Effects Of Tillage Practices On Soil Microbiological Characteristics Of Wheat-pea Rotation System In Rainfed Areas Of Central Gansu

Soil microbes are an important part of soil ecosystems and are closely related to soil quality.Suitable tillage measures and straw management methods can create a good soil environment for soil microbes,which is of great significance for improving soil quality and sustainable agricultural development.The study relied on the long-term conservation tillage positioning experiment established in 2001 in rainfed areas of central Gansu.In 2017,we studied the impact of traditional tillage(T)and three conservation tillages;no-tillage with straw mulching(NTS),no-tillage and nomulching(NT),traditional tillage with straw burying(TS)on soil temperature,soil water content,soil organic carbon,soil total nitrogen,soil microbial biomass carbon and nitrogen,soil microbial community(bacteria and fungi)abundance and diversity during the growth period of spring wheat and peas.The aim of the study was to explore the impact and the underlying mechanism of tillage in wheat-pea rotation system on soil microbiology.The main findings are as follows:1.Compared with traditional tillage,conservation tillage significantly increased microbial biomass carbon and nitrogen content in 0-30 cm soil layer during crop maturity,with no-tillage with straw mulching being the most significant.Compared with T treatment,the soil microbial biomass carbon and soil microbial biomass nitrogen content in 0-10 cm soil layer of spring wheat at maturity stage were increased by 40.43% and 30.56% respectively,while the soil microbial biomass carbon and soil microbial biomass nitrogen content in 10-30 cm soil layer of pea at maturity stage were increased by 64.64% and 41.25% respectively.2.No-tillage(NTS?TS)are more effective than traditional tillage to improve the OTU species of fungi in 0-30 cm soil layer and bacteria in 0-10 cm soil layer during pea ripening period,and the special groups are relatively high,and the OTU of bacterial was higher than that in fungi,The dominant species of bacteria were Actinomycetes(36.80%),Proteobacteria(15.24%),Chloroflexi(10.47%)and Acidobacteria(10.29%).The Ascomycota(61.58%)and Basidiomycea(15.22%)were dominant fungi species,Actinomycetes and Basidiomycea were endemic dominant populations.3.Compared with traditional tillage,conservation tillage can significantly reduce soil temperature,increase soil water content,and increase soil organic carbon content.Compared with T treatment,the average soil temperature of 0-15 cm soil layer in the growth period of spring wheat and pea under NTS treatment decreased by 1.43? and 2.17?,respectively.The average water content of 0-30 cm soil layer in the growth period of spring wheat under NTS treatment was 17.10% higher than that in T treatment;Under the NTS treatment,the soil organic carbon content in the 0-10 cm and 10-30 cm soil layers increased by 26.02% and 19.57%,respectively.There was significant(P<0.05)or extremely significant(P<0.01)correlation between soil temperature,water,organic carbon and soil microbial properties(SMBC,SMBN,bacteria,fungi).In summary,The bacterial OTU of wheat pea rotation system was higher than that of fungi in rainfed areas of central Gansu.the dominant species of bacteria were Actinomycetes,Proteobacteria,Chloroflexi,Acidobacteria and the dominant species of fungi were Ascomycota and Basidiomycea.The Conservation tillage with no-tillage straw mulching can improve microbial habitat,thus improving soil microbial diversity,increasing microbial biomass carbon and nitrogen content,and increasing soil carbon and nitrogen retention,which is conducive to improving soil quality.