| Using pesticide is a key measure in modern agriculture. Pesticide has an important effect on solving the food crisis caused by population explosion and maintaining the stable and sustainable development of agriculture. As a key measure of guaranteeing the output of food, fertilizers were applied widely in farming. Atrazine, Which has high activity towards the weed, low toxicity in the environment, belong to the selective systemic conductive triazine herbicides. The paper studied the compound pollution of atrazine and fertilizer. In this research paper, what were mainly studied was the effects of atrazine on the soil microbe and enzyme activity under the long-term fertilization conditions and its degradation in different fertility soils, meanwhile, what were studied was the seasonal succession of soil microbe and enzyme activity. These researches can offer bases and evidences for the safely and rationally applying of the pesticides and fertilizers so as to reduce the environmental pollution. The results could be summarized as follows:1. We studied the effects of long-term fertilization on the soil hydrogen peroxidase, invertase, urease, phosphatase activities. The results were as follows: Long-term application of fertilizers, especially the treatment of NPK +M could significantly promoted the soil invertase, urease and phosphatase activities. Long-term application of fertilizers reduced the soil hydrogen peroxidase activity. Soil in the treatment of NPK+M had significantly lower of hydrogen peroxidase in four treatments. Hydrogen peroxidase activity increased from April to July in 2002 and gradually reached a maximum in July, then decreased gradually. Invertase activity remained stable during the wholeexperimental period. Phosphatase remained the high activity from April to June, then decreased during the later period. Urease varied complicatedly.2. The study of the effects of long-term fertilization on the population of the soil microbe groups demonstrated that long-term fertilization augmented the population of bacteria, fungi and actinomycetes. Soil in the treatment of NPK+M had significantly higher numbers of bacteria than the treatments else. Soil in the treatment of NPK had significantly high numbers of fungi. The numbers of actinomycetes with the treatment of NPK were lower than with the treatments of NPK+M or NPK+S. The numbers of bacteria increased from April to July in 2002 and gradually reached a maximum in July, then remained stable during the later period. The numbers of fungi increased from April to August in 2002 and gradually reached a maximum in August, then decreased. The numbers of fungi with the treatment of NPK+S didn't renew during the later period, whereas the numbers of fungi with the treatments else renewed in the end of September. The numbers of actinomycetes increased from April to July in 2002. The numbers of actinomycetes with the treatment of NPK+M increased till August, then gradually decreased.3. The study of the effects of long-term fertilization on the population of the soil microbe physiological groups demonstrated that long-term fertilization augmented the numbers of azotobacteria. Soil in the treatment of NPK+M had significantly higher numbers of ammonifiers than the treatments else. Long-term fertilization augmented the numbers of nitrifiers obviously. Long-term fertilization augmented the numbers of cellulose-decomposing bacteria obviously, and moreover, the numbers of cellulose-decomposing bacteria with the treatments of NPK, NPK+M and NPK+S varied similarly. The numbers of azotobacteria remained the high level from June to August. The numbers of ammonifiers increased from May to August gradually and reached a maximum in August, then decreased from August to September and remained stable in the whole September. The numbers of nitrifiers varied complicatedly. The numbers of cellulose-decomposing bacteria with thetreatment of CK remained stable during the whole experimental period, which with the treatments else varied similarly, that is, there we... |
PDF Full Text Request