浙江低丘红壤供钾强度和容量关系及其应用

采用多点玉米田间试验和室内分析相结合的方法,研究了浙江省20个低丘红壤钾素供应的强度和容量关系,并求得相应的参数。供钾强度指标(AR0)变幅为0.0004499～0.006579,平均为0.002001(molL-1)0.5;供钾容量指标(-△K0)变幅为0.3153～4.057,平均为1.578cmolkg-1;钾素供应的缓冲容量(PBC)变幅为442.2～941.2,平均为680.3cmolkg-1(molL-1)0.5。以20个玉米田间试验子粒相对产量、总干物质相对产量、无钾处理玉米吸钾量以及土壤速效钾、酸溶性钾和缓效钾作为参比标准,与AR0、-△K0和PBC作相关分析,结果表明:AR0、-△K0与土壤速效钾、酸溶性钾、玉米子粒相对产量,总干物质相对产量和无钾处理玉米吸钾量之间达极显著相关(P=0.01),与缓效钾呈显著相关(P=0.05)。PBC与玉米子粒和总干物质相对产量之间达极显著相关、与土壤速效钾之间达显著相关。因此,AR0和-△K0能很好地反映土壤供钾能力,PBC在一定程度上也能表征土壤钾肥力。6个参比标准与AR0、-△K0和PBC之间的多元回归分析结果比简单地一元回归分析结果要好,把AR0、-△K0和PBC结合起来综合说明土壤供钾能力和钾素的生物有效性是可行的。

STUDY ON THE QUANTITY AND INTENSITY RELATIONSHIP OF POTASSIUM AND ITS APPLICATION IN UPLAND RED EARTH OF ZHEJIANG

Twenty field experiments of K effect on corn were conducted in the upland red earths in Zhejiang Province. The quantity and intensity relationships of soil K were measured. Results showed that K supplying intensity (AR⁰), K supplying capacity (-△K⁰) and K supplying buttering capacity (PBC) ranged from 0.0004499 - 0.006579, 0.3153~ 4.057 and 442.2-941.2 with an average of 0. 002001(molL^-1)^0.5, 1. 578cmol kg^-1. and 683.3 emol kg^-1(molL^-1)^-0.5, respectively. Available K, HNO₃ soluble K and slowly available K of soil; relative grain yield, relative total dry matter yield and K uptake of corn in NP plots were used as reference to check the practical applicability of AR⁰,-△K⁰ and PBC. The correlation analysis showed that the AR⁰ and -△K⁰ were very significantly correlated(p=0.01) with available K, HNO₃ soluble K, relative grain yield, relative total dry matter yield and K uptake(NP plot) of corn, significantly correlated (p=0.05) with the slowly available K. PBC were very significantly correlated (p-0.01) with the relative grain yield and relative total dry matter yield of corn, and significantly correlated with soil available K. So, AR⁰ and -△K⁰ were the excellent indexes to evaluate soil K supplying powr and the PBC, in a certain degree, could characterize soil K fertility. Also, we found that multiple regression analyses between the reference standards and paraments of AR⁰,-△K⁰ and PBC were better than the simple correlation, suggesting a intergrated test of AR⁰, -△K⁰ and PBC is necessary to estimate supplying power and availability to plant of soil K.