Studies On The Environmental Evaluation And The Relation Of Pests' Growth And Decline Of The Producing Area In The Rice Main Production Region Of Hunan Province

Agriculture is a foundation of the national economy. In order to carry out the strategy of the sustainable development and realize the sustainable development of the agriculture and rural economy, the agricultural ecological environment must be protected, the farm-produce pollution must be controlled and the security system of farm produce quality must be established. The soil, irrigation water and atmosphere are the important factors which farm-produce depend on. Their condition affects directly the quality of the farm produce. In recent years, because of the pollution, such as waste water, waste gas ,waste residue from the factory and mining area , urban sanitary sewage and agriculture chemical , chemical fertilizer ,etc, the environment of producing area has been polluted and destroyed seriously .So evaluation on the environmental quality in the rice producing area is very important for developing the uncontaminated rice produce property. And the evaluation results will offer scientific basis for the base choice, construction ,and environmental protection of the rice main production region.This thesis bases on the investigation of environmental quality of the producing area in the rice main production region of Hunan Province for the first time, the soil, irrigation water and atmosphere quality have been sampled and monitored separately. According to Environmental Quality Standards of Soil, Standards of Irrigation Water quality, Ambient Air quality Standard, and exerting individual event pollution index and synthetic pollution index, quantitatively made a comprehensive appraisal and study of the soil, irrigation water and atmosphere quality of this region. The result of study shows: The soil, irrigation water and atmosphere quality of the rice main production region all belong to second grade generally at present, whose class of pollution is warn grade, Among which it is the most outstanding that the cadmium of soil environmental exceeds standard, accounts for 22%; The soil environmental quality of Heshan and Hengyang county has been slightlypolluted. The total cadmium of irrigation water exceeds standard, accounts for 15%; The irrigation water of Hengyang county is the worst in quality, but it is unpolluted on the whole. The sulfur dioxide exceeds standard most, accounts for 17.16% in the atmospheric environment; the atmospheric environment of Changsha County also has been slightly polluted. Base on the investigation and observe in the field and find that the pollution area of the sulfur dioxide in the atmospheric environment, the quantity of the rice main pest population increase obviously, while the quantity of their natural enemies obviously reduces. Therefore, the environmental quality of the producing area of the rice main production region is the key factor to restrict the quality safety of farm produce and agricultural sustainable development. On the basis of understanding environmental quality state of producing area, have separately proposed that some control countermeasures and measures from policy aspect, management aspect and technological aspect, in order to improve and protect the environmental quality of the producing area of the rice main production region, guarantee quality safety of farm produce and agricultural sustainable development.