Effect of nutrient management interventions on system productivity of rice-ragi sequence in Coastal Andhra Pradesh

A field experiment was conducted during kharif season of 2017 & 2018 and rabi season of 2017–18 and 201819 on sandy loam soil of the Agricultural College Farm, Bapatla to evaluate the system productivity of rice- no till ragi cropping system with seven treatments in kharif and in rabi season each kharif treatment divided into four sub treatments. The experiment consisted of seven treatments viz., T_։: 100% RDF (100-60-40 N-P-Kkg ha⁻¹); Т_г: 100% RDF + soil application of ZnSO₄ @ 50 kg ha⁻¹; T₃:125% RDF + soil application of ZnSO₄ @ 50 kg ha⁻¹; T₄: 75% RDF + poultry manure @ 0.821 ha⁻¹ + soil application of ZnSO₄ @ 50 kg ha⁻¹; T_s: 75% RDF + FYM @ 5.0 t ha⁻¹ + soil application of ZnSO₄ @ 50 kg ha⁻¹; T₆: 50% RDF + poultry manure @1.6 t ha⁻¹ + soil application of ZnSO₄ @ 50kgha⁻¹ and T_?: 50% RDF + FYM @ 10 t ha⁻¹ + soil application of ZnSO₄ @ 50 kgha⁻¹. The experiment was laid out in Randomized Block Design and replicated thrice during kharif rice and in rabi four sub treatments i.e, S_yNo fertilizer, S₂:100%, RDF (30-30-20 N-P-K kg ha⁻¹), S₃:75% RDF (22.5–22.5–15 N-P-K kg ha⁻¹) and S₄:50% RDF (15-15-10 N-P-K kg ha⁻¹) and hence, split plot design was adopted. Maximum rice equivalent yield of ragi (8108, 8570 and 8339 kg ha⁻¹ in both the years and in pooled data respectively) as well as system productivity of rice-ragi (13452, 14036 and 13744 kg ha⁻¹ in both the years and in pooled data respectively) sequence was observed with 50% RDF + FYM @ 101 ha⁻¹ + ZnSO₄ @ 50 kg ha⁻¹ as residual effect, among the fertilizer levels, S₂ level i.e., 100% RDF (30-30-20 kg N-P-K ha⁻¹) on succeeding ragi crop (7413, 8003,7708 and 11893,12641, 12267 kg ha⁻¹ rice equivalent yield and system productivity respectively in both the years and in pooled data).