干湿循环老化生物炭对土壤理化性质及水稻产量的影响OA

[Objective]Biochar can improve soil quality and crop productivity,but its environmental aging,including repeated dry-wet cycles,may alter its properties and efficacy.This study experimentally investigated how dry-wet cycle-induced biochar aging affects its ability to regulate paddy soil properties and rice growth.[Method]The experiment was conducted in pots from 2023 to 2024 using rice straw biochar.It consisted of four treatments:biochar not undergoing to dry-wet cycling(CK),biochar undergoing three dry-wet cycles(C3),six dry-wet cycles(C6),and ten dry-wet cycles(C10).Changes in soil pH,soil organic carbon(SOC),dissolved organic carbon(DOC),soil nitrogen forms,redox potential(Eh),rice yield,and irrigation water-use efficiency were measured under each treatment.[Result]①Biochar undergoing six dry-wet cycles(C6)produced the greatest increases in soil pH,SOC,and DOC contents and optimized soil redox conditions during key rice growth stages.②C6 significantly increased soil ammonium nitrogen content at the tillering stage and promoted nitrate nitrogen accumulation at the jointing-booting stage,thereby improving soil nitrogen retention and supply.③Compared with CK,C6 achieved the highest grain yield and irrigation water-use efficiency,increasing grain yield in 2023 and 2024 by 11.2%and 14.7%,respectively,while reducing irrigation water use by 4.9%and 3.9%,respectively.[Conclusion]Subjecting biochar to undergo six dry-wet cycles enhanced its capacity to improve paddy soil properties by optimizing soil pH,carbon and nitrogen balance,and redox condition,thereby creating a favorable condition for rice growth and simultaneously increasing grain yield and irrigation water-use efficiency.