Study On Effects Of Varieties, Row Spacing And Irrigation Strategies On Crops Yields And Wue In Winter Wheat-Summer Maize System

The study was carried out in Quzhou experimental station, China Agricultural University, during the year 2010-2012. Four experiments were conducted in the study. The first one is the comparison of 6 varieties. The second one is the study on effects of irrigation, which was arranged at grain filling stage during the growth of summer maize, on the yield of summer maize and soil moisture of winter wheat seeding stage. Two treatments was arranged in this experiment, that is irrigating 15 days before harvest of maize and no irrigation. The third experiment is the comparison of the lodging resistance of maize in the two different configurations. The first configuration is 120cm in line spacing and 10cm in row spacing. The second configuration is 60cm in line spacing and 20cm in row spacing.Conclusions of the study can be listed as follows.(1) Varieties of long growth period can take advantage of solar and water more efficiently. Nowadays, the harvest of summer maize is too early to fully use the resources of solar and water, and thus cannot gain higher yield in the winter wheat-summer maize system.(2) Irrigation at grain filling stage during the growth of maize makes some difference in maintaining the leaf function and increasing grain weight but the difference is not obvious.(3) Irrigation at grain filling stage during the growth of maize has the effects of increase the soil moisture of winter wheat seeding stage as well as satisfy the need of summer maize. Thus, it makes sense to reduce the burden of irrigation facilities at the early growth stage of winter wheat. Besides, it does good to enhance tillering of winter wheat and increase the crop yield.(4) Nowadays, farmer tends to increase the planting density of summer maize in production. However, high crop density reduce the lodging resistance of maize and increase the risk of production. Too low crop density is not acceptable either, for it decreases the yield of summer maize. This study found that proper density of summer maize could increase the lodging resistance of the crop as well as its yield, and thus played an important role in the efficient use of the resources.Taking into account all these experiments conducted in this study, the thesis concludes that any single measure aimed at increasing the yield of summer maize and winter wheat cannot work effectively by itself. To increase the yield of these two kinds of crop and guarantee the efficient use of resources, we should regard the winter wheat-summer maize system as a whole and design a set of agronomic strategies which work well to coordinate with each other.