施肥水平对不同氮效率水稻氮素利用特征及产量的影响

摘要

[Objective] The relationship of grain yield and nitrogen (N) utilization characteristics in rice cultivars with different N use efficiencies (NUE) was studied under different fertilizer levels.This study will provide reference data for the cultivation of high-NUE rice cultivars and rice breeding.[Method] For this purpose,two rice cultivars differing in NUE were chosen for this study,one with high-NUE (Dexiang 4103) and the other with low-NUE (Yixiang 3724).Fertilizer was applied at three levels,including low (75 kg N·hm2,37.5 kg P2O5·hm-2,75 kg K2O·hm-2,N1P1K1),medium (150 kg N·hm2,75 kg P2O5·hm-2,150 kg K2O·hm-2,N2P2K2),and high rates (225 kg N·hm-2,112.5 kg P2O5·hm-2,225 kg K2O·hm-2,N3P3K3).A no-N treatment was included for each level as the control.The effect of fertilizer levels on grain yield and N utilization characteristics in rice cultivars with different NUE,and its absorption,translocation and distribution of N from heading and maturity stage were studied.[Result] The results showed that rice cultivars with different NUE and fertilizer levels significantly affected accumulation,translocation and distribution of N at main growth stages and each growing stage,N utilization characteristics and grain yield.Rice cultivars exhibited markedly stronger effects on N recovery efficiency,1 000-grain weight,and total spikelets number,compared to fertilizer application levels.An opposite trend was observed in N accumulation at different growth stages,N translocation in leaves and stem-sheaths at grain filling stage,and grain yield.Compared with N1P1K1,N2P2K2 promoted N accumulation at main growth stages and each growing stage,increased N harvest index,and facilitated N translocation in vegetative organs at grain filling stage,ultimately improved grain yield and NUE in both rice cultivars.The N2P2K2 treatment produced higher yield than other fertilizer treatments of the same rice cultivars and thus was regarded as the optimal NPK fertilizer application.Applying the N3P3K3 treatment resulted in a higher N retention in leaves and stem-sheaths at grain filling stage and a lower N translocation conversion rate of vegetative organs,thereby reduced the grain yield and NUE.The results also showed that total spikelets number,high seed setting rate,N accumulation at main growth stages,and N harvest index,more than those of low-NUE rice cultivar.However,1000-grain weight was not unique characteristics of rice cultivar with high-NUE.In addition,compared with low-NUE,the high-NUE rice cultivar was more beneficial to N translocation and redistribution from leaves and stem-sheaths to panicle at grain filling stage,and then improved grain yield and NUE,especially,N transportation efficiency of stem-sheath in high-NUE rice cultivars had a significant positive correlation (r=0.699*-0.743*) with different indexes of N physiological efficiency,N recovery efficiency,and N agronomic efficiency,and which is the important reason for high-NUE rice cultivar further to increase yield and NUE.The N transportation efficiency of stem-sheath might be a candidate indicator for high yield and high-NUE in different varieties of rice.To improve N transportation efficiency of stem-sheath in high NUE from heading to maturity stage,this is an important way to promote rice yield at the same time as increasing N use efficiency.[Conclusion] Compared to low NUE,the results suggest that the high-NUE is more beneficial to N translocation and redistribution from stem-sheath to panicle,high total spikelet number and seed setting rate at grain filling stage,which is the key factor behind yield gap.High-NUE and suitable N2P2K2 combined application was considered to be optimum under the experimental conditions.Correlation analysis indicated that the increase of N accumulation,promote N translocation of leaves and stem-sheath during the period from heading to maturity,especially improve the N transportation efficiency of stem-sheath is helpful to the high-yield and high-NUE in rice.%[目的]研究不同施肥水平下不同氮效率杂交水稻产量差异与氮素吸收和利用的关系,以期为水稻品种改良和高产高效栽培技术提供依据.[方法]以氮高效品种(德香41 03)和氮低效品种(宜香3724)为材料,通过设置低肥(75 kg N·hm-2,37.5 kg P2O5·hm-2,75 kg K2O·hm-2,记为N1P1K1)、中肥(150 kg N·hm-2,75 kg P2O·hm-2,150 kg K2O·hm-2,记为N2P2K2)、高肥(225 kg N·hm-2,112.5 kg P2O5·hm-2,225 kg K2O·hm-2,记为N3P3K3)3种施肥水平,并在各施肥水平下均增设一不施氮处理,研究其对不同氮效率水稻产量和氮素利用效率的影响及其结实期氮素吸收、转运和分配特性.[结果]品种与施肥水平对杂交稻主要生育时期及各生育阶段氮素的累积、转运、分配,以及氮素利用特征和产量均存在显著影响;品种对氮肥回收利用率、千粒重,以及总颖花数的影响均不同程度的高于施肥水平的调控效应;施肥水平对主要生育时期及各生育阶段氮素的累积,结实期叶片和茎鞘氮的运转,以及产量调控作用显著.N2P2K2相对于N1P1K1处理能促进不同氮效率水稻主要生育时期及各生育阶段氮素的累积,提高氮收获指数,促进结实期叶片和茎鞘中氮素的运转,进而显著提高稻谷产量及氮肥利用效率,且N2P2K2均显著高于同品种下其他的肥料施用处理,为本试验最佳的氮磷钾肥施用模式;N,P3K3处理易造成结实期叶片及茎鞘中氮滞留量增加,氮转运贡献率显著降低,导致产量及氮肥利用效率显著降低.氮高效品种具有总颖花数、结实率高的特征,其主要生育时期氮素累积量,氮素干物质生产效率,氮素稻谷生产效率及氮素收获指数等均显著高于氮低效品种,但千粒重并不是氮高效品种所独有的特征;此外,氮高效品种结实期更有利于叶片与茎鞘氮素的运转及穗部氮素的累积,尤其氮高效品种具有较高的茎鞘氮素转运率,其与氮肥生理利用率、回收利用率及农艺利用率均存在显著正相关性(产0.699*-0.743*),是导致不同氮效率品种氮肥利用效率、产量差异的重要因子,可作为氮效率及品种鉴选的评价指标,也可以以进一步提高抽穗至成熟期氮高效水稻品种茎鞘氮素运转率,作为实现水稻高产与氮高效利用协调统一的另一重要途径.[结论]本试验条件下,氮高效品种具备的结实期茎鞘高氮素转运、高总颖花数及结实率是优于氮低效品种而形成产量差异的主要因素,N2P2K2为氮高效品种配套的最优氮磷钾肥施用模式.提高抽穗期至成熟期氮累积量,促进叶片与茎鞘氮运转量,尤其应提高茎鞘氮素运转率,可实现高产与氮高效利用的同步提高.