中国生态农业学报(中英文)

Research progress on the effects of soil freeze-thaw on plant physiology and ecology

DU Ziyin, CAI Yanjiang, WANG Xiaodan, YAN Yan, LU Xuyang, LIU Shuzhen

2014, 22(1): 1-9. doi: 10.3724/SP.J.1011.2014.30941

Abstract(1420) PDF(2246)

Abstract:
Soil freeze-thaw, which mainly refers to repeated freezing and thawing due to changes in soil temperature, is a natural phenomenon in seasonally frozen or permafrost regions. Freeze-thaw not only affects soil physicochemical and biological properties, but also alters the ecophysiological processes of plants. This has been noted to significantly influence the productivity of ecosystems in high latitude and altitude areas with vast frozen grounds. This paper reviewed the effects of freeze-thaw on the physiological and ecological processes of above-ground and below-ground parts of plants and the response characteristics of alpine vegetation ecosystem to different freeze-thaw patterns. The paper summarized the ecophysiological characteristics under different climatic conditions and habitat stresses in terms of photosynthesis, biomass and productivity, root growth and response to moisture and temperature stress. The shortage in studies on soil freeze-thaw and ecophysiological processes of plants were also addressed. It was concluded that frequent soil freezing and thawing dramatically influenced the distribution patterns and ecological functions of vegetation under changing global environment, which was especially stronger in alpine ecosystems.

Comparative study of nitrogen budget in three different vegetable planting patterns under greenhouse condition

GUO Ruihua, YANG Yu-bao, LI Ji

2014, 22(1): 10-15. doi: 10.3724/SP.J.1011.2014.30467

Abstract(1388) PDF(1112)

Abstract:
Nitrogen use efficiency reflects the amount of N assimilation of crops, which is a critical for agricultural production. Unreasonable N application and excessive fertilizer-N input have frequently resulted in soil compaction, groundwater pollution and low quality crop products. This has received a considerable researcher and consumer attention in recent years. A simple formula introduced in this study to determine apparent nitrogen budget (ANB) was as follows: ANB = NI NO, NI is N input and NO is N output. Data from a long-term field experiment initiated in 2002 at the Quzhou Agricultural Experimental Station were used to determine ANB under three planting patterns of vegetable. The planting patterns included organic pattern, low-input pattern and conventional pattern. The study aimed to provide reference materials for the development of a sustainable high-yield planting pattern. Based on the results, a significant difference was noted among soil total nitrogen content in 0 20 cm soil layer of the three planting patterns during the growth period of eggplants. The nitrogen contents in 0 20 cm soil layer of the organic, low-input and conventional patterns were 2.6 g·kg^-1, 1.7 g·kg^-1 and 1.3 g·kg^-1, respectively. Total nitrogen input in the organic, low-input and conventional patterns was 1 150 kg·hm^-2, 1 182 kg·hm^-2 and 1 433 kg·hm ^-2, respectively. The corresponding total nitrogen uptake by crops was 178 kg·hm^-2, 135 kg·hm^-2 and 116 kg·hm^-2, respectively. Also eggplant yield under the three cropping patterns in 2011 was 93 458 kg·hm^-2, 93 320 kg·hm^-2 and 90 209 kg·hm^-2, respectively. Net nitrogen surplus for the growth period of the eggplants was 971 kg·hm^-2, 1 046 kg·hm^-2 and 1 317 kg·hm^-2, respectively. The eggplant yield under organic pattern was respectively 0.1% and 3.6% higher than that under low-input and conventional patterns. Net nitrogen surplus under organic pattern was 7.2% and 26.3% lower than that under low-input and conventional patterns. From the above results, it was concluded that organic pattern was contributed the highest to soil N accumulation and had the highest yield and lowest net nitrogen surplus. This led to the highest nitrogen use efficiency when compared with the low-input and conventional patterns. The paper compared ANB in three different planting patterns of eggplants under greenhouse condition and contributed to sustainable and high-yield organic production practices in China.

Estimation of carbon balance under different land uses and long-term fertilizations in black soils of Northeast China

LI Haibo, HAN Xiaozeng

2014, 22(1): 16-21. doi: 10.3724/SP.J.1011.2014.30411

Abstract(1553) PDF(1319)

