中国生态农业学报(中英文)

Research progress on the impacts of low light intensity on rice growth and development

DU Yan-Xiu, JI Xin, ZHANG Jing, LI Jun-Zhou, SUN Hong-Zheng, ZHAO Quan-Zhi

2013, 21(11): 1307-1317. doi: 10.3724/SP.J.1011.2013.30238

Abstract(1645) PDF(3305)

Abstract:
Light is an important environmental factor for healthy growth and development of plants. Global warming has increased the occurrence of overcast, rainy and low light intensity. Light stress has been known to adversely affect shade tolerance, healthy growth and development of rice. This paper reviewed research progress on the impact of low light stress on photosynthesis, vegetative growth, yield and quality of rice. Several studied noted that low light stress affected every aspect of vegetative growth (plant height, tiller number, root growth, stoma regulation and chlorophyll development), photosynthesis, dry matter accumulation and partition, and yield and quality of rice. Light not only provided energy for photosynthesis but was also a signal for photomorphogenes. Plant light receptors sensed changes in ambient light signal (including light quantity/fluoresce, quality/wavelength, direction and duration) which correspondingly regulated photomorphogens. Shades induced low light stress in crops. Plant phytochromes detected changes of red/far-red light ratio under shade conditions, leading to a series of changes in morphological traits. These so called shade-avoidance syndrome included accelerated elongation of hypocotyls, internodes and petioles, upward leaf movement (hyponasty), and accelerated flowering and apical dominance. However, shade tolerance lacked classical shade-avoidance syndrome. It also increased specific leaf area, photosystem (PSII︰PSI) ratio, reduced chlorophyll a/b ratio and increased physical defense. There was less research on shade-avoidance syndrome and shade tolerance of rice. The review further discussed how different shade materials affected light quality (wavelength), and how shade-avoidance syndrome was reduced by using rice phytochrome genes and light signal-related transcription factor genes identified in Arabidopsis thaliana. Countermeasures were then suggested to relieve low light stress during rice growth. The problems and prospects of future research in this field were also discussed.

Effect of low nitrogen application and soybean intercrop on soil greenhouse gas emission of sugarcane field

ZHANG Ying, WANG Jian-Wu, WANG-Lei, YANG Wen-Ting, WU Peng, LIU Yu, TANG Yi-Ling

2013, 21(11): 1318-1327. doi: 10.3724/SP.J.1011.2013.0000030295

Abstract(1340) PDF(1376)

Abstract:
This study discussed the effect of different sugarcane intercropping patterns and nitrogen dosages on soils greenhouse gas emission and the related impact on crops yield. The study further strengthened the theoretical basis for measuring agriculture-based greenhouse gas emission. It analyzed emission fluxes of greenhouse gases (CO₂, N₂O and CH₄) in sugarcane//soybean intercropping systems with crops line ratios of 1∶1 (SB1) and 1∶2 (SB2), monocropped sole sugarcane(MS)under two nitrogen levels (N2, 525 kg·hm^-2 and N1, 300 kg·hm^-2) and monocropped soybean under zero nitrogen supply using the static chamber/gas chromatographic technique during the crop growth season. Results showed that compared to the sugarcane monoculture, cumulative emissions of CO₂ and N₂O in SB2 under low nitrogen dose (SB2-N1) respectively decreased by 35.58% and 56.36%. Also cumulative CH₄ emission increased by 7.02%. Soils in different cropping patterns and nitrogen dosages served as sources of CO₂ and N₂O, sink of CH₄ during crop growth season. After nitrogen application, CH₄ absorption rate decreased while CO₂ and N₂O flux rates increased. CO₂ emissions (kg·hm^-2·a^-1) under MS-N1, SB1-N1, SB2-N1, MS-N2, SB1-N2, SB2-N2 and MB treatments were 5 096.89, 6 422.69, 3 283.20, 4 103.29, 4 475.84, 4 775.31 and 4 780.35, respectively. Cumulative N₂O emissions (kg·hm^-2·a^-1) under MS-N1, SB1-N1, SB2-N1, MS-N2, SB1-N2, SB2-N2 and MB treatments were 4.61, 5.11, 2.15, 3.13, 3.72, 5.60 and 3.11, respectively. Also cumulative CH₄ emissions (kg·hm^-2·a^-1) under MS-N1, SB1-N1, SB2-N1, MS-N2, SB1-N2, SB2-N2 and MB treatments were 13.68, 21.78, 12.72, 5.53, 11.36, 4.77 and 9.97, respectively. Land equivalent ratio (LER) values in sugarcane//soybean intercropping systems exceeded 1.0 during 2009 and 2012. The study showed that SB2 cropping system was the best one under low nitrogen conditions.

