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Accueil du site → Master → Chine → 2008 → Simulation of Soil Desiccation Effects and Soil Water Carring Capacity of Grain Crop Fields on Dryland in Middle Areas of Loess Plateau

Northwest University of Science and Technology (2008)

Simulation of Soil Desiccation Effects and Soil Water Carring Capacity of Grain Crop Fields on Dryland in Middle Areas of Loess Plateau

Wang Xue Chun

Titre : Simulation of Soil Desiccation Effects and Soil Water Carring Capacity of Grain Crop Fields on Dryland in Middle Areas of Loess Plateau

Auteur : Wang Xue Chun

Grade : Master’s Theses 2008

Université : Northwest University of Science and Technology

Résumé partiel
Application developed by the United States Environmental Policy Integrated Climate the model-WinEPIC, simulation studies from 1960 to 2000 the central Loess Plateau different precipitation types different fertility levels on the basis of extensive investigations rainfed grain crop yield and field observations of deep soil moisture different cropping patterns in rainfed grain production levels and deep soil desiccation effects, evaluate the productivity of rainfed grain stability and different fertility levels under different cropping patterns, soil desiccation of the food for the Loess Plateau sustainable provide a scientific basis for development. The main progress achieved as follows : (1) crop yield and soil water survey results show that : continuous cropping of winter wheat and spring corn production showed a trend of decline in volatility influenced by precipitation. Rotation conditions, the yield of winter wheat are more susceptible to the influence of precipitation, while the yield of spring corn stubble impact easier. Productive farmland soil moisture was significantly lower than the low-yielding farmland, farmland soil drying phenomenon is more pronounced in the range of 1 3m, 3m or less also began to reduce the signs of soil moisture. (2) by continuous cropping of winter wheat Changwu Dryland, Jinzhong semiarid area of ??continuous spring maize, Changwu Dryland Wheat Maize Rotation three cropping patterns in different fertility levels of simulation accuracy verification that : After adjustment WinEPIC model for different fertility under continuous cropping of winter wheat, even as grain yield of spring corn and wheat Maize Rotation and farmland soil moisture dynamics simulation is more accurate, suitable for the Loess Plateau winter wheat continuous cropping, spring maize continuous cropping and wheat the jade rotation system analog. (3) Luochuan, Changwu, Yan’an, Shouyang continuous spring maize production in the simulation of the 41-year period, the annual average of 4.40t/hm2, 4.23t/hm2, 3.75t/hm2, 2.50t / hm2. Increase fertilization rate, long Wu gt ; the Luochuan gt ; the Yan’an gt ; Shouyang. Water use efficiency, the Luochuan gt ; the Yan’an gt ; Changwu gt ; Shouyang, the same area to improve water use efficiency increased with fertilization level. 0 7m depth the monthly effective soil water content the Luochuan gt ; long Wu gt ; the Yan’an gt ; Shouyang, the first two regional soil moisture is less stable. With the improvement of fertilization level, month by month farmland soil available water average presents the trend of lower volatility, compared with N0 N60, N120, N180, N240, N300, respectively, to reduce 166mm, 299mm, 295mm, 416mm, 421mm. All Spring Maize 0 7m depth soil moisture profile distribution, soil moisture experienced reduced year by year, the dry soil layer gradually thickened after the drying process, there are a stable soil dry layer. Soil desiccation speed N0, N60, N120, N180, N240, N300 in turn increases Luochuan, Changwu, Yan’an, Shouyang turn, increases. Fertility level is one of the main factors that affect the final distribution of the soil dry layer. Integration of the different regions under different fertility level continuous cropping of spring corn yield, water use efficiency, fertilizer yield rate of the water carrying capacity, 0 7m soil moisture profile distribution, from the sustainable use of yield and soil moisture angle and consider even for Luochuan spring corn yield level of 5.25 5.54t/hm2 appropriate, the appropriate level of fertilization N240 N300 appropriate and 5.25 5.45t/hm2 Changwu N300 N240 appropriate value in Yan’an were 4.26 4.58t/hm2, N180 N240, in Shouyang 2.34 2.74t/hm2 N120 N180. (4) In 1960 to 2000, during the simulation study, Luochuan Changwu, Yan’an, Shouyang continuous cropping of winter wheat yield annual average of of as 2.77t/hm2 2.70t/hm2 1.97t/hm2, 1.00t/hm2

Mots clés : Loess Plateau Rainfed grain WinEPIC model Soil moisture Fertility Soil desiccation

Présentation (Dissertation topics)

Page publiée le 27 mai 2015, mise à jour le 5 décembre 2017