• Authors:
    • Zhang, S.
    • Jiang, Z.
    • Cai, J.
    • Zhong, C.
    • Wang, L.
  • Source: Journal of Northwest A & F University
  • Volume: 39
  • Issue: 7
  • Year: 2011
  • Summary: Objective: This paper studied the distribution patterns and morphological variations of fine roots in walnut ( Juglans regia)-wheat ( Triticum aestivum) agroforestry system to provide theoretical basis for the interspecific relationship research and management of agroforestry ecosystem. Method: With walnut, wheat monocropping ecosystem as control, samples were collected by soil coring method. WinRHIZO root analysis system was conducted to measure root morphology parameters. Moreover, differences of the fine roots spatial distribution and morphological variations between the agroforestry ecosystem and monocropping ecosystem were analyzed. Result: (1) The vertical gravity center of walnut fine root length in agroforestry ecosystem is 35.49 cm, compared with that in walnut monocropping ecosystem, which is 29.97 cm, moving down 5.52 cm. The distance between the radial gravity centers of walnut fine root length and the tree in agroforestry ecosystem is 0.91 m, which is 0.08 m closer to the tree than that (0.99 m) of walnut in monocropping ecosystem. The vertical gravity center of wheat root length in agroforestry ecosystem is 18.46 cm, compared with that in wheat monocropping ecosystem, which is 26.04 cm, moving up 7.58 cm. (2) The total mean root length density of walnuts in agroforestry ecosystem is 83.6 cm/dm 3, which is 135.6 cm/dm 3 in walnut monocropping ecosystem. The former decreases 38% than the latter. The total mean root length density of wheat in agroforestry ecosystem is 1.74 cm/cm 3, which is 1.22 cm/cm 3 in wheat monocropping ecosystem. The former increases 42% than the latter. (3) In 0-30 cm soil depth, the specific root length of walnut is 5 149.34 cm/g in agroforestry ecosystem, which is greater than 3 624.68 cm/g in walnut monocropping ecosystem. But in 30-100 cm soil depth, the specific root length of walnut is 2 626.59 cm/g in agroforestry ecosystem, which is smaller than the 3 906.9 cm/g in walnut monocropping ecosystem; In 0-50 cm soil depth, the specific root length of wheat is 10 019.5 cm/g in agroforestry ecosystem, smaller than the 11 811. 7 cm/g in wheat monocropping ecosystem. In 50-100 cm soil depth, the specific root length of wheat is 14 328.9 cm/g in agroforestry ecosystem, greater than the 13 389.6 cm/g in wheat monocropping ecosystem. Conclusion: In agroforestry ecosystem, most of the root competitions appear in 0-30 cm soil depth and radial 1.5-2.0 m to the tree. As responses to adapt to the competition and maximize access to resources in soils in agroforestry systems, the spatial distribution and morphology in fine roots might have a high plasticity during the growth of walnut and wheat.
  • Authors:
    • Yang, W.
    • Liu, W.
    • Wan, Y.
    • Zhang, J.
    • Xiang, D.
    • Yong, T.
  • Source: Acta Prataculturae Sinica
  • Volume: 20
  • Issue: 6
  • Year: 2011
  • Summary: The aim of this paper was to study the mechanisms of interspecific nitrogen facilitation and transfer in the relay strip intercropping systems of "wheat/maize/soybean" and "wheat/maize/sweet potato". The methods of root barrier and 15N-isotope dilution were used to investigate the nitrogen transfer, nitrogen uptake and residual effect in the two relay strip intercropping systems. Comparing the no barrier with solid barrier, the results showed that in-season 15N uptake and 15N recovery efficiency of wheat increased remarkably, and 15N% abundance left in soil and total N content reduced obviously. In the "wheat/maize/soybean" system, the in-season 15N uptake and 15N recovery efficiency, 15N% abundance left in soil and total N content of maize with no barrier increased by 25.16%, 25.16%, 13.89% and 10.15%. But in the "wheat/maize/sweet potato" system, the value of above indices reduced by 15.98%, 15.99%, 17.37% and 5.19%. For soybean, the in-season 15N uptake and 15N recovery efficiency, 15N% abundance left in soil reduced, the soil total N content increased by 3.03%. For sweet potato, the in-season 15N uptake and 15N recovery efficiency increased, 15N% abundance left in soil and total N content reduced by 0.91% and 4.95%. In the "wheat/maize/soybean" system, the 15N uptake and 15N recovery efficiency of wheat and maize obtained from previous wheat, maize and soybean were higher than that of the "wheat/maize/sweet potato" system. The 15N uptake and 15N recovery efficiency of soybean obtained from previous wheat or maize were lower than that of sweet potato, but that from previous soybean was higher than that from previous sweet potato. The "wheat/maize/soybean" system was more beneficial to increase annual nitrogen uptake, nitrogen residual effect and maintaining soil fertility.
