Nematode communities in greenhouse soil of different ages from Shenyang suburb

Abstract

51 SummaryThe distribution of nematode communities with depth in greenhouse soil of different ages from Shenyang suburb was investigated in October 2004. Thirteen families and 23 genera were observed in our study. Heterocephalobus was dominant genus in all treatments. The numbers of total nematodes and trophic groups declined with soil depth but increased with greenhouse age. Bacterivores were the most abundant trophic group in all treatments, followed by plant parasites and omnivores-predators, while fungivores were the least, only accounted for less than 4 % of the total abundance. Maturity index (MI) and plant parasite index (PPI) were effective in distinguishing differences in nematode community structure in different ages of greenhouses. The numbers of total nematodes were positively correlated with soil organic carbon, total nitrogen, nitrate, and electrolytic conductivity, but negatively with soil pH.

Temporal dynamics of soil nematode community structure under invasive Ambrosia trifida and native Chenopodium serotinum

“…All extracted nematodes in each sample were counted and identified to genus level using an inverted compound microscope. The classification of trophic groups (1) bacterivores; (2) fungivores; (3) plantparasites; and (4) omnivores-predators, based on known feeding habitats or stoma and esophageal morphology (Yeates et al, 1993;Renčo, 2002;Liang et al, 2005a;Hua et al, 2006;Liu et al, 2006). Nematode taxonomic and functional diversity was analysed by the following approaches: Simpson index was calculated to determine effects of plant species on nematode taxonomic diversity (De Deyn et al, 2004); Nematode taxa consisted of genera (De Deyn et al, 2004).…”

“…1). Nematodes were extracted from 100 g (fresh weight) of soil from each sample using sugar flotation and centrifugation Liu et al, 2006), the nematode abundance was expressed per 100 g dry weight soil (Liang et al, 2005a). All extracted nematodes in each sample were counted and identified to genus level using an inverted compound microscope.…”

Effects of land use history and inoculation with Fusarium oxysporum f. sp. cucumberinum Owen on soil nematodes communities

“…As compared with open vegetable soils, the kinds of carbon sources that could be metabolized by native microbes in plastic greenhouse soils greatly decreased, revealing that microbial diversity had decreased since land use change (Lin et al, 2004). Previous reports have concentrated mainly on soil microorganisms, and few studies have yet been carried out on the impacts of the land use change on soil fauna (Liu et al, 2006). Among soil fauna, nematodes possess many characteristics that make them ideal as bioindicators for soil health assessment (Bongers, 1990;Yeates & Bongers, 1999;Liang et al, 2005).…”

“…Consequently, violently disturbed soil quality is detected in greenhouse, such as acidification, * corresponding author .... secondary salination, nutrition enrichment and nutrient unbalance due to intensive management, heavy fertilization and abnormal mini-climate (Li et al, 1996;Liu et al, 2006;Shen et al, 2008). On the other hand, when the same crop or its related species are cultivated on the same soil successively, soil sickness expressed as a reduction in both crop yield and quality will be triggered.…”

“…Besides, soil nematodes feeding on bacteria and fungi play an important role in the detritus food web (Bongers, 1990;Chen & Ferris, 2000;Berkelmans et al, 2003). Recently, many reports have shown agricultural management practice such as tillage, fertilization, pesticide application would result in disturbance and subsequent succession or recovery of the soil ecosystem which is reflected in the composition of nematode fauna (Neher, 1999;Freckman & Ettema, 1993;Liang et al, 2005;Liu et al, 2006;Li et al, 2007). The plant-pathogenic fungi Fusarium oxysporum f. sp.…”