| 摘要: |
| 【目的】研究坡耕地转变为青花椒林地和弃耕地后土壤微团聚体组成、分形维数和土壤肥力变化,以及分形维数与土壤肥力之间的关系，为坡耕地退耕后青花椒种植和土壤管理提供参考。【方法】以川东丘陵区青花椒林（2，5，9和14年，分别以QHJ-2、QHJ-5、QHJ-9和QHJ-14表示）、弃耕地（14年，QGD）和坡耕地（CK）为研究对象，测定土壤微团聚体组成、养分含量、酶活性与微生物数量，运用分形模型和隶属函数法分别计算微团聚体分形维数和土壤肥力综合值，并探讨土壤微团聚体分形维数（D）、特征微团聚体组成比例（PCM）和粒径＜0.02 mm与2~0.02 mm土壤微团聚体含量的比值（RMD）与土壤肥力间的关系。【结果】坡耕地退耕为青花椒林和弃耕地促进了大粒径土壤微团聚体含量的增加和小粒径土壤微团聚体含量的降低。坡耕地转变为青花椒林地后，土壤养分含量、微生物数量和酶活性均显著增加，相同退耕年限下，青花椒林地土壤养分含量、微生物数量和酶活性均优于弃耕地。土壤肥力综合值表现为QHJ-14＞QHJ-9＞QGD＞QHJ-5＞QHJ-2＞CK。土壤PCM、RMD和D均随着青花椒种植年限的延长而降低。土壤PCM、RMD和D与土壤养分含量、微生物数量和酶活性及土壤肥力综合值呈显著负相关(P<0.05)。【结论】坡耕地种植青花椒和弃耕有利于改善土壤微团聚体的组成，促进小粒径微团聚体向大粒径微团聚体聚合，能有效提高土壤肥力；土壤PCM、RMD和D可作为坡耕地退耕后土壤肥力变化的综合评价指标。 |
| 关键词: 青花椒 微团聚体 分形维数 土壤肥力 生化特性 |
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| 基金项目:四川省科技厅项目(16NZ0067，2006YZGG-10，2011NZ0098-10，2016NYZ0035，18KJFP0206)；国家科技支撑计划项目(2001BA606A-06，2006BAC01A11，2011BAC09B05) |
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| Effect of planting Zanthoxylum armatum on fractal dimension and biochemical characteristics of soil micro-aggregates |
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TANG Hailong,GONG Wei,WANG Jingyan,et al
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| Abstract: |
| 【Objective】This study evaluated the effect of converting slope farmland to Zanthoxylum armatum plantation or abandon farmland on soil micro aggregates composition,fractal dimension and soil fertility characteristics and the relationship between fractal dimension of soil particles and soil fertility to provide basis for cultivation and soil management of Z.armatum plantation conversed from slope farmland.【Method】Soil samples were collected from Z. armatum plantation with ages of 2,5,9 and 14 years (QHJ-2,QHJ-5,QHJ-9 and QHJ-14),farmland (CK) and abandon farmland (14 year-old,QGD) in hill areas of eastern Sichuan for determination of soil micro aggregate composition,nutrient content,enzyme activity and microbial number.Fractal model method and membership function method were used to calculate soil micro aggregate fractal dimension and soil fertility comprehensive,respectively.The soil micro-aggregate fractal dimension (D),characteristic micro-aggregate composition ratio (PCM) and ratio of 2 to 0.02 mm particle size fraction (＜0.02 mm/(2-0.02) mm,by RMD) after conversion of farmland to Z.armatum plantation were explored.【Result】The conversion of slop farmland to Z.armatum plantation and abandon farmland increased large particle content,while decreased small particle content in soil micro-aggregates.Soil nutrient content,microbial number and enzyme activity were increased significantly.After same years of conversion,all soil biochemical properties of Z.armatum plantation were better than that of QGD.The comprehensive soil fertility values were in the order of QHJ-14>QHJ-9>QGD>QHJ-5>QHJ-2>CK.Soil PCM, RMD and D decreased with the increase of plantation age.Soil PCM,RMD and D had significantly negative correlations with soil nutrient contents,numbers of microorganisms,enzyme activities,and the comprehensive value of soil fertility (CVSF) (P＜0.05).【Conclusion】Conversion of slop farmland to Z. armatum plantation and abandon farmland promoted the transform of smaller soil micro-aggregates to larger ones,and improved soil micro-aggregate composition and soil fertility.Soil PCM,RMD and D can be used as integrated quantitative indexes to evaluate soil fertility after conversion of slop farmland to Z.armatum plantation and abandon farmland. |
| Key words: Zanthoxylum armatum micro-aggregates fractal dimension soil fertility biochemical properties |