Abstract:
Soil carbon pool is an important component of terrestrial ecosystem with higher carbon storage and the atmospheric CO₂ pool compensation capacity via CO₂ flux from soil surface, which is of great significance to global carbon cycle and carbon budget. Therefore tiny changes in soil carbon pool have a strong impact on atmospheric CO₂ concentration. This study aimed to assess carbon budget at ecosystem scale by comparing soil carbon efflux, net primary productivity (NPP) and net ecosystem productivity (NEP). The assessment was done through soil-atmosphere interface analysis as influenced by land use change and long-term fertilization in croplands of maize-soybean-wheat rotation system in the black soils of Northeast China. The land use types were grassland (GL) and bareland (BL) and farmlands with three long-term fertilization patterns including non-fertilization (NF), nitrogen, phosphorus and potassium fertilization (NPK), and organic manure amended NPK (NPKOM). Static chambers used to collect gas samples in cropland treatments were of two types - one used to collect gas samples from whole soils and the other to collect gas samples from non-rhizospheric soils. Soil carbon flux was determined by CO₂ concentration detection in a gas chromatograph (Shimadzu GC-2010) equipped with a flame ionization detector (FID). The annual cumulative CO₂ flux was calculated based on soil CO₂ flux rate. The three-year averaged annual carbon flux (R_ann) and annual microbial respiration (R_m) decreased in the order of NPKOM > GL > NPK > NF > BL. In addition, significant difference was noted in R_{ann_{and R_m among the five experimental treatments (P < 0.05). However, no significant difference was observed between grassland and NPKOM plots (P > 0.05) in terms of soil CO₂ fluxes. For cropland treatments, R_ann and R_m were significantly (P < 0.05) higher in NPKOM than in NPK and NF. However, no significant difference was found in annual carbon flux in root-free soils (R_rfann) among the three cropland treatments. Total biomass and carbon sequestration in grassland was significantly (P < 0.05) higher than that in other four plots. This was particularly so for grass roots which sequestered 10 20 times of carbon as against cropland treatments. NPP decreased in the order of GL > NPKOM > NPK > NF > BL, with a significant difference among the five treatments (P < 0.05). Grassland NPP increased by 32% 96% compared to cropland treatments. Also NPPs of NPKOM and NPK were respectively 46% and 49% higher than that of NF. NEP was positive for grassland and cropland, indicating net sinks of atmospheric CO₂ at the ecosystem scale. For cropland, carbon sequestration under NPKOM was not significantly (P > 0.05) higher than that under NPK. This was due to the "priming effect" of organic amendment resulting in increased soil respiration and a significant decrease in NEP. In terms of carbon balance through soil-atmosphere interface, grassland soil was the net sink under realistic management practices. In contrast, bareland and cropland soils served as the net sources. To date, carbon storage in arable soils tends to decline. However, increase in organic input could enhance carbon sequestration and thereby attain a new carbon equilibrium.}}

Effects of tannic acid on active aluminum forms distribution in tea garden soils with different pH

SU Youjian, LIAO Wanyou, WANG Yejun, ZHANG Yongli, LUO Yi, HU Shanguo

2014, 22(1): 22-30. doi: 10.3724/SP.J.1011.2014.30393

Abstract(1234) PDF(1447)

Abstract:
The effects of tannic acid on the distribution of active aluminum forms in typical tea garden soils with different pH in Pu'er of Yunnan Province and Nanchang of Jiangxi Province were studied by field observations and laboratory analyses. The tested 4 active aluminum forms in tea garden soils are exchangeable aluminum [Al³⁺], unimer hydroxyl aluminum [Al(OH)²⁺ and Al(OH)₂⁺ ], acid-soluble aluminum [Al(OH)₃⁰ ] and humic-acid aluminum [Al-HA]. Experimental results showed that at tannic acid addition level of 0 0.4 mmol·kg^-1 in Nanchang tea garden and 0 2.0 mmol·kg^-1 in Pu'er tea garden, soil exchangeable aluminum content decreased whereas hydroxyl aluminum, acid-soluble aluminum and humic-acid aluminum increased significantly with increasing soil pH. When the concentration of tannic acid exceeded 2.0 mmol·kg^-1, the inhibition effect of high concentration of tannic acid on active aluminum content strengthened with increasing soil pH. The variation trend in 20 40 cm soil layer was similar to that in 0 20 cm soil layer. Generally, active aluminum content in upper soil layer was less than that in subsoil layers and the total content of active aluminum in Pu'er tea garden soil was higher than that in Nanchang tea garden soils. Correlation analysis showed that soil pH was positively correlated with soil pH buffle capacity (pHBC), hydroxyl aluminum, humic-acid aluminum (r = 0.852, 0.796, 0.960; P < 0.01, 0.01, 0.01) in 0 20 cm soil layer. pHBC showed a significant negative correlation with exchangeable aluminum (r = 0.904, P < 0.01) and hydroxyl aluminum (r = 0.645, P < 0.05) and a positive correlation with humic-acid aluminum (r = 0.795, P < 0.01). At tannic acid concentration of 0 0.4 mmol·kg^-1, soil pH significantly increased to a peak before steadily decreasing. The relationship between pH (Y_pH) and tannic acid concentration (CDN) was best described by the following equation - Y_pH = 0.04CDN + 3.82 (R² = 0.95, P < 0.01). When the concentration of tannic acid increased to 8.0 12.0 mmol·kg^-1, soil pH remained unchanged. It was thus clearly noted that the effects of tannic acid on active aluminum content were not the same in different regions of tea garden soils. Low concentration of tannic acid improved soil content of various forms of activie aluminum. With increasing amounts of tannic acid, however, contents of various forms of active aluminum were inhibited. With increasing soil pH, high concentrations of tannic acid inhibited the release of active aluminum. Both pH and tannic acid in garden soils had a mutual weakening effect on active aluminum.

