Response of desi cotton (Gossypium arboreum) to nitrogen, phosphorus and potassium fertilization in western Uttar Pradesh

Abstract

Three different trials with nitrogen, phos- 1,521 kglha. However, increase in flower phorus and potassium were conducted on initiation and plant height decreased the Lohit desi cotton (Gossypium arboreum seed-cotton yield considerably. These results L.) during the rainy (kharif) season of 1987, are partly in accordance with the findings 1988 and 1989 at Bulandshahr. The soil was reported3by Brar et al. (1992). sandy loam in texture with pH 7.5, organic Application of 60 kg Pha gave the high- carbon 0.57%, cation-exchange capacity 9.6 est seed-cotton yield, which differed signifi- meq1100 g, available P 12.4 kglha and K cantly from 0, 20 and 80 kg Pha. However, 208 kg/ha. The treatments comprising com- it did not show any significant difference binations of 6 levels of N and 5 levels each from 40 kg Pha for seed-cotton yield. On an of P and K (Table 1) were tried in random- average, the increase in seed-cotton yield ized block design with 5 replications for ni- with 40 and 60 kg Pha over 0, 20 and 80 kg trogen and 6 replications for P and K trials. Pha was 16.64 and 18.46, 14.46 and 16.19 The P and K were applied as basal dose and and 17.63 and 19.46% respectively. Appli- N in 2 splits (half as basal and rest half top- cation of P up to 30 kglha i n c r ~ dthe - dressed at flowering). The crop was sown seed-cotton yield significantly over the con- during the second fortnight of May in each trol. Shama et al. (1988) also reported in- ear. The pooled data of 3 years were creased seed-cotton yield with P. The sig- , kdysed statistically. nificant increase in yield of seed-cotton due The variation in seed-cotton yield due to to P is attributed to flower initiation, number different levels of N was significant .and the of bolls and boll weight. No significant re- maximum seed-cotton yield was obtained sponse was observed with the application of with 60 kg Nha (Table 1). There was an in- potassium. crease owing to 60 kg Nha in seed-cotton The N and P curvilinear regression of or- yield by 65.6, 34.6,4.6, 27 and 77.9% over thogonal polynomial was significant. The 0, 30, 90, 120 and 150 kgha respectively. functiona1,relationships between seed-cotton The results confirm the findings of yield and N and P were best fitted by the Bharadwaj et al. (1988). The significant in-u equations (Table 2). crease in yield-contributing characters, viz. The yield response was 1,438.32 kglha at number of bolls and boll weight, with 60 kg the economic optimum rate of 74.44 kglha Nlha application resulted in yield up to for N and 1,634.84 kglha at the optimum