基于小麦产量与籽粒锰含量的磷肥优化管理

【目的】通过研究我国北方八省区不同土壤有效磷水平和施磷量条件下小麦产量和籽粒锰含量的变化规律,为提高小麦产量、调控小麦锰营养水平和保障粮食安全生产提供依据。【方法】于2018—2019年在我国北方山西、陕西、甘肃、宁夏、青海、新疆、内蒙古、黑龙江8个省区的34个地点布置田间试验,设置农户施肥、监控施肥和监控无磷3个处理,研究北方八省区小麦的产量和籽粒锰含量及不同土壤有效磷水平下监控施磷及不施磷对小麦产量和籽粒锰含量的影响。【结果】在我国北方八省区,小麦产量平均为6 066 kg·hm^-2,籽粒锰含量平均为42 mg·kg^-1。籽粒锰含量<32 mg·kg^-1的试验点占8.8%,>44 mg·kg^-1的占36.8%,籽粒锰含量偏高的问题应引起注意。随土壤有效磷含量增加,小麦产量和籽粒锰含量均显著提高,有效磷含量20—30 mg·kg^-1时小麦产量最高,有效磷含量>40 mg·kg^-1时籽粒锰含量最高。监控施肥与农户施肥处理相比,其磷肥用量平均降低了45.4%,但两者产量分别为6 358和6 222 kg·hm^-2,籽粒锰含量分别为42.8和43.6 mg·kg^-1,无显著差异。不同土壤有效磷水平下,监控施肥处理的小麦产量均无显著降低;土壤有效磷<10 mg·kg^-1时,不施磷肥降低了小麦籽粒锰含量,也降低了产量,而监控施肥仅降低了籽粒锰含量;其他土壤有效磷水平下,监控施肥均不降低籽粒锰含量。土壤有效锰含量亦随土壤有效磷含量的提高而升高,小麦籽粒锰含量与土壤有效锰含量呈显著正相关。【结论】为实现小麦高产和适宜的籽粒锰含量,土壤有效磷应维持在20—30 mg·kg^-1;采用监控施肥技术科学优化施磷,不会降低小麦产量,但当土壤有效磷含量<10 mg·kg^-1,不施磷肥虽能降低小麦籽粒锰含量,但存在小麦减产的风险。

Optimal Management of Phosphorus Fertilization Based on the Yield and Grain Manganese Concentration of Wheat

【Objective】To keep the manganese (Mn) nutritional balance of wheat grains and ensure the safety, yield and quality in wheat production region of eight provinces in Northern China, the changes of concentration and accumulation of Mn in wheat grains and grains yield at different levels of soil available phosphorus (P) and different treatments of P fertilization were investigated. 【Method】During 2018-2019, 34-site field experiments were conducted with three P treatments, including farmers’ fertilizer application (FF), recommended fertilizer application based on soil nitrate and P test (RF), and recommended fertilizer application without P (RF-P). The wheat yield, the concentration of Mn in wheat grain were tested, and the effects of P fertilization on wheat yield and the Mn concentration of grain at different levels of soil available P were studied. 【Result】In wheat production region of eight provinces in Northern China, the average wheat yield was 6 066 kg·hm^-2, and the average concentration of Mn in grains was 42 mg·kg^-1. Those test sites with concentration of Mn in grains less than 32 mg·kg^-1 or higher than 44 mg·kg^-1, accounted for 8.8% and 36.8%, respectively, which suggested that the problem of high concentration of Mn in grains should be paid attention to. With the increase of soil available P, both wheat yield and concentration of Mn in grains increased significantly. The wheat yield reached to the highest when the available P was in the range of 20-30 mg·kg^-1, while the concentration of Mn in grains reached to the highest when the available P>40 mg·kg^-1. P fertilizer was reduced with an average of 45.4% under the RF treatment. However, the wheat yields of RF and FF were 6 358 and 6 222 kg·hm^-2, respectively, and the concentration of Mn in grains were 42.8 and 43.6 mg·kg^-1, respectively, which showed no significant difference. At different levels of soil available P, RF could maintain a high wheat yield. When soil available P<10 mg·kg^-1, RF-P reduced not only the concentration of Mn in grains, but also reduced the wheat yield, while RF only reduced the concentration of Mn in grains. RF did not reduce the concentration of Mn in grains under other levels of soil available P. In addition, the concentration of diethylene triamine pentaacetic acid-manganese (DTPA-Mn) in soil increased following the increasing of soil available P. Furthermore, the concentration of Mn in grains were positively correlated with the concentration of soil DTPA-Mn. 【Conclusion】In wheat production region of eight provinces in Northern China, the soil available P should be maintained in the range of 20-30 mg·kg^-1 to achieve high wheat yield and suitable concentration of Mn in grains. The use of RF technology would not reduce the wheat yield. RF-P reduced the concentration of Mn in grains when the soil available P<10 mg·kg^-1, but there was a risk of reducing the wheat yield.