森林与环境学报2024，Vol.44Issue(3)：225-232,8.DOI:10.13324/j.cnki.jfcf.2024.03.001
土壤碳氮磷和酶化学计量特征对原始林转换的响应
Responses of soil C,N,P,and enzyme stoichiometry to primary forest conversion
摘要
Abstract
To elucidate the stoichiometric dynamics of organic C,N,P,and extracellular enzymes in soil in typical agricultural and forestry lands,primary evergreen broad-leaved forests and converted plantations,orchards,sloping croplands,and paddies with similar geographical backgrounds and clear land-use history in western Hunan Province were selected.The space-for-time substitution method was applied to reveal the effect of primary forest conversion on the contents of organic C,total N,and total P;activities of extracellular enzymes,including their:stoichiometric ratios;relationships with labile C,N,and P fractions at a soil depth of 0-40 cm.Compared to the primary forest,the contents of soil organic C,total N,and total P in the orchard and sloping cropland were much more greatly reduced(40%-79%)than that in plantations and paddies.The reduction was similar in topsoil and deep soil,indicating relatively unfavorable conditions for organic C and nutrient preservation in deep soil under orchards and sloping croplands.No significant differences in soil C-N-P ratios were observed among the orchards,sloping croplands,paddy fields,and primary forests.The C-N-P ratios in soil were 60%-124%higher in plantations than in primary forests,indicating co-limitation by N and P in the soil under the plantation.The β-glucosaminidase,β-N-acetyl glucosaminidase,leucine aminopeptidase,and acid phosphatase activities were reduced by 18%-64%in the converted land-use sites than in the primary forest.Compared to that of the primary forest,the stoichiometric ratios of C-and P-acquiring enzyme(EC/P)in the topsoil under the orchard and sloping cropland were significantly reduced,whereas the EC/P ratios in the 20-40 cm deep soil were significantly increased.The contents of organic C,total N,total P,enzyme activities,and their ratios were significantly correlated with the contents of the labile C,N,and P fractions in soil.Primary forest conversion resulted in substantial reductions in soil organic C,total N,and total P contents and extracellular enzyme activities in the topsoil and at depths of 20-40 cm deep.This indicates a reduction in microbial substrate availability and soil quality/health degradation.The responses of the stoichiometric ratios of soil organic C,total N,and total P contents and enzyme activities to primary forest conversion were relatively weak.Whether these stoichiometric ratios can effectively indicate the soil health change remains further exploration.关键词
湘西北/深层土壤/土壤养分/生态化学计量学/胞外酶活性/土地利用Key words
northwestern Hunan province/deep soil/soil nutrient/ecological stoichiometry/extracellular enzyme activity/land use分类
农业科技引用本文复制引用
肖华翠,梁万栋,李源钊,盛浩,周萍..土壤碳氮磷和酶化学计量特征对原始林转换的响应[J].森林与环境学报,2024,44(3):225-232,8.基金项目
湖南省重点研发计划项目"变更耕地地力快速提升关键技术研究与应用"(2023NK2026) （2023NK2026）
国家自然科学基金项目"亚热带丘陵区典型农林用地底土有机碳稳定机理研究"(41571234) （41571234）
科技基础资源调查专项课题"长江中下游耕地质量要素收集与扩展"(2021FY100504). （2021FY100504）
