Collective effects of irrigation and nutrients on agronomic performance of upland cotton (Gossypium hirsutum L.)
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Abstract
Cotton is regarded as backbone of Pakistan economy; as textile industry entirely dependent on cotton for raw material; while cotton seed is principal source of edible oil production contributing around 80% to the domestically produced total edible oil. In enhancing crop yields and fiber quality, optimum use of NPK fertilizers and irrigation frequency is critical; while interactive effect of these two major factors on cotton is not fully understood. Therefore, this research was conducted to examine the interactive effect of NPK fertilizers and irrigation frequency on cotton growth, development and yield. The NPK treatments included: 124-62-62 kg ha-1 (10% beyond recommendation); 112-56-56 kg ha-1 (recommended) and 100-50-50 kg ha-1 (10% less than recommendation); while tested irrigation frequencies included: 7 irrigations (30, 45, 60, 75, 90, 105, 120 DAS); 6 irrigations (30, 50, 70, 90, 110, 130 DAS [existing recommendation] and 5 irrigations (30, 55, 80, 105, 130 DAS). The interaction study showed that growth and yield contributing traits were optimally influenced in positive direction under the interactive effect of 124-62-62 kg ha-1 NPK × 5 irrigations. The seed cotton yield ha-1 was slightly higher (3482 kg) in crop fertilized with 124-62-62 kg ha-1 NPK × 7 irrigations as compared to seed cotton yield of 3456.50 and 3448 kg ha-1 realized in the interactive effect of NPK at 124-62-62 kg ha-1 × 6 irrigations and NPK at 124-62-62 kg ha-1 × 5 irrigations; while the least seed cotton yield (2691 kg ha-1) was obtained in treatment interaction of 100-50-50 kg ha-1 × 7 irrigations. However, 7, 6 and 5 irrigations regardless of rate of NPK application showed similarity (P>0.05) in agronomic performance of cotton; while NPK level of 124-62-62 kg ha-1 (10% higher than existing recommendation) showed economically viable results. Hence, the treatment based on interaction of NPK @124-62-62 kg ha-1 × 5 irrigations (at 30, 55, 80, 105, 130 DAS) could be practically suggestible for cotton growers, particularly while growing newly evolved variety Sindh-1.
Keywords: Cotton, variety Sindh-1, Interactive effect NPK, Irrigation frequency, Seed, Lint and yield