Effect of basal nitrogen fertilization time on nitrogen fertilizer use in flue-cured tobacco

XIE Zhi-Jian, TU Shu-Xin, ZHANG Qin, XU Chang-Xu, LI Jin-Ping

2013, 21(11): 1328-1332. doi: 10.3724/SP.J.1011.2013.30355

Abstract(1170) PDF(1106)

Abstract:
Flue-cured tobacco (FCT) is a nitrogen-sensitive plant with strict requirements for nitrogen (N). Reasonable application of N fertilizer not only favors N absorption and utilization as nutrient, but also improves tobacco leaf quality. A field experiment was carried out to determine the effects of basal N fertilization time (0 d, 15 d and 30 d before tobacco seedling transplant) on N use parameters by FCT plant in the main tobacco production area of Hubei Province. The results showed that dry matter accumulation (DMA) and N content in tobacco leaf and stem increased with earlier basal fertilization time. For basal fertilizer application times of 15 d and 30 d before seedling transplant, DMA/N content respectively increased by 16.4%/1.5% and 22.6%/8.7% in tobacco leaf and by 2.5%/13.4% and 12.7%/33.9% in tobacco stem. Basal fertilizer application time did not significantly (P > 0.05) influence N recovery efficiency. However, it significantly (P < 0.05) decreased agronomic N use efficiency by 35.2% and 37.4% and physiological N use efficiency by 35.4% and 41.6% respectively for basal fertilizer application times of 15 d and 30 d before seedling transplant. Furthermore, basal fertilization time was negatively correlated with agronomic N use efficiency, physiological N use efficiency and partial factor productivity of applied N. However, agronomic N use efficiency was positively correlated with physiological N use efficiency and partial factor productivity of applied N. Also physiological N use efficiency was positively correlated with partial factor productivity of applied N. In terms of N absorption and utilization and dry matter accumulation in tobacco leaf, it was advantageous to apply basal N fertilizer 15 d and 30 d before tobacco seedling transplant.

Effect of potassium application rate on potassium absorption, distribution and yield of spring maize under different soil fertilities

HOU Yun-Peng, ZHANG Lei, KONG Li-Li, YIN Cai-Xia, QIN Yu-Bo, LI Qian, XIE Jia-Gui

2013, 21(11): 1333-1339. doi: 10.3724/SP.J.1011.2013.30308

Abstract(1539) PDF(1129)

Abstract:
Field experiments were conducted to study the effects of different potassium dosages on potassium absorption, distribution and yield of maize in high (Yushu City) and low (Gongzhuling City) fertility soils in Jilin Province. The results showed that potassium dosages of 83.3 kg(K2O)·hm^-2 and 113.9 kg(K₂O)·hm^-2 produced the highest maize yields while potassium dosages of 75.1 kg(K₂O)·hm^-2 and 103.1 kg(K₂O)·hm^-2 were most economic for Gongzhuling and Yushu, respectively. The highest and optimum economic yields for Gongzhuling respectively increased by 3.70% and 3.68% compared with Yushu. Potassium fertilizer application effectively improved maximum potassium absorption and dry matter accumulation rates of maize. It also caused maximum dry matter accumulation and potassium absorption rate to occur early during the growth season. When potassium dose exceeded 60 kg(K₂O)·hm^-2, maximum dry matter accumulation and potassium uptake rates in Gongzhuling were higher than those in Yushu. Appropriate dosage favored high translocation (rate and amount) of potassium from vegetative organs to grain and also increased grain nutrient efficiency ratio. Grain nutrient ratio in Yushu was less than that in Gongzhuling by 0.5% 1.7%. Except potassium fertilizer treatment of 60 kg(K₂O)·hm^-2, the agronomic efficiency of potassium, partial factor productivity of potassium and recovery efficiency of potassium in Gongzhuling were higher than those in Yushu by 7.3 8.8 kg·kg^-1, 4.4 8.3 kg·kg^-1, 1.6% 6.2%, respectively. To improve maize yield along with the benefits and use efficiency of potassium, the recommended optimum potassium dosages for Yushu (high soil fertility) and Gongzhuling (low soil fertility) areas were 75 kg(K₂O)·hm^-2 and 103 kg(K₂O)·hm^-2, respectively.

Comparative analysis of carbon and nitrogen mineralization in soils under alpine meadow, farmland and greenhouse conditions in Tibet

MA Li-Na, WANG Xi-Ming, DAI Wan-An, PAN Jian-Ling, CHEN Xiao-Peng, SHANG Zhan-Huan, GUO Rui-Ying

2013, 21(11): 1340-1349. doi: 10.3724/SP.J.1011.2013.30469

Abstract(1150) PDF(1522)