Effects of row spacing and seeding rate on radiation use efficiency and grain yield of wheat

WU Lanfang, OU-YANG Zhu

2014, 22(1): 31-36. doi: 10.3724/SP.J.1011.2014.30568

Abstract(1307) PDF(1158)

Abstract:
This study investigated the effects of row spacing (RS) and sowing rate (SR) on vegetative growth, radiation use efficiency (RUE) and grain yield of winter wheat. A field experiment was carried out in 2007 2008 at the Yucheng Comprehensive Experimental Station of Chinese Academy of Sciences, which is located in the North China Plain. The experiment included 9 treatments consisting of 3 row spacings and 3 sowing rates. The row spacings were 20 cm, 25 cm and 30 cm whereas the sowing rate were 6 kg·667m 2, 9 kg·667m^-2 and 12 kg·667m^-2. The treatments were laid out in a randomized complete block design with three replicates. Plots were 6 m long and 8 m wide and border rows were excluded from sampling to eliminate edge effects. Plant stem density, leaf area index were determined at seedling, jointing, booting, flowering, filling, milky-ripe and harvest stages, grain yield and yield compliments were determined at harvest stage. The intercepted radiation was measured from reviving to maturity stage. The results showed that row spacing had greater effect on winter wheat growth than sowing rate. Furthermore, there was no significant interaction between row spacing and sowing rate. The change trend in plant stem density varied within row spacing and was constant within sowing rates. Although the most tillers per plant was under row spacing of 20 cm, the spike rate of tillers was the least. The change in leaf area index (LAI) was the same as that in plant stem density. However, leaf area duration (LAD) increased with both widening row spacing from 20 cm to 30 cm and increasing sowing rate from 6 kg·667m^-2 to 12 kg·667m^-2. Grain yield and radiation use efficiency (RUE) increased significantly with widening row spacing under the same sowing rate, which was strongly correlated with stem density. Average grain yield increased by 81.62 g·m^-2 and 162.53 g·m^-2 as row spacing increased from 20 cm to 25 cm and 30 cm. Meanwhile average RUE increased by 0.18% and 0.35% as row spacing increased from 20 cm to 25 cm and 30 cm. Sowing rate slightly affected grain yield and RUE. Moreover, there was no obvious interaction effect of row spacing by sowing rate on grain yield and RUE. The results indicated that row spacing generally had a greater effect on wheat vegetative growth, grain yield and RUE than sowing rate. It was therefore strongly suggested to change from the conventional row spacing of 15 20 cm to the more efficient row spacing of 25 30 cm of wheat production and good field conditions in the North China Plain. Sowing rate also increased appropriately on the basis over conventional rates, which increased grain yield and RUE of wheat.

Estimation of water consumption as affected by measurement locations of soil water content in drip irrigated tomato in solar greenhouses

ZHAO Weixia, LI Jiusheng, WANG Zhen, LI Yanfeng, ZHANG Zhiyun

2014, 22(1): 37-43. doi: 10.3724/SP.J.1011.2014.30508

Abstract(1188) PDF(1579)

Abstract:
Placements of soil moisture sensor have been key considerations in obtaining representative soil water content in crop root zones for irrigation schedules. In this article, the distribution of soil water content in the wetted volume from a line source was studied in drip irrigated tomato in solar greenhouse condition. Through comparison of tomato water consumption determined from measured water content by moisture sensors at different locations, suitable placements of sensors were discussed. The results indicated that irrigation quota range of 14 25 mm increased soil water content in the 0 40 cm soil layer, and daily mean soil water content in wetted soil volume was 75% 100% field capacity throughout tomato growth season. Wetted soil volumes generated by adjacent emitters along the drip lines fully overlapped after several sequential irrigation events, forming lateral zones with approximately uniform distribution of water content around the drip lines. There was no significant difference between mean soil water content along the depth of 0 40 cm layer. The variation tendency of soil water content with time at different horizontal locations from drip lines was synchronous in character, without any obvious hysteresis quality. Assuming that the 0 40 cm layer was the root zone with 80% root concentrated, an irrigation quota range of 14 25 mm caused deep percolation from the bottom of the root zone with a certain spatial variability. Seasonal deep percolation accounted for 13% of irrigation amount during tomato growth season. The differences in tomato water consumption at different locations from drip lines were within 10%, except for the seedling and blossom fruiting stages. The experimental results suggested that high frequency drip irrigation sustained suitable soil water condition in the root zone. One profile of soil water content measured in the proximity of drip lines was adequate for the proper estimation of water consumption of drip irrigated tomato in solar greenhouse conditions.

