Integrated weed management in foxtail millet [Setaria italica(L.)P. Beauv.]

Abstract

Millets serve as a vital staple food in Asia and Africa, ensuring food security and nutrition. Millet cultivation is found to be increasing due to its climate resilience and nutraceutical importance. Foxtail millet (Setaria italica (L.) P. Beauv) locally known as thenai, is one of the oldest cultivated millets in India. However, millets also face challenges from weeds, especially in rainfed conditions, causing drastic yield reduction. The present study entitled “Integrated weed management in foxtail millet [Setaria italica (L.) P. Beauv.]” was carried out at the Department of Agronomy, College of Agriculture, Vellanikkara, from January 2024 to April 2024. The objective of the experiment was to develop economically viable integrated weed management practices for foxtail millet. The experiment was laid out in a randomized block design with eight treatments and three replications. The variety used for the experiment was DHFT-109-3, released from UAS, Dharwad. The crop was sown at a spacing of 30 cm x 10cm. The eight treatments were T1- stale seedbed technique, T2- straw mulching in the interspaces, T3 – pre-emergence application of oxyfluorfen @ 0.10 kg/ha (at 0-3 DAS) followed by hand weeding at 25-30 DAS, T4 - pre-emergence application of pretilachlor 30% + pyrazosulfuron ethyl 0.75% WG (premix) @ 0.10 kg/ha (at 0-3 DAS) followed by hand weeding at 25-30 DAS, T5 - Live mulching with green gram @25 kg ha-1, T6 - Brown manuring with green gram @ 25 kg ha-1, T7 - Handweeding at 25 and 45 DAS, T8 - Unweeded control. In the stale seedbed technique, after land preparation, weeds were allowed to germinate for 15 days before sowing the crop, and the emerged weeds were destroyed using non-selective herbicide glufosinate ammonium @ 0.5 kg ha-1. In straw mulching (T2), rice straw (@ 5t ha-1) was spread in the interspaces of the crop to prevent weed germination. In live mulching(T5), green gram grown in the interspaces of the crop was uprooted at 15 DAS and spread in between rows. Similarly in brown manuring, 2,4-D @ 0.5 kg ha-1 was sprayed 15 days after the establishment of green gram. Weed management had no significant effect on plant height within the treatments throughout the crop growth period. The number of tillers and productive tillers was higher in weed managed plots compared to unweeded control, and all the tillers were found to be productive irrespective of the treatments. The highest grain yield (1655 kg ha-1) was recorded in hand-weeded control, which was followed by straw mulching in the interspaces (1516 kg ha-1). The highest straw yield (3620 kg ha-1) was obtained from hand-weeded control, which was on par with straw mulching in the interspaces (3466 kg ha-1). Hand-weeded control (5275kg ha-1) resulted in higher drymatter production, and it was followed by straw mulching in the interspaces (4983 kg ha-1). Hand weeding twice at 25 and 45 DAS reduced the weed density and weed dry matter which in turn increased the yield. Straw mulching in the interspaces of foxtail millet increased the moisture availability to crop and weed suppression due to the unavailability of sunlight, which ensured healthy growth of the crop and ultimately enhanced grain production. High soil moisture, smaller grain size, and selective nature of the pre-emergence herbicides (oxyfluorfen and pretilachlor +pyrazosulfuron ethyl) resulted in phytotoxicity causing 66 per cent reduction in foxtail millet population though they were effective in weed control. Weed density and weed dry matter accumulation at 15 DAS were lowest in herbicide-applied treatments (T3 and T4), while unweeded control and hand weeding showed higher values. At 25 DAS, hand weeding twice at 25 and 45 DAS showed lower weed density and weed dry weight, and it was statistically on par with herbicide applied treatments (T3 and T4), followed by straw mulching (T2). At 45 and 75 DAS, hand weeding twice (at 25 and 45 DAS) recorded as the lowest weed dry weight and highest weed control efficiency, followed by herbicide-applied treatments (T3 and T4). There were no significant differences among treatments with respect to soil physiochemical properties after the experiment. The highest net returns and B: C ratio were realized in treatment brown manuring with green gram (Rs. 17330/- and 1.26 respectively) followed by straw mulching in interspaces (Rs. 11930/- and 1.17 respectively). Increased net returns and benefit-cost (B: C) ratio obtained from brown manuring with green gram can be due to the reduced labour cost compared to other treatments, and it was lower in straw mulching due to the increased cost of straw. Eventhough hand weeding at 25 and 45 DAS was found to be the best and efficient method of weed control in foxtail millet, it is economically not feasible. Straw mulching in the interspaces of foxtail millet was economically effective for summer rice fallows in terms of easiness in straw availability as well as soil moisture conservation. Pre-emergence application of herbicides (oxyfluorfen, pretilachlor + pyrazosulfuron ethyl) is not suitable for weed management in direct sown foxtail millet due to the small grain size of crop and non-selective action of the herbicides, which inhibited the germination of the crop along with weed seeds.