DISTRIBUTION OF VESICULAR-ARBUSCULAR MYCORRHIZAL FUNGI IN THE NATURALECOSYSTEM

Natural occurrence of vesicular-arbuscular mycorrhizal (VAM) fungi in Haryana soils showed that VAM sporulation was more intensive in the rh izosphere of nonlegumes than of legumes. Maximum number of spores (342 spores per 50 g of soil) was observed in the rhizosphere of mustard, followed by chickpea, wheat, pearl millet and pigeonpea. Four VAM gene ra viz. Glomus, Gigaspora, Sclerocystis and Acaulospora, were present there. Soil pH, total soil P, available P, type of soil, soil moisture and cropping season all variables influenced the VA mycorrhizal popul ation in the natural ecosystem. Numbers of VAM spores highly correlate d with the presence of total soil P and soil pH indirectly affected th e VAM population through the total soil P. The spore population was ab undant in sandy soils as compared to loamy sands. Drier soils had high er number of VAM spores. In summer, the VAM population in soil was les s as compared to winter season.