Residual Effect of Water Soluble Fertilizers on Productivity and Nutrients Uptake of Cowpea in Aerobic Rice-cowpea Cropping Sequence under Fertigaton

A field experiment was under taken at University of Agricultural Sciences, GKVK, Bengaluru, Karnataka state, India to study the residual effect of fertigation of water soluble fertilizers on productivity and nutrients uptake of cowpea under aerobic rice-cowpea cropping sequence during Kharif 2015-16 and 2016-17 with 16 treatments replicated thrice in randomized block design. Significantly higher plant height (58.47 cm), number of branches plant-1 (11.71) and total dry matter accumulation plant-1 (70.60 g) were recorded in fertigation with 100% RDF through water soluble fertilizer at 8 DI. Likely, similar treatment 100% RDF through water soluble fertilizer at 8 DI was recorded significantly higher number of pods plant-1 (16.58), pod length (16.67 cm), seeds per pod (16.10), test weight (11.93 g), seed yield (12.94 q ha-1) and haulm yield (26.17 q ha-1). While higher total uptake of N, P and K by cowpea (68.94, 14.67 and 61.39 kg N, P and K ha-1, respectively) was recorded in 100% RDF through water soluble fertilizers at 4 DI (T5) than all other treatments. 100% RDF through WSF at 8 DI (T8) was recorded notably higher total Ca, Mg and S uptake by cowpea (50.71, 24.71 and 12.09 kg Ca, Mg and S ha-1, respectively). Significantly higher uptake of total Fe, Zn and Cu by cowpea crop (680.23, 91.30 and 38.27 g ha-1, respectively) was recorded with 100% RDF through water soluble fertilizers at 8 DI (T8). Total uptake of Mn was recorded higher by cowpea was observed (181.67 g ha-1) in 100% STCR dose through water soluble fertilizers at 4 DI (T11).