Development Research On The Main Companion Communinity During Rice Growing In Rice-duck Complex Ecosystem

With the rapid development of the society and fast increase of population, more and more materials people ask for the nature, which requires that land can provide higher productivity to meet the needs of people's increasing food demand. In order to increase paddy yield, every year large quantities of fertilizer, pesticide, growth regulator and so on agrochemical are used in cropland ecosystem, which not only kill and wound the helpful biology in paddyfield, pollute the environment, destroy the natural ecosystem, but also increase the leftover in paddy field. It heavily restricts the sustainable development of paddy produce. With the increasing of environment pollution, the requirements of people for the environment-protection agriculture have been increasingly intensive. How to combine the traditional agriculture and modern agriculture organically, to head to a new road of sustainable increasing development, to produce more "green food", to meet people's demand are the hot and difficulty spots for agricultural science and technology workers.The article summarized rice-duck complex ecosystem's current research situation and developing tendency in China and the outside country. Regard ecology as the theoretical direction, the authors studied the different plant diseases and insect pests' emergence rules in rice-duck complex ecosystem, and counted a large amount of data. Through an analysis of these data, we set up the corresponding mathematics model; through calculation, we analyzed that the ecology reason of duck-fed in paddyfield can prevent and cure plant diseases and insect pests, found out the corresponding mathematics analysis method, and drew the result of study of the following.Utilize the statistics of the field to set up improved life table model. The calculated out result showed that in rice-duck commensalisms area, the livability of rice planthoppers' first age grade was reduced with increase on date. The analysis indicated that the duck's movement mainly do effect on the livability of rice planthoppers and affect rice planthoppers' birthrate of each period. Therefore duck can have comparatively obvious prevent and cure influence on rice planthoppers. And through setting up regressive model, we found out that the relation between the total amount of rice planthoppers and the temperature. According to the temperature information at the time, the emergence information of rice planthoppers can be approximately estimated. By calculation, we can know the proportionate relationship of two types of rice planthoppers which comparatively heavily emerged in Hunan province, the fixedquantity relationship among the ratio of grey rice planthoppers, white-back rice planthoppers and the max average temperature, average sunshine time, average humidity and average rainfall at several periods of time in the past. The above calculated out result also can approximately forecast the ratio of grey rice planthoppers and white-back rice planthoppers at next period of time, and can calculate out the total amount of grey rice planthoppers and white-back rice planthoppers and their respective ratio in the total amount of rice planthoppers and the max average temperature, average sunshine time, average humidity and average rainfall at several periods of time in the past presented the linear relation. Using the above conclusion, we can approximately forecast the total amount of grey rice planthoppers and white-back rice planthoppers and their respective ratio in the total amount of rice planthoppers. And again utilizing the relationship among total amount of rice planthoppers, total amount of grey rice planthoppers and black-grey rice planthoppers, and their ratio, we can obtain the relevant amount and data of grey rice planthoppers and black-grey rice planthoppers.Through these data, we can guide the preventing and curing.Through the set up model, and the stat. data showed that duck had greater influence on grub of chilo suppressalis(walker) and gained better prevent and cure impact. But if it was after a long time, the influence was...