Application of oxyfluorfen and pendimethalin to control weeds on soybean plantation

The appearance of weeds on crops has led to the significant loss of crop yield. Therefore, chemical control with herbicides has been an important tool for rapid and efficient weed management in crops. The objective of this study was to evaluate the effect of herbicides oxyfluorfen and pendimethalin against weeds on soybean plantation. This research employed Randomized Completely Block Design (RCBD) Factorial with 2 factors. The first factor was the type of herbicides: oxyfluorfen and pendimethalin. The second factor was herbicide doses: 0, 500, 1000, 1500 and 2000 g a.i ha-1, applied on soybean at 1 day after planting (DAP). The percentage of weed control, percentage of weed coverage, weed species, weed population, and weed dry weight were observed at 3, 5, 7 and 9 weeks after planting (WAP). The results revealed that different types and doses of herbicide applied has affected the percentage of weed control, percentage of weed coverage weed species and weed dry weight.

The influence of rainfall and tillage on wheat yield parameters and weed population in monoculture versus rotation systems

Extreme climate events (ECEs) of drought are becoming common in Mediterranean areas and farmers need adapt agricultural practices to achieve sustainability. This field study took place in to gain insight into the effects of seasonal rainfall, tillage and crop systems on wheat yield and weed parameters. Conventional (CT), minimum (MT) and no-tillage (NT) systems in wheat monoculture and rotation cropping systems were tested during 3 years of study (2014–2015, 2015–2016 and 2016–2017). Growing Season Rainfall (GSR) was the most influential factor on yield parameters and weed population. In 2016–2017, categorized as an extreme climate event by drought, the GSR accounted for 43.4% of the historical average. This year, the wheat yield (373 kg ha−1) and harvest index (0.18) were the lowest. In 2015–2016, scarcer autumn rainfall (44 mm) affected the weed germination period, reducing the density (17 plants m−2) and diversity of weed species (3 species m−2) while yield was favoured by high winter and spring rainfall (247 mm). Our study revealed that tillage effects was not significant on wheat yield, but NT systems consistently showed higher weed density and diversity than CT and MT despite the irregular GSR during this study. The rotation system presented higher values of wheat grain yield (781 kg/ha) and dry straw biomass (1803 kg/ha) but also weed biomass (48.54 g m−2) compared to monoculture (27.50 g m−2). NT and rotation combined increased the weed community although did not reduce the wheat yield compare to conventional systems even with an ECE of drought.

Effect of Maize (Zea mays L.) and Legume Intercropping Systems on Weed Dynamics

The field experiments were conducted during two consecutive seasons of kharif (June to October), 2016 and 2017 at the Experimental Research Farm, ICAR Research Complex for NEH Region, Nagaland Centre, Medziphema, Nagaland, India. The treatments consisted of four planting geometries i.e. maize+black gram (1:1), maize+black gram (2:2), maize+soybean (1:1) and maize+soybean (2:2) and three weed management practices i.e. weedy check, pre-emergence application of pendimethalin @ 1.0 kg a.i. ha-1+one hand weeding (1HW) at 30 DAS and two hand weedings (2HW) at 20 and 40 DAS. The experiment was laid out in Randomized Block Design with two factors comprising twelve treatment combinations and replicated three times. The results revealed that among the planting geometry, maize+soybean (2:2) recorded the highest weed control efficiency (WCE) and reduced the weed population, fresh weight and dry weight of monocot and dicot weed at 60 DAS and gave the maximum maize equivalent yield (4374.96 kg ha-1). Among the weed management, 2HW at 20 and 40 DAS recorded the lowest weed population, fresh weight, dry weight and the highest weed control efficiency (WCE) of monocot and dicot weed at 60 DAS and the maximum maize equivalent yield as 4591.10 kg ha-1 which was at par with the pre-emergence application of pendimethalin @ 1.0 kg a.i. ha-1+1HW at 30 DAS as 4461.80 kg ha-1. The highest net return (` ha-1), return per rupee invested and B: C ratio were recorded from the pre-emergence application of pendimethalin @ 1.0 kg a.i. ha-1+1HW at 30 DAS with ` 36624.05 ha-1 which was closely followed by 2HW at 20 and 40 DAS with Rs. 35428.81 ha-1.

