Enumeration of arthropods density in context to plant diversity and agricultural (organic and conventional) management systems.

摘要

Arthropods were inventoried in fields and woody hedgerows of organic and conventional agricultural fields situated in Bahour-Puducherry, India. The objective was to access the total abundance, family richness and composition of arthropods in two different agricultural systems (organic and conventional). The study was conducted twice a month from August 2008 to October 2010 by visual searching and pitfall trap methods in crop fields and adjacent hedgerows of organic and conventional fields. A total of 2,59,722 individual's arthropods belonging to 185 families were recorded during the study. The study showed that beneficial and phytophagous arthropods differed in their abundance/richness in organic and conventional sites both in visual searching and pitfall traps methods. Phytophagous arthropods were more abundant in field margins with hedgerows, while beneficial arthropods were abundant in crop fields. The study also demonstrated a strong relationship between plant composition and management strategies. The arthropod species composition was highly influenced by crop species, habitats, total hedgerow length and Shannon diversity index influence. In general, the number of beneficial arthropods was always higher in the organic plots in relation to the conventional ones, reflecting on the Shannon index diversity. Higher population was represented by the individuals belonging to the taxa/order Arachnida (mites, spiders and pseudo-spiders), Oribatida, Collembola (spring tails) and Coleoptera (insects). The prime importance is to consider both local organic management practices and marginal woody hedgerow in conserving beneficial arthropods population, to maintain soil fertility and sustainable productivity in long term.