Evaluation on comprehensive ecological benefits of different hedgerow patterns on slope-farmland in purple soil area

PU Yulin, XIE Deti, NI Jiupai, WEI Chaofu

2014, 22(1): 44-51. doi: 10.3724/SP.J.1011.2014.30685

Abstract(1319) PDF(1248)

Abstract:
Hedgerow patterns have been used to control soil and water loss, agricultural non-point source pollution (especially nitrogen and phosphorus from slope-farmlands) in hilly areas. A comprehensive and rational evaluation of the ecological benefits of hedgerow patterns in slope-farmlands was critical for further evaluating eco-economic and social benefits of hedgerows. This has been deemed necessary for promoting and popularizing the application of optimized hedgerow patterns in hilly areas. However, critical questions (e.g., the use of unilateral evaluation indexes) have persisted relative studies on evaluation of the ecological benefits of hedgerow. These indexes have generally not accounted for controlling agricultural non-point source pollutants. Hence this paper established an evaluation index system including indexes for soil and water loss, agricultural non-point pollutants, anti-erosion forces and land productivity. It also evaluated the comprehensive ecological benefits of Amorpha fruticosa, Vetiveria zizaniodes, Medicago sativa and Eulaliopsis binata hedgerow patterns on slope-farmlands of the southwestern purple soil zone. The weights of the evaluation indexes were integrated in analytical hierarchy process and entropy weight decision-making calculations. The results showed a significant increase in comprehensive ecological benefits. The indexes for comprehensive ecological benefit (A), soil and water conservation one (B₁), agricultural non-point source pollutant control (B₂), soil anti-erosion force (B₃) and land productivity (B₄) of hedgerow patterns increased by 206.4% 301.9%, 228.6% 278.4%, 212.6% 346.6%, 93.7% 126.0% and 23.6% 35.8%, respectively, compared with the conventional cross-slope farming pattern. The order of different type ecological benefits for hedgerow patterns was B₂ (1.165) > B₁ (0.962) > B₄ (0.495) > B₃ (0.332). The order of improvement of comprehensive ecological benefits for different hedgerow patterns was A. fruticosa > V. zizaniodes Vetiver on 20° slope-farmland, M. sativa > E. binata in 13° slope-farmland. The mean increase in comprehensive ecological benefit of hedgerow patterns on 20° slope-farmland was 295.0%, which was higher than that of 13° slope-farmland by 211.0% over the conventional cross-slope farming pattern. Therefore maintaining shrub hedgerow patterns on slope-farmlands of southwest purple hilly region (especially on lager than 20° slope- farmlands) greatly increased the comprehensive ecological benefits.

Effect of physical characteristics of leaf on resistance of cucumber to aphis

REN Jia, ZHOU Fucai, CHEN Xuehao, HU Qijing, YANG Aimin, ZHOU Jianhua, SHAO Jiuzhi, QIAN Yuanyuan

2014, 22(1): 52-57. doi: 10.3724/SP.J.1011.2014.30655

Abstract(1320) PDF(1267)

Abstract:
With laboratory experiments and field trials, the survival rate, reproduction rate and population index of Aphis gossypii in 13 cucumber varieties were investigated. The aim of the study was to determine the role of cucumber leaf in resistance to aphid, the correlation between the physical characteristics of cucumber (e.g., hair density, vascular bundle depth and surface wax content) and the population index of aphids. The results showed that the survival rate and fecundity of aphid nymph in different cucumber varieties were significantly different (P < 0.05). The aphid nymph survival rate was lowest (40.16%) in resistant variety 'Axin' and highest (55.86%) in susceptible variety 'pepino'. Significant differences were observed in fecundity rate among different cucumber varieties. Farrowing number of single aphid in susceptible varieties exceeded 60 while it was less than 48.25 in resistant variety 'EP6392'. Physical leaf characteristics (e.g., hair density, vascular bundle depth and surface wax content) were significantly different among different cucumber varieties. Leaf hair density of high-susceptible variety 'Sichuancunjin' (372.63 number·cm^{-2) was 1.96 times that of high-resistant variety 'Axin' (190.50 number·cm^{-2). Leaf vascular bundle depth of high-resistant variety 'Axin' (0.50 mm) was significantly deeper than those of high-susceptible variety 'Xiuyan' (0.38 mm) and 'pepino' (0.40 mm). Also leaf surface wax content in high-resistant variety 'Axin' (4.56 mg·g^{-1) was 3.80 times that of susceptible variety 'Yihuang' (1.19 mg·g^{-1). The correlation among hair density, vascular bundle depth and surface wax content of cucumber leaf and aphid population index was also analyzed in the study. A significant positive correlation existed between leaf hair density and population index of A. gossypii. This correlation was strongly expressed in the regression equation of Y = 8.312 1x + 10.700 0, with r = 0.819 8 and P = 0.000 6. Also significant negative correlations were noted between aphid population index and cucumber leaf vascular bundle depth and surface wax content. The correlations were clearly expressed by the regression equations of Y = 0.004 2x + 0.557 1 with r = 0.682 9 and P = 0.010 1 for leaf vascular bundle depth and aphid population index, and then Y = 0.181 0x + 8.286 8 with r = 0.752 7, P = 0.003 0 for surface wax content and aphid population index. The multi-step regression equation of population index (Y) and hair density (X₁), vascular bundle depth (X₂) and surface wax content (X₃) was Y = 38.624 6 + 0.043 1X₁ - 39.165 3X₂ - 1.044 3X₃ with r² = 0.830 7. The respective path coefficients of the equation were →Y = 0.414 2, →Y = 0.166 0, →Y = 0.206 7. All the resultssuggested that vascular bundle depth was the most critical factor influencing the resistance of cucumber to aphid.}}}}