Weed Classification Using Explainable Multi-Resolution Slot Attention

In agriculture, explainable deep neural networks (DNNs) can be used to pinpoint the discriminative part of weeds for an imagery classification task, albeit at a low resolution, to control the weed population. This paper proposes the use of a multi-layer attention procedure based on a transformer combined with a fusion rule to present an interpretation of the DNN decision through a high-resolution attention map. The fusion rule is a weighted average method that is used to combine attention maps from different layers based on saliency. Attention maps with an explanation for why a weed is or is not classified as a certain class help agronomists to shape the high-resolution weed identification keys (WIK) that the model perceives. The model is trained and evaluated on two agricultural datasets that contain plants grown under different conditions: the Plant Seedlings Dataset (PSD) and the Open Plant Phenotyping Dataset (OPPD). The model represents attention maps with highlighted requirements and information about misclassification to enable cross-dataset evaluations. State-of-the-art comparisons represent classification developments after applying attention maps. Average accuracies of 95.42% and 96% are gained for the negative and positive explanations of the PSD test sets, respectively. In OPPD evaluations, accuracies of 97.78% and 97.83% are obtained for negative and positive explanations, respectively. The visual comparison between attention maps also shows high-resolution information.

Burial Environment Drives Seed Mortality of Kochia (Bassia scoparia), Wild Oat (Avena fatua), and Volunteer Canola (Brassica napus) Irrespective of Crop Species

Models of weed population demography are critical to understanding the long-term viability of management strategies. The driving factors of weed seedbank persistence are often underrepresented in demographic models due to the cumbersome nature of seedbank research. Simplification of weed seedbank dynamics may induce substantial error in model simulations. A soil bioassay was conducted to determine whether growth of different crop species, including wheat (Triticum aestivum L.), canola (Brassica napus L.), and field pea (Pisum sativum L.), differentially impact seed mortality of kochia [Bassia scoparia (L.) A.J. Scott], wild oat (Avena fatua L.), and volunteer canola in seven burial environments in western Canada. Weed seed survival after the 7 week burial period varied widely among burial environments (from 8% to 88% when averaged among weed and crop species), whereas growth of the different crop species had negligible impact on seedbank persistence. Among environments, wild oat seed survived the greatest (79%), followed by kochia (20%), and volunteer canola (6%). Weed seed survival was associated with soil physical properties (texture) and seed microsite characteristics (temperature), but not crop species or soil chemical properties. Overall, these data support the need for greater integration of soil and environmental parameters into models of weed population demography.

Evaluation of Pre and Post Emergence Herbicides in Greengram (Vigna radiata L.) during Kharif and Rabi Seasons in the Uplands of Krishna Zone of Andhra Pradesh

