不同恢复年限对柠条林地土壤养分含量和酶活性的影响

Effects of restoration years on soil nutrients and enzyme activities in Caragana korshinskiis forest land soils

摘要:

【目的】探明不同恢复年限对沙化区柠条林地土壤养分和酶活性的影响。【方法】以甘肃省环县甜水镇 3、7、15、21 a 的人工柠条(Caragana korshinskii)林地以及沙荒地为研究对象，分别采集 0~20、 20~40、40~60 cm 层土样，测定分析不同恢复年限、不同土层土壤养分指标和酶活性之间的变化规律及差异性。【结果】(1)土壤中的有机碳、全氮、硝态氮、铵态氮、速效磷、速效钾含量和过氧化氢酶、蔗糖酶、脲酶、碱性磷酸酶的活性随着恢复年限的增加呈增加趋势，pH 值随恢复年限增加逐渐减小；(2)沙荒地中，土壤养分含量和酶活性在 0~20 cm 土层最低，在 0~40 cm 土层中显著低于林地，柠条林地内土壤养分含量和酶活性随着土层深度的增加表现出明显的“表聚”现象；(3)相关分析表明，土壤中的有机碳、全氮、速效氮、速效磷、速效钾含量、过氧化氢酶、蔗糖酶、脲酶、碱性磷酸酶活性之间彼此均呈极显著正相关(P＜0. 01)，与 pH 值呈极显著负相关(P＜0. 01)。【结论】不同年限的柠条林对 0~20 cm 土壤养分含量和酶活性的影响最为明显。

Abstract:

【Objective】 This research aimed to explore the effects of with different restoration years on soil nutri‐ ent and enzyme activity in Caragana Korshinski forest land soils.【Method】 The C. korshinskii shrubland and sandy land were taken as the research objects in desertification area，3 a，7 a，15 a and 21 a，Tianshui Town，Huanxian County，Gansu Province. Soil samples were collected from 0~20 cm，20~40 cm， and 40~60 cm layers to analyze the changes and differences between soil nutrient indexes and enzyme activities in C. korshinskii shrubland among different restoration years and soil layers.【Result】(1) The content of organic carbon，total nitrogen，nitrate nitrogen， ammonium nitrogen， available phosphorus， available potassium and the activity of catalase， sucrase，urease，alkaline phosphatase in the soil increased with the restoration years；(2) In the sandy land， the soil nutrient and enzyme activ‐ ity were the lowest in the 0~20 cm soil layer. They were significantly lower than those in the C. korshinskii shru‐ bland in the 0~40 cm soil layer. The soil nutrient and enzyme activity in the shrubland showed obvious "surface aggre‐ gation" phenomenon with the increase of soil depth；(3) Correlation analysis showed that the content of organic car‐ bon，total nitrogen， available nitrogen， available phosphorus，available potassium and the activity of catalase，su‐ crase， urease and alkaline phosphatase were all significantly positively correlated with each other (P＜0. 01)，and ex‐ tremely significantly negatively correlated with pH (P＜0. 01).【Conclusion】C. korshinskii shrubland at different ages significantly affected soil nutrient and activity in the layer of 0~20 cm.