Effects Of Different Fertilization On Nutrients And Biological Characteristics Of Multigrain Soils

The black soil region of the Northeast is a substantial grain production base in China.However,in recent years,irrational fertilizer application has led to a decline in soil fertility and has also affected the soil microbiological environment.As an essential crop in China,grain crops are widely grown in the northeastern region.In this study,we used grain crops such as mung bean,kidney bean,red bean and sorghum as the research platform for locational fertilization trials in the black soil area,and set up 9 treatments:mung bean/kidney bean without fertilizer,mung bean/kidney bean with chemical fertilizer,mung bean/kidney bean with organic fertilizer,red bean without fertilizer red bean with chemical fertilizer,red bean with organic fertilizer,sorghum without fertilizer,sorghum with chemical fertilizer and sorghum with organic fertilizer,to investigate the effects of different fertilizer treatments and various cereal species on soil nutrients,soil enzyme activity and soil microbial diversity.The study provides a scientific basis for rational fertilizer application and various cereal cultivation in black soil areas.The findings of the study are as follows:（1）The soil p H of mung bean and red bean was higher than that of sorghum under the same fertilizer treatment.Soil organic matter increased significantly after chemical fertilizer and organic fertilizer were applied to mung bean.Under the condition of chemical fertilizer and organic fertilizer,the contents of total phosphorus and available potassium in soil of Mung Bean and red bean were obviously higher than that of sorghum,but the contents of total phosphorus in red bean were obviously higher than that of sorghum.Under the condition of chemical fertilizer,the content of available phosphorus of mung bean and red bean was 126% and 91% higher than that of sorghum,while under the condition of organic fertilizer,the content of available phosphorus of sorghum was 77% and 222% higher than that of mung bean and red bean.（2）Fertilizer application reduced soil urease activity compared to no fertilizer and organic fertilizer application;sucrase activity was significantly lower in the organic fertilizer treatment for mung bean than chemical fertilizer.In red bean soils,soil enzyme activities were all reduced by chemical fertilizer application and compared to no fertilizer application,soil catalase and phosphatase activities were significantly reduced by 13% and 66%.A comparison of the soil enzyme activities of different miscellaneous crops showed that mung bean and red bean soils had higher sucrase and urease activities than sorghum;sorghum soils had higher catalase activity than mung bean and red bean.Soil sucrase,urease and phosphatase activities were higher in mung bean and red bean than in sorghum under the same fertilizer treatments,except for red bean,where phosphatase activity was lower than in sorghum.Soil phosphatase activity was higher in sorghum than in mung bean and red bean,while soil phosphatase activity was higher in sorghum than in mung bean and red bean—the primary role of various cereal species in influencing soil enzyme activity.（3）Both chemical and organic fertilizer applications effectively increased the richness and diversity of the soil microbial community,while organic fertilizer application reduced the homogeneity of the soil bacterial community.The analysis of microbial diversity of different miscellaneous crops showed that the richness,diversity,and evenness of soil microbial community structure were higher in kidney beans and red beans than in sorghum.The application of organic and chemical fertilizers reduced the proportion of dominant bacterial phyla in the soil of miscellaneous crops,but the overall soil bacterial community performed stably.The proportion of dominant fungal phyla in soil was higher in sorghum than in kidney bean and red bean under the same fertilizer application conditions.The soil microbial community structure varied among the different grain crops,with high similarity in bacterial de-community between kidney bean and red bean and significant differences in soil fungal community structure among the three various crops.In summary,fertilizer application and grain crops species were closely related to soil nutrients,soil enzyme activities and soil microbial diversity.Different fertilizer application conditions could increase soil enzyme activities and some soil nutrient contents and also help to enhance soil microbial diversity;other grain crops also changed soil nutrients,soil enzyme activities and soil microbial diversity;it was also found that fertilizer application and grain crops species did not singly affect the soil but interacted with each other.