  • Authors:
    • Wang, R.
    • CHEN-Zhi
    • Sun, Y.
    • Zhao, Y.
  • Source: Journal of Northwest A & F University - Natural Science Edition
  • Volume: 39
  • Issue: 4
  • Year: 2011
  • Summary: Objective: The paper uncovered the wheat and potato strip intercropping farmland's resistance effects to wind erosion in the agro-pastoral ectone in order to provide theoretical foundation and techonological direction. Method: Based on agro-pastoral mixed areas of Yinshan Mountain in Inner Mongolia, soil-erosion testing experiments were conducted on three stubble coverage farmland (wheat stubble coverage, coverage 65% and 76%, stubble height 20 cm and 30 cm; naked oats stubble coverage, coverage 90%, stubble height 30 cm) under 5 scheduled velocities (6, 9, 12, 15 and 18 m/s) by means of the movable wind tunnel and its suited velocity and sand sampling equipments. The author analyzed the change disciplinarian of the surfaces' aerodynamic roughness and wind erosion amount with the increasing distance of tested points (3, 3.75, 4.5, 5.25 and 6 m) from wind tunnel experiment section entrance (Simulating conservation tillage farmland's stubble widths). Result: The roughness of three kinds of surface showed early increasing and subsequent decreasing trend with the increasing distance of tested points from wind tunnel experiment section entrance under different velocities and the majority reached the max when the distance was 5.25 m; The wind erosion amount revealed rapid decreasing trend with the increasing distance of tested points from wind tunnel experiment section entrance under different velocities, the decreasing trend of wind erosion amount was gentle when the distance reached 5.25 m. Conclusion: Conservation tillage farmland's stubble height and vegetation coverage increase anti-wind erosion significantly. Anti-wind erosion effect of conservation tillage farmland tends to be more steady and significant when conservation tillage farmland effective width reaches 5.25 m.
  • Authors:
    • Ren, H.
    • Rosen, C.
    • Qing, C.
    • Fan, M.
    • Alva, A.
  • Source: Journal of Crop Improvement
  • Volume: 25
  • Issue: 1
  • Year: 2011
  • Summary: Potato ( Solanum tuberosum L.) is the fourth most important food crop in the world after corn, wheat, and rice. It is adapted to a wide range of growing conditions, producing high yields with a near-optimum balance of nutrients for human consumption. China is the world's largest potato producer and continues to account for a large part of the global increase in potato production. Although the potato can be highly productive, it has a relatively shallow root system and often requires significant nutrient inputs to maintain tuber productivity and quality. Each metric ton of tubers removes approximately 3.8 kg nitrogen (N), 0.6 kg phosphorus (P), and 4.4 kg potassium (K). Proper nutrient management, therefore, is extremely important for sustaining high tuber yield and quality. Lack of adequate balanced fertilization in China is reportedly a yield-limiting factor in some areas. For example, potassium (K) is very important for producing a potato crop with high tuber yield and quality. Limited K resources in China and continued cropping have resulted in below-adequate levels of soil K in many regions of the country, which will impact potato production. On the other hand, based on U.S. experience, the high nutrient demand by potato, application of high rates of fertilizer, and production on coarser textured soils can result in nutrient losses. Nutrient best-management practices are developed with the objective of optimizing production, net returns, and minimizing environmental degradation. In general, optimal N management has had the most important impact on tuber yield and quality compared with the other essential elements. Best management practices for N fertilization include appropriate selection of rate, source, timing, and method of application. Optimal management of irrigation is also important to improve N-uptake efficiency and minimize N losses while maintaining high yields and quality. Phosphorus is another key nutrient important from both production and environmental standpoints. Adequate P is required for optimum tuber-set, while excessive rates may result in soil-P buildup and potential runoff problems. This review will focus on various management techniques to maximize nutrient-uptake efficiency by potatoes.
  • Authors:
    • Guo, R.
    • Xu, H.
    • Lin, T.
    • Tian, L.
    • Cui, J.
