为明确长江中下游稻油轮作区不同秸秆还田方式对土壤养分和作物产量的影响。试验于2016—2023年在江西省九江市的典型稻油轮作区进行了为期7年的秸秆还田定位试验，设置稻油2季秸秆均不还田(CK)、仅油菜季水稻秸杆还田(T1)、仅水稻季油菜秸秆还田(T2)及稻油两季秸秆均还田(T3) 4个处理，分别测定了2022年水稻季及2022—2023年油菜季各作物关键生育期地上部和地下部干物质含量、成熟期作物产量和土壤养分含量。结果表明，与不还田相比，秸秆还田显著增加土壤pH、有机质及N、P、K等养分含量。以T3处理较为突出，其在水稻季和油菜季分别显著提高土壤pH值9.7%和12.9%、碱解氮32.9%和25.5%、有效磷33.5%和24.3%、速效钾56.3%和58.6%、全氮22.9%和33.0%、有机质26.6%和50.8% (P < 0.05)。水稻干物质积累随生育期延长呈先增后降趋势，T2处理对干物质积累起到显著促进作用，而T3处理对水稻生育前期干物质积累产生一定抑制。与不还田相比，秸秆还田提高了水稻籽粒产量，以T2增幅最大，为13.9% (P<0.05)。油菜干物质积累随生育期延长持续增加，以T2处理对油菜干物质积累促进最显著。与不还田相比，T2处理油菜籽粒产量增幅最大，为20.0% (P < 0.05)。相关分析表明，速效钾与水稻结实率呈极显著正相关(r = 0.84**, P < 0.01)，全氮和速效钾分别与油菜单株分枝角果数(r = 0.705*, r = 0.623*, P < 0.05)、油菜籽粒产量(r = 0.623*, r = 0.690*, P < 0.05)呈显著正相关，表明秸秆还田提高了土壤全氮和速效钾含量可能是导致作物产量提高的主要原因。综合土壤养分、干物质积累及作物产量，水稻季油菜秸秆还田表现最佳，可在长江中下游区域进行推广与应用。
A seven-year field study from 2016 to 2023 was conducted on typical paddy soil in Jiujing city, Jiangxi province, to evaluate the effects of different straw returning methods on soil nutrients and crop yield in a rice-rapeseed rotation system in the middle-lower Yangtze Plain of China. The study included four treatments: no straw returning (CK), rice straw returning during the rapeseed season (T1), rapeseed straw returning during the rice season (T2), and straw returning during both the rape and rice seasons (T3). Measurements of shoot and root dry matter, crop yield, and soil nutrient content were taken at key growth stages during the 2022 rice season and the 2022–2023 rape season. The results indicated that, compared with CK, straw returning significantly increased soil pH and the contents of organic matter, and N, P, K, and other nutrients. The T3 treatment was particularly effective, significantly increasing soil pH by 9.7% and 12.9%, alkali-nitrogen by 32.9% and 25.5%, available phosphorus by 33.5% and 24.3%, available potassium by 56.3% and 58.6%, total nitrogen by 22.9% and 33.0%, and organic matter by 26.6% and 50.8% (P < 0.05) in the rice and rape seasons, respectively. Dry matter accumulation in rice initially increased and then decreased as the growth period extended. The T2 treatment significantly promoted dry matter accumulation, whereas the T3 treatment inhibited it during the early stages of rice growth. Compared with straw removal, straw returning increased rice grain yield, with the largest increase of 13.9% observed in the T2 treatment (P < 0.05). In rapeseed, dry matter accumulation continued to increase with the growth period, and the T2 treatment most significantly promoted this accumulation. Compared with CK, the T2 treatment resulted in the largest increase in rapeseed grain yield, by 20.0% (P < 0.05). Correlation analysis showed that available potassium was significantly positively correlated with the rice seed setting rate (r = 0.84**, P < 0.01). Total nitrogen and available potassium were significantly positively correlated with the number of pods per plant (r = 0.705*, r = 0.623*, P < 0.05) and rape yield (r = 0.623*, r = 0.690*, P < 0.05). These findings suggest that the major reason for the yield increase may be the elevated content of soil total nitrogen and available potassium due to straw returning. Considering soil nutrients, dry matter accumulation, and crop yield, rape straw returning during the rice season (T2) performed best and could be recommended for promotion and application in the middle and lower reaches of the Yangtze River.