不同灌溉和施肥模式对水稻产量、氮利用和稻田氮转化特征的影响

Effects of Different Irrigation and Nitrogen Application Regimes on the Yield, Nitrogen Utilization of Rice and Nitrogen Transformation in Paddy Soil

[目的]阐明常规淹灌和干湿交替灌溉下,不同施肥模式对水稻关键生育期氮吸收转运、氮素利用率和稻田氮转化特征的影响及其与水稻产量的关系,以期为绿色高效稻田水肥管理提供理论依据。[方法]2018—2019年连续进行2年,以杂交籼稻中浙优1号为供试材料,设常规淹灌(FI)、干湿交替(AWD)2种灌溉模式以及空白对照(N0)、常规施氮(PUN100)、减氮20%(PUN80)、缓控释复合肥减氮20%+生物炭(CRFN80-BC)和稳定性复合肥减氮20%+生物炭(SFN80-BC)5种施肥模式,对比分析了不同灌溉和施肥模式下水稻产量、氮吸收利用及稻田氮转化特征。[结果](1)与FI灌溉模式相比,AWD灌溉显著增加了各处理水稻产量(P<0.05),CRFN80-BC和SFN80-BC处理水稻产量分别达9721 kg·hm^(-2)、10056 kg·hm^(-2)(2018年)和9492 kg·hm^(-2)、9907 kg·hm^(-2)(2019年),且均显著高于PUN80和PUN100处理(P<0.05),这可能与水稻穗粒数、有效穗增加密切相关。(2)与N0、PUN100和PUN80处理相比,AWD灌溉显著提高了抽穗前CRFN80-BC和SFN80-BC处理水稻茎鞘和叶片氮累积量、抽穗至成熟期茎鞘和叶片氮转运量及其氮转运贡献率;同时,显著增加了成熟期0—30 cm剖面稻田可溶性总氮(dissloved total N,DTN)和NO3-含量,并有效降低稻田渗滤液中DTN、NH4+和NO3-质量浓度。(3)相关分析结果表明,水稻产量与营养生长期叶片和茎鞘氮累积量,抽穗后氮转运量和氮转运贡献率,成熟期水稻氮素利用率和稻田氮有效性显著正相关,表明适宜的水氮管理能协同促进氮素在水稻中的吸收和运转畅通,增加稻田氮素有效性,进而显著提高水稻产量和氮素利用率。[结论]综合2年水稻产量与氮素吸收利用、稻田氮素有效性特征,干湿交替灌溉下生物炭配施缓控释/稳定性复合肥能有效提高水稻高产群体构建、氮吸收转运和氮素利用效率,并降低稻田氮淋溶损失。

[Objective]in order to provide a theoretical basis for rational management of irrigation and nitrogen(N),the effects of the different water and nitrogen application models on the nitrogen absorption and translocation,and nitrogen use efficiency of indica hybrid rice,nitrogen transformation characteristic in paddy soil and their relationships with rice yield were studied.[Method]Using the indica hybrid rice Zhongzheyou 1 as experimental material,a two-factor experiment was conducted in 2018 and 2019,including two irrigation regimes(flood irrigation,FI;alternate wet and dry irrigation,AWD)and five nitrogen application types(zero nitrogen,N0;traditional nitrogen level,PUN100;80%of traditional nitrogen level,PUN80;80%of control-released nitrogen fertilizer plus biochar,CRFN80-BC;80%of stable compound nitrogen fertilizer plus biochar,SFN80-BC).The grain yield,nitrogen absorption and utilization of rice,and nitrogen transformation characteristic in paddy soil were measured.[Result](1)AWD significantly increased the rice yield in relative to that under FI conditions,and rice yields under CRFN80-BC and SFN80-BC treatments were significantly higher than that under PUN80 and even PUN100 treatments(P<0.05).Their values were 9721 kg·hm^(-2)and 10056 kg·hm^(-2) in 2018,and 9492 kg·hm^(-2) and 9907 kg·hm^(-2) in 2019,respectively,which was closely related to the increased rice spikelet or tillering number under the AWD condition.(2)Compared with N0,PUN100 and PUN80 treatments,AWD significantly improved the nitrogen accumulation of leaf and stem-sheath before the heading stage,nitrogen translocation and the contribution of nitrogen translocation to panicle from the heading to maturity stage under CRFN80-BC and SFN80-BC treatments.It also significantly increased the contents of the dissolved total nitrogen(DTN)and NO3-in 0-30 cm soil depths at the maturity stage,but greatly suppressed the concentrations of DTN,NH4+and NO3-in soil leachate.(3)Rice grain yield was significantly and positively correlated with the nitrogen accumulation of nutritional organs(e.g.leaf and stem-sheath),nitrogen translocation and their nitrogen contribution to panicle,and nitrogen use efficiency and soil nitrogen availability at the maturity stage.It indicated that the suitable water and nitrogen management could collaboratively improve the fluency of the nitrogen absorption-translocation in rice and nitrogen availability in paddy soil,which were beneficial for the improvement of rice yield and nitrogen use efficiency.[Conclusion]Given the results of grain yield,nitrogen utilization and nitrogen availability in rice paddy of the two years,it could be concluded that control-released/stable compound fertilizers combined with biochar could significantly increase the construction of high-yield rice population,rice nitrogen absorption and translocation,and nitrogen use efficiency under AWD irrigation condition,and also reduce the nitrogen leaching loss in paddy soil.