Impacts of golden apple snail (Pomacea canaliculata) on water quality and microbes

PAN Dongli, ZHANG Jiahui, LONG Jun, ZHANG Jia'en, ZHAO Benliang, LUO Mingzhu

2014, 22(1): 58-62. doi: 10.3724/SP.J.1011.2014.30482

Abstract(1501) PDF(1874)

Abstract:
Golden apple snail (Pomacea canaliculata) is one of the 16 most harmful exotic species in China. Due to its strong adaptability, omnivorous habit and high ability of reproduction, it has made serious damage to aquatic ecosystems like paddy fields. A laboratory experiment was conducted to examine impacts of golden apple snail (GAS) on water environment and influence of GAS excretion on the growth of yeast and actinomycete. The main experimental results showed that the culture solution of GAS appeared to be weak acid, while that of the control was weak alkaline. The turbidity, contents of total P and total N increased significantly as the culture time elapsed. Moreover, the culture solution of GAS resulted in significant increase in both amounts of yeast and total microbes, but there were no significant differences for either yeast or actinomycete among the treatments of different GAS densities. This study indicates that golden apple snail invasion would probably cause environmental problems of water eutrophication and quality deterioration. These findings may be helpful for assessing the ecological risk of GAS invasion.

Functional analysis of DA1-Related Protein 2 in Arabidopsis under salt stress

YANG Lei, ZHAO Hongtao, WANG Zhijuan, LI Xia

2014, 22(1): 63-71. doi: 10.3724/SP.J.1011.2014.30396

Abstract(1464) PDF(2538)

Abstract:
Salt stress inhibits plant growth and development, resulting in low crop yield. Therefore, the mechanism of plant response to salt stress has received much attention in plant science research. Early development (including seed germination and greening) is not only critical for seedling establishment and subsequent plant growth and development, but is also more sensitive to salt stress. However, the molecular mechanisms underlying plant salt tolerance during this developmental stage has remained largely unknown. In this study, we identified a gene, DAR2 (DA1-Related Protein 2), which regulated primary root growth by map-based cloning in Arabidopsis. We noted that DAR2 gene was induced by 200 mmol·L^-1 NaCl in 10-day-old Col-0 seedlings. GUS staining showed that the expression of pDAR2::GUS was altered, suggesting that DAR2 gene was induced in root tip and leaf apex phloem. We counted the Col-0 and dar2-3 seed germination and greening rates in different MS medium - 0 (CK), 100 mmol·L^-1 NaCl, 150 mmol·L^-1 NaCl, 200 mmol·L^-1 NaCl, 150 mmol·L^-1 KCl and 200 mmol·L^-1 mannitol. These results showed that compared with the wild type, either seed germination or greening of dar2-3 mutant obviously delayed with gradual increase in NaCl concentration. Under 150 mmol·L^-1 KCl and 200 mmol·L^-1 mannitol treatments, dar2-3 mutant seed germination and greening delayed in relation to the wild type. Interestingly, the mutant exhibited increased sensitivity to NaCl, KCl and mannitol treatments during seed germination and greening compared with the wild type. These results suggested that while DAR2 was effective in mediating plant response to general osmotic stress, it was not specific to ion stress in the early growth and development phase. Our findings provided novel insights into salt tolerance and enhanced crop resistance to salt stress.

Planting benefits and development measures of new agricultural greenhouse circulation model in North China-A case study on conjoined greenhouse pattern of "vegetable/fruit-edible fungus" in Xushui County

ZHOU Ying, QIU Jianjun, YIN Changbin, LI Guichun, ZU Junming, DU Yanqin, LEI Dongxia

2014, 22(1): 72-79. doi: 10.3724/SP.J.1011.2014.30361

Abstract(1394) PDF(1399)

