Effects On Crops Growth, Resource Utilization And Soil Ecological Environment Under Paddy-upland Multiple Cropping Rotation Systems

Maintaining farmland soil fertility, increasing multiple cropping index of farmland,and using pesticides and fertilizers rationally are part of the center of gravity of modern agriculture. Paddy-upland multiple cropping rotation patterns which is one of the major advantages of farming systems in southern China, can improve cropping index and enrich the soil environment of farmland. It plays an important role in the resource optimal allocation of paddy field, soil nutrients benign loop, crops stable yield, soil-nourishing,saving fertilizer, increasing farmers income, agricultural environmental protection and high-efficiency utilization of agricultural resources. This study, on the basis of two consecutive years of field trials, researched the effects of paddy-upland multiple cropping rotation systems on crops growth, resource utilization and soil ecological environment. The results are as follows:1. Paddy-upland multiple cropping rotation patterns could improve rice growth dynamics and increase rice yield, including winter crops yield, rice grain yield and groups biomass, which the “rape- peanut- late rice” and “vegetables- peanut ? corn- late rice”performed better. The patterns of “vegetables- peanut ? corn- late rice” and “potato-corn ? soy- late rice” can ensure more effective tiller, and are more favorable for rice growth. A variety of paddy-upland multiple cropping rotation patterns can effectively increase the chlorophyll content of late rice, which “rape- peanut- late rice” and“vegetables – peanut ? corn- late rice” are the most significant.2. The paddy-upland multiple cropping rotation patterns on the root dry weight of population, shoot dry weight of population and dry weight of total plant all increase gradually with development progress of late rice, and can improve shoot dry weight of population and dry weight of total plant of late rice compared with “winter fallow- early rice- late rice”. The pattern of “vegetables- peanut ? corn- late rice” promoted more obviously on the root dry weight of population and the pattern of “milk vetch- early rice-late rice” performed better on the shoot dry weight of population and the dry weight of total plant. In short, the patterns of “milk vetch- early rice- late rice” and “vegetables-peanut ? corn- late rice” posted a better performance from the various indexes generally.3. Comprehensive analysis shows that, the efficiency for solar energy utilization, the utilization of effective accumulated temperature of annual, water use efficiency and land utilization under the paddy-upland multiple cropping rotation patterns were higher than“winter fallow- early rice- late rice”. The “vegetables- peanut ? corn- late rice ? oilrape- peanut- late rice” and “milk vetch- rice- late rice ? oil rape- peanut- late rice”performed better, and should be promoted.4. Paddy-upland multiple cropping rotation patterns can improve the pH value,organic matter and the release of soil available N, P, K. The “milk vetch- early rice- late rice ? oil rape- peanut- late rice” or “vegetables- peanut ? corn- late rice ? oil rape-peanut- late rice” helps to improve soil fertility better than others. Paddy-upland multiple cropping rotation patterns improve soil aeration can increase microbial diversity, increase the number of soil bacteria, azotobacter, fungi and make the actinomycetes microbial community structure and function more stable, which “milk vetch- early rice- late rice”and “vegetables- peanut ? corn- late rice” performed better, and the performance of the soil enzyme activity was also better.5. Paddy-upland multiple cropping rotation patterns after two years showed that the soil of TOC showed first increasing and then decreasing, the LOC of tillering stage is highest and mature stage is lowest, the SMBC is highest in tillering stage and the DOC reached the highest in the mature stage. The maximum and minimum difference of TOC observed at the booting stage and mature stage, the LOC's at turning green stage and booting stage, DOC's at mature stage and turning green stage, SMBC's at tillering stage and turning greening stage. The soil TOC and DOC of “winter fallow- early rice- late rice” has biggest variation. The soil LOC of “rape- peanut- late rice” has the biggest variation. The SMBC of “milk vetch- early rice- late rice” has maximum amplitude. The pattern of “potato – maize ? soybean- late rice? vegetables- peanut ? corn- late rice”can guarantee higher soil TOC content at booting stage. The pattern of “milk vetch- early rice- late rice? oil rape- peanut- late rice” ensure the superior content of soil LOC in the early and middle growth of late rice. The DOC of “oil rape- peanut- late rice? potato –maize ? soybean- late rice” reached higher content in turning green stage and mature stage, and its SMBC is higher at booting stage and heading stage. All has significant differences. The relationship of comprehensive analysis of various soil organic carbon and its fractions in size is TOC>LOC>SMBC>DOC.