【作者】 蒋斌；

【导师】 李军；

【作者基本信息】 西北农林科技大学 ， 生态学， 2008， 硕士

【摘要】 随着全球干旱趋势加剧和水资源短缺态势的日益显现,同时由于农田土壤肥力和粮食产量的持续提高,农田土壤水分利用率不断提高,黄土高原旱作粮田土壤水分收入量不断降低,土壤水分支出量不断增大,引起旱作高产粮田土壤水库中有效水分含量持续下降,以深层土壤水分持续亏缺为特征的土壤干层形成已经成为旱地粮食持续高产和稳产的严重隐患。在广泛调查在广泛调查和野外实地观测的基础上,应用美国研制的环境政策综合气候模型-WinEPIC,模拟研究了1960～2000年期间黄土高原半湿润区不同肥力水平下旱作粮田产量水平和深层土壤干燥化效应,探讨了旱作粮田土壤水分利用的适宜强度和土壤水分承载力,为促进黄土高原旱作农田土壤水分持续高效利用和粮食生产稳产发展提供科学依据。取得的主要研究进展如下:(1)黄土高原半湿润区旱作粮田作物土壤水分调查结果显示:随着年降水量趋势性降低和农田肥力水平逐渐提高,旱作粮田深层土壤湿度逐渐降低,土壤干层逐渐加深和加厚。高产粮田的土壤水分明显低于低产粮田,粮田土壤干燥化现象在1～3米范围内较明显,在3米以下也开始出现土壤水分减少的迹象。(2)组建了宝鸡和洛川等研究地区的逐日气象要素序列、土壤剖面理化性状、作物生长参数等WinEPIC模型数据库。模型验证结果表明,经过修订的Win EPIC模型对不同肥力处理下连作冬小麦、连作春玉米的籽粒产量和农田土壤水分变化动态模拟较为准确,适用于黄土高原冬小麦连作和连作春玉米的模拟研究。(3)在1960～2000年模拟研究期间,宝鸡和洛川N0、N90、N120、N150和N180等5种肥力水平下连作冬小麦产量因年降水量的依次递减而降低,宝鸡平均值分别为1.588 t/hm~2、2.306 t/hm~2、3.327 t/hm~2、3.981 t/hm~2和4.764 t/hm~2,洛川分别为1.444 t/hm~2、1.940 t/hm~2、2.454 t/hm~2、2.866 t/hm~2和3.241 t/hm~2。宝鸡麦田易受氮素胁迫,洛川麦田易受干旱胁迫。水分利用效率和施肥增产率两地差异均显著,均表现为宝鸡>洛川。宝鸡0～7m土层逐月土壤有效含水量和稳定性高于洛川。0～7m土层土壤湿度剖面分布变化动态表明,在经历了土壤湿度逐年降低、土壤干层逐年加厚的干燥化过程后,均出现了稳定的土壤干层,宝鸡和洛川各施肥处理麦田干层厚度相同,均为3m、3m、4m、4m和5m。土壤干燥化速度随肥力水平的增加而增大,宝鸡低于洛川。从增产和土壤水分可持续利用角度统筹考虑,宝鸡和洛川旱作小麦田土壤水分承载力分别为4.500 t/hm~2和2.700 t/hm~2。维持当地旱作小麦田土壤水分承载力的适宜施肥量:宝鸡为N165 kg/hm~2和P80 kg/hm~2,洛川为135 kg/hm~2和P65 kg/hm~2。(4)在1960～2000年模拟研究期间,宝鸡和洛川N0、N60、N120、N180和N240处理春玉米产量因年降水量逐年降低而降低,宝鸡平均值分别为2.681 t/hm~2、3.949 t/hm~2、5.403 t/hm~2、6.110 t/hm~2和6.358 t/hm~2,洛川分别为3.086 t/hm~2、3.574 t/hm~2、4.133 t/hm~2、4.828 t/hm~2和5.253 t/hm~2。水分利用效率和施肥增产率地区间差异均显著,均表现为宝鸡>洛川,同一地区内随施肥水平的提高水分利用效率增大。宝鸡0～7m土层逐月土壤有效含水量和稳定性高于洛川。随着施肥水平的提高,N0、N60、N120、N180和N240处理春玉米田逐月土壤有效含水量平均值呈现波动性降低趋势。0～7m土层土壤湿度剖面分布变化动态显示,在经历了土壤湿度逐年降低、土壤干层逐年加厚的干燥化过程后,均出现了稳定的土壤干层,宝鸡和洛川春玉米田干层厚度相同,N0、N60、N120、N180和N240处理均为2m、3m、4m、4m和5m。土壤干燥化速度随肥力水平的增加而增大,宝鸡低于洛川。从增产和土壤水分可持续利用角度统筹考虑,宝鸡和洛川旱作春玉米田土壤水分承载力分别为6.000 t/hm~2和4.000 t/hm~2。维持当地旱作春玉米田土壤水分承载力的适宜施肥量:宝鸡为N160 kg/hm~2和P80 kg/hm~2,洛川为N100 kg/hm~2和P50 kg/hm~2。更多还原

