Evaluation of the Impact of Herbicidal Weed Management Practices on Weed Density, Yield Attributes and Yield of Irrigated Chickpea (Cicer arietinum L.)

In the Rabi season of 2021-22, an experiment was conducted at the Agronomy Research Farm of CCS Haryana Agricultural University in Hisar. The aim was to examine how herbicidal weed management affects irrigated chickpea. The experiment was laid out in Randomised Block Design (RBD) with thirteen treatments, each repeated three times. The treatments included various herbicides applied at different stages, such as pre-plant incorporation (PPI), pre-emergence (PRE), and post-emergence (POE). Interestingly, the Ready mix (RM) herbicide application of pendimethalin + imazethapyr (RM) @ 1000 g a.i ha-1, applied both as PPI and PRE, outperformed the herbicides applied solely as PPI, PRE, or POE. Among the herbicidal treatments, the combined during PPI and PRE stages exhibited excellent control over a diverse weed population, leading to a significant increase in chickpea yield compared to the weedy check. The number of seeds per pod, pods per plant, and branches per plant varied significantly with different weed control treatments. Weed-free plots showed the highest values in these parameters. The uncontrolled growth of weeds in the weedy check resulted in a 55.2% reduction in seed yield as compared to weed-free plots. The maximum seed yield (1968 kg ha-1) and favorable yield attributes were observed in the weed- free treatment, statistically comparable to the yield obtained from two hand weeding at 30 and 50 days after sowing (1940 kg ha-1). Among herbicidal treatments, the highest seed yield was achieved with the PRE application of pendimethalin + imazethapyr (RM) @ 1000 g a.i. ha-1 (1827 kg ha-1). The dominant weed flora consisted of Chenopodium album, Fumaria parviflora and Anagallis arvensis. Density of different weed species was significantly influenced by different weed control treatments. All the weed control treatments significantly reduced the total weed density and dry matter accumulation by weeds in comparison to weedy check. Weed free and two hand hoeing reduced the weed population drastically which was statistically at par with PRE application of pendimethalin + imazethapyr (RM) at 1000 g a.i. ha-1. Chenopodium album, Fumaria parviflora and Anagallis arvensis were effectively controlled by RM irrespective of its time of application.

Yield and Economics of Onion as Influenced by Pre and Post Emergence Herbicdes

Onion (Allium cepa L.) weed interference lowers bulb yield and financial return for onion growers who pay for labour. During the Rabi seasons of 2011–12 and 2012–13, a field experiment was worked out at the Horticultural College and Research Institute, Dr.Y.S.R Horticultural University, Venkataramanagudem, Tadepalligudem, West Godavari District, A.P to examine the effects of pre and post emergence herbicides on the economics of onion cv.N–53. Ten pre- and post-emergence herbicide treatments (Pendimethalin, Oxyflourfen, Imazethapyr, and Quizalofopethyle) and their combinations, reproduced in a random block design, made up the experiment. Significantly, T9 (weed free-hand weeding at 30, 60, and 90 DAT) outperformed the other treatments in terms of gross and net returns, which was followed by T8 (Oxyfluorfen 0.125 kg a.i as PE + Quizalofopethyl @ 75g a.i per hectareas POE) and T6 (Pendimethalin 0.75 kg a.i as PE + Quizalofop ethyl @ 75 a.iper hectare). When compared to T6 (Pendimethalin @ 0.75 kg a.iper hectare as PE + Quizalofop ethyl @ 75 g a.iper hectare as POE), T8 (Oxyfluorfen @ 0.125 kg a.iper hectareas PE + Quizalofop ethyl @ 75 g a.iper hectare as POE) had a considerably greater B:C ratio. Hand weeding made farming more expensive. This suggested that chemical weed treatment was used to obtain the most profit per acre.

Evaluation of Mulching Methods and Legume Intercropping on Weed Control Efficiency and Agronomic Traits of Pearl Millet (Pennisetum glaucum)

Aim: To evaluate the weed control efficiencies of different mulching practices and legume intercropping in transplanted pearl millet.Study Design: Randomized Complete Block Design (RBD).Place and Duration of Study: The field trial was conducted during the Rabi season of 2022 at the school of agricultural sciences in Karunya Institute of technology and sciences, Coimbatore, Tamil Nadu.Methodology: The field trial consists of 8 treatments viz., T1 - PE of Atrazine 0.5kg/ ha +1 Hand Weeding at 30 DAT, T2 - Two Hand Weeding at 15 and 30 DAT, T3 - Paddy straw mulching at 5t/ ha 3 DAT, T4 - Black polythene mulching at 3 DAT, T5 - Black silver polythene mulching at 3 DAT, T6 - Intercropping of pulses (cowpea) (1:1), T7 - Intercropping of pulses (cowpea) (1:1) + PE Pendimethalin 0.75 kg/ ha, T8 - Un weeded check.Results: Results of the experiment proves that the intercropping of cowpea in pearl millet along with the pre-emergence application of pendimethalin proves to be beneficial and advantageous in terms of returns per rupee invested for profitable crop production, rather than going for polythene mulches. Hence adoption of legume intercropping in pearl millet, along with the usage of mild herbicides like pendimethalin, will be an economically viable and environmentally sustainable weed management practice for improving the yield of pearl millet.

