Studies on Earliness of Bt Cotton Influenced by Moisture Conservation and Fertilizer Levels under Rainfed Condition

A field experiment was conducted at Cotton Research Station, Nanded (M.S.) India during kharif season of 2019 and 2020 to study effect of moisture conservation practices and fertilizer levels on earliness of Bt cotton under rainfed condition. The trial was conducted with Bt cotton hybrid NHH 44 (BG II) in split plot design and was replicated thrice. Four moisture conservation treatments (M1- flat bed, M2- opening of furrow at 60 DAS, M3- application of superabsorbent @ 12.5 kg ha-1 and M4- broad bed and furrow) were evaluated in main plot along with four NPK levels (F1- 80:40:40 kg ha-1, F2 - 100:50:50 kg ha-1, F3 -120:60:60 kg ha-1 and F4 - 140:70:70 kg ha-1) in sub plot. The broad bed and furrow (BBF) practice of moisture conservation was found to have significantly higher seed cotton yield (1369 kg ha-1) and per cent share to the total seed cotton yield was 58.58 per cent in first picking over control. However, opening of furrow recorded more seed cotton yield (1125 kg ha-1) and its share to total yield was 47.97 per cent at second picking. Seed cotton yield in second picking was significantly increased in moisture conservation practices. The BBF was found to have earliness with respect to various indices (Bartlett’s index, combined picking and day index, fraction of first picking index, mean maturity date index and production rate index) followed by other moisture conservation practices over flat bed.

Fertilizer levels didn’t affect seed cotton yield in first picking. Higher fertilizer levels of F3 and F4 being significant over lower levels for seed cotton yield in second picking; showed delayed crop maturity based on various earliness indices.