Validation Cropping Systems and Input Management in Calcareous Vertisols

Inputs were tested and validated to supply optimum P and Zn content in index leaf of Bt hybrid cotton during squaring to flowering stage, such as seed treatment with NPK consortia to encourage soil biological activities in low organic carbon highly Calcareous Vertisols alongwith 75% RDF. Bentonite sulphur @20 kg ha-1 yr-1 soil application (SA) + RDF; Sagarika seed treatment @ 0.2% alongwith twice foliar sprays @ 0.002% at squaring and flowering + RDF; Nano ZnO 4% Seed treatment twice foliar sprays@0.004% + RDF produced significant agronomic response during 2019, exception was during 2020, the magnitude was 50% less due twice torrential (>60-100mm) and five times medium (25-50mm) rains during July and August months upset the reproductive physiology of cotton, shedded all the fruiting bodies, unable to maintain index leaf NPK, besides heavy pink bollworm attack. All these treatments were applied with 100% RDF @90:45:45 N:P2O5:K2O granular, two splits of basal spot application having 6.5% Sulphur containing, N: P2O5: K2O @ 22.5 kg ha-1 twice on 15, 30 DAS and twice as Urea at 45 and 60 DAS, Bentonite Sulphur @ 20 kg ha-1 +RDF or seed treatment and foliar applications of bio-stimulants Sagarika @ 0.02% and twice foliar applications of the same @ 0.002% and Nano ZnO @ 0.004% twice produced 67-86 ppm Zn in index leaf of the Bt hybrid cotton, similar to that of chelated Zn 0.5%. These inputs produced 161-287 kg lint ha-1 i. e. more than double 38 to 50% due to better nutrient uptake, biomass production, boll number with more than ₹. 15 to 30, 000/- ha-1 profitability and 1.5 to 2.2 C:B ratio, FUE 1.6 to 1.2 and lowest cost of production in both the years. Large scale OFTs in Kalmeshwar Tq, Nagpur district (M.S.) India in highly Calcareous soils, on suitable field and horticulture crops, irrigations and inputs management confirmed the beneficial effect of RDF 150% @120:60:60 N:P2O5:K2O three splits fertilizers mixture of SSP + Urea + 20:20:0:13 soil application and also Bentonite sulphur or with and without two winter irrigations in late September besides seed treatment with PGPRs or Sagarika 0.002% before sowing and twice foliar applications with the same or alongwith chelated micronutrients 0.5% + WSF 17:44:0 and 0:0:50 2.0% + Boron 0.3% alternately with ZnSO4 0.5% or nano ZnO 0.004% alongwith Urea 2% and Boron 0.3% or were help full in doubling the seed cotton yields besides reducing the pre mature leaf reddening by maintaining optimum index leaf nutrient content.