耕作方式对土壤螨类群落结构的影响

Effect of tillage systems on community structure of soil mites

  • 摘要: 土壤螨类是土壤生态系统中重要的指示生物之一。为探讨耕作方式对土壤螨类数量、类群数、群落结构以及垂直分布的影响, 试验选取位于东北黑土区中国科学院海伦农田生态系统国家野外科学观测研究站中5种耕作方式(免耕耕作、少耕耕作、平翻耕作、组合耕作和旋耕耕作)试验区内土壤螨类为研究对象, 采用改良干漏斗(Modified Tullgren)法, 于2009年5月、6月和7月3个时期分离0~15 cm土层中的土壤螨类。结果表明: 耕作方式对土壤螨类数量和类群数存在显著影响, 3个时期共捕获土壤螨类2 441只, 免耕耕作、少耕耕作、组合耕作、旋耕耕作和平翻耕作分别捕获土壤螨类366只、436只、553只、819只和267只, 分别隶属于13科、18科、13科、14科和11科。传统的旋耕耕作具有最高的土壤螨类个体数量, 而保护性耕作中的少耕耕作具有最高的土壤螨类类群数。不同时期耕作方式对土壤螨类垂直分布的影响不同, 5月除免耕耕作外其他4种耕作方式均较好地保持了土壤螨类垂直分布的表聚特征, 即0~5 cm土层中土壤螨类的数量显著(P<0.05)高于其他两层(5~10 cm, 10~15 cm), 其中组合耕作和少耕耕作在3个时期中均较好地保持了土壤螨类的表聚特征, 且少耕耕作较好地保持了土壤螨类的多样性。MGP分析结果表明: 土壤甲螨群落随季节的变化在组成上发生变化, 从最初的高等甲螨为优势类群转化为低等甲螨为优势类群, 免耕和少耕的这种趋势较其他耕作方式更为明显, 少耕耕作3个时期土壤甲螨的组成类型分别为P型、G型和O型, 而免耕耕作3个时期土壤甲螨的组成类型分别为P型、O型和G型。少耕和免耕两种保护耕作方式较其他耕作方式更有利于土壤螨类群落结构的稳定性及多样性的保持, 有利于农田土壤生态环境的保护。

     

    Abstract: Soil mites has been used as an important bio-indicator of soil ecosystem. An experiment was set up to determine the effects of tillage systems on individual number, family number, community structure and vertical distribution of soil mites. The experiment was conducted at the National Observation Station of Hailun Agroecology System in Northeast China. The tillage systems used for the experiment included no-tillage, limited tillage, moldboard plough, combination tillage and rotary tillage. Soil samples were collected from 0~15 cm soil layer under different tillage systems in May, June and July of 2009 and modified Tullgren method used to extract soil mites from the soil samples. The individual and family numbers were significantly affected by different tillage systems. A total of 2 441 soil mites were captured in the study. There were respectively 366, 436, 553, 819 and 267 soil mites under no-tillage, reduced tillage, combination tillage, rotary tillage and moldboard plough, corresponding to 13, 18, 13, 14 and 11 families under each tillage system. The highest individual number of soil mites was in rotary tillage field while the highest family number of soil mites was in limited tillage field. The vertical distribution of soil mites was affected by different tillage systems and sampling times. With the exception of no-tillage, there was faunal accumulation in the soil surface layer in May under the tillage systems. The individual number of soil mites was significantly higher in the 0~5 cm soil layer than in the 5~10 cm and 10~15 cm soil layers (P < 0.05). Also faunal accumulation in the soil surface layer at all the three sampling times was noted under combined tillage and limited tillage systems. Soil mites diversity was preserved under limited tillage. MGP analysis showed that the composition of soil oribate mites changed with season. The dominant family of soil oribate mites changed from senior oribate to junior oribate mites, which was more obvious under no-tillage and limted tillage than the other tillage systems. While the composition type of soil oribate mites was P, G and O under limited tillage at the three sampling times, it was P, O and G under no-tillage system. Conservation tillage systems (i.e., no-tillage and limited tillage) better preserved community diversity and stability of soil mites than the other tillage systems. Conservation tillage was also protective for soil environment.

     

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