油菜施钾效果及土壤速效钾临界值初步判断

对湖北省近10多年的80个油菜施钾试验数据进行了统计分析。结果表明，油菜施用钾肥具有明显的增产和增收效果，油菜施钾效果与土壤速效钾含量水平密切相关，与土壤缓效钾含量呈一定的负相关，但相关性不显著。土壤质地明显影响钾肥效果，总体而言，轻质土壤施钾效果高于粘质土壤。土壤速效钾临界值研究结果表明，按照Cate—Nelson方法，以不施钾对照处理占施钾处理产量的90％为依据，初步估计轻质土壤和粘质土壤的速效钾(K)临界值分别为103mg／kg和84mg／kg；以施钾产投比为2作为依据，估计轻质土壤和粘质土壤的速效钾临界值分别为55mg／kg和46mg／kg；以施钾产投比为1．5作为依据，估计其临界值分别为103mg／kg和74mg／kg。

Response of rapeseed yield to K application and primary study of soil critical available K content for rapeseed

A statistics was made based on the data of 80 potash fertilization (K) field trials during 1990--2002 in Hubei province, the main rapeseed product region. The results showed that K application both significantly in- creased rapeseed yield and improved profit. It was showed that the response of rapeseed to K was significantly innu- enced by soil available K content and yield increment with K application had significant negative correlation with soil available K level. Comparatively, yield increment with K application had negative correlation with soil slowly a- vailable K level, but the correlation was not significant. The results also indicated that soil texture had influence on effect of K on rapeseed incrment, which increment in light texure soil was larger than that in clay soil. According to Cate -- Nelson method, based on relative yield of CK/ + K at 90% level the soil critical availab1e K was 103mg/kg for light soil and 84mg/kg for clay soil. Based on VCR at 2 level the soil critical available K was 55mg/kg for light soil and 46mg/kg for clay soil, and based on VCR at 1. 5 level the soil critical available K was 103mg/kg for light soil and 74mg/kg for clay soil, respectively.