Effect of Organic Amendments on Soil Nematode Community Composition, Nematode Infectivity and Plant Growth

Abstract

Purpose: The effect of organic amendments on soil nematode community composition and pathogenicity on S.melongena L.was evaluated by comparing the nematode faunal composition in an amended soil with non-amended soil.

Methodology: Prior to soil enrichment, the undisturbed plot was assessed to determine the endemic nematode community composition. Organic amendment was administered to the undisturbed plot and nematode population dynamics was determined. Planting was done 14 days after application of organic amendment after which soil samples were collected from the experimental plot at 30, 60 and 90 days intervals. Root samples of the S. melongena L. were also collected at the same interval. The modified Bearmann's extraction technique was used to determine the soil and endophytic population of nematodes. Soil samples were collected from two different depths, 0-5cm and 6-10cm depths.

Findings: There was variability in depth related occurrence of nematode genera and species, with abundance and species diversity declining as depth increased prior to amendment (p>0.05). This variability was replicated in the experimental plots after amendment (p<0.05). The study revealed that the soil enrichment strategies have a great influence on the spatial and temporal distribution of nematode community composition. In this study, the application of organic amendments stimulated trophic affiliation of nematodes such that the fungivores; Aphelenchoides spp., Aphelenchus spp., Tylenchusi spp. and Ditylenchus spp. were common at 0-5cm depth along with the specialist plant feeders (parasitic nematodes). The presence of K-strategists such as Xiphinema spp.indicated maturity and stability of the environment