Manual Weed Control Research Articles

Effectiveness of Weed Control on Two Varieties of Corn (Zea Mays L.) in West Aceh Regency

This research aims to find out which weed control techniques are most effective in suppressing weed growth on corn plants, to find out the interaction of manual, mechanical, and chemical weed control on corn plants, to find out the influence of weed control techniques on the production and growth of corn plants. This research be carried out in West Aceh Regency on corn farming land in the Pante Ceureumen District. The time allocation is from April to June 2014. The research was conducted using a randomized block design with a factorial pattern with two factors being studied. The first factor is the weed control technique (T): no control, manual control, using husk charcoal, chemical, atrazine + mesotrion