湖南省油菜施钾效应及土壤速效钾临界值研究

2005-2008年在湖南省油菜主产区布置67个田间试验,研究施钾对油菜籽产量的影响及土壤速效钾含量对施钾效应的影响,并对土壤速效钾临界值进行初步判定。结果表明,油菜施钾具有明显的增产和增收效果,平均增产率19.1%,增产范围为33-1 587 kg/hm2,平均增产332 kg/hm2,每千克K2O平均增加2.5 kg油菜籽,其中51个试验施钾增产效果在10%以上;施钾平均产投比为1.4,产投比大于1.5的试验占35.8%。土壤速效钾含量对施钾产量效应及经济效应均有明显影响,土壤速效钾与施钾增产量及产投比分别呈极显著和显著负相关。以不施钾处理占施钾处理产量的90%为标准,初步估计土壤速效钾临界值为106 m g/kg;以施钾产投比2.0和1.5为标准,估计其临界值分别为70 m g/kg和100 m g/kg。

Study on Effect of K Application on Rapeseed and Critical Level of Soil Available K in Hunan Province

67 field trails of potassium fertilizer（K） application on rapeseed were carried out in main rapeseed production regions of Hunan province during 2005 to 2008 to investigate the effect of K on rapeseed yield and preliminarily determine the critical level of soil available K.The results showed that K fertilizer application could significantly increase yield and profit of rapeseed,and the increasing rate of rapeseed yield among 51 trails was over 10%,and the average increasing rate of all trails was 19.1%.The range of yield increment was from 33 kg/hm2 to 1587 kg/hm2,and the average value was 332 kg/hm2.Rapeseed yield was increased by 2.5 kg per 1 kg K2O application.The average ratio of output to input（ROI） was 1.4,and the ROI of 35.8% trails were higher than 1.5.There were significantly negative correlation between the yield increment, ROI and soil available K respectively.Based on the relative yield of CK/＋K at 90% level,the critical level of soil available K was 106 mg/kg,and based on ROI at 2.0 and 1.5,the critical level of soil available K were 70 mg/kg and 100mg/kg,respectively.