Studies Of Ecological And Yield Effect Of Potato In Rainfed Farming System By Surface Seeding

This thesis adopted potato conservation tillage that in dry farming region in western loess plateau as the research object, and by these 6 treatments: conventional tillage(T), surface seeding in the stubble mulched ditch with plastic film mulched ridge (PDSS), shallow seeding in the stubble mulched ditch with plastic film mulched ridge(PDSSH), surface seeding on ridge with stubble(RSS), surface seeding in flatten culture with stubble (FSS) and surface seeding in the stubble mulched ditch without plastic film mulched ridge(DSS), the growth indexes of the crop in every growth period, soil water content, soil temperature, yield, water use efficiency and the nutrient content in soil layer after harvest have been studied, in order to provide technical support and theoretical basis for the development of potato conservation tillage in dry farming region in western loess plateau. The results are as follows:1. The height of the no-tillage with stubble retention was higher than conventional tillage, except RSS at squaring stage; the dry matter accumulation of the no-tillage with stubble retention was lower than conventional tillage 16.23% at seedling stage, at squaring stage and flowering stage dry matter accumulation was PDSS>PDSSH>T>DSS>RSS>FSS, dry matter accumulation of the no-tillage with stubble retention was lower than conventional tillage 16.23% at mature stage.2. No-tillage with stubble retention treatment can increase the moisture storage, and especially for the 0-80cm soil layer. In the whole growth stages, Soil water at 0～30cm profile of no-tillage was respectively increased 16.9%～48.1%,15.7%～47.7%,14.3%～44.8%,21.1%～54.7% and 11.2%～47.1%; Soil water at 30～80cm profile of no-tillage was respectively increased 10.2%～37.3%,2.4%～23.6%,2.6%～24.2%, 11.2%～36.1 %,7.9%～21.2%.3. Different tillage methods have different warming and cooling effects on different soil layer. The daily mean temperature of every soil layer under different tillage methods changed in arc parabolic curve with the atmospheric temperature, and the no-tillage with stubble retention has warming effect on the 0-10cm soil layer, and the treatment of PDSS also has significant warming effect, but in the 10-25cm soil layer, the temperature of no-tillage with stubble retention was iower than that of the conventional tillage, and it has cooling effect, but it's not significant.4. The organic matter content of soil under the no-tillage with stubble retention were all higher than that of T, and the organic matter content of 0-10cm soil layer was highest under PDSS treatment, and the content of total N, total P and total K decreased with the soil depth increased, and the content of the all were all higher under the no-tillage with mulch methods than that of the T, but there's little difference between every no-tillage with mulch method.5. Under the all no-tillage with stubble retention except RSS, the yield and water use efficiency were all higher than that of T. Yield: PDSS>PDSSH>FSS>DSS>T>RSS, respectively increased 11.18%, 7.99%, 6.28%, 0.90%,RSS was decreased 2.89%, water use efficiency: PDSS>PDSSH> FSS>DSS>T>RSS, respectively increasedl4.81%, 4.71%, 4.65% and 2.38%, RSS was decreased 5.16%.