Response Of Soil Nutrient And Micribiogical Characteristics To Different Rice Cultivation Patterns

With the increasing of agricultural intensification,the issues of non-point pollution,food safety and shortage of resources brought out by agricultural production have become the focus of attention.The rice-frog planting pattern is an agricultural model for integrated planting rice and raising frog.The rice-frog planting pattern could reduce the non-point pollution caused by agricultural production,improve the quality of rice,and realize the sustainable agricultural production.In this paper,a field experiment was conducted to investigate soil nutrient and microbiological characteristics response to rice-frog cultivation patterns in conventional cultivation(CR),green rice-frog ecosystem(GR)and organic rice-frog ecosystem(OR)under long-term management.The results of this study were as follows:1.Different planting patterns had significant effects on soil physical and chemical properties and nutrients.Compared with CR,the soil bulk density of GR and OR decreased by 9.8% and 13.1%,soil water storage increased by 6.2% and 12.3%,the content of soil TOC increased by 5.5%and 40.5%,the content of soil AN increased by 12.8% and 56.5%.the content of soil AP increased by 0.8% and 22.7%.Compared with CR,the content of soil AK of GR decreased by 2.0%,and OR increased by 28.7%.Therefore,from the perspective of the quality of paddy soils,long-term rice-frog model could improve the soil physical properties and nutrient content.2.Different planting patterns had significant effects on soil microbial characteristics.Compared with CR,the SMBC and SMBN of GR and ORincreased by 19.6%,31.0% and 14.9%,26.0%,the number of soil bacteria increased by 16.1% and 20.7%,actinomycetes increased by 1.4% and6.4%,fungi increased by 9.5% and 19.8%,soil urease activity increased by25.8% and 39.7%,protease activity increased by 4.0% and 14.4%,sucrase activity increased by 7.7% and 12.3%.Compared with CR,the neutral phosphatase activity of GR decreased by 9.3%,and that of OR increased by 15.5%.All the indexes above are important biological indicators to evaluate soil fertility,therefore,rice-frog model can effectively improve the soil fertility of paddy.3.CR,GR and OR were significantly different in soil nutrient index.OR was mainly characterized by TOC,AN,AP and AK.Soil protease activity activities,soil actinomycetes and fungi were the main features of GR,and soil bulk density was the main characteristic of CR.4.The nitrogen loss of GR and OR in paddy field was 16.1% and23.3% lower than that of CR in two years.The phosphorus loss of paddy field was 39.7% and 45.1% higher than CR and GR in two years.That indicated that the rice-frog model could effectively control the nitrogen loss in paddy field,if the phosphorus loss from the source was controlled,the organic fertilizer with less phosphorus could be used.5.Rice yields for the three models of two years were CR 7.51t/ha and7.63t/ha,GR 6.39t/ha and 6.26t/ha,OR 6.44t/ha and 6.61 t /ha.