RESUMO
In the Kharif grain sorghum growing areas of Karnataka, the sorghum production suffers greatly due to weed problem, which offers limitations to crop. It was found that weed infestation become unmanageable throughout the growing period by the traditional methods of interculturing and manual weeding due to continuous and heavy rains during entire vegetative and early reproductive stages of Kharif sorghum. Hence, integration of herbicides with some cultural operations and use of pre-emergence, post-emergence herbicides in combination with mechanical methods can prove to be more successful. A field experiment entitled “Weed management in kharif grain sorghum” was conducted during Kharif 2019 at ARS, Hagari in deep black soil with neutral reaction (pH 7.50), organic carbon (5.5 g kg-1), available nitrogen (248.00 kg ha-1), available phosphorus (36.75 kg ha-1) and available potassium (312.00 kg ha-1). An experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. There were fourteen treatments comprising of weed management practices. The dominant weeds observed in the experimental fields were among grasses Brachiaria reptans, while in broad leaved weeds, Amaranthus viridis and among sedges, Cyperus rotundus. Significantly lower population of grasses, sedges, and broad leaved weeds, weed dry weight, weed index (%) and higher weed control efficiency throughout the crop growth period was noticed in sequential pre-emergence application of atrazine 50 WP @ 0.50 kg a.i. ha-1 as PE fb 2,4-D Na Salt 80 WP @ 0.75 kg a.i. ha-1 as PoE at 25 DAS except weed free treatment. Atrazine 50 WP @ 0.50 kg a.i. ha-1 as PE fb 2,4-D Na Salt 80 WP @ 0.75 kg a.i. ha-1 as PoE at 25 DAS recorded significantly higher plant height, dry matter accumulation, leaf area, test weight, grain yield, straw yield, harvest index, gross return, net return and benefit cost ratio (160.8 cm, 183.4 gplant-1, 24.1 dm2 plant-1, 30.53 g, 4195 kg ha-1, 9891 kg ha-1, 29.80 %, Rs. 1,03,675ha-1, Rs. 71,636 ha-1and 3.24, respectively) except weed free and it was on par with atrazine 50 WP @ 0.50 kg a.i. ha-1 as PE fb IC at 25 DAS and HW at 25 DAS and IC at 40 DAS.
RESUMO
A field experiment was conducted at experimental farm, AICRP on Integrated Farming Systems, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani (M.S.) during kharif seasons of 2020-21 on to study the “Impact of high density planting and weed management practice on growth and yield of Bt. cotton. (Gossypium hirsutum L.)” Treatment consist of Twelve treatment combinations comprising Three planting densities in main plot that is (S1-120 cm x 45 cm (18518 plants ha-1), S2- 80 cm x 60 cm (20833 plants ha-1) and S3- 90 cm x 45 cm (24691plants ha-1) and four weed management practices that is W1 - Stale seedbed technique + PoE Pyrithiobac Sodium 10% EC @ 62.5 g ha-1 + Quizolfop-ethyl 5% EC @ 50 g ha-1 + Straw mulching, W2 - Stale seed bed technique +PoE Glufosinate ammonium 13.5% SL @ 0.7 kg ha-1 + Hand weeding, W3 - Weed Free and W4 - Weedy Check.The mean maximum AGR for plant height were recorded under high density planting 90 cm x 45 cm. Among different growth intervals 61-90 DAS recorded maximum AGR for plant height (1.664 cm day-1 plant-1), while mean maximum AGR for dry matter (2.358 g day-1 plant-1) were recorded between 91-120 DAS under high density planting 120 cm x 45 cm. Among weed management practices, weed free treatment recorded mean maximum AGR for plant height (1.645 cm day-1 plant-1) 61-90 DAS interval, while mean maximum AGR for dry matter (2.441 g day-1 plant-1) were recorded between 91-120 DAS. The mean CGR, RGR and LAI were also maximum under weed free treatment.