Abstract:
Current facility vegetable industry development has been significantly improved in Xushui County of Hebei Province that it has now become the emerging industry with high farmer income. However, problems gradually emerge in the production process with the expansion of vegetable industry. Problems such as vast areas of sunlight greenhouses, equipment of relatively simple infrastructure, backward environmental control, poor production management and low labor productivity have been all too rampant issues in facility vegetable industry. Xingnong Vegetables Professional Cooperatives in Xushui County changed the greenhouse structure and improved the two aspects of planting patterns via cleaner production, exploration of circular agriculture mode of "vegetable/fruit-edible fungus" planting based on conjoined greenhouses of mushroom-house/vegetable greenhouse and opening up new path to facility vegetable industry development. This paper studied economic benefits and development measures of "vegetable/fruit-edible fungus" stereo planting cycle of agriculture. The research objectives were to determine the costs and economic benefits of conjoined greenhouses, executing quantitative comparative analysis of economic efficiencies of conjoined greenhouses and common greenhouses, and putting forward development measures for conjoined greenhouse planting cycle of agriculture. The research method combined the normative analysis and empirical analysis. Firstly, the design structure and cultivation measures of conjoined greenhouses were comprehended through field investigation and interview with farmers, and then the industry chain structure and characteristic patterns of the mode were analyzed. Secondly, the costs and economic benefits of conjoined greenhouses and common greenhouses were compared by track monitoring and questionnaire survey. Based on the three years of research data, the paper concluded that economic benefits of "vegetable/fruit-edible fungus" mode were higher than the other four ordinary greenhouse modes. In comparison with eggplant, green pepper, tomato and towel gourd outputs of the four vegetables, the annual net incomes of conjoined greenhouses were respectively 6.3, 3.5, 2.3 and 1.1 times that of traditional greenhouses. Because conjoined greenhouse mode greatly improved labor productivity, it was worth the wide promotion in North China. Finally, development measures of conjoined greenhouse planting cycle of agriculture were advance. These included establishing diversified investment and financing mechanisms, improving subsidy system in production processes, building vegetable marketing systems and establishing standardization of pollution-free vegetable bases.

Hyperspectral estimation models for total potassium content of Kuerle fragrant pear leaves

CHAI Zhongping, CHEN Bolang, JIANG Ping'an, SHENG Jiandong, LI Shanshan, LIU Mao, MENG Yabin

2014, 22(1): 80-86. doi: 10.3724/SP.J.1011.2014.30595

Abstract(1638) PDF(1886)

Abstract:
The conventional analysis of nutrient elements required destructive sampling, highly complex processes, highly time consuming and difficult nutrition diagnosis process in fruit trees. However, hyperspectral remote sensing technology has been reported to resolve the problems of destructive sampling and rapidly diagnose nutrient elements of plant. To monitor the state of nutrients in Korla fragrant pear in a non-destructive, timely and quick manner, an SVC HR-768 portable spectrometer was used to measure the spectral reflectance of leaves in the field of 20-year Korla fragrant pear tree under different K fertilization rates. The total K content was analyzed in the lab, and the relationships between total K content of leaves and original spectrum, first derivative spectrum, high spectral parameters established. The results showed that a single linear model built at 425 nm between total potassium content and original spectrum significantly described the relationship, with an adjusted determination coefficient (R²) of 0.913. Another linear model built at 630 nm between total potassium content and the first order derivative spectrum was similarly significant, with an adjusted R² of 0.986. The relationships bewteen total potassium content of leaf and green peak position (Rg), red valley position (Ro) were extremely significant in selecting hyperspectral feature variables. Results also showed that the adjusted R² was above 0.96 for all the built linear models. After evaluation of all the built models, the model Y = 1 136.835X₆₃₀ + 50.709 (X₆₃₀ is the first derivative spectrum at 630 nm) was the best for predicting total potassium content (Y) of Korla fragrant pear leaf.

Comparison of red-edge parameters for spring wheat chlorophyll content at different growth stages in irrigated and dry-land regions

JIN Yanhua, XIONG Heigang, ZHANG Fang, WANG Lifeng

2014, 22(1): 87-92. doi: 10.3724/SP.J.1011.2014.30456

Abstract(1312) PDF(1152)

Abstract:
Red edge parameters were used to estimate chlorophyll content of spring wheat in irrigated land and dry land regions. The study analyzed the determination processes of canopy spectral, chlorophyll content, leaf width and seedling height of spring wheat in different regions, irrigated land and dry land regions. Then the strongest correlation between red edge position and chlorophyll content of spring wheat in different regions was used to establish optimally efficient models for simulating chlorophyll content in irrigated and dry lands. The results showed that red edge position of irrigated land was highest, followed by dry land in shady slope, then dry land in half shady/sunny slope and dry land in sunny slope. The red edge positions of spring wheat grown at different lands were deviated to long wave from setting to flowering stages, and to short wave from flowering to milking stages. The peak value of red edge of spring wheat in irrigated land and dry land in shady slope followed a "unimodal" curve at setting and milking stages, and a "dimodal" curve at other stages. The peak value of red edge of spring wheat grown at dry land in half shady/sunny slope also followed a "dimodal" curve at heading and flowering stages, and "unimodal" curve at setting, joining and milking stages. "Unimodal" curve was outstandingly a unique feature of dry land in sunny slope for all the growth stages of spring wheat. The red edge area of spring wheat was largest at irrigated land, and smallest at dry land in sunny slope. Irrespective of the stage, a significant correlation was noted between chlorophyll content and red edge position of spring wheat. From setting stage to milking stage, the estimated determination coefficient of regression (R²) for irrigated land exceeded 0.82 with a root mean square error (RMSE) of less than 1.26. Then R² for dry land spring wheat exceeded 0.81 (all correlation coefficients highly positive) with RMSE of less than 1.70. Thus it was possible to use red edge position to estimate chlorophyll content of spring wheat. The results provided new insights into the methods to using hyper-spectral information to monitor wheat growth and yield.

