Effects Of Long-term Fertilization On Soil Chemical Properties, Microbial Flora Composition And Activity

Agricultural sustainable development depends on the soil sustainable utilization,the soil sustainable utilization requires the soil fertility maintenance and improvement. The soil fertility includes physical fertility, soil chemical fertility and biological fertility.Fertilization is one of the biggest effect of agricultural measures on soil fertility.Black soil is one of the main cultivated soils in China, mainly distributed in the two provinces of northeast grain producing areas of Jilin and Heilongjiang provinces in China, accounting for 1/2 of total cultivated area land of two provinces. Although black reclaimming late of late, but because entrusts with heavy responsibility, the content of soil organic matter decreased, a large amount of nutrient loss, soil layer becomes thin, soil fertility decline. Therefore, this research takes the long-term experiment of national black soil and fertilizer efficiency in Gongzhuling City,Jilin Province, as the platform under Jilin province high yield of Maize, research the effect of long-term fertilization on soil chemical and biological fertility index during maize growth period, and the correlation analysis. In the corn five key growth stage(seedling, jointing, blossom period, grain filling period and harvest period)collecting soil samples, soil samples were determined with chemical index, enzyme activity,microbial biomass carbon, nitrogen and microbial quantity index, and the data were subjected to statistical analysis, conclusions are drawn as follows:The dynamic change of soil total nitrogen, alkali hydrolyzable nitrogen, total phosphorus, available phosphorus, total potassium and available potassium content in maize growth period presents strong regularity. Compared with NPK and CK, the long-term chemical fertilizer and organic fertilizer significantly increased soil organic matter, total nitrogen, alkali hydrolyzable nitrogen, total phosphorus, available phosphorus and available potassium content in corn growth period. The regularity of ammonium nitrogen and nitrate nitrogen in maize growth period is poor, but content of NPK+M2 treatment was the highest, compared with the CK and NPK treatment, five period the average ammonium nitrogen and nitrate nitrogen content respectively increasing 16.6% and 24.4%, 1.42 times and 1.16 times.The regularity of pH in the maize growth period is not strong, compared with NPK and NPK+1.5M1 treatment, other organic fertilizer or straw with fertilizer pH decreased less.The activities of hydrogen peroxidas, urease and phosphatase showed changes in roughly the same during corn growth period among different long term fertilization treatment: from seedling to jointing stage rising, peaked at the jointing stage and then decreasing to the lowest at grain filling stage, occurring a rising trend the harvest period.The change of sucrase activity is slightly different: increasing from seedling to blossom period, blossom stage to harvest decreasing.The changes of microbial biomass carbon and nitrogen is roughly the same during corn growth period under long term fertilization treatment:seedling to jointing stage decreased,elongation stage to anthesis increased and reached the peak,flowering stage to harvest decreased.Soil microbial quantity changes during corn growth period under long term fertilization treatment: from seedling to jointing stage did not change significantly, the flowering period increased rapidly and reached the peak, flowering stage to grain filling stage decreased.At the same growth period of maize in different fertilization treatments,the activity of soil urease,phosphatase,sucrase, microbial biomass carbon and microbial biomass nitrogen change regularity was:1.5NPK+M1>NPK+M2>NPK+M1>NPK+M1(R)>NPK+S>NPK> CK.The change regularity of hydrogen peroxidas activity and soil microorganisms number in maize different developmental stages is differences.Overall, compared with CK and NPK, the application of organic fertilizer and chemical fertilizer obviously increases the catalase activity and soil microorganisms number.Organic matter, total nitrogen and available potassium content and biological indicessignificantly or very significantly positive correlation; total phosphorus and available phosphorus content and phosphorus bacteria number does not exist significant positive correlation, and other biological indicators significantly or very significantly positive correlation;the content of total potassium and nitrogen content and cellulose decomposing bacteria not related, and other biological index significantly or very significantly positive correlation;the content of nitrate nitrogen and urease, phosphatase, catalase, microbial biomass carbon and nitrogen, cellulose decomposing bacteria, nitrifying bacteria significantly positive correlation,and denitrifying bacteria was extremely significant positive correlation; ammonium nitrogen and pH and all the biological indicators do not exist significant correlation.