黄土丘陵区3种典型人工阔叶纯林枯落物分解对土壤性质极化的影响

【目的】探讨黄土丘陵区3种典型人工阔叶纯林枯落物分解对土壤性质极化的影响，为防治森林土壤退化和连栽障碍提供科学依据。【方法】在位于黄土高原中部半湿润黄土丘陵区的陕西黄陵县，选择刺槐、辽东栎和小叶杨3种典型人工阔叶纯林为研究对象，采集林地腐殖质层土壤和枯落物（当年枯落叶及细根），分别设“土壤+枯落叶”、“土壤+根系”、“土壤＋枯落叶+根系”和土壤不与任何枯落物混合（对照）4种处理方式，进行室内混合培养试验，共培养120 d，分析枯落物分解对土壤生物学和化学性质极化的影响。【结果】1）在刺槐林地，枯落叶分解主要引起土壤pH值、过氧化氢酶活性和微生物数量负向极化，根系分解主要引起pH值、速效磷含量负向极化；但就土壤总体性质而言，枯落叶和根系均引起了正向极化，且根系影响大于枯落叶，二者混合分解对土壤的影响总体表现为相互抑制。2）在辽东栎林地，枯落叶分解主要引起蔗糖酶、多酚氧化酶、过氧化氢酶活性及速效磷、速效钾含量负向极化，根系分解主要引起过氧化氢酶活性和速效钾含量负向极化；但就土壤总体性质而言，枯落叶分解引起了负向极化，而根系分解引起了较弱的正向极化，且二者混合分解对土壤的影响总体表现为较弱抑制作用。3）在小叶杨林地，枯落叶分解主要引起蛋白酶、过氧化氢酶活性及速效磷含量负向极化，根系分解主要引起蛋白酶、过氧化氢酶活性及微生物数量和速效磷含量负向极化；就土壤总体性质而言，枯落叶和根系均引起了负向极化，且根系影响较明显，二者混合分解对土壤的影响总体表现为相互促进。【结论】从枯落物分解对土壤性质极化影响的总体结果来看，刺槐比较适宜在该地区一定时间内继续连栽，其次为辽东栎，而小叶杨不适宜。

Effect of litter decomposition on soil properties polarization of three typical artificial pure broadleaved forests in the Loess Hilly Area

【Objective】 The study was about the effect of litter decomposition on soil properties polarization of three typical artificial pure broadleaved forests in the Loess Hilly Area,which can provide scientific basis for the prevention of soil degradation and continuous plantation obstacle.【Method】 In Shaanxi Huangling county which is located in semi-humid loess hilly area,the middle of Loess Plateau,humus soil and litter(leaf litter and fine roots) were sampled in three typical artificial pure broadleaved forests including Robinia pseudoacacia,Quercus liaotungensis and Populus simonii,and set 4 treatments including "soil+leaf litter","soil+roots","soil+leaf litter+roots",and control "soil" for laboratory incubation experiments.All treatments were incubated for 120 days,then the effect of litter decomposition on soil biological and chemical properties polarization was analyzed.【Result】 1)In the R.pseudoacacia woodland,leaf litter decomposition resulted in negative polarization of soil pH value,catalase activity and microbe quantity;Roots decomposition resulted in negative polarization of soil pH value and available P.According to the comprehensive soil properties,both leaf litter and roots resulted in positive polarization,and roots showed greater effect than leaf litter;The mixed decomposition of leaf litter and roots showed inhibitory effect on soil properties.2)In the Q.liaotungensis woodland,leaf litter decomposition resulted in negative polarization of soil sucrase,polyphenoloxidase,catalase,available P and available K;Roots decomposition resulted in negative polarization of catalase activity and available K.According to the comprehensive soil properties,leaf litter decomposition resulted in negative polarization,but roots decomposition produced weak positive polarization;The interaction between them showed weak inhibitory effect on soil properties.3)In the P.simonii woodland,leaf litter decomposition resulted in negative polarization of protease,catalase and available P;roots decomposition induced negative polarization of protease,catalase,microbe quantity and available P.According to the comprehensive soil properties,both leaf litter and roots resulted in negative polarization,and roots showed greater effect than leaf litter;the mixed decomposition of leaf litter and roots showed promoting effect on soil properties.【Conclusion】 In general,from the effect of litter decomposition on soil properties polarization,R.pseudoacaci was more suitable for successive planting in this area during a certain time,followed by Q.liaotungensis,but P.simonii was not suitable.