Department of Agricultural Chemistry and Soil Science, Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal, 736165.
*Present address: Department of Chemistry, A.B.N. Seal College, Cooch Behar.
**Present address: Department of Chemistry, North Bengal University, Darjeeling, West Bengal.
Five extractants were tried viz., Bray-1, Bray-2, Olsen, Mehlich-1 and AB-DTPA to assess the available P status in the soils of four land uses namely; tea garden, orchard, cultivated land and forest in tarai region of West Bengal. Biological availability of P was estimated by growing wheat in Neubauer seedling technique. In the soils of all land uses the highest amount of soil P was extracted by Bray-2 extractant. The extracting power of different extractants was not in the same order for all the soils. The extracted amount of P by various extractants was correlated with inorganic P fractions. Except Bray-2, all the soil tests had highly significant positive correlation with Fe-P and Al-P. Bray-1-P explained the highest variation in P uptake by wheat in orchard (86%) and cultivated land soils (87%) while Bray-2-P explained the maximum variation in P uptake for tea garden (75%) and forest (83%) soils. Bray reagents were found to be the most efficient extractants for these land use soils under acidic tarai agro-climatic region of West Bengal.
Soil P tests, land use, inorganic P forms, P uptake by wheat
