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20171
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Subject: Soil Science × Author: Anjali × End date: 2019 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    STUDIES ON THE DISTRIBUTION OF ZINC FORMS IN SOME CULTIVATED SOILS OF OUTER HIMALAYAS
    (CSKHPKV, Palampur, 2017-07) Anjali; Sharma, V.K.
    Understanding the spatial distribution of various forms of zinc (Zn) in soils helps in predicting its short- and long-term availability for sustainable crop production. In the present investigation, 101 surface soil samples, representing major soils (Entisols & Inceptisols) and land use types of cultivated lands in Outer Himalayas of Himachal Pradesh, were collected to study the spatial distribution of Zn forms and their relationship with important soil properties. The soil samples were collected at 0-15 cm depth from cultivated soils under maize-wheat, paddy-wheat, vegetable-based & sugarcane-based cropping sequences and at 0-30 cm depth from orchards of mango, mandarin, guava and litchi and analyzed for important soil properties and Zn forms using standard methods. Sand (%), silt (%), clay (%), textural class, soil pH (1:2.5), electrical conductivity (dS m-1 ), organic carbon (%), cation exchange capacity {cmol(p+) kg-1}, base saturation (%) and calcium carbonate (%) in cultivated soils of Outer Himalayas ranged from 40 to 80, 12 to 45, 6 to 24, loamy sand to sandy clay loam, 6.1 to 7.8 (slightly acid to slightly alkaline), 0.142 to 0.372, 0.305 to 1.525, 4.7 to 13.3, 60 to 77 and 0.05 to 2.20, respectively. Available N, P, K, Ca, Mg, S, Cu, Fe, Mn and Zn in the soils studied were low to medium, low to medium, medium, medium to high, medium to high, low to medium, sufficient, sufficient, sufficient and deficient to sufficient, respectively. Per cent soil samples deficient in N, P, S and Zn were 26, 47, 59 and 39, respectively. Such a spatial variation may be explained in light of pedo-genesis and prevailing nutrient management practices. Water soluble, exchangeable, specifically adsorbed, organically bound, Mn-oxide bound, Al- and Fe-oxide bound, residual and total Zn in soils under different land use types varied from 0.057 to 0.365, 0.171 to 0.575, 0.33 to 3.07, 3.40 to 17.97, 1.30 to 10.82, 4.76 to 32.75, 14.78 to 79.50 and 30.44 to 130.65 mg kg-1 with mean values of 0.167, 0.366, 1.57, 9.31, 5.40, 17.77, 52.96 and 87.53 mg kg-1 , respectively. On an average, water soluble, exchangeable, specifically adsorbed, organically bound, Mn-oxide bound, Al- and Fe-oxide bound and residual Zn constituted about 0.20, 0.45, 1.77, 10.61, 6.02, 19.94 and 61.01 per cent of total Zn, respectively. There were significant and positive correlations between different chemical pools of Zn, indicating the existence of dynamic equilibrium among them. Clay, organic carbon and cation exchange capacity were significantly and positively correlated with each form of Zn; while sand, pH and calcium carbonate were negatively correlated. Silt was significantly and positively correlated while electrical conductivity and base saturation were negatively correlated with most of Zn forms. Such interrelationships indicated that basic soil attributes studied are important factors affecting the distribution of Zn forms in the study area. Among all, per cent clay, organic carbon and cation exchange capacity exhibited better correlations with each form of Zn. Further, soils with lower values of clay, organic carbon and cation exchange capacity contained less amount of soil Zn in each pool as compared to soils higher in those soil arributes. Therefore, former soils require relatively more attention on Zn fertilization as compared to latter ones for sustaining soil productivity.