Abstract:
Soil carbon and nitrogen in vegetable fields are the core elements of soil quality and environmental pollution. The decrease of soil C/N ratio of vegetable fields under greenhouse conditions causes an imbalance in soil carbon and nitrogen content. An effective way of adjusting soil carbon and nitrogen conditions in vegetable fields has been by improving soil quality and decreasing environmental pollution. Furthermore, there has been little research on soil carbon and nitrogen mineralization under greenhouse conditions in the Tibetan region. After transformations of alpine meadows and farmlands into solar greenhouse vegetable fields, there was the need to study the characteristics and processes of soil mineralization. In this study therefore, carbon and nitrogen mineralization in soils of alpine grassland, farmland and greenhouse (1-year, 5-year) were analyzed in an indoor incubation experiment. The results showed that soil carbon mineralization in different soil types mainly occurred during the first seven days (0 7 d) after treatment. Soil carbon mineralization was higher under alpine grassland than in farmland and 5-year greenhouse conditions (P < 0.05). There was no significant difference between the 1-year greenhouse and 5-year greenhouse soil conditions in terms of carbon mineralization (P > 0.05). This was attributed to soil nutrient and soil microbial environment sensitivity to temperature. Soil CO₂-C accumulation in farmland soil was higher than in alpine grassland soil. It was also higher in alpine grassland soil than in the 1-year greenhouse and 5-year greenhouse soils. However, the differences in soil organic carbon mineralization and accumulation among alpine grassland, farmland, 1-year greenhouse and 5-year greenhouse soil conditions were not significant (P > 0.05) at 28 days after treatment. Soil nitrogen mineralization mainly happened in different soil types during the first three days (3 d) after treatment. With delayed incubation, the main process of soil nitrogen mineralization was nitrogen fixation. Soil inorganic nitrogen content in alpine grassland, farmland, 1-year greenhouse and 5-year greenhouse soils at 28 days after incubation were 29.04%, 75.94%, 66.86% and 65.70% of that at 0 day, respectively. The results showed that soil nitrogen mineralization capacity of alpine grassland soil was stronger than farmland, 1-year greenhouse and 5-year greenhouse soils. Soil nitrogen mineralization capacity of farmland was weaker than alpine grassland, 1-year greenhouse and 5-year greenhouse. Also soil nitrogen mineralization capacities of 1-year greenhouse and 5-year greenhouse were similar. Moreover, soil mineralization processes were similar among different soil conditions.

Effect of spatio-temporal deficit irrigation and nitrogen supply on water and nitrogen use of tomato

LIU Xiao-Gang, ZHANG Yan, ZHANG Fu-Cang, CAI Huan-Jie, LI Zhi-Jun, YANG Qi-Liang

2013, 21(11): 1350-1357. doi: 10.3724/SP.J.1011.2013.30451

Abstract(1353) PDF(1100)

Abstract:
For sustainable water use in protected agriculture, crop-specific and water-saving irrigation techniques that do not negatively affect crop productivity must be developed. Globally, successful attempts have been documented regarding the use of deficit irrigation methods. Regulated deficit irrigation (RDI) and controlled alternate partial root-zone irrigation (CRAI) have been used to improve irrigation water use efficiency (IWUE) of various crops. Because nitrogen (N) has been the most widely used fertilizer, N demand was likely to grow in the future. Thus the optimization of water and fertilizer use in vegetable production was a critical water/fertilizer-saving strategy. Four irrigation treatments under CRAI and three N levels were explored for optimum modes of water and fertilizer supply in vegetable production under water-saving irrigation in a pot tomato experiment. The irrigation treatments were W_HW_H (high water level through out growth period), W_HW_L (high water level at flowering and fruit-setting stages with low water level at full-fruit stage), W_LW_H (low water level at flowering and fruit-setting stages with high water level at full-fruit stage) and W_LW_L (low water level through out growth period). Then the N levels included NH [high N, 0.45 g(N)·kg^-1], N_M [medium N, 0.30 g(N)·kg^-1] and N_L [low N, 0.15 g(N)·kg^-1]. Using conventional irrigation (CI) as control experiment, the effect of spatio-temporal of deficit controlled deficit irrigation (STCDI), which combined RDI and CRAI, and N rates on the vegetative parts of tomato dry matter accumulation (DMA), irrigation water use efficiency (IWUE), N accumulation (N_A) and soil water and mineral N distribution were studied. Compared with CI, the results showed that W_HW_H, W_LW_H, W_HW_L and W_LW_L under CRAI decreased tomato DMA by 4.52%, 11.93%, 17.76% and 23.94%, respectively. They respectively decreased N_A by 1.74%, 12.86%, 15.50% and 22.47%. The four irrigation treatments decreased N dry matter production efficiency (NDMPE) by 2.24%, 3.93%, 2.55% and 0.89% and increased IWUE by 12.39%, 8.99%, 15.02% and 12.96%, respectively. DMA, IWUE and N_A of N_A were highest under CRAI. Compared with N_L, N_M and N_H decreased tomato NDMPE by 6.87% 12.70% and 17.81% 24.38% while increasing soil NO₃^--N content by 31.64% 159.58% and 57.37% 297.37%, respectively. High DMA, IWUE and N_A were obtained under W_HW_H, CRAI and N_M. The optimum mode for water and N supply under CRAI was 80% of CI irrigation (which was 70% 85% of soil field capacity) and nitrogen rate of 0.30 g(N)·kg^-1(dry soil).