【Abstract】 With the global trend of drought and water shortage exacerbated , along with enhancement of soil fertility and grain yield on farmland simultaneously,soil water use efficiency enhanced remarkably,available soil water amount of high-yield grain field of dryland on loess plateau dropped continually,soil water depletion in deep soil layers led to desiccated soil layer has already became hidden barrier of sustainable development of high and stable yield grain production on the region. Based on the extensively investigation of crop yield and deep soil moisture on various crop fields, WinEPIC model was used to simulate major grain crop yields and the effects of deep soil desiccation under different fertilization treatments on semi-humid region of the loess plateau during 1960 to 2000. Suitable soil water use intensity and soil water carrying capacity on grain crop fields of dryland on loess plateau were discussed. The results provided scientific foundation for sustainable and high-efficiency soil water use and stable development of grain production of dryland on loess plateau. Progresses of the study were as following:(1) The investigation result of grain crop yield and soil moisture in semi-humid region of loess plateau indicated,along with precipitation reduced and fertilizer application enhanced, soil moisture in deep soil layers of grain crop fields decreased gradually,desiccated soil layers was deepening and thickening gradually. Soil desiccation phenomenon was obvious in 1-3 m soil layers,and soil moisture reduction also occurred in deep soil layers below 3m.(2) The databases of daily weather variable sequences,physical and chemical properties of soil profile,crop growth parameters of WinEPIC model at Baoji and Luochuan were built for the simulation. The model verification results show that the simulation result of crop yield and dynamic change of soil water for continuous winter wheat and continuous spring maize was precise. The WinEPIC model could be used to simulate continuous winter wheat and continuous spring maize production on loess plateau.(3) During 1960-2000 simulation period,continuous winter wheat yield at Baoji and Luochuan under five fertilization treatments(N0,N90,N120,N150 and N180) decreased with the precipitation reduction. Its average yield were 1.588,2.306,3.327,3.981 and 4.764 t/hm~2 at Baoji, and 1.444,1.939,2.454,2.866 and 3.241 t/hm~2 at Luochuan, respectively. wheat fields at Baoji was more vulnerable to nitrogen stress,while wheat fields at Luochuan was more vulnerable to drought stress. Water use efficiency (WUE) and the rate of increased yield by fertilizer of continuous winter wheat appeared as Baoji was higher than Luochuan. Monthly available soil water in 0～7 m soil layers of Baoji was higher than Luochuan,and which at Baoji was more steady than Luochuan. Average monthly available soil water decreased as fertilizer amount increased. The annual changes of simulated soil moisture distribution in 0-7 m profile on wheat fields at Baoji and Luochuan showed that a steady desiccation layer shaped after annual soil moisture reduction and desiccated soil layer thickened gradually. Thickness of desiccated soil layer of wheat fields under various fertilization treatments of Baoji and Luochuan were same as 3,3,4,4 and 5 m respectively. Soil desiccated rate increased along with fertilizer increased on wheat fields. Considering yield increase and sustainable soil water use,soil water carrying capacity of wheat field was 4.500 t/hm~2 at Baoji and 2.700 t/hm~2 at Luochuan, respectively. The corresponding fertilizer application amount for soil water carrying capacity on winter wheat field was N165 kg/hm~2, P80 kg/hm~2 at Baoji, and N 135 kg/hm~2, P65 kg/hm~2 separately.(4) During 1960-2000 simulation period,continuous spring maize yield at Baoji and Luochuan under five fertilization treatments(N0,N60,N120,N180 and N240) decreased with precipitation reduction. and its average yield was 2.681, 3.949, 5.403, 6.110 and 6.358 kg/hm~2 at Baoji, 3.086, 3.574, 4.133, 4.828 and 5.253 t/hm~2 at Luochuan, respectively. Maize fields at Baoji was more vulnerable to nitrogen stress while at Luochuan was more vulnerable to drought stress. Water use efficiency (WUE) and the rate of increased yield by fertilizer of continuous spring maize at Baoji were higher than Luochuan. Monthly available soil water in 0~7 m soil layers of spring maize field at Baoji was higher than Luochuan,and which at Baoji was more steady than Luochuan. Average monthly available soil water decreased as fertilizer amount increased. The annual changes of simulated soil moisture distribution in 0-7 m profile on maize fields at Baoji and Luochuan showed that a steady desiccation layer shaped after annual soil moisture reduction and desiccated soil layer thickened gradually. Thickness of desiccated soil layer of maize fields under various fertilization treatments of Baoji and Luochuan were same as 2,3,4,4 and 5 m respectively. Soil desiccated rate increased along with fertilizer increased on maize fields. Considering yield increase and sustainable soil water use,soil water carrying capacity of maize field was 6.000 t/hm~2 at Baoji and 4.000 t/hm~2 at Luochuan, respectively. The corresponding fertilizer application amount for soil water carrying capacity on maize field was N160 kg/hm~2, P80 kg/hm~2 at Baoji, and N 100 kg/hm~2, P50 kg/hm~2 separately.更多还原