  • Source: Xinjiang Agricultural Sciences
  • Volume: 48
  • Issue: 5
  • Year: 2011
  • Summary: Objective: In order to substantially know the weeds community and its characteristics in cotton field under mulch-drip irrigation of the south Xinjiang, an investigation on weeds was conducted. Finally a theoretical base of weeds control was provided in cotton subregions of the Southern prematurity and medium ripening taha. Method: Laid heavy stress on the years of cotton field with drip irrigation in townships of Avati County, weed community and quantities were investigated, including comparing with weeds community under the different mode of cotton. Result: There were a lot of weeds species in different cotton mode, including 9 families 15 kinds. Their main species were gramineous, compositae and chenopodiaceae families which had great effect on cotton growth. Conclusion: Compared with cotton fields under outdoor sowing, conventional irrigation and mulch-drip irrigation, the dry weight of weeds root hade significantly lower. The reason was that enough water and nutrient were supplied in time in cotton field under mulch-drip irrigation. The weeds quantity of annual shallow roots and broad-leaved had tendency to increase. The weeds had two harm peaks in the cotton growth period, and peak harm appeared earlier and continued for longer time.
  • Authors:
    • Lu, X.
    • Hou, Z. A,
    • Wang, H. J.
    • Xie, H. X.
    • Li, J.
    • Gong, J.
  • Source: Xinjiang Agricultural Sciences
  • Volume: 47
  • Issue: 10
  • Year: 2011
  • Summary: Objective: Effect of water, nitrogen and density coupling on the growth of hybrid cotton under film drip irrigation were studied. Method: A field experiment was carried out to study the growth and output of cotton treated by 8 test schemes of different water, nitrogen and density. Result: The results showed that the effect of water quantity on cotton yield was the most significant, the next was nitrogen and density. The yield of cotton was increased along with increasing of water and nitrogen quantity followed by nitrogen quantity and planting density. Conclusion: These results suggested that water and nitrogen in field farming should be used cautiously.
  • Authors:
    • Xu, Y. L.
    • Gao, S.
    • Wang, J. C.
    • Han, X. F.
  • Source: Journal of China Agricultural University
  • Volume: 16
  • Issue: 3
  • Year: 2011
  • Summary: To explore the effect of under-mulch-drip irrigation on canopy photosynthesis, canopy structure and yield formation of hybrid cotton planted in Xinjiang, an experiment with limited drip irrigation was carried out under field condition. The results were as follow: limited drip irrigation caused water deficiency in cotton field, reduced canopy apparent photosynthesis (CAP) and leaf area index (LAI); under this treatment, the canopy respiration rates (CR) and the ratio of CR to total CAP were higher in fully flowering stage but fell rapidly in full boll stage. The limited drip irrigation increased leaf mean foliage inclination angle (MFLA), transmission coefficient for diffuse penetration (TCDP) and transmission coefficient for radiation penetration (TCRP), with low light interception rate; On the other hand, excessive drip irrigation promoted the over-rapid growth of hybrid cotton, canopy leaf source capacity (CLSC) and high dry matter accumulation. But CR increased rapidly at late growth stage, and CAP was at its minimum level, result in low yield. In the case of hybrid cotton, under appropriate irrigation treatment, CAP was higher, and LAI increased sharply. It maintained at a higher LAI level at late stage, so it had a steady growth and optimal leaf physiological function which led to higher yield. Studies showed that the suitable amount of drip irrigation for Zhaofeng-1 in South Xinjiang was 3 000-4 125 m 3/nm 2. Its corresponding yield was 7 714.3-8 289.5 kg/hm 2. The ideal canopy photosynthesis characteristic and canopy structure targets of hybrid cotton were discussed.
  • Authors:
    • Lu, X.
    • Xie, X.
    • Wang, H. J.
    • Ye, J.
    • Hou, Z. A.
    • Hou, S.
  • Volume: 47
  • Issue: 9
  • Year: 2011
  • Summary: A field experiment was conducted to study cotton growth and nitrogen uptake in response to different water and nitrogen application rates under drip irrigation with saline water. Three irrigation water salinity levels were set as 0.35 (S 1), 4.61 (S 2) and 8.04 (S 3) dS/m; two water and nitrogen application rates were set as 405 (L 1), 540 (L 2) mm and 240 (N 1), 360 (N 2) kg/hm 2, respectively. The results showed that plant height of cotton were influenced significantly by water salinity, application rates of water and interaction between them, and the interaction among water salinity, water application rate and nitrogen application rate at earlier growth stage, but mainly affected by water application rate at the later stage. The order of plant height were S 2 > S 1 > S 3 with water application 540 mm (L 2), while no significant difference were found on the growth of plant height between two nitrogen rates. The dry matter accumulation of the cotton stem and leaves are influenced significantly by the interaction among water salinity, application rates of water and nitrogen application, but cotton bolls and total dry matter accumulation are not significantly influenced by the interaction. Nitrogen uptake of cotton was influenced significantly by water salinity, application rates of water and nitrogen, and interactions between two of them or among the three factors. Total nitrogen content of cotton reduced with water salinity increasing, but increased evidently when water application rate was increased. Those results suggest that higher water application rate can enhance nitrogen uptake of cotton under drip irrigation with saline water.
