Dtpa-extractable zinc and its availability in valley soils of manipur

Information regarding distribution of zinc in soils is important for understanding its chemical reactions and bioavailability in wetland as well as upland rice soils for application of fertilizers and increasing yield of reice plants. Thus, a study on relationship between physico-chemical properties and DTPA-extractable Zn content of rice soils were done, for that thirty six surface soil samples (0-20cm) were collected from different paddy fields of four valley districts of Manipur namely Imphal-east, Imphal-west, Thoubal and Bishnupur district using Stratified Random Sampling. . All the soil samples were acidic in reaction with pH ranging from 4.90 to 6.00 with mean value of 5.32. The Electrical Conductivity of the soils varied from 0.05 dSm¬¬¬-1 to 0.26 dSm -1 at 250C with a mean value of 0.11 dSm¬¬¬-1. The analyzed soils showed organic carbon content 0.79 to 3.51 % with a mean value of 2.68% and cation exchange capacity of the soils 8.3 to 24.4 [cmol (p+) kg-1] with mean value was 17.34 [cmol (p+) kg-1]. The studied soils were mostly clay in texture with 20.0 per cent to 73 .2 per cent content. Considering 0.6 mg kg-1 as the general critical limit of available zinc (DTPA-Zn) in soils, 91.67% of the soils are sufficient in zinc (DTPA-Zn) ranging from 0.55 to 1.26 mg kg-1 with mean value of 0.89 mg kg-1 in the soils. DTPA-Zn showed significant negative relationship with soil pH (r= -0.483**) indicating the availability of Zn decreases with increase pH.