negative effects on landscape patterns and attributes. Simple block landscape patterns built in rural landscape construction projects eliminated landscape characteristics among different regions, forming similar landscapes in different areas. Field roads, ditches and field ridges were important linear landscapes with high densities in all three areas. Management patterns of shelterbelts were bad as interval distances between main shelterbelts were always larger than required optimal length for wind prevention. Over use of impervious surface pavements was a critical environmental risk in rural infrastructure construction. This risk was more serious in rural areas with strong economic support than in areas with weak economic investment. Excessive impervious surface pavements such as roads had reached 28.46% and 56.19% in Daxing Region and Changshu City, respectively, while it was only 5.6% in Quzhou County. Based on the evaluation of wood-cover and live vegetation volume, linear shelterbelt was nearly as importance as wood-plots at the local scale. Shelterbelts faced risks of simple vegetation structure, low tree species diversity and missing shelterbelt in range of 18% 38%. Simulation of the basic, standard and optimal scenarios showed a large potential for the improvement of wood-cover and live vegetation volume in rural areas through planting linear vegetation. Land use pressure was not simulated for linear vegetation distributions in marginal lands along roads, ditches and river banks. Through legitimate and appropriate planning and construction, wood-cover potentially increased by 0.58% 1.16% while live vegetation volume increased by 2.22% 19.59% under the standard scenario. Furthermore, the optimal scenario had higher growth of wood-cover and live vegetation volume. It was important to pay more attention to linear vegetation, including shelterbelt, in rural landscape planning for purpose of ecological improvement. The study revealed that evaluation at local scale was efficient in quantitatively identifying the shortcomings of current local landscape in terms of ecological conservation.
Editor-in-chief：LIU Changming
Competent Authorities：Chinese Academy of Sciences
Sponsored by：Institute of Genetics and Developmental Biology, Chinese Academy of Sciences; China Ecological Economics Society
Organizer：Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences
ISSN 2096-6237
CN 13-1432/S
- Chinese core periodicals
- Core Chinese Sci-Tech Periodicals
- China's Top Science and Technology Periodicals
- Covered by Chinese Science Citation Database (CSCD)
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