Effect of Rock Phosphate Enriched Compost on Soil Micro Nutrient Status and Uptake of Finger Millet-owpea Cropping System in Sandy Loam Soils of Southern Dry Zone of Karnataka

Abstract:

A field experiment was conducted at Zonal Agricultural Research Station, VC Farm, Mandya during kharif 2017, summer 2018, kharif 2018 and summer 2019 to study the effect of rock phosphate enriched compost on soil micronutrient status and uptake after harvest of finger millet-cowpea cropping system. Prior to initiation of the field experiment, three different composts viz., urban solid waste compost (USWC), vermicompost and farm yard manure (FYM) were enriched with rock phosphate at 5 per cent. Field experiment consisting of eleven treatment combinations comprising recommended N and K, and P through varied levels of enriched composts. The experiment was laid out in RCBD design with three replications and the test crops were finger millet and cowpea. The initial P2O5 of the experimental site was very high (133.58 kg ha-1). The results revealed that application of recommended N and K + 75 per cent P supplied through enriched USWC (T5) had significantly higher DTPA extractable soil micronutrients viz., Cu (1.62 and 1.54 mg kg-1), Zn (1.85 and 1.78 mg kg-1), Fe (5.35 and 5.27 mg kg-1) and Mn (17.67 and 16.58 mg kg-1) in pooled data of both finger millet and cowpea, respectively. In pooled analysis, treatment T5 recorded significantly higher uptake of Cu (139.22 and 194.03 g ha-1), Zn (165.80 and 261.37 g ha-1), Fe (185.22 and 443.64 g ha-1) and Mn (183.74 and 332.04 g ha-1) in grain and straw of finger millet, respectively. Similarly, in residual cowpea, grain and haulm uptake was noticed higher in T4 (recommended N and K + 50 per cent P supplied through enriched USWC), T5, T7 (recommended N and K + 50 per cent P supplied through enriched vermicompost) and T8 (recommended N and K + 75 per cent P supplied through enriched vermicompost) treatments.