追氮时期和施钾量对小麦氮素吸收运转的调控

【目的】氮肥追施时期和钾肥用量是影响小麦高产高效的重要因素,研究这两个营养元素的相交效应,为小麦的合理施肥提供理论依据。【方法】以强筋小麦‘济麦20’为供试品种,设置盆栽试验。同位素示踪技术进行研究。氮肥用15N标记,追施氮肥时期设返青期和拔节期两个施肥时期。施钾量设K2O 0(K0)、50(K1)、100 kg/hm2(K2)三个水平。于开花期采集全株样本,成熟期将植株分为籽粒和植株两部分,分析氮素含量,计算氮素吸收、分配以及氮素利用率。【结果】虽然追氮时期和施钾量互作对‘济麦20’籽粒蛋白质含量的影响未达到显著水平,但钾肥对小麦氮素吸收、运转及分配的影响因追氮时期不同而有所差异。不施钾(K0)返青期追氮处理,小麦植株氮素积累量、氮素转移量及贡献率均达到最高; 在施用K2O 50 kg/hm2处理(K1)下,拔节期追施氮肥能有效提高小麦开花期植株氮素积累量、成熟期植株和籽粒来自土壤的氮积累量、氮素转移量及贡献率,并最终显著提高产量。由此,提高了小麦氮素积累量、转移量、籽粒产量、氮肥生产效率及收获指数,在施用钾肥100 kg/hm2(K2)条件下,两个追氮时期处理均不利于‘济麦20’氮素利用效率及籽粒产量的提高。【结论】本试验条件下,在K2O 50 kg/hm2施用量、拔节期追施氮肥条件下更有利于强筋小麦‘济麦20’对氮素的吸收、利用和高产的形成。

Regulation of nitrogen topdressing stage and potassium fertilizer rate on absorption and translocation of nitrogen by wheat

【Objectives】 The objective is to explore the variation of nitrogen absorption, assimilation and distribution affected by nitrogen topdressing time and potassium fertilizer rate in winter wheat ‘Jimai 20’.【Methods】 Using high gluten wheat cultivar ‘Jimai 20’ as test meterial and the 15N tracer technique, a pot experiment was adopted with two nitrogen topdressing time (reviving and elongation stage) and three potassium basal application rate (K2O 0, 50 and 100 kg/hm2). Plant samples were collected at enthesis stage, and grain and plant samples at maturaity stage to determine the nitrogen contents, calculate the nitrogen absorption, utilization and distribution.【Results】 Although the interaction between N use stage and K rate had no significant effect on grain protein content of ‘Jimai 20’, the effects of K rate on nitrogen absorption, assimilation and distribution varied with N use stage. The nitrogen accumulation amount, translocation amount and contribution proportion of wheat all reached the maxima on the condition of K0 and nitrogen applied at reviving stage. Under K2O rate of 50 kg/hm2, nitrogen applied at elongation stage could effectively improve the nitrogen accumulation amount at the anthesis, nitrogen accumulation of plant and grain from soil, nitrogen translocation amount and contribution proportion of wheat at the maturity, and finally improve the grain yield significantly. The interaction between the nitrogen topdressing stage and potassium fertilizer rate has no significant effect on the grain protein content of Jimai 20. There are differences in effects of potassium fertilizer on the nitrogen absorption, assimilation and distribution among different nitrogen topdressing stages. Under the condition of nitrogen applied at the green-turning stage and without potassium fertilizer (K0), the nitrogen accumulation amount, nitrogen translocation amount and contribution proportion of wheat all reach the maxima. While under the condition of nitrogen applied at the elongation stage, proper potassium application rate (K1) could increase the nitrogen accumulation amount, nitrogen translocation amount, grain yield, nitrogen productive efficiency and nitrogen recovery index respectively. However, the excessive potassium fertilizer (K2) is not benefical to the improvement of the nitrogen use efficiency and grain yield. 【Conclusions】 It is beneficial to the nitrogen absorption, nitrogen utilization and formation of high yield for wheat(Jimai 20) under the condition of K2O rate of 50 kg/hm2 and nitrogen applied at the elongation stage.