Optimization of spacing and time and dose of Defoliant application for High-Density Planting system in cotton

Abstract

A field experiment was conducted at Cotton Research Station, Srivilliputtur from October 2017 to February 2018 to optimize spacing and time and dose of defoliant application to suit high-density planting system in cottonunder irrigated conditions. The experiment was conducted in a split-plot design with three replications. The treatments consisted of three levels of plant spacings (100 x 10 cm, 60 x 15 cm and 75 x 30 cm) in main plot and four treatments with time and doses of defoliant application of Dropp Ultra (Tembotrione 34.4 % SL) at 200 ml/ha at 120 DAS, 200 ml/ha at 130 DAS, 2000 ppm (500 ml/ha) at 120 DAS and 2000 ppm (500 ml/ha) at 130 DAS were accommodated in subplot. The results revealed that though the normal spacing of 75 x 30 cm produced higher number of sympodial branches and bolls per plant, it was comparable with that of HDPS with 100 x 10 cm spacing. Among the three spacings, 100 x 10 cm with a plant population of 1,00,000 plants/ha (HDPS) registered the highest seed cotton yield of 2063 kg/ha which was comparable with closer spacing of 60 x 15 cm with 1,11,111 plants/ha (1947 kg/ha) and significantly superior than the existing recommended spacing of 75 x 30 cm with 44,444 plants/ha (1779 kg/ha). Higher gross income, net income and higher benefit-cost ratio were also recorded with HDPS followed by 60 x 15 cm. Dropp ultra application at the rate of 200 ml/ha on 130 DAS was found to be effective for higher seed cotton yield and economic benefits.

DOI

https://doi.org/10.29321/MAJ.2019.000304

Pages

499 - 501

Creative Commons

Copyright

© The Author(s), 2026. Published by Madras Agricultural Students' Union in Madras Agricultural Journal (MAJ). This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited by the user.

Keywords