钾肥用量对大蒜—棉花套作体系产量和土壤钾素有效性的影响

为明确钾肥用量对大蒜—棉花套作体系产量和土壤钾素有效性的影响,确定2季作物最佳钾肥施用量,为黄淮海平原大蒜—棉花套作地区合理施用钾肥提供依据。于2013—2016年在山东省金乡县进行连续4年7季的田间定位试验,试验设CK(0kg/hm~2),K90(90kg/hm~2),K180(180kg/hm~2),K270(270kg/hm~2)4个不同施钾量(K_2O)处理。大蒜和棉花单季施钾量相同(K_2O 0,90,180,270kg/hm~2),各处理氮肥和磷肥施用量一致。分析不同施钾量对大蒜、棉花产量及产量构成的影响,明确不同施钾量对棉花收获后0—100cm土层速效钾含量和0—20cm土壤钾素形态的影响。结果表明:与CK相比,不同施钾处理棉花显著增产18.4%~72.7%,皮棉产量随施钾量的增加而增加,但K270与K180处理皮棉产量和经济效益差异不显著;施钾显著提高了棉花单株成铃数和单铃重,对衣分含量无显著影响。与CK相比,不同施钾处理大蒜蒜薹显著增产10.1%~64.2%,鳞茎显著增产8.7%~93.3%。2016年K270处理蒜薹产量较其他处理显著增产6.6%~64.8%,鳞茎显著增产32.5%~93.3%。大蒜经济效益以K270处理最高。增加钾肥施用量显著提高了棉花收获后0—20cm土壤速效钾含量,但各处理60—100cm土层速效钾含量差异不显著。经过4年7季施肥后,K90,K180,K270处理较CK不同程度提高了0—20cm土壤水溶性钾(13.6,20.1,26.1mg/kg)、非特殊吸附钾(10.4,19.6,53.4mg/kg)、非交换性钾(34.3,53.9,140.1mg/kg)和全钾含量,提高了水溶性钾和非特殊吸附钾的比例。综合土壤环境因素、作物产量和经济效益,建议该大蒜—棉花套作区棉花施钾量为K_2O 180kg/hm~2、大蒜施钾量为K_2O 270kg/hm~2。

Effects of Potassium Application Rates on Crop Yield and Soil Potassium Content in a Garlic-Cotton Intercropping System Under a Four-year Located Experiment

Effects of potassium fertilizer application rates on crop yield,economic benefit and soil potassium content were studied in a cotton-garlic intercropping system by a four-year located experiment.There were four treatments,CK (K2O 0 kg/hm2),K90 (K2O 90 kg/hm2),K180 (K2O 180 kg/hm2) and K270 (K2O 270 kg/hm2).The results showed that K fertilizer application significantly increased cotton yield by 18.4％ -72.7％.Lint cotton yield increased with the increase of potassium application rate,but no significant difference was observed between K180 and K270.The bolls and boll weight were significantly increased compared with CK.Potassium application increased garlic bulb and bolt yield by 10.1％-64.2％ and 8.7％ 93.3％,respectively,compared with CK.K270 had the highest bulb yield in 2016.Soil available K content increased in the 0-20 cm soil layer with the increase of potassium application rate but no significant difference was observed among treatments in the 60-100 cm soil profiles.After four-year fertilization,water-soluble K content of K90,K180,and K270 was increased by 13.6,20.1,and 26.1 mg/kg,respectively;nonspecifically adsorbed K content was increased by 10.4,19.6,and 53.4 mg/kg,respectively;and non-exchangeable K content was increased by 34.3,53.9,and 140.1 mg/kg,respectively compared with CK.The overall results suggest that the appropriate potassium application rate is K2O 180 kg/hm2 for cotton and K2O 270 kg/hm2 for garlic in the cotton-garlic intercropping area.