Effect of Nitrogen and Weed Management Practices on Growth and Yield of Blackgram (Vigna mungo L.)

A research trail was conducted in Kharif 2022, at Crop research form, SHUATS, Prayagraj. To study the “Effect of nitrogen and weed management practices on growth and yield of Blackgram” (Vigna mungo L.). The treatments consist of three levels of nitrogen (15, 30 and 45 kg/ha) and weed management practices (Hand weeding twice (20 & 40 DAS), Pendimethalin (0.75ml/ha) Pre-emergence (5 DAS), Imazethapyr (75g/ha) Post-emergence (25 DAS) are included. Experiment were laid out in randomized block design with 10 treatments each replicated thrice. The result showed that viz: significantly higher plant height (64.49 cm), number of nodules/plant (23.80), number of branches/plant (6.40), pods/plant (32.13), seeds/pod (8.20), grain yield (1223.33 kg/ha), Stover yield (2472.67 kg/ha), lower weed population/m2 (4.06) recorded in (treatment 9) Nitrogen (45 kg/ha) + Imazethapyr (75 g/ha) Post-emergence.

Performance of herbicides in sugarcane straw / Dinâmica de herbicidas em palha de cana-de-açúcar

The process of mechanical harvesting of sugarcane generates a large deposition of straw on the soil surface, providing a coverage that several studies have found important for reducing the weed population. Although such coverage reduces weed infestations, additional management, including chemical control, is still needed. Thus, this study aimed to evaluate the leaching of atrazine, pendimethalin, metribuzin, clomazone, diuron and hexazinone in sugarcane straw. The experiment was conducted at the School of Agronomic Engineering at UNESP (Sao Paulo State University) - Botucatu/SP. The sugarcane straw was collected in the field, cut and placed in quantities of 10t ha-1 in the capsules used as experimental units. The experimental design was completely randomized, using six herbicide treatments and four replications. Within 24 hours after the herbicides were applied in capsules with straw, five different rainfalls (5, 10, 20, 50 and 100mm) were simulated. The leached water was collected for chromatographic analysis. The herbicide percentages that crossed the straw layer were statistically correlated with the rainfall amount by the Mitscherlich model that compares the facility of herbicide removal from sugarcane straw. In summary, pendimethalin did not present quantified transposition of the product by sugarcane straw even with a rain simulation of 100 mm. Furthermore, two different profiles of facility to transpose the herbicides in straw were found: one for metribuzin and hexazinone that crossed quickly through the straw layer and another for atrazine, diuron and clomazone that required more rainfall to be leached from coverage to the soil according to the maximum removable amount of each herbicide.

O processo de colheita mecanizada de cana-de-açúcar gera uma grande quantidade de palhada depositada na superfície do solo e vários trabalhos destacam a importância da manutenção dessas coberturas em sistemas de cana crua, com destaque na redução da população de plantas daninhas. Mas, apesar de a cobertura vegetal reduzir a infestação das plantas daninhas, medidas complementares, como o controle químico, ainda são necessárias. Dessa forma, o objetivo deste estudo foi avaliar a transposição dos herbicidas atrazine, pendimethalin, metribuzin, clomazone, diuron e hexazinone em palha de cana-de-açúcar. O experimento foi desenvolvido na Faculdade de Ciências Agronômicas da UNESP - Botucatu/SP. A palha da cana-de-açúcar foi coletada em campo, cortada e colocada em quantidades de 10t ha-1 em recipientes plásticos utilizados como unidades experimentais. O delineamento experimental foi inteiramente casualisado, e foram testados seis tratamentos (atrazine, pendimethalin, metribuzin, clomazone, diuron e hexazinone) e quatro repetições. Nas cápsulas com palha e pulverizadas, foi realizado, no período de 24 horas após a aplicação, a simulação de diferentes lâminas de chuva (5, 10, 20, 50 e 100mm) e coletada a água lixiviada para posterior quantificação cromatográfica. Como análise estatística, os herbicidas foram correlacionados com as lâminas de chuva e foi usado o modelo de Mitscherlich para ajuste dos dados, que permitiu comparar a facilidade de remoção dos herbicidas pela palha. Em síntese, para o pendimethalin, não se observou transposição quantificada do produto pela palha de cana-de-açúcar, mesmo com uma lâmina de 100mm de chuva. Foram encontrados dois perfis diferentes de facilidade de transposição dos herbicidas em palha: um para o metribuzin e hexazinone, que passaram rapidamente pela camada de palha, e outro para atrazine, clomazone e diuron, que precisaram de uma quantidade superior de chuva para serem lixiviados da cobertura vegetal, em função da quantidade máxima removível dos herbicidas.