  • Authors:
    • Grant, C.
    • Cai, D.
    • Wu, X.
    • Sun, Y.
    • Feng, Z.
    • Zhang, D.
    • Zhang, X.
    • Zhao, Q.
    • Meng, C.
    • Dai, K.
    • Yang, Y.
    • Wang, X.
    • Jia, S.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 90
  • Issue: 3
  • Year: 2011
  • Summary: A field micro-plot experiment for winter wheat was conducted in an irrigated winter wheat ( Triticum aestivum)-summer maize ( Zea mays L.) rotation system in Mazhuang, Xinji of Hebei province in the North China Plain, using the 15N isotope method to determine the effects of N application (rates and timing), and irrigation frequency on urea- 15N fate, residual-N and N recovery efficiency (NRE) of wheat. The experiment was conducted under two irrigation treatments (I2 and I3, representing for two and three irrigations, respectively), at three N rates (150, 210, and 270, kg ha -1), divided between two 15N-labeled applications of basal- 15N (90 kg ha -1) and topdress- 15N (60, 120, and 180, kg N ha -1, respectively). The total N uptake by wheat (ranging from 186 to 238 kg ha -1) and the fertilizer-derived N (Ndff, about 34-55%) were measured. The Ndff from labeled basal- 15N and from labeled topdress- 15N were about 15-22% and 16-40%, respectively. The NRE (measured either as recovery in grain or as the total N recovery in the plant) was higher with I3 (39-41 or 47-49%) than with I2 (35-40 or 42-47%), showing maximum NRE in grain of about 40% both at N210 with I2 and at N150 with I3 treatment. The NRE by the first wheat crop (in grain or the total N recovery in plant) was higher with labeled topdress- 15N (39-48 or 45-56%) as compared to that with labeled basal- 15N (30-37 or 36-45%), while the unaccounted N losses were lower with labeled basal- 15N (14-22%) relative to labeled topdress- 15N (14-35%). Higher residual N in soils was found with labeled basal- 15N (41-51%), as compared to labeled topdress- 15N (18-35%). Residual N in the 0- to 150-cm soil depth ranged from 26 to 44% while the unaccounted N losses ranged from 14 to 30%. Recovery of residual N by the 2nd and 3rd crops in the rotation was 5-10% in the maize crop and a further 1.7-3.5% in the subsequent wheat crop. The accumulated N recovery and the unaccounted N losses in continuous wheat-maize-wheat rotations derived from labeled topdress- 15N were 54-64% and 16-37%, respectively while they were 47-53% and 16-28%, respectively from labeled basal- 15N. This study also suggested that an N rate of 210 kg ha -1 (with a ratio of basal-N to topdress-N of 1:1.3) with two irrigation applications could optimize wheat grain yields and NRE, under the water limited conditions in North China Plain.
  • Authors:
    • Cao, G. D.
    • Xia, J.
    • Zhu, H. W.
    • Tu, J. N.
    • Wang, S. M.
    • Yang, Y.
    • Li, B.
  • Source: Xinjiang Agricultural Sciences
  • Volume: 48
  • Issue: 3
  • Year: 2011
  • Summary: Objective: To study the regularities of the distribution of water, temperature and salinity in drip irrigation cotton field during freeze-thaw season. Method: Based on the data of field survey and laboratory test, this experiment analyzed water, temperature and salinity of each layer of the soil in arid drip irrigation cotton field within the freeze-thaw season. Result: The result showed that the surface soil begins to freeze in late November, and reaches maximum freezing depth in early February, the soil is completely melted in early April. The amplitude of soil temperature is respectively 19.95degreesC and 10.25degreesC at 5 cm and 170 cm depth. In the process of soil freezing, the soil water and salinity show ascendant trend within 0-60 cm depth from November 29th, 2009 to February 11th, 2010. In melting process (February 11th, 2010 April 21th, 2010), the vertical change of soil water and salinity is complicated. Water-salinity vertical distribution have little change within 60-200 cm. The features of temporal variability coefficient of soil water and salinity showed as follow: the variability coefficient of surface soil salinity is greater than bottom during the freeze-thaw period, the change of soil water is greater than soil salinity within 0-80 cm, the temporal variability coefficient of the soil water and salinity have low variability within 80-200 cm. Conclusion: The present study provided useful data for further research on soil water, temperature and salinity distribution during freeze-thaw period, and have certain reference value on soil improvement, agricultural irrigation and other related issues.