施钾对我国甘薯产量和土壤钾素平衡影响的Meta分析

Effects of potassium application on yield and potassium balance of sweet potato field in China:A meta-analysis

【目的】甘薯是喜钾作物,合理施用钾肥对甘薯生产至关重要。本研究整合已有的研究结果,定量分析施钾对我国甘薯产量和土壤钾素平衡的影响,为钾肥合理施用提供理论指导。【方法】数据来自2000—2020年公开发表的有关我国甘薯钾肥田间试验的论文,共采集到548组数据。利用Meta分析方法,定量分析我国甘薯施钾产量效应以及对不同因素的响应,并探究不同施钾量对甘薯钾素平衡的影响。【结果】与不施钾相比,施钾使我国甘薯产量显著增加18.0%。对照组产量水平显著影响甘薯施钾增产效果,随对照组产量的提高,施钾的增产效应逐渐降低;在低和中对照组产量水平(≤25 t/hm^(2)和25~35 t/hm^(2))下,最优施钾量分别为225~300和300~375 kg/hm^(2),而在高对照组产量水平(>35 t/hm^(2))下,不同施钾量之间的增产效应没有明显差异。土壤条件是影响甘薯施钾增产效应的重要因素,土壤有机质、全氮、有效磷和速效钾对施钾增产效应具有极显著影响,其中,在土壤有机质含量>20 g/kg、全氮含量>1 g/kg、有效磷含量10~20 mg/kg和速效钾含量≤50 mg/kg时,施钾的增产效应最明显;在不同土壤速效钾(AK)含量下,施钾的增产效应随着施钾量的增加均呈先增加后降低的趋势,当AK≤50 mg/kg时,施钾量为225~300 kg/hm^(2)增产效应最好,当AK在50~100 mg/kg时,施钾量为300~375 kg/hm^(2)有更好的增产效应,当AK>100 mg/kg,施钾效果不稳定。对于钾素平衡来说,甘薯秸秆不还田时,施钾量>225 kg/hm^(2)可以维持土壤钾素平衡;当秸秆还田时,施钾量>75 kg/hm^(2)能更好维持土壤钾素平衡。【结论】施钾对提升我国甘薯产量有重要作用,施钾效果与土壤有机质、全氮、有效磷和速效钾含量密切相关,而施钾水平也影响土壤钾素平衡。因此,在甘薯生产中,应综合考虑土壤肥力因素,确定适宜的施钾方案,以促进甘薯增产并改善土壤钾素平衡。

【Objectives】Sweet potato is a potassium-loving crop,and its production relies heavily on K fertilizer application.This study was designed to integrate existing research results and quantitatively analyze the effects of K application on sweet potato yield and K balance.We aim to clarify sweet potato yield's response characteristics to K application under different factors,thus,providing theoretical guidance for K application.【Methods】This study collected literature on the effect of K application on sweet potato yield published in China from 2000 to 2020.In total,548 datasets were collected and subjected to a meta-analysis to analyze the effect of K application on yield increase and the influence of different K application rates on K balance.【Results】K application increased sweet potato yield by 18.0%compared with no K application(P<0.05).The increase on sweet potato yield though K fertilizer application was significantly(P<0.001)affected by yield level of the control group.The higher the yield recorded in the control plot,the lower the sweet potato yield's response to K fertilizer application.At low and medium yield levels of the control group(≤25 t/hm^(2) and 25−35 t/hm^(2)),the optimal K application rate was 225−300 kg/hm^(2) and 300−375 kg/hm^(2),respectively.At high yield levels>35 t/hm^(2)),there was no significant(P>0.05)yield response to different K application.Soil organic matter(SOM),total N,available P,and available K(P<0.001)affected the yield increase effect of difference K application.The effect of K application on sweet potato yield was higher when SOM>20 g/kg,total N>1 g/kg,available P=10−20 mg/kg and available K(AK)≤50 mg/kg.The effect of K application on sweet potato yield showed a parabola trend with an increase in the K quantity applied.The appropriate K application rate for maximum yield was 225−300 kg/hm^(2) when AK≤50 mg/kg,300−375 kg/hm^(2) when AK between 50 and 100 mg/kg,and not necessary when AK>100 mg/kg.The required K application rate was>225 kg/hm^(2) to maintain soil K balance when sweet potato straw was not returned to the field,and that was>75 kg/hm^(2) when straw was returned to the field.【Conclusions】In China,the K application enhances sweet potato yields.K application has a strong relationship with SOM,total N,available P,and available K.Maintaining soil K equilibrium also necessitates potassium application.Specific soil conditions should dictate the K treatment regime for sweet potato production.