Background: Greengram crop is grown round the year as a catch crop in different cropping systems of the uplands of the Krishna Zone of Andhra Pradesh. The practice of application of pre emergence herbicide like pendimethalin is very popular with the farmers for the control of weeds in the uplands, both in kharif and rabi seasons. Further spraying of a selective post emergence herbicide is also practiced by farmers. However, some of the weeds of kharif viz., Phyllanthus maderaspatensis and rabi viz., Chrozophora rottleri could not be controlled with these herbicides due to their late emergence or due to development of partial resistance to these herbicides. Certain new pre (PE) and post emergence (PoE) herbicides viz., pendimethalin 30% + imazethapyr 2%, acifluorfen sodium 16.5% + clodinafop propargyl 8%, fomesafen 11.1% + fluazifop -p-butyl 11.1%, are recommended in crops like soybean and groundnut. However, there is need to test these herbicides available in market for their suitability to control the weeds in greengram. Methods: A field experiment was carried out at Regional Agricultural Research Station, Lam, Guntur, Andhra Pradesh, with an objective to evaluate selected PE and PoE herbicide mixtures in greengram managing the major weeds of greengram grown in vertisols of Krishna Zone of Andhra Pradesh during Kharif and rabi seasons of 2018 under upland conditions. Result: Among the two PE herbicides tested on greengram, pendimethalin 30% + imazethapyr 2% @ 0.75 + 0.05 kg/ha was found to be more effective in reducing the weed density and dry matter compared with pendimethalin 30% @ 0.75 kg/ha. The PoE herbicide mixtures tested viz., fomesafen 11.1% + fluazifop -p-butyl 11.1% @111g/ha, propaquizafop 2.5% + imazethapyr 3.75% @ 50+75 g/ha were on par with imazethapyr 10% @ 50g/ha in controlling the weed population without having any adverse affect on the growth and yield of greengram during kharif and rabi.

A REVIEW ON NON-CHEMICAL WEED MANAGEMENT IN MAIZE (ZEA MAYS L.)

Weed is omnipresent species that compete with major crops for light, nutrients, space, and water for their growth and development and ultimately deteriorate the ideal environment for crops growth. In the present context, herbicide application is the easiest and seemingly economical approach for weed control in south-Asian countries. In contrary, the side effects of herbicide on health and environment impose to adopt for the non-chemical method of weed management. This paper reviewed the menace of herbicide, crop weed association, the critical period of crop-weed competition, and different methods of organic weed control implemented especially for maize. The main objective of this review is to maneuver a weed control strategy for maize other than the chemical application. The findings of different research suggested that a critical period of crop-weed competition in maize lies between 2 to 8 weeks after crop sowing. Many mechanical methods for weed control in maize proved efficient but seemed labour intensive and biological methods provided maximum security against specific weed species. The cultural method in combination with other methods effectively reduced the weed population in the maize field. It was found that, if various components of non-chemical weed management are implemented systematically, we can control the weed population with higher economic return and achieve the goal of organic food production with sustainable solutions. Weed control in the organic system focuses on management techniques designed to prevent weed emergence, give a competitive advantage to the main crop, and act for sustainable solutions. The non-chemical integrated weed management system is recommended to reduce the use of herbicide and for sustainable production. A review of non-chemical weed management in maize could be helpful for researchers to provide useful, sustainable, and environmentally friendly solutions to farmers to solve the problem of weed infestation in the maize crop along with substantial yield improvement.

Effect of Chemical to Herb Control on Performance of Sesame (Sesamum indicum) under Irrigated Conditions

Weed management greatly influences on weed infestation and yield of sesame under irrigated condition. An experiment was conducted at Bagusala farm, M.S. Swaminathan School of Agriculture, CUTM, Paralakhemundi, Odisha to find out the effectiveness of pre and post emergence herbicides on performance of summer sesame under irrigated conditions. The soil of experimental site was sandy clay loam in texture, slightly acidic in reaction with pH of 6.4. The experiment was laid out in randomize block design with three replications, assigning twelve treatments combinations of chemical application irrigated sesamum cultivation. The yield with hand weeding at 20 and 40 DAS was comparable with Pendimethalin @ 500 g a.i ha-1 3 DAS + Imazethapyr @ 60g a.i ha-1 at 20 DAS, Imazethapyr @ 60g a.i ha-1 at 20 DAS, Oxadiargyl 80wp @ 60g a.i ha-1 3 DAS and Oxadiagyl @ 40 g a.i ha-1 3 DAS + Imazethapyr @ 60 g a.i ha-1 20 DAS and significantly superior over all other treatments. The weed number observed in all chemical weed control treatments was significantly lower than un-weeded control. Application of herbicides was found to be effective in reduction of weed population in summer sesamum under irrigated conditions. The weeds can be effectively controlled through application herbicides in sesame grown under irrigated conditions during summer season.