石灰性土壤中锰素营养的研究——Ⅲ.土壤中MnSO4的转化及不同形态锰的含量变化

STUDY ON NUTRITION OF Mn IN CALCAREOUS SOILS Ⅲ. TRANSFORMATION OF APPLIED Mn AND DIFFERENT FORMS OF Mn IN SOILS

摘要:

土壤中养分的存在形态不同对作物的可给性不同。从植物营养的角度虽然可将土壤中的锰分为三种形态:即速效锰(为作物直接吸收利用的二价锰)、缓效锰(主要为三价锰的氧化物,易于转化为二价锰)和无效锰(不易为作物吸收利用的四价锰),但用试验手段却很难获得这些结果。习用的方法是采用某种提取剂以提出某一形态的锰。本文根据盆栽试验和土壤测定的资料^[1,2],对易还原态、代换态、有机络合剂络合态、磷酸盐溶解态以及水溶态锰在石灰性土壤中的转化和含量变化进行了初步探讨。

Abstract:

In calcareous soils, after application of MnSO₄ for dozens of days, about 70% of applied Mn transformed into easily reducible Mn, yet, little applied Mn transformed into chelated or phosphate-soluble Mn. While the rates of Mn application increased, the amount of exchangeable Mn decreased significantly. This phenomenon, perhaps, could be attributed to the strong absorption of newly-formed Mn-oxides to soil Mn of eachangeable form. It was observed that the exchangeable and chelated Mn were very unstable in plant-grown mils, in fact, the violent uptake of plants. The easily reducible Mn, however, did not change very mach in a period of time, so it was easy to define the status of this form in a soil, what is more, this form was the only one that related with Mn uptake of plants. The conclusion is that in calcareous soils both chelated and exchangeable Mn are of little importance in the nutrient status of a soil and easily reducible Mn exceedingly affects soil Mn supply for plant requirement.