不同提取方法测定的土壤钾的有效性比较研究

COMPARISON BETWEEN SOIL POTASSIUM DETERMINATION METHODS IN AVAILABILITY OF THE POTASSIUM THEY EXTRACTED

以122个油菜钾肥田间试验的籽粒产量和植株吸钾量为标准，分别采用1 mol L-1“中性醋酸铵、1mol L-1。沸硝酸和0．2mol L-1。四苯硼钠3种浸提剂测定试验基础土壤的钾素含量，并按浸提剂种类和速效钾、缓效钾将其分类，通过相关性分析探索土壤有效钾的准确测定方法，行建立与之对应的土壤钾素丰缺指标。研究结果表明，不同方法的提取能力有所不同，沸硝酸钾含量〉四苯硼钠钾含量〉醋酸铵钾含量。用醋酸铵法和四苯硼钠法测得的土壤钾素的生物有效性均较好，其中又以四苯硼钠法更好。氏江流域冬油菜区醋酸铵法浸提的土壤钾素“低”、“中”、“高”和“极高”指标分别为〈45mgkg、45-115mgkg-1、115～190mgkg-1。和〉190mgkg；四苯硼钠法浸提的土壤钾素“低”、“中”、“高”和“极高”指标分别为〈125mgkg、125～415mgkg、415～755mgkg。和〉755mgkg。综合结果表明四苯硼钠法和醋酸铵法测得的土壤钾索含量与油菜相对产量和相对吸钾量间呈极显著相关关系。据此建立的土壤钾素丰缺指标可以用来指导长江流域油菜的测土配方施肥，另外此区域应该重视并合理的施用钾肥。

Based on the grain yields and plant K uptakes of the 122 K fertilizer field experiments conducted on rape as reference ,three different extractants （i. e. , 1 tool L-1 neutral NH4OAc, 1 mol L-1 boiling HNO3 ,0.2 tool L-1 NaBPh4 ） were used to extract soil K in the experiment soils,and the data were sorted by extractants and by available K and slowly available K. Then correlation analysis was done of the data to define which one was the accurate determination method for soil available K and corresponding indices for soil K abundance and deficiency were established. It was found that the three extractant varied in extraction capacity and displayed an order of NH4OAc-K 〉 Boiling HNO3-K 〉 NaBPh4-K. The soil Ks extracted with NH4OAc and NaBPh4 were higher in bio-availability and NaBPh4 the highest. For winter rape fields in the Yangtze River valley, the index of ＂Low＂ ,＂ Medium＂ ,＂ High＂ and ＂Very High＂ for soil NH40Ac-K and NaBPh4-K was 〈45 mgkg ,45-115 mgkg-I,115-190mgkg-~ and 〉190mgkg-1 and 〈125 mgkg-1,125 ~415 mgkg-1,415 ~ 755 mg kg-1 and 〉 755 mg kg-~, respectively. Suumarization of the results showed that the relative yield and relative plant uptake was highly significantly correlated with soil K content extracted with the NaBPh4 and NH4OAc method. The soil K critical indices established using the methods and through the field experiments can be used as reference for soil test based fertilizing recommendation for winter rape production in the valley. Moreover, it is essential to pay more attention to rational K fertilization in the region.