Methods of Cotton (Gossypium hirsutum) Establishment and Direct and Residual Zinc Fertilization Effects on Productivity, Quality and Energetics of Onion (Allium cepa) under Cotton-Onion Cropping System

摘要

A field experiment was conducted during rainy (kharif) and winter (rabi) seasons of 2013-14 and 2014-15 to evaluate the methods of cotton establishment and direct and residual zinc fertilization effects on productivity, quality and energetics of onionunder cotton-onion cropping system. Onion re-corded higher bulb yield, bulb quality, nutrient content, energetics and economics after transplantedcotton as compared to direct sown cotton and differences were significant with transplanted cotton as compared to direct sown cotton and differences were significant with respect to economic parameters. Direct application of 5.0 kg Zn ha 1 and residual effect of 5.0 and 7.5 kg Zn ha 1 to cotton recorded statistically similar values of bulb yield, bulb qual ity, nutrient content, energetics and economics which were significantly superior to control and residual effect 2.5 kg Zn ha~(-1). Bulb yield was found to increase by 4.6, 13.4and 12.2% and 14% during 2013-14 and 9.6, 22.4 and 26.2% and 29.2% during 2014-15 due to residual effect of 2.5, 5.0 and 7.5 kg Zn haand direct effect of 5.0 kg Zn /ha, respectively. Transplanted plots recorded slightly highergrade 'A' bulbs as compared to direct sown plots. Direct effect of 5.0 kg Zn harecorded higher grade 'A' bulbs which was at par with residual effect of 5.0 and 7.5 kg Zn ha ' and significantly different from control and residual effect of2.5 kg Zn ha~(-1). Direct application of 5.0 kg Zn ha~(-1) recorded significantly higher protein content (4.48 and 4.38), which was at par with residual effect of 5.0 kg Zn ha 1 (4.41 and 4.30) and 7.5 kg Zn ha~(-1) (4.44 and 4.36) in the first season and it was also at par with residual effect of 2.5 kg Zn ha ~' (4.28) in the second season, respectively.Irrigation water use efficiency also increases due to increasing level of zinc fertilization. Residual effectof 5.0 and 7.5 kgZnha~(-1) recorded higher energy productivity, energy use efficiency and energy intensity. Both residual and direct effect of Znfound to enhance the quality of bulb in terms of Zn enrichment. Direct sown plots recorded slightly higher soil zinc content as compared to the transplanted plots and residual effect of 7.5 kg Zn ha~(-1) recorded higher soil zinc content than all otherresidual effect of treatments. Successive increase in Zn level caused significant increase in system productivity, production efficiency, economic efficiency and irrigation water productivity up to application of 5.0 kg Zn ha~(-1). Residual effect of 5.0/7.5 kg Zn ha~(-1) applied to Bt cotton was significant on productivity and profitability of succeeding onion and it was on par with direct application of 5.0 kg Zn ha~(-1) applied to onion.