Application and validation of AquaCrop model in simulating biomass and yield of oil flax in Northwest China

LI Yue, NIU Junyi, GUO Lizhuo, GAO Zhenni, SUN Xiaohua

2014, 22(1): 93-103. doi: 10.3724/SP.J.1011.2014.30650

Abstract(1557) PDF(2366)

Abstract:
Many crop-growth models have been established for predicting the effects of soil, water and nutrient on grain/biomass yield and water productivity of different crops. However, most of the crop-growth models were still at research stage and only few have been applied in actual production processes due to limitations in simulation input data. To predict the influence of water and nutrient on yield, biomass and water productivity of oil flax, a water-driven crop model, AquaCrop model, developed by FAO was used to simulate and validate the growth of oil flax under different irrigation and nitrogen/phosphorus levels. In the study, field experiment with 9 nutrients treatments (3 nitrogen levels and 3 phosphorus levels) under four irrigation levels were conducted at Yuzhong Field Station. The experimental data collected in 2011 was used to simulate yield, biomass and canopy cover and data collected in 2012 to validate the model. The performance of model was evaluated from model efficiency (E), determination coefficient (R²), root mean square root (RMSE) and mean absolute error (MAE). The results showed that the prediction errors of the calibrated yield and biomass of the AquaCrop model under different irrigation and nitrogen/phosphorus treatments were 0.97 < E < 0.99, 0.11 < RMSE < 0.33 and 0.11 t·hm^-2< MAE < 0.42 t·hm 2. These were in accordance with measured data in the experiment study in 2012 (0.96 < E < 0.99, 0.11 < RMSE < 0.42 and 0.11 t·hm^-2< MAE < 0.39 t·hm^-2). Furthermore, the simulated results of canopy cover and biomass matched observed values. The predicted yield of oil flax by the AquaCrop model was more accurate under intensive irrigation treatment than under deficient irrigation treatment. The FAO AquaCrop water-driven model had higher simulation precision when oil flax was simulated in Northwest China with different irrigation treatments and field management practices. The model showed broad application prospects in China.

Comprehensive evaluation of agricultural water-saving potential in the middle reaches of Hei River using genetic projection pursuit model

ZHAO Xining, WANG Yubao, MA Xueming

2014, 22(1): 104-110. doi: 10.3724/SP.J.1011.2014.30905

Abstract(1696) PDF(1657)

Abstract:
A comprehensive evaluation of agricultural water-saving potential is the basis for agricultural water planning. Currently, however, insufficiencies of quantitative research have precluded the comprehensive evaluation of regional agricultural water-saving potential. This study therefore focused on agricultural water-saving potential in the middle reaches of Hei River, which is located in the northwest inland of China. Based on the principle of analytical hierarchy, a comprehensive evaluation index system of the regional agricultural water-saving potential was established, which combined a series of statistical data and participatory rural appraisal which took into account the impacts of socio-economic development, hydrology and water resources, agricultural water resources development and utilization, agricultural water-saving level and ecology on regional water-saving potential. Given that the evaluation indexes were incompatible, the projection pursuit model (based on genetic algorithm) was used to evaluate agricultural water-saving potential. The model used the optimum projection vector to evaluate the directional contribution of each index in the comprehensive evaluation system. Projection index value was used to evaluate future achievable agricultural water-saving potential of the district and counties in the study area. The districts/countries included Ganzhou District, Minle County, Linze County, Gaotai County and Shandan County. Results indicated that the index ratios of water conservancy investment to GDP, impermeable channel area and pipeline irrigation area had significant influence on regional agricultural water-saving potential. Then per capita grain yield index, per capita water resources index and water supply modulus index had little influence on regional agricultural water-saving potential. The projected values [Z(i)] for Ganzhou District, Minle County, Linze County, Gaotai County and Shandan County in 2005 were 1.366 5, 1.170 4, 1.239 1, 1.259 6 and 1.158 6, respectively. This showed that agricultural water-saving levels of Ganzhou District, Gaotai and Linze Counties were higher than other counties/districts. These other counties/districts were at a lower level and had large agricultural water-saving potential. This study provided scientific basis and decision-making support for developing regional agricultural water-saving technology.

