北方麦区小麦产量与籽粒氮磷钾含量对监控施钾和土壤速效钾的响应

Response of Wheat Yield and Grain Nitrogen,Phosphorus and Potassium Concentrations to Test-Integrated Potassium Application and Soil Available Potassium in Northern Wheat Production Regions of China

【目的】分析我国北方麦区监控施钾下小麦产量与养分吸收分配变化与土壤速效钾的关系,为节约钾资源,实现小麦丰产优质可持续发展提供理论依据。【方法】于2018—2020年在我国北方麦区43个地点进行田间试验,研究不同土壤速效钾水平下监控施钾对小麦产量、产量构成、籽粒氮磷钾含量及养分吸收分配的影响。【结果】北方麦区农户小麦施钾不足和过量问题同时存在。小麦产量随土壤速效钾含量升高显著增加,在土壤速效钾含量150—180 mg·kg^(-1)时,小麦产量达到最高,为6340 kg·hm^(-2)。土壤速效钾过高并不能持续提高小麦产量,当土壤速效钾含量>180 mg·kg^(-1)时,小麦产量显著降低,平均为5409 kg·hm^(-2)。与农户施肥相比,在土壤速效钾含量<90、90—120、120—150和>180 mg·kg^(-1)时采用监控施肥技术增加了钾肥用量,在速效钾含量150—180 mg·kg^(-1)时减少了钾肥用量,各土壤速效钾水平下采用监控施肥技术施用钾肥均提高了小麦产量,且在速效钾含量<90和>180 mg·kg^(-1)时显著增产。土壤有效磷含量>30 mg·kg^(-1)时,土壤速效钾含量120—150或>180 mg·kg^(-1)时,不施钾肥小麦产量有降低的趋势。土壤速效钾含量升高显著提高了小麦籽粒氮含量,农户施肥和监控施肥处理的籽粒氮磷钾含量无显著变化,速效钾含量>180 mg·kg^(-1)时不施钾肥的小麦籽粒磷钾含量显著降低。速效钾含量>150mg·kg^(-1)时,监控施肥的钾肥偏生产力与钾肥吸收效率较农户施肥显著提高。【结论】在北方麦区,土壤速效钾含量150—180mg·kg^(-1)时,合理施肥可使小麦产量达较高水平,但当土壤有效磷较高,超过30 mg·kg^(-1)时,不施钾肥小麦有减产风险。应根据土壤速效磷钾和小麦产量水平监控施肥,合理确定钾肥用量,实现北方麦区小麦丰产高效生产。

【Objective】It is of great importance to clarify the relationships of changes in wheat grain yield and grain nutrients absorption and distribution to test-integrated potassium(K)fertilizer application and soil available K,for the purpose of high yield,high quality,green production of wheat and saving K resources in northern wheat production region of China.【Method】In this research,a 43-site field experiment was conducted in northern wheat region of China from 2018 to 2020,to investigate effects of test-integrated K application on grain yield,yield components,grain nitrogen(N),phosphorus(P),and K concentrations,and nutrients uptake and absorption of wheat at different soil available K levels.【Result】The insufficient and excessive K application occurred widely in northern wheat production region.With the increase of soil available K level,the wheat yield increased significantly and reached the maximum value of 6340 kg·hm^(-2) at the available K of 150-180 mg·kg^(-1).Excessive soil available K was not able to further increase the grain yield,and it significantly decreased to 5409 kg·hm^(-2) when soil available K was higher than 180 mg·kg^(-1).Compared with the farmers’fertilizer application rate(FF),the recommended K fertilizer rate(RF)by the test-integrated fertilizer application was decreased at the soil available K level of 150-180 mg·kg^(-1),and increased at the other levels.The RF was found to have increased the wheat yield in comparison to FF with the yield increase significant at soil available K lower than 90 mg·kg^(-1) and higher than 180 mg·kg^(-1).When the soil available P was higher than 30 mg·kg^(-1) and the soil available K was at 120-150 mg·kg^(-1) or higher than 180 mg·kg^(-1),the wheat yield of no K application(RF-K)showed a tendency to decrease in comparison to RF.With the increase of soil available K level,wheat grain N concentration increased significantly,but no significant difference was observed in the grain N,P,and K concentrations between FF and RF.Compared with RF,the grain N,P,and K concentrations under RF-K significantly decreased when the soil available K was higher than 180 mg·kg^(-1).When the soil available K was higher than 180 mg·kg^(-1),the K partial factor productivity and K fertilizer uptake efficiency under RF were significantly higher than those under FF.【Conclusion】The reasonable fertilization could get high wheat yield when the soil available K was at 150-180 mg·kg^(-1),but the wheat yield might be reduced without K fertilization when the soil available P was higher than 30 mg·kg^(-1).Therefore,the K fertilizer rate should be recommended based on the target wheat yield and soil available P and K levels,for the purpose of yield stabilization,quality improvement,and efficiency increase in the northern wheat production regions of China.