不同种植年限的菠萝园土壤养分变化及其与酶活性的关系

对不同种植年限（1、5、10、15和20年）的菠萝园土壤养分及其与酶活性的相关性进行了研究，结果表明：1）不同种植年限对菠萝园土壤养分有显著性影响；土壤有机质和全氮含量随种植年限的延长而逐渐下降，在0～20cm土层中，种植第1年的土壤有机质含量与种植第10、15和20年的土壤有机质含苣达湿著性差异；全氮则与第5、10、15和20年的达显著性差异；2）在0～20cm土层中，土壤碱解氮的下降表现为：种植第1年的与第5、10、15和20年的达显著性差异，但后面各年限间的变化没有规律，并且差异不显著；随着种植年限的延长，速效钾含量呈规律性下降，第1、5年与第10、15和20年的差异显著；3）菠萝园土壤的有机质、全氮和速效养分与过氧化氢酶、蔗糖酶和酸性磷酸酶的活性均表现出显著或极显著相关．

Relation of Soil Nutrient Change and Enzymatic Activity for Different Planting Years in a Pineapple Orchard

This paper studied the correlation of soil nutrient change with enzymatic activity for different planting years （ 1,5, 10,15 and 20 years） in a pineapple orchard. The results show the following： （ 1 ） Different planting years have a significant influence on soil nutrient changes in the pineapple orchard, organic content and total nitrogen become lower and lower along with the increase of the planting years. There is a remarkable difference comparing the organic content in the first planting year with the organic content in the subsequent 10, 15 and 20 years at 0 -20cm soil layer; （2）The decrease of 0 -20cm soil layer alkaline hydrolysis nitrogen is very remarkable the first planting year compared with the 5, 10,15 and 20 year decrease, but there is no regular change in the following years and the change is not significant; （3） The soil organic matter, total nitrogen and available nutrients, catalase, and urease and acid phosphates activity were correlated remarkably.