Coupling state of agricultural eco-economic system under emission mitigation and sink enhancement of non-point source pollution--A case study of Zhong County in the Three Gorges Reservoir Region

XIAO Xincheng, XIE Deti, NI Jiupai

2014, 22(1): 111-119. doi: 10.3724/SP.J.1011.2014.30540

Abstract(1196) PDF(1824)

Abstract:
The Three Gorges Reservoir Area is a key control region of eco-environmental construction in China. However, how to achieve agro-economic development and control agricultural non-point source pollution in the region have emerged as difficult issues in recent years. To verify the coupling process of agricultural eco-economic system under emission mitigation and sink enhancement, data from the Zhong County (a typical non-point source pollution control district in the Three Gorges Reservoir Area) was used to develop eco-agriculture and non-point source pollution control. Then an equation-driven model of the construction structure was studied in terms of the interrelationship and interaction paths of the various elements of agricultural resources, agricultural development and agricultrual eco-economic coupling system in the Three Gorges Reservoir Aarea of Zhong County under the backdrop of emission mitigation and sink enhancement of non-point source pollution policies and measures. The paper put forward 6 basic assumptions based on 4 latent variables (emission mitigation and sink enhancement of non-point source pollution policies and measures, agricultural resources, agricultural development and coupling degree of agricultural eco-economic system) and the corresponding observation variables. Based on these elements, the paper designed a coupling model of the agricultural eco-economic system. The empirical results revealed that the path coefficient of the interrelationship between agricultural non-point source pollution control measures and agricultural resources utilization was 0.79. This suggested that the government's emission mitigation and sink enhancement measures promoted rational utilization of agricultural resources in the region. The path coefficient of the interactive relationship between emission mitigation and sink enhancement measures of agricultrual non-point source pollution and agricultural development was 0.80. This also suggested that the measures and policies were strong incentive for agricultural development in the study area. The path coefficient of the relationship between agricultural development and resources utilization was 0.77, indicating that agro-economic development in the region was based on reasonable agricultural resources utilization. Emission mitigation and sink enhancement measures positively influenced the coupling process of agricultural eco-economic system. The path coefficient was 0.85, which suggested that the measures in the study area significantly improved the coupling process. The utilization of agricultural resources and development positively influenced the process of agricultural eco-economic system coupling. The respective path coefficients were 0.91 and 0.89, indicating that the coupling process of agro-industry and agro-resources system conformed to the nature of agricultural development. Considering the structural relationship between the latent variables, it was noted that under background of non-point source pollution emmission mitigation and sink enhancement measures, agriculturla resources and economic development were the key elements of system coupling. The elements formed an effective perspective for understanding the coupling process of the system.

Application of count models in estimating recreational values of pond aquaculture

FAN Xiaoyun, YANG Zhengyong, TANG Keyong, ZHANG Xinzheng, YANG Huaiyu

2014, 22(1): 120-126. doi: 10.3724/SP.J.1011.2014.30690

Abstract(1291) PDF(1453)

Abstract:
With the rapid development of the third industry, recreational fishery has become one of significant sectors of fishery economy in China. At the same time, the increasing investment in the recent decade on the recreational fishery has made this industry more valuable in Shanghai. The literatures show that there are a few researches focused on the recreational values of pond aquaculture ecosystems, and the suitability of methods and models which may be used to analyze these values should be estimated. Owing to the lag of researches on the estimation methods, these eco-service values were not scientifically explained. Based on the investigation in Qingpu, Jiading and Fengxian, three suburban districts of Shanghai, this paper estimated the recreational values of the pond aquaculture ecosystems in these areas with count models of individual travel cost method (ITCM). The effectiveness of Poisson Model and Negative Binomial Regression Model were compared. The estimated value of the pond aquaculture ecosystems in Qingpu District this time and those results of former studies in the same area was also compared to analyze the stability of individual travel cost method (ITCM) and the zone travel cost method (ZTCM). The results showed that: ① estimated values of pond aquaculture ecosystems were sensitive to the models used, Negative Binomial Regression Model was more effective than Poisson Model when the data had discrete characteristics; ② it was feasible to use the estimated values by individual travel cost method and zone travel cost method as the upper and lower limits of pond aquaculture ecosystem services values respectively, the ratio of the values estimated by the two methods was 4.98︰1; ③ the recreational values in the three districts were approximately 20 863.34 Yuan·hm^-2·a ^-1, 57 997.03 Yuan·hm^-2·a ^-1 and 522.73 Yuan·hm^-2·a ^-1, respectively. The results suggest that stakeholders should recognize the existence and importance of these types of ecosystem services values, support the development of recreational fishery, protect the pond aquaculture ecosystems, and make full use of these ecosystems to promote the sustainable development of tour industry and aquaculture and increase fish farmers' income in these areas.

2014 Vol. 22, No. 1