Effect of deep-plow and mulching during fallow period on soil water and wheat water use efficiency in dryland

WEN Fei-Fei, SUN Min, DENG Lian-Feng, ZHAO Wei-Feng, GAO Zhi-Qiang

2013, 21(11): 1358-1364. doi: 10.3724/SP.J.1011.2013.20798

Abstract(1226) PDF(1371)

Abstract:
Dryland wheat is very critical in China's wheat production. But as water is a major limiting factor of dryland wheat production, high water use efficiency is an important issue in dryland wheat production. Currently, a significant progress has been made in rainwater harvesting and soil water retention in dryland wheat fields. The deep-plow, sub-soiling and mulching cultivation techniques have been vital water retention practices for increased dryland wheat production. However, precipitation during fallow season, which accounts for about 60% of the annual precipitation, has been largely ignored. Thus this study combined mulching and water retention cultivation technique to use fallow period rainfall, improve soil water retention capacity and ensure adequate soil water for spring wheat cultivation. A field experiment was carried out to study the effects of deep-plow at 15 d (15 DAH) or 45 d (45 DAH) after harvest and the applications of WPM (water permeability plastic film mulching) and LFM (liquid film mulching) immediately after deep-plow on soil water and wheat water use efficiency. The results showed that compared with 15 DAH, deep-plow at 45 DAH significantly improved soil water storage capacity during the 65 d (fallow period) and 316 d (booting stage of next crop of wheat) after harvest, 120 300 cm soil water storage before wheat sowing and also wheat water use efficiency. Deep-plow and mulching during fallow period also significantly improved soil water storage capacity at 65 d and 316 d after harvest, 0 300 cm soil storage capacity before sowing and wheat water use efficiency. Soil moisture condition was best under deep-plow with WPM. Also compared with 15 DAH, deep-plow at 45 DAH significantly reduced soil dry-up rate of 60 300 cm layer during sowing to jointing stage, 0 60 cm and 120 240 cm layer during jointing to anthesis stage, and 180 300 cm layer during anthesis to maturity stage. Soil moisture regulation effect of WPM after deep-plow was best during jointing to anthesis stage. Thus deep-plow after rain in fallow period improved soil water storage and wheat water use efficiency. Soil moisture regulation effect was best under WPM after deep-plow. The study therefore recommended deep-plow and WPM after rainfall during fallow period (about late July to early August), to ensure soil water conservation in dryland wheat fields and to preserve high, stable yields and water use efficiency of dryland wheat.

Effects of elevated CO₂ concentration and different water conditions on winter wheat growth and water use

LIU Yue-Yan, LIU Hui-Ling, QIAO Yun-Zhou, SHI Chang-Hai, DONG Bao-Di, LI Dong-Xiao, SI Fu-Yan, JIANG Jing-Wei, ZHAI Hong-Mei, LIU Meng-Yu

2013, 21(11): 1365-1370. doi: 10.3724/SP.J.1011.2013.30225

Abstract(1454) PDF(1216)

Abstract:
Elevated CO₂ concentration has been the main cause of climate change and has gained considerable attention due to its important impacts on crop growth and yield formation. Winter wheat, a major food crop in China, is mainly cultivated in the arid and semiarid regions of the country. It is therefore critical to study the growth and water use of winter wheat under different water and CO₂ conditions. In this study, winter wheat was grown in a pot experiment in closed chambers subjected to two concentrations of CO₂ [(396.1±29.2) μmol·mol^-1 (A) and (760.1±36.1) μmol·mol^-1 (E)] and two soil water contents [70% 80% (sufficient) and 50% 60% (drought) of field capacity]. Plant growth, aboveground biomass, grain yield and water use efficiency (WUE) at different stages were analyzed. The results showed that although elevated CO₂ had no significant effect on plant height and ear length, it respectively increased biomass by 28.6% and 18.6% under sufficient and drought water conditions. Elevated CO₂ also respectively increased grain number and grain yield by 24.3% and 32.6% under sufficient water conditions and by 15.5% and 22.6% under drought conditions. Elevated CO₂ showed no significant effect on the 1000-grain weight. Elevated CO₂ increased evapotranspiration respectively by 8.5% and 4.6% under sufficient and drought water conditions. It also respectively increased population WUE by 17.7% and 13.7% and grain WUE by 24.8% and 17.1% under sufficient and drought water conditions. Elevated CO₂ increased Pn by 15.6% and 12.9%, decreased Gs by 22.7% and 18.2% and Tr by 8.9% and 7.5% under sufficient and drought water conditions, respectively. Chlorophyll and water potential also increased under elevated CO₂. There was a higher increase in water potential (7.7%) under sufficient water conditions while chlorophyll increased respectively by 7.5% and 3.8% under sufficient and drought water conditions. The results suggested that the effect of elevated CO₂ on winter wheat growth, yield and WUE also depended on water conditions. The positive effects exceed the negative effects under sufficient water conditions. Grain yield improvement under elevated CO₂ and was mainly driven by increased grain number.

