The Conservation Tillage For Soil And Water Control On Loess Slope Farmland In The Western Region Of Henan Province

Dry and soil erosion caused by the asymmetric rainfall distribution are big problems of agricultural production and environment. These problems are much serious in bess plateaus. Good soil tillage management is one of the methods to solve it. Measuring soil water and runoff in field observation plot, and studying erosion mechanism by laboratory rainfall simulation, this study evaluates the tillage methods, which is the best one to conserve soil and water. The result is: Through comparing the soil water content in one year period on winter wheat slope farmland under different tillage treatment in bess ravine western henna province, we can know that the tillage treatment changes the water infiltration and evapotranspiration, so it changes the soil water content. No-tillage has higher water content during one-year period. Sub-tillage soil gets highest water conservation 195mm during rain period, and has higher evapotranspiration volume at beginning of wheat grow, but comes smaller at last. conventional tillage treatment has the similar procedure of water change with sub-tillage, but the water content is much lower. Mulch acts an important role in conservation tillage. The restore and consume of water in two crop plot is lowest in five tillage treatment; the water volume restored is only 112mm. Fallow in dry area is very favor to reserve soil water. Tillage treatments affect soil water distribution in soil profile. The annual average soil profile water content in no-tillage plot is highest, two- crop plot is lowest. Water use in no-tillage soii is mainly in upper layer. Sub-tillage breaks the plough layer, so the water consuming and infiltration is much deeper. From the few runoff data we conjecture that reduced tillage is easier produce runoff because of it get a layer soil dust on soil surface and there is no mulch on it. There are good effects of Sub-tillage and no-tillage to reduce runoff erosion. At beginning, soil erosion rate is low, and then it becomes much higher and keeps stable. In interrill erosion, rain intensity acts an important role in erosion and splash erosion attributes a lot to the soil erosion. Straw mulch protects soil from erosion of rain and promotes infiltration, so reduce runoff and splash erosion. The runoff sediment has higher clay content than the surface soil, and the splash soil has higher fine sand content. The available nitrogen lost with the erosion soil, and the content in runoff sediment is higher than in surface soil. The available nitrogen content has higb relative coefficient with clay content, For summary, Rainfall intensity is the crucial factor of erosion, and the straw mulch plays important role for control soil erosion. Sub-tillage and no-tillage get good straw mulch, so they reduce occurring of runoff and intensity, also the soil water evapotranspiration. Sub-tillage breaks plough layer and promote water infiltration, so it gets best conservation of water for winter wheat using. Conventional tillage also promote water infiltration and has the similar regulation of water changing with sub-tillage, but it has no straw mulch, then water conservation is less than sub-tillage. Reduced tillage is worst for conservation soil and water. Two crop tillage has lowest soil water content because of the crop extracting lots of water during raining season, so fallow is useful for restore soil water in dry region.