Research On The Biological And Environmental Effects Of Rice In Inadequate Irrigation And Less Fertilizer Condition

Water shortage is one of the most serious problems in our country. In our country agriculture has consumed the 80% of total water consumption and the paddy rice occupied 65% of agriculture water comsumption. The agriculture production is perplexed by water shortage and the paddy rice production is most serious effected. Every year the paddy rice output always reduces because of drought. When the drought is serious, the output reduced more, even extremely. But in our country agriculture wastes water seriously, the farmland water use efficiency was low, which cannot reach 50%of developed country.The nitrogen fertilizer dosage of the Chinese paddy rice occupied 37% of that of the whole world's. The paddy rice nitrogen fertilizer dosage of Chinese paddy field is 180 kg/hm2 in average, this dosage is 75% higher than world average dosage. The Chinese paddy field nitrogen fertilizer dosage has consumed about 24% of the total nitrogen fertilizer usage.The increasing use of the fertilizer, raised the yield of the farm crop, but often makes a lot of fertilizer waste because of inappropriate amount in use and the absurdity method of apply fertilizer. And when the excessive fertilizer enters into the water, the environment is polluted and turned worse, and the ecosystem system would be out of tune.Long-term surfeit use of excessive fertilizer will make the physical property of soil worsen, the soil harden and leanness. On the contrary this will urge the increment use of fertilizer. When such series of occurrence happens, the agriculture cost increases and results in polluting the environment and agriculture.This thesis aims at the problem of water shortage and environments pollution caused by excessive use of water and fertilizer in paddy rice production currently. The physiological characteristics of rice were studied, Pot trial, field test and the soil culture model test were designed and different water stress, and the fertilizer uses level were established. The resultsindicated that the appropriate humidity coerce and little apply fertilizer to anticipate the combination, can repress the invalid tiller, regulate a top and bottom of paddy rice part and the nutrimental backlog of the plant and the seed grain allotment.At the same time, according to the experiment data, water and nitrogen fertilizer coupling function was buil t up originally under this condition of experimenting. Water and nitrogen fertilizer interaction coupling effects were analyzed. The reference for the region's water and nitrogen management and the estimate yields can be provided by all the work.