Effect of partial root-zone drought stress on root growth of maize

LI Rui, HU Tian-Tian, NIU Xiao-Li, DAI Shun-Dong, WANG Xu-Dong

2013, 21(11): 1371-1376. doi: 10.3724/SP.J.1011.2013.30248

Abstract(1325) PDF(1287)

Abstract:
The effects of partial root-zone drought stress on root growth in maize were studied in split-root and solution culture experiments. Sub-root samples were scanned for root length and area using CI-400 computer image analysis system (CID Ltd, USA). Maize plants were subjected to water stress by regulating the osmotic potential of the solution using polyethylene glycol (PEG-6000) in the experiment. Water was supplied at four levels - CK (sufficient water supply), 0.2 MPa (low water stress), 0.4 MPa (medium water stress) and 0.6 MPa (high water stress) for 6 days. After that, the roots were divided into two parts, one part was re-watered, and the other part was imposed continuously four water supply levels - over eight time periods - 0 h, 6 h, 12 h, 1 d, 3 d, 5 d, 7 d and 9 d. Compared with CK, growth of the re-watered roots part significantly increased after drought stress. While the re-watered half was larger than the stressed half of the root, the total root length was not significantly different under different water stress treatments. The increasing strength of the re-watered half of the root at the four different levels was different. The order of strength for the treatments was CK > 0.2 MPa > 0.4 MPa > 0.6 MPa. After preprocessing stage of total root osmotic stress, both sides of the root showed signs of water stress. Root length, area and dry weight in the re-watered root-zone and total root length and area of plant in the 0.2 MPa treatment were either close to or higher than the control treatment. Water absorption of the root system was influenced by re-watering after root-zone drought stress, which was compensated for root growth. Appropriate drought stress increased root area, but did not significantly increase total root length and dry root weight. Under the experimental conditions, the compensation effects of maize root system were related to the degree and time of drought stress.

Dynamic simulation of apple yield and dynamic response of deep soil moisture under rain-fed apple orchards of different planting densities at Baoji

FAN Peng, LI Jun, ZHANG Li-Na, CAO Yu, GUO Zheng

2013, 21(11): 1377-1385. doi: 10.3724/SP.J.1011.2013.30332

Abstract(1256) PDF(1301)

Abstract:
More apples have been planted in recent years at Baoji, developing into a major apple cultivation area in the Loess Plateau where apple industry was critical for local rural economic development. Baoji is in a semi-humid climate zone where apple orchards are mainly rain-fed without artificial irrigation. Because apples need plenty water for growth, there has been deep soil desiccation in apple orchard fields which has in turn caused severe fluctuations in apple yield. Thus apple production bases in the region have faced a serious threat to sustainable, long-term development. To determine long-term variations in yield and soil water of rain-fed apple orchards of different planting densities in semi-humid climate tableland and gully-land regions of the Loess Plateau, apple yield and the 0 15 m layer soil moisture dynamics in apple orchards of 6 different planting densities at Baoji in 1965-2009 were quantitatively simulated and analyzed using the WinEPIC model. From planting densities of D1 (2 m × 3 m), D2 (2 m × 4 m), D3 (2.5 m × 4 m), D4 (3 m × 4 m), D5 (4 m × 4 m) and D6 (4 m × 5 m), and planting years of 1 45 years, the study determined the optimum planting density and cultivation period of rain-fed apple orchards. The results showed that for the 42 years (1968-2009) of apple production, yields of apple orchards of different planting densities initially increased gradually and then declined with severe fluctuations. The average apple yield of the first 21 years was significantly higher than that of the second 21 years in the 42 years of apple production. Apple yield improved with increasing planting density from D1 to D3 and some times D4, which was 833 1 000 plants per hectare. Apple yields of different planting densities changed positively with precipitation trend. With increasing planting density, soil available water capacity in the 0 15 m soil layer in apple orchards decreased, while formation rate of dried deep soil layer increased. Based on the trend and amplitude of variations in yield during 1968-2009, the number of drought stress day, available soil water capacity and soil moisture distribution, the optimum planting density was D3 or D4, and the optimum cultivation period of rain-fed apple orchards was 30 years at Baoji.

Influence of karst mountain under-forest economy modes on soil infiltration in Southwest China

QIN Hua-Jun, HE Bing-Hui, ZHAO Xuan-Chi, YANG Ming-Shan, ZHANG Ye, DENG Xue-Mei

2013, 21(11): 1386-1394. doi: 10.3724/SP.J.1011.2013.30503

Abstract(1289) PDF(1609)

