稻作水炭运筹下氮肥吸收转运与分配的15N示踪分析

15N Tracer-based Analysis of Effects of Water and Biochar Management on Nitrogen Absorption,Transport and Distribution in Rice

为揭示水炭运筹管理模式下水稻对不同阶段施用氮肥的吸收利用情况,采用田间小区试验与微区结合的方法,应用15 N示踪技术分别标记施用的基肥、蘖肥和穗肥,以常规淹灌作为对比,研究两种灌溉模式不同水炭运筹下水稻对基肥、蘖肥、穗肥的吸收利用、积累和转运,以及水稻成熟期不同阶段施用的氮肥在植株各器官的分配情况。试验结果表明:合理的水炭运筹能够显著提高水稻成熟期地上部的氮素总积累量、氮肥吸收利用率和产量;不同水炭运筹下肥料对氮素总积累量的贡献率为17.81%~20.60%,两种灌溉模式之间的差异不显著(P>0.05);水稻对基肥、蘖肥和穗肥的吸收利用率分别为15.55%~23.31%、31.68%~44.91%、48.82%~71.18%,施加适量的生物炭能够显著提高基肥、蘖肥和穗肥的吸收利用率,浅湿干灌溉模式下水稻植株除对基肥的吸收利用率较低外,对蘖肥和穗肥的吸收利用率均优于常规淹灌;水稻蘖肥和穗肥吸收利用率与肥料总氮素吸收利用率呈极显著正相关(P<0.01),基肥、蘖肥和穗肥氮素转运对籽粒的贡献率与相应的吸收利用率呈极显著正相关(P<0.01)。合理的水炭运筹能够提高肥料氮素转运对籽粒的贡献率和氮肥吸收利用率,降低氮肥在土壤中的残留。

In order to reveal the uptake and utilization of nitrogen fertilizer at different stages in rice under water and biochar management,the method of combining field plot experiment with micro-area was used,and the 15 N tracer technique was used to mark the application of basal fertilizer,tiller fertilizer and panicle fertilizer respectively.Taking conventional flooding irrigation as a comparison,the uptake,utilization,accumulation and transportation of basal,tiller and panicle fertilizer in rice under different water and biochar managements and the distribution of nitrogen fertilizer applied at different stages of rice maturity in different organs under two different irrigation modes were studied.The results showed that reasonable water and biochar management could significantly increase the total nitrogen accumulation,nitrogen uptake and utilization efficiency and yield of aboveground parts of rice at maturity stage.The contribution rate of fertilizer to total nitrogen accumulation under different water and biochar managements was about 17.81%~20.60%.There was no significant difference between the two irrigation modes(P>0.05).The uptake and utilization rates of basal fertilizer,tiller fertilizer and panicle fertilizer in rice were 15.55%~23.31%,31.68%~44.91%,48.82%~71.18%,respectively.The application of appropriate amount of biochar could significantly improve the uptake and utilization rates of basal tiller,tiller and panicle fertilizer.The uptake and utilization rates of tiller fertilizer and panicle fertilizer under dry-wet-shallow irrigation mode were better than those under conventional flooding irrigation except basal fertilizer.The uptake and utilization rates of tillering and panicle fertilizers were positively correlated with the total nitrogen uptake and utilization rates of fertilizers(P<0.01),and the contribution rate of nitrogen transport of basal,tiller and panicle fertilizer to grain was positively correlated with the corresponding uptake and utilization rates(P<0.01).Reasonable water and biochar management can improve the contribution rate of nitrogen transport to grain and the utilization rate of nitrogen absorption,and reduce the residue of nitrogen fertilizer in soil.The results can provide theoretical basis and technical support for the application of water and biochar management model in paddy field in cold black soil region.