Vol. 12, Issue 8 (2023)

Author(s):
T Subramani, TP Swarnam, Sirisha Adamala and I Jaisankar

Abstract:
In Andaman and Nicobar islands, vegetables crops are cultivated during post monsoon period (Nov – May) and experience severe water stress during reproductive stages. Under this context, the field experiments were conducted to study the effect of moisture stress management practices on growth, yield attributes and yield of Okra (Arka Nikita) during dry periods (Feb-May) of 2021 and 2022. The experiment was conducted in strip plot design with three horizontal treatments (Surface irrigation + residue mulch, Drip + plastic mulch, Sub-surface drip irrigation) and four vertical treatments (Hydrogel, hydrogel + K spray, hydrogel + Ca spray, hydrogel + K & Ca spray) in three replications. The irrigation was given through drip, subsurface drip and surface irrigation. Pusa hydrogel was applied through seedling dipping. The fertilizer was given as per the recommended dose (100: 60:50 NPK kg/ha). Potassium Nitrate and Calcium Nitrate were applied as foliar spray at flowering and 15 days after the first spray. In Okra, drip irrigation with plastic mulching recorded maximum fruit length (15.0 cm), no. of fruits (14.9), fruit weight (20.4 g) which resulted in higher yield (303 g/plant, 9.68 t/ha) followed by sub-surface drip irrigation. Application of hydrogel + K & Ca foliar spray recorded maximum fruit length (15.0 cm), no. of fruits (14.5), fruit weight (19.6 g) which resulted in higher yield (286 g/plant, 9.15 t/ha) and at par with hydrogel + K spray. Maximum relative leaf water content (53.8%), Maximum membrane stability index (71.0), total chlorophyll (1.8 mg g^-1) and lesser proline content (27.8 mg g^-1) were recorded in drip irrigation + plastic mulching. Similarly, maximum RLWC (53.4%), membrane stability index (67.3), total chlorophyll content (1.65 mg g^-1) and minimum proline (24.5 mg g^-1) were recorded in hydrogel + foliar spray of K & Ca. Higher water use efficiency (327 kg/ha-cm) was observed in drip irrigation + plastic mulch. The maximum net return (₹ 2,31,200) was recorded in drip irrigation + plastic mulch which was followed by sub-surface drip irrigation. Similarly, maximum net return (₹2,26,333) was recorded in the treatments which received hydrogel + foliar spray of K & Ca. Hence, it can be concluded that drip irrigation + mulching, hydrogel and foliar spray of K and Ca is best option to mitigate the moisture stress in okra under island condition.