Abstract:
This study aimed to determine the relationship between different under-forest economy modes and soil moisture permeability in the karst mountain of Southwest China. Soil infiltration and the influence factors of six different under-forest economy modes in Chongqing City were studied, with the pure forest as the control. The study showed significant differences in soil infiltration among different under-forest economy modes and soil layers. Infiltration was highest (449 mL) in 0 10 cm soil layer under the mode of fungi cultivation in Dendrocalamus latiflorus forest. The second highest (427.5 mL) was under the mode of grass cultivation in Ficus lacor forest, followed the soil under the mode of poultry feeding in D. latiflorus forest (389.4 mL). Soil infiltration was poorest (241.5 mL) under the mode of fungi cultivation in Eucalyptus robusta forest. Soil infiltration in each under-forest economy mode decreased with increasing soil depth. The common infiltration model was the most suitable for simulating soil infiltrating processes in the study area, followed by the Kostiakov equation, and then the Horton equation. Soil infiltration evaluation via correlation analysis showed that the strongest soil infiltration capacity was of the mode of fungi cultivation in D. latiflorus forest. This was fol-lowed by the mode of grass cultivation in F. lacor forest and then poultry feeding in D. latiflorus forest. Fungi cultivation in E. robusta forest performed the least in terms of soil infiltration. Correlation analysis between soil infiltration and physiochemical properties showed significant positive correlation between soil infiltration and organic matter (β₁), moisture content (β₂), total soil porosity (β₃) and the 0.005 0.01 mm soil particle content (β₆) (P < 0.01). Also significant negative correlation existed between soil infiltration and soil bulk density (β₈) and 0.05 0.25 mm particle content (β₅) (P < 0.01). According to the correlation analysis, eight indexes of soil physiochemical properties (which significantly influenced soil infiltration) were noted. Comprehensive parameters of soil infiltration (a) and soil physiochemical properties (β) were obtained by the Principal Component Analysis. Then linear regression models of the indicators of soil infiltration and comprehensive parameters (a and β) were built as α= 0.249a₁+0.254a₂+0.252a₃+0.254a₄, β=0.167β₁+0.183β₂+0.200β₃+0.174β₄ 0.145β₅+0.131β₆+0.106β₇ 0.200β₈. In the models, a₁ was initial infiltration rate, a₂ was stable infiltration rate, a₃ was average infiltration rate, a₄ was total infiltration; β₄ was non-capillary porosity, β₇ was content of 0.001 0.005 mm soil particles.

Correlation analysis of soil physical and chemical properties under different planting patterns of blood orange garden in hilly areas of Chongqing City

LI Tian-Yang, HE Bing-Hui, TIAN Jia-Le, ZHANG Yi, YAN Jian-Mei, HE Xiao-Rong, LI Jian-Xing

2013, 21(11): 1395-1402. doi: 10.3724/SP.J.1011.2013.30246

Abstract(1321) PDF(1451)

Abstract:
Agroforestry, as a form of land use, is an effective technique to preserve mountain ecology and environment. To evaluate the ecological benefits of mountain agroforestry for guiding future land use planning, the physical and chemical properties of the 0 10 cm and 10 20 cm soil layers of agroforestry patterns of blood orange-sweet potato (I), blood orange-peanut (II), blood orange-maize (III), blood orange-eggplant (IV) and pure blood orange (V) were evaluated by using a grey correlation analysis. The paper also comprehensively discussed the differences in effects of different patterns on soil bulk density, soil porosity and soil nutrients contents in blood orange key demonstration area of Hebian Town of Bishan County, Chongqing City. The results suggested that soil bulk density, non-capillary porosity, total porosity, and contents of soil organic matter, total nitrogen, alkali-hydrolysis nitrogen, available phosphorus and available potassium under the same cultivation pattern were significantly lower in 0 10 cm soil layer than those in 10 20 cm soil layer. Also capillary porosity, total phosphorus and total potassium of different soil layers under the same cultivation pattern were not significantly different between two soil layers. Differences in soil bulk density, porosity and soil nutrients contents in the same soil layer among different cultivation patterns were either significant (P < 0.05) or extremely significant (P < 0.01). Soil bulk density was highest and non-capillary porosity, total porosity, and contents of soil organic matter, total nitrogen, total phosphorus, alkali-hydrolysis nitrogen, available phosphorus and available potassium lowest under pure blood orange. However, the total potassium in the 0 10 cm soil layer was slightly higher under pure blood orange than under blood orange-peanut pattern, and those in the 10 20 cm soil layer lowest. Contents of soil organic matter, total nitrogen and alkali-hydrolysis nitrogen of the 0 10 cm soil layer were highest under blood orange-maize pattern. Under blood orange-eggplant pattern, soil organic matter and available potassium contents in the 10 20 cm soil layer were highest. Then under blood-sweet potato pattern, total phosphorus and total potassium contents were highest. Also under blood orange-peanut pattern, available phosphorus content was highest. A comprehensive evaluation of the improvement in soil nutrients of different agroforestry patterns was done using grey correlation analysis. Based on the analysis, the order of improvement in soil nutrients in the 0 10 cm soil layer was blood orange-sweet potato > blood orange-maize > blood orange-eggplant > blood orange-peanut > pure blood orange. It was blood orange-sweet potato > blood orange-eggplant > blood orange-maize > blood orange-peanut > pure blood orange for the 10 20 cm soil layer. Surface vegetation diversity, below-ground root system distribution, and biological and ecological characteristics of each cultivation pattern were the main reasons for the differences in soil physical and chemical properties.

