Systematic Experiments And Effect Analysis Of All Year Conservation Tillage In Two Crops A Year Region

The systematic experiment of conservation tillage in two crops a year region has been designed and performed according to the maximum benefit of resources, environment and production, based on the research achievements of conservation tillage technology in one crop a year regions. Series experiments and embedded theory study have been conducted for estimating the feasibility of water saving in conservation tillage and guiding irrigation. At the same time, the evaporations of soil water under the condition of conservation tillages are measured and its mathematic model is studied and significant research achievements have been obtained. Simulating experiment has been done for investigating rainfall infiltration effected by straw coverage under the condition of small precipitation. The main results in Ph.D program included:1. The field experiments of all year conservation tallige has been designed and conducted in two crops a year region of Central China using theory analysis combing production practice. The system of conservation tillage for two crops a year region has been set up in first time.2. The resources, environment and production benefits in two crops a year region are analyzed systematically. The field experiments results show that application of conservation tillage system can increase organic matter, nitrogen, phosphor and kalium in the 0-10cm soil layer. If the whole straws are put in the field ground, it would not only solving the problem of straw accumulation but also reduce letting out CO2 into atmosphere and lighten greenhouse effect. Using corn-wheat fully no-tillage and all mulch covered in the field it could save water 1110-1268 m3 per hectare a year. There are about 2600000 hectare croplands in Hebei province. That will decrease irrigation water 2.89 X 109~3.3X 109m3. Comparing with conventional tillage, conservation tillage will increase famer income 667yuan/hm2 in average, and 1546yuan/hm2 at most.3. The evaporation model of conservation tillage system in two crops a year region during the period of corn seedling has been established for the first time. The effects of surface water content, rate of straw mulch, soil temperature and leaf area index on evaporation have been investigated and exponential regression model of four parameters has been set up. It can be used for forecasting the evaporation amount. The stage integral model of evaporation amount has been inchoately set up for forecasting field evaporation amount and guiding irrigation, therefore, the system of conservation tillage can be for then developed and perfected.4. The corn and wheat residue mulching effects on redistributing the soil water have been studied detailedly by using artificial rainfall, thus it could solve the problem that some scholar doubt about whether residue mulching can increase the soil water content under the small amount rainfall.