Soil Water Availability And Use Under Mulch Tillage In Dry Land Of Western Shanxi Province

Drought is the typical characteristic in the west of Shanxi province. The main aim for the area is to fight drought and conserve water for agricultural production. As a new soil management method in the arid, semi-arid and semi-humid drought area, mulch tillage could improve soil environment by reduced tillage, no tillage, subsoiling and mulching, and then achieve the goal of sustainability of soil quality for high and stable yield. Based on 10 years field experiments, the effects of mulch tillage on the soil water and water use of corn was studied and analyzed systemically. The main results included:1. Mulch tillage could maintain higher soil water content by avoiding soil water losses, especially in seedling stage. Along with the growing up of crop, the effects of mulch tillage on soil water relatively decreased. With the increasing of soil layers, the effects of mulch tillage on soil water also decreased. Compared with conventional tillage method, the mulch tillage practice increased soil water content. Few differences in soil water content were observed among the three precipitation type years, but the effects of mulch tillage on soil water in dry years was evident.2. Mulch tillage could increase soil available water in soil layer. The average experiment results of 10 years demonstrated that the total soil available water was 42.4% under no-tillage with mulch treatment higher than that of conventional tillage, and 28.8% higher than direct drilling. The soil available water increased with increasing of straw-mulch, the effects of mulch tillage on the increase of soil available water in dry and severe dry years was more significant than in normal years, also the influence was obviously with increasing of straw-mulch.3. Compared with conventional tillage, mulch tillage practices could decrease crop evaportranspiration, but the differences were not significant among various treatments. From the view of straw-mulch amount, the corn evaportranspiration decreased with increasing of straw. Also no-tillage or mulch practice could decrease soil evaporation, raise transpiration of corn, and the effects of no-tillage or mulch method were evident with increasing of straw. From the point of intensity of evaporation and transpiration, conventional tillage practice was relatively highest. No-tillage or mulch method could decrease evaporation intensity to a certain degree. To the water consumption characteristic of corn, the water consumption of corn in total growth duration was maximal in normal years, less in dry years and minimal in severe dry years, especially during the stage of sowing to seedling.4. Mulch tillage delayed the corn stage of sowing to seedling, seedling to flowering, but had little effects on growing period after flowering stage of corn. Also due to mulch tillage practice, the growing duration was prolonged with the increase of straw amount. Mulch tillage could increase seedling rate of corn, and the influence was obvious with increasing of straw amount. Mulch tillage could significantly decrease corn height, corn stalk width and leaf area index during stage of seeding and shooting. And the effects could be evident with increasing of straw amount. During the stage of heading, mulch tillagepractice could enhance corn height, stalk width and leaf area index, and the effect of straw-mulch (7500kg/ha) was most among all tillage methods. Also mulch tillage could increase yield of com, and the effect was evident with increasing of straw amount. The treatment of straw-mulch (7500kg/ha) was the best choice considering the agricultural production.5. Mulch tillage could increased corn yield. The yield increased as the straw increasing. Among the mulch tillage practices, yield of treatment of no-tillage with mulch (7500kg/ha) or no-tillage with mulch (10500kg/ha) was highest; conventional tillage and direct drilling was lowest. The rate of yield increasing highest was severe dry year type and the yield of no-tillage with mulch (7500kg/ha) was higher 72. 96% than that of conventional tillage. In normal and dry years, t...