Competitiveness of intercropped maize cultivars in the Loess Plateau, China

WANG Xiao-Lin, ZHANG Sui-Qi

2013, 21(11): 1403-1410. doi: 10.3724/SP.J.1011.2013.30275

Abstract(1351) PDF(1510)

Abstract:
The competitive expression of intercropped maize cultivars with different characteristics for water, nutrient, dry matter partitioning and yield factors were studied in an experiment in the Loess Plateau region of China. To determine the competitiveness of intercropped maize cultivars with regards to growth and yield formation, two maize cultivars (compact cultivar "ZD958" and semi-compact cultivar "SD16") were intercropped in alternative rows under two densities (45 000 plants·hm^-2, 75 000 plants·hm^-2) conditions. The dynamic changes in dry matter of different plant organs, plant height, ear height, grain yield and yield components were investigated. The results showed that stem to leaf ratio (SLR) increased during vegetative growth and decreased after grain filling due to competition between cultivars. Intercropping increased SLR under low planting density, while significant decreased SLR under high planting density. This was more evident under high density intercropping, especially for "ZD958". Root to shoot ratio (RSR) limited redundant root growth, thereby saved resources. The RSR decrease was clear under intercropped treatments with significant differences between the low and high intercropping density. Two different cultivars with special morphology under intercropping conditions had root and canopy structures favorable for higher grain yield. With increasing intercropping density, spike to height ratio (SHR) and harvest index (HI) significantly increased. Meantime the decrease in SHR under low density of intercropping was more obvious than that of monocropping. Also SHR increased markedly under high intercropping density. The changes for "ZD958" were especially obvious. These evidences showed that intercropping improved the productive potential of maize. The structural factors of yield varied with significant decreases in spike length and thickness. However, the obvious shrinking of the length of bald needles suggested high grain pollination ratio. Finally, the analysis of competitive ratio (CR) showed that "ZD958" was more competitive than "SD16" under intercropping conditions. However, both "ZD958" and "SD16" showed distinct features which were mutually complementary for resources utilization. Intercrop competition was therefore an effective cultivation strategy for high productivity and beneficial competition among cultivars that increased water and nutrient use efficiency.

Identification of two cross combinations of F₁ Solanum tuberosum by SSR molecular marker

ZHANG Zi-Qiang, YU Xiao-Xia, JU Tian-Hua, YU Zhuo, CUI Kuo-Shu, WANG Dan

2013, 21(11): 1411-1415. doi: 10.3724/SP.J.1011.2013.30602

Abstract(1214) PDF(1643)

Abstract:
Cross breeding has been a major breeding method of potato and F₁ hybrid generation authenticity identification critical for objectively obtaining individual plant characteristics. To raise new potato (Solanum tuberosum) varieties with good quality, high yield, strong disease resistance and drought resistance, "J07-6" and "Longshu No.3" were respectively cross bred with "Favorita" and F1 hybrids derived. A total of 86 individual F1 hybrid authenticity of two hybrid combinations of "Favorita" × "J07-6" and "Favorita" × "Longshu No.3" were identified using the SSR molecular markers. Out of 43 pairs, 2 pairs of SSR primers (STM1049 and S7) were selected and used in marker analysis of the hybrid and parent crops. The banding patterns of "Favorita" × "J07-6" and "Favorita" × "Longshu No.3" hybrids were divided into four groups - complementary pattern of parents, deletion pattern, male specific pattern and female specific pattern. A total of 34 individual F₁ hybrids of "Favorita" × "J07-6"and 27 individual F₁ hybrids of "Favorita" × "Longshu No.3" were authentically identified. This showed that SSR molecular marker technology was feasible for potato hybrid authenticity identification. The results of this study laid the needed reference for hybrid breeding of excellent potato strains.

Effects of intensified corn stalk degradation by biocontrol agents on soil microbial community in continuous cucumber cropping

ZHANG Ting, LI Shi-Dong, MIAO Zuo-Qing

2013, 21(11): 1416-1425. doi: 10.3724/SP.J.1011.2013.30400

Abstract(1400) PDF(1294)

Abstract:
Stunted crop growth, yield decline and disease susceptibility have been associated with monoculture cropping. Soil borne diseases have emerged as the main obstacle to continuous cropping, which current biological techniques have failed to overcome. In recent years, however, intensified corn stalk degradation by biocontrol agents has been a widely used technique in winter greenhouses in North China. This technique combining application of crop stalk and biocontrol agents, which can improve soil quality, reduce soil diseases, increase crop productivity, etc. Thus this study aimed to investigate what effects this technique has on soil microbial community in continuous cucumber cropping. The dynamics of fungi, bacteria, actinomycetes, biocontrol agents and pathogens in cucumber fields were determined using both the plate culture counting and terminal-restriction fragment length polymorphism (T-RFLP) methods. The results showed that intensified corn stalk degradation by biocontrol agents significantly influenced soil microbial community in cucumber fields. After treatment, the number of fungi in soils of the second crop (6.33×10⁴ CFU·g^-1) was lower than that in the first crop (1.81×10⁵ CFU·g^-1) while bacteria and actinomycetes showed the reverse trend. Bacteria to fungi (B/F) ratio increased from 222.30 at the end of the first crop to 667.16 at the end of the second crop. The contents of biocontrol agents, Purpureocillium lilacinum and Bacillus subtilis, remained stable in soils under continuously cropped cucumber. Although insignificantly, the amount of pathogen Fusarium oxysporum f. sp. cucumerinum decreased. On the other hand, soil bacteria diversity significantly increased. This somehow promoted beneficial bacteria TRF139 propagation while inhibiting harmful bacteria TRF341 and TRF501. Moreover, the technique improved cucumber yield by 25.9% under continuous cropping and reduced root-knot nema-tode disease index by 71.4% at the end of the third crop. Thus the combination of corn stalk and biocontrol agents positively influenced soil microbes and their community structures, promoted biocontrol agent colonization within a few crops, inhibited the growth of pathogens and subsequently improved the health of soil microenvironment.

