长期不同氮、 磷用量对冬小麦籽粒锌含量的影响

【目的】小麦是我国西北地区主要的粮食作物,主要种植在低锌的石灰性土壤上,其籽粒锌含量普遍较低,难以满足人们的锌营养需求,因此提高冬小麦籽粒中的锌含量对保证人体健康具有非常重要的意义。氮素、 磷素供应不足或过量会影响冬小麦对锌的吸收与利用,本文基于黄土高原南部9年的长期定位试验,研究了长期不同氮、 磷肥用量对旱地冬小麦籽粒锌含量的影响及籽粒锌含量与氮、 磷吸收与分配的关系,以期为有效调控冬小麦籽粒锌营养品质和优化旱地冬小麦氮、 磷肥管理提供理论依据和切实可行的措施。【方法】田间定位试验开始于2004年10月,位于陕西杨凌西北农林科技大学农作一站。采用单因素完全随机区组设计,重复4次。供试小麦品种为小偃22,整个生育期不灌水。试验一为小麦施氮量试验,在施磷量为P2O5100 kg/hm2的基础上,设置0、 80、 160、 240、 320 kg/hm2 5个氮肥(N)水平;试验二为小麦施磷量试验,在施氮量为N 160 kg/hm2的基础上,设置P2O5 0、 50、 100、 150、 200 kg/hm2 5个磷肥水平。分别于2011～2013年连续两年进行田间取样,测定小麦籽粒产量及其构成因素,籽粒、 茎叶和颖壳中的氮、 磷、 锌含量,计算小麦地上部的氮、 磷、 锌吸收量。【结果】小麦施氮量试验表明,氮肥用量不超过N 320 kg/hm2时,小麦籽粒锌含量和地上部锌吸收量与施氮量呈极显著的正相关关系,施氮量每增加N 100 kg/hm2,籽粒锌含量平均提高4.0 mg/kg,地上部锌吸收量平均提高36.4 g/hm2;籽粒中的锌含量与氮含量之间、 地上部的锌吸收量与氮吸收量之间也均呈极显著的正相关关系,籽粒氮含量每增加1 g/kg,籽粒锌含量平均提高2.0 mg/kg,地上部氮吸收量每增加100 kg/hm2,其锌吸收量平均提高142.9 g/hm2。小麦施磷量的试验结果表明,施磷量不超过200 kg/hm2时,籽粒锌含量与施磷量呈极显著的负相关关系,施磷量每增加P2O5 100 kg/hm2,籽粒锌含量平均下降9.2 mg/kg;籽粒锌含量与磷含量也呈极显著的负相关关系,籽粒磷含量每增加1 g/kg,籽粒锌含量平均降低24.0 mg/kg;地上部锌吸收量与施磷量、 地上部磷吸收量之间均没有显著相关关系。【结论】综合考虑冬小麦籽粒产量和籽粒锌含量,建议这一地区冬小麦的施氮量和施磷量分别控制在N 160～240 kg/hm2和P2O5 50～100 kg/hm2。

Effects of long-term N and P fertilization with different rates on Zn concentration in grain of winter wheat

【Objectives】Wheat is one of the staple food crops in northwestern China,and mainly grown in calcareous soil with low available Zn, and grain Zn concentration is consequently low and hardly meets with the nutritional demands of Zn from local people. Therefore, improving wheat grain zinc concentration is of great significance for human health.N and P applications influence the uptake and utilization of Zn by winter wheat. Based on a long-term (2004-2013), a two-year study was conducted during 2011-2013 to investigate the effects of long-term different N and P fertilization rates on Zn concentration of winter wheat grain to lay a theoretical foundation for effective regulation of grain zinc nutritional quality of winter wheat, and propose practical measures for optimizing nitrogen, phosphorus fertilizer management in winter wheat production. 【Methods】 The long -term field experiment is located in the experiment station of the Northwest AF University, Yangling, Shaanxi Province. The experiments were arranged in completely randomized block design with four replications. The local winter wheat cultivar of Xiaoyan22 was used as test crop. The experiment of long-term different N fertilization rates, is compossed of five N rates of 0, 80, 160, 240 and 320 kg/ha, and the experiment of long-term P fertilization is composed of five P application (P2O5) rates of 0, 50, 100, 150 and 200 kg/ha. Winter wheat samples were collected in 2011-2013 years to test grain yield and its component factors, N, P and Zn concentrations of grain, straw and glume, and to calculate N, P and Zn contents in the aerial plant part. 【Results】Both the grain Zn concentration and Zn uptake in the aerial plant part are positively correlated (P0.01) with the N application rate, when the rate is less than 320 kg/ha. By adding each 100 kg/ha N, the grain Zn concentration is increased by 4.0 mg/kg, and the Zn uptake increased by 36.4 g/ha. There is positively correlation (P0.01) between the grain N concentration and N in the aerial plant part. Each increase N 1 g/kg grain of leads to by 2.0 mg/kg of increase in Zn. Each increaseof 100 kg/ha N uptake in the aerial plant part leads to its Zn increase by 142.9 g/ha. However, when the P application rate is less than 200 kg/ha, the grain Zn concentration is observed to be negatively (P0.01) correlated with the P application rate and the grain P concentration, with each 100 kg/ha P application rate increase, the grain Zn concentration is found decreased by 9.2 mg/kg, and with each 1 g/kg grain P concentration increase, the grain Zn concentration is decreased by 24 mg/kg. The Zn uptake in the aerial plant part is not significantly correlated with the P application rate and P uptake in the aerial plant part. 【Conclusions】 For a better balance between the grain yield and grain zinc concentration, application rates of N and P are suggested to be controlled respectively within N 160-240 kg/ha and P2O5 50-100 kg/ha in this area.