氮炭耦合对干热区土壤微生物和番茄产量品质的影响OA

[Objective]Dry-hot regions are characterized by high temperatures and limited water availability,which constrain crop productivity and soil health.Nitrogen fertilization and biochar application can improve soil health and crop growth,but their optimal combination remains unclear.Using tomato as a model crop,this paper studied the effects of different combinations of nitrogen fertilizer and biochar on soil properties,rhizosphere microbial communities,tomato yield and fruit quality.[Method]The experiment was conducted in a mulched drip-irrigated tomato field.There were four biochar application rates:0(B0),10(B10),20(B20)and 30(B30)t/hm2,each combined with four nitrogen fertilization rates:0(N0),150(N1),225(N2),and 300(N3)kg/hm2.The effects of different treatments on soil physicochemical properties,soil enzyme activities,and the community structure and diversity of bacteria and fungi in the rhizosphere,tomato yield and fruit quality were measured.[Result]①The combined application of nitrogen fertilizer and biochar significantly affected tomato yield and quality.Among all treatments,B30N2 showed the best overall performance,increasing tomato yield to 103.75 t/hm2 and lycopene content to 96.08 mg/kg,representing increases of 34.48%and 113.99%,respectively,compared with CK.②The combined application of biochar and nitrogen fertilizer altered bacterial community structure.It significantly increased bacterial richness and diversity but reduced fungal alpha diversity.B30N2 increased the Chao1,ACE,and Observed species indices by 30.73%,30.54%,and 30.63%,respectively,and increased the Shannon and Simpson indices by 15.23%and 0.90%,respectively,compared with CK.In contrast,B30N2 reduced fungal alpha-diversity indices by 31.30%,31.34%,31.26%,5.01%,and 3.18%,respectively,compared with CK.③Variance partitioning analysis indicated that soil physicochemical properties,enzyme activities,and microbial factors jointly contributed to variation in tomato yield and quality,with physicochemical properties and enzyme activities being the dominant explanatory factors,accounting for 37.7%of the total variation.④Redundancy analysis showed that soil ammonium nitrogen and Basidiomycota accounted for 22.6%and 16.8%of the variation,respectively.[Conclusion]The combined application of nitrogen fertilizer and biochar improved the rhizosphere environment and enhanced tomato yield and fruit quality in the dry-hot valley region.The B30N2 treatment showed the best overall performance,promoting bacterial richness and diversity while reducing fungal alpha diversity.These findings suggest that B30N2 is a promising nitrogen-biochar management strategy for improving tomato productivity and regulating rhizosphere microbial communities in dry-hot regions.