Study On The Effects Of Different Returning Methods Of Banana Straw On Soil Microflora And Nutrients

During the banana harvest period,many straws are directly discarded in the banana garden,which was not properly utilized and resulting in a waste of available resources and a negative impact on soil health.In this study,three experiments were set up: the effects of different returning methods of banana straws on plant growth and soil nutrients were explored by field experiment;the microflora characteristics of banana straw under different returning modes were analyzed by pot experiment.Field culture experiments were carried out to investigate the decomposition characteristics of banana straw and the change process of soil microbial flora nutrients under different returning modes.Four treatments were set in the field experiment,which were: Banana straw mulched and returned(T1);Banana straw buried deep and returned to the field(T2);Banana straw buried deep and returned to the field with 10% less fertilizer application added(T3);No straw returned(CK).The results showed that soil nutrient content of T2 treatment was significantly higher than that of other treatments after 20 days after banana straw returned;Besides,banana yield and fruit quality were also significant increased in T2 treatment.Three treatments were set up in the pot experiment: F: Banana straw mulched;T:Banana straw deep buried;CK: No straw returned.The results showed that compared with CK treatments,relative abundance of Basidiomycota in T and F treatments were increased by 1.3% and 2.8%,respectively.Relative abundance of Actinobacteria were increased by1.9% and 3.2%,respectively.The bacterial community richness(Chao1)and diversity(Shannon)among all treatments were T>F>CK,and there were no significant difference in the fungal community.The results of microbial community structure analysis showed that there were significant differences among the treatments.Number of OTUs shared in T and F treatment was significantly higher than that shared in T and CK,and number of OTUs differed between T and F was significantly lower than that of CK.Correlation between Aspergillus and Ramlibacter and the other OTUs were increased in T treatment.,the metabolic of cofactors and vitamins were significantly higher than that in F and CK treatments.Three treatments were set up in the field culture experiment,BR: Banana straw mulched;BDR: Banana straw deep buried and returned;CK: No straw returned.The results showed 20 days after returned,the banana straw decomposition reached the peak value.The dry matter,N,P and K contents of soil in BDR treatment were significantly lower than those of BR treatment during 10-50 days after returned.The soil nutrient content and enzyme activity in BDR treatment were significantly higher than those in other treatments after 20 days.There were significant differences in bacterial community structure among different treatments.The fungal community structure of BDR treatment was significantly different from that of BR and CK treatment.The variation trend of relative abundance of dominant bacteria in BR and CK treatment was similar while significantly different from BDR treatment.The relative abundance of Penicillium and Chaetomium was significantly increased in BDR treatment during 20-30 days after straw returned.In addition,relative abundances of Penicillium,Clonostachys,Talaromyces and Naumovozyma were significantly positively correlated with the dry matter,N,P and K contents of banana straw;the richness of soil microbial community and Penicillium might be the main factor in promoting the banana straw decomposition and soil nutrient content improvement.