Isolation of highly pathogenic pathogens and identification of formae speciales of Rehmannia glutinosa L.

LI Zhen-Fang, YANG Yan-Qiu, WU Lin-Kun, SHU Yang, ZHAO Yong-Po, HUANG Wei-Ming, ZHANG Zhong-Yi, LIN Wen-Xiong

2013, 21(11): 1426-1433. doi: 10.3724/SP.J.1011.2013.30313

Abstract(1302) PDF(2082)

Abstract:
Rehmannia glutinosa is an important medicinal plant in China that requires 8 10 years plastochrone for replanting, making it almost impossible for continuous cropping. Previous studies had shown that soil-borne diseases caused by microbial imbalance in rhizosphere microecology were the main obstacles to continuous cropping of R. glutinosa. However, little has been reported on the identification of formae speciales of R. glutinosa. Thus this study used the PDA-plate method after microscopic identification and analysis of ITS fungi identification to successfully screen 31 strains of Fusarium from soil under continuous cropping of R. glutinosa. Pathogenic detection results showed that strain Fusarium moniliforme (No. RPP009), F. solani (No. CCS013), F. graminearum (No. CCS024), Monographella nivalis (No. CCS038) and F. oxysporum (No. CCS043) were highly pathogenic. These strains severely decreased the height (by 23.40%~30.20% compared with CK) and fresh weight (by 23.58%~38.94% compared with CK) of R. glutinosa seedlings within 3 days after inoculation, subsequently causing organ deformation and death after 2 weeks. Further host biotype identification test results showed that F. oxysporum (No. CCS043) and M. nivalis (No. CCS038) strains only infected R. glutinosa and not other materials used in the experiment. The leaves of lower part of disease plants repeatedly turned hydropenic at noon and eventually withered followed by plant death after 3 5 days. Microscopic examination showed that stem vascular system in diseased plants turned brown or duck which led to the disagglomeration of spongy tissues. Underground root tubers then eventually ducked and decayed. The preliminary analysis suggested that the two identified strains were formae speciales of R. glutinosa.

Differences in Cd-tolerance of rice and screening for Cd low-accumulation rice germplasm resources

ZHANG Xi-Zhou, ZHANG Hong-Jiang, LI Ting-Xuan, YU Hai-Ying

2013, 21(11): 1434-1440. doi: 10.3724/SP.J.1011.2013.30478

Abstract(1343) PDF(1830)

Abstract:
To develop genetic materials for breeding Cd-safe rice cultivars, the difference in Cd tolerance among rice parent materials were compared, and low Cd accumulation rice germplasms identified. The characteristics of growth and Cd accumulation of 145 rice parent materials were studied by using hydroponic method. Rice germplasms with low Cd accumulation were also identified based on Cd tolerance indices and Cd concentration. The results indicated that while dry weight (DW) and plant height (PH) of tested rice materials were inhibited on different extents under the stress of Cd ions, root lengths and root-to-shoot ratios were increased. Maximum Cd concentration and accumulation were 2.79 and 6.45 times the minimum of the restorer line materials, respectively. Similarity, maximum Cd concentration and accumulation were 2.00 and 2.98 times the minimum of the maintainer line materials, respectively. Based on Cd tolerance identification, the restorer line and maintainer line materials were divided into five groups, respectively. A total of 13 restorer line materials with low Cd accumulation were obtained. They were "MR183", "MR86", "R047", "R364", "Luhui 602", "Luhui 615", "Luhui 17", "GR548/M63//527_2", "R18", "Chenghui 838", "GR548/M63//M63_5", "GRL17/IRBN95-199_3" and "GRL17/ATTP//L17_3". Also an additional 2 maintainer line materials ("Yuxiang B" and "D62B") low in Cd accumulation were obtained. Among high Cd tolerant materials, maximum Cd concentration and accumulation were 1.97 and 2.03 times the minimum of the restorer line materials, respectively. Furthermore, maximum Cd concentration and accumulation were 1.43 and 1.40 times the minimum of the maintainer line materials, respectively. No significant difference was noted in Cd concentration and accumulation between the restorer and maintainer line materials. Identification Cd-safe rice germplasms and breeding Cd-safe rice cultivars were critical for Cd risk for human health.

2013 Vol. 21, No. 11