Departamento de Tecnologia Rural, Universidade Federal Rural de Pernambuco, CEP 52171-900, Dois Irmãos, Recife, PE, Brasil.
Environ Monit Assess. 2012 Jun;184(6):3529-44. doi: 10.1007/s10661-011-2206-4. Epub 2011 Jul 16.
Nematodes present high potential as a biological indicator of soil quality. In this work, it was evaluated relations between soil physical properties and nematode community under sugarcane cropping and remaining of Atlantic Forest areas in Northeastern Pernambuco, Brazil. Soil samples were collected from September to November 2009 along two 200-m transects in both remaining of Atlantic Forest and sugarcane field at deeps of 0-10, 10-20, 20-30, 30-40, and 40-50 cm. For soil characterization, it was carried out analysis of soil size, water content, total porosity, bulk density, and particle density. The level of soil mechanical resistance was evaluated through a digital penetrometer. Nematodes were extracted per 300 cm(3) of soil through centrifugal flotation in sucrose being quantified, classified according trophic habit, and identified in level of genus or family. Data were analyzed using Pearson correlation at 5% of probability. Geostatistical analysis showed that the penetration resistance, water content, total porosity, and bulk density on both forest and cultivated area exhibited spatial dependence at the sampled scale, and their experimental semivariograms were fitted to spherical and exponential models. In forest area, the ectoparasites and free-living nematodes exhibited spherical model. In sugarcane field, the soil nematodes exhibited pure nugget effect. Pratylenchus sp. and Helicotylenchus sp. were prevalent in sugarcane field, but in forest, there was prevalence of Dorylaimidae and Rhabditidae. Total amount of nematode did not differ between environments; however, community trophic structure in forest presented prevalence of free-living nematodes: omnivores followed by bacterial-feeding soil nematodes, while plant-feeding nematodes were prevalent in sugarcane field. The nematode diversity was higher in the remaining of Atlantic Forest. However, the soil mechanical resistance was higher under sugarcane cropping, affecting more directly the free-living nematodes; especially Dorylaimidae which was the most sensible to changes in soil physical properties.
线虫具有作为土壤质量生物指标的巨大潜力。本研究评估了巴西东北部伯南布哥州大西洋森林保留区和甘蔗种植区土壤物理性质与线虫群落之间的关系。2009 年 9 月至 11 月，在大西洋森林保留区和甘蔗田各采集两条 200m 长的样带，在 0-10、10-20、20-30、30-40 和 40-50cm 深处采集土壤样本。为了进行土壤特性分析，测定了土壤粒径、含水量、总孔隙度、容重和颗粒密度。通过数字 penetrometer 评估土壤机械阻力水平。使用蔗糖离心浮选法从每 300cm³土壤中提取线虫，对其进行定量分析，并根据营养习性进行分类，鉴定到属或科水平。使用 5%概率的 Pearson 相关性分析数据。地统计学分析表明，森林和种植区的穿透阻力、含水量、总孔隙度和容重在采样尺度上均具有空间依赖性，其实验半变异函数拟合为球状和指数模型。在森林区，外寄生线虫和自由生活线虫呈球状模型。在甘蔗田中，土壤线虫呈纯 nugget 效应。甘蔗田中普遍存在 Pratylenchus sp.和 Helicotylenchus sp.，而在森林中，Dorylaimidae 和 Rhabditidae 较为常见。线虫总量在两种环境中没有差异；然而，森林中线虫群落的营养结构以自由生活线虫为主：杂食性线虫其次是细菌食性土壤线虫，而在甘蔗田中以植物食性线虫为主。在大西洋森林保留区，线虫多样性更高。然而，在甘蔗种植区，土壤机械阻力更高，这对线虫的影响更为直接，尤其是对线虫科（Dorylaimidae）的影响最大，该科对线状线虫对土壤物理性质的变化最为敏感。
