摘要:
文章以重庆市丰都县三坝乡土地整理项目为例,分别对土地整理前(2012年12月)52个采集点和土地整理后(2013年3月)28个采集点,采用野外采样和室内分析相结合的方法,研究了土地整理对岩溶区土壤微生物群落结构、土壤微生物生物量碳(SMBC)、氮(SMBN)及酶活性(过氧化氢酶、脲酶、蔗糖酶)的影响,结果表明:(1)土地整理对土壤微生物影响显著,土地整理后比整理前土壤中的放线菌数量降低,真菌数量增加。(2)在0~20 cm 土层,整理前后 SMBC 和 SMBN 含量变化显著,SMBC 含量整理后比整理前降低了20.33%, SMBN 含量整理后比整理前减少了47.84%;土地整理改变了整理前 SMBC、SMBN 含量随土层深度变化递减的规律,使 SMBC、SMBN 含量分别在亚表层(20~40 cm)出现最小值68.34 mg/kg和最大值33.58 mg/kg。(3)整理前后土壤脲酶和过氧化氢酶均在0~20 cm和20~40 cm 同一土层差异显著,蔗糖酶活性在各土层差异均显著。土地整理使土壤脲酶和过氧化氢酶活性降低,蔗糖酶活性提高。(4)有机质对表层 SMBC、SMBN含量和脲酶活性呈显著正相关,pH 值与土壤酶活性呈显著正相关。
Abstract:
Land integration is an important measure to build high-standard prime farmland.It can improve production and living conditions of farmers and enhance the comprehensive land productivity.This study takes the land integration project in the karst area of Sanba township,Fengdu county in Chongqing City as an example.It collected 52 points before this project (December 2012)and 28 typical points afterwards (March 2013).Through field sampling and laboratory analysis,this paper have studied the effect of this project on soil microbial structure,soil microbial biomass carbon (SMBC),soil microbial biomass nitrogen (SMBN) and enzyme activity including catalase (CAT),urease (URE),and sucrase(INV)activity of soil microorgan-isms in the low hilly area.Our objective was to describe the distribution characteristics before and after fin-ishing land integration.The results show that,(1)the implementation of this project has imposed significant effect on soil microbial.After the land integration,the number of actinomycetes decreased in the soil than the previous state,and the number of fungi increased.(2 )Land integration reduced overall SMBC and SMBN content in 0 to 20 cm soil,of which SMBC content was decreased by 20.33% and SMBN content de-creased by 47.84%,respectively.In vertical distribution,land integration changed the rule that SMBC and SMBN contents vary with soil depth,showing their minimum values 68.34 mg/kg and maximum value 33.58 mg/kg in the subsurface of 20 to 40 cm.(3)In the same soil,land integration has caused significant differences between urease activity and catalase activity in 0 to 20 cm and 20 to 40 cm,while invertase activi-ties were significant different in 0 to 20 cm,20 to 40 cm and 40 to 60 cm soil levels.After land integration, urease and catalase activity decreased,and invertase activity improved,each in the soil tends to be uniform as well.(4)Organic material is significantly positively correlated with surface SMBC and SMBN contents and urease activity,and pH shows a significant positive correlation with soil enzyme activity.The change of SMBC and SMBN contents and soil enzyme activity can be used as indicators to determine the soil fertility level and soil fertility effect before and after land integration,and it can help to carry out soil improvement and soil fertility work in the area after land integration.
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