摘要
室内分析结合温室盆栽试验研究了土壤磷素植物有效性和无机磷酸盐的解吸特性之间的关系。供试材料为浙江省分布较广的四种代表性土壤,并以吸磷能力较强的黑麦为指示植物。结果表明,在四种供试土壤上黑麦吸收磷与解吸磷之间的相关性都比与两种常规化学方法浸提磷之间的相关性更为显著。不仅如此,黑麦吸收磷与解吸磷间在数量上较化学浸提磷要接近的多,并且在各供磷强度下以及不同土壤上都符合较好。黑麦吸收磷或解吸磷(Q)随土壤供磷强度(I)变化的Q—I关系能够很好地符合Langmuir方程;而Olsen-P和Brayl-P对供磷强度的关系与该方程的符合性在酸性土壤上要差得多。可见,植物吸收磷与磷酸盐解吸有内在联系。结果还表明,由拟合Langmuir方程计算得的最大解吸缓冲容量(MBCD)能够很好解释不同性质土壤间磷肥利用率的差异,它较之最大吸附缓冲容量(MBCA)能够更好指示土壤中磷的植物有效性。但平衡解吸缓冲容量反映土壤供磷能力更为灵敏,可望成为好的土壤磷诊断指标。
Both laboratory analysis and pot experiments in greenhouse were conducted by using four typical soils widely distributed in Zhejiang province and rye as testing plant to study the relationship between plant-availability of P and characteristics of phosphate desorption in soils. The results obtained demonstrated that P uptake of rye plant was correlated more significantly with desorbed-P than with Olsen-P or Bray 1-P. What is more interesting is that the plant-absorbed P was much more compatible with desorbed-P than with Olsen-P or Bray 1-P in quantity uander various levels of P intensity. The Q-I relationship of either P uptake of rye plant or desorbed-P against P intensity fitted much better with the Langmuir equation than that of Olsen-P or Bray 1-P against P intensity as far as the four tested soils are concerned. It suggested that plant-availability of phosphorus in soil was essentially related with phosphate desorption behavior. The maximum buffering capacity of desorption (MBCD) obtained from the Langmuir equation was found to explain well the variability in the recovery percentage of the applied fertilizer P by rye plant on different soils. Compared with the maximum buffering capacity of adsorption (MBCA), MBCD is a better physico chemical index for evaluating the plant-availability of phosphorus in soils. However, it seems that the equilibrium buffering capacity of desorption may become the most promising index for diagnosing soil P status.
出处
《土壤学报》
CAS
CSCD
北大核心
1991年第3期302-308,共7页
Acta Pedologica Sinica