Study On Soil Water Characteristics And Crop Water Requirement In Different Parent Materials Of Purple Soil

Abstract: This article aspects of purple hilly region in the middle part of Sichuan Basin as studied area, adopting the methods of variance analysis and relative analysis to research the characteristics of soil water and crop water requirement in different soil parent material types, and analyze the impact of soil parent material on the characteristics of soil water and crop water requirement The result of study as follows:(1) Soil bulk density of different parent material purple soil increases from top to bottom as a whole though change in the soil profile. In the different parent material purple soil, J_2s has the maximum general variability in soil bulk density, and variability is 6.91%. J_3s has the minimum general variability in soil bulk density, and variability is 4.22%. In the same soil horizon, different parent material purple soil has discrepancy. In layer A, the discrepancy of J_3P and J_3S reaches significant level, and the discrepancy of J_3P and J_2S reaches extremely significant level, and J_3S and J_3S has little discrepancy. In layer B, the discrepancy of J_2S and J_3S reaches extremely significant level. In layer C, the discrepancy of J_3P and J_2S or J_3S reaches extremely significant level, and J_2S and J_3S has little discrepancy. Generally speaking, the average of soil bulk density is J_3P＞J_2S＞J_3S in layer A, and J_3S＞J_3P＞J_2S in layer C.(2) Different parent material purple soil has differences in soil texture. The general result of soil sand grain content is J_3S＞J_2S＞J_3P, and their value are 604.24g/kg,537.35 g/kg,437.92 g/kg.So soil sandgrain content is all high. The discrepancy of J_3P and J_2S or J_3S reaches extremely significant level, and J_2S and J_3S has little discrepancy. On the other hand ,the general result of soil clay content is J_2S＞J_3P＞J_3S, and their value are 234.90g/kg,230.43g/kg,160.39g/kg. So soil clay content is also all high. The discrepancy of J_3S and J_2S or J_3P reaches extremely, significant level, and J_2S and J_3P has little discrepancy.(3) Soil water retention capability of all the three parent material purple soil reduces from top to bottom in the soil profile, and the result of soil sand grain content is J_3S＞J_2S＞J_3S. Soil moisture characteristic curve fit coefficient of the all the three is above 0.98, and reaches extremely significant level. Furthermore, J_2S has the higher fitting character than the other two. Saturated soil water content, field water capacity and wilting coefficient of all the three parent material purple soil also reduces from top to bottom in the soil profile, but effective water content increases from top to bottom in the soil profile except the layer B of J_3S. The result of saturated soil water content, field water capacity and wilting coefficient is J_3P＞J_2S＞J_3S, and the result of effective water content is J_2S＞J_3P＞J_3S.(4) Among the affecting factors of the characteristics of soil water, the result of impact degree is soil clay content＞soil bulk density＞soil structural coefficient.(5) On the condition of different parent material in total growing period, winter wheat's characteristic of water requirement coincides with summer corn, and the result is J_3S＞J_2S＞J_3P. The field water capacity, wilting coefficient and effective water content have negative correlation with crop water requirement, and the linear negative correlation of field water capacity, effective water content and crop water requirement is above the significant level. Generally speaking, the discrepancy of different parent material soil texture causes the different characteristic of soil water, and furthermore, affects the crop water requirement.(6) The discrepancy of soil water characteristic and crop water requirement in different parent material purple soil, requires that region agricultural production should process scientific zoning, and adopt relevant and reasonable measures to improve reasonable and efficient utilization of soil moisture in allusion to region condition. Then promote the positive cycle of soil ecosystem and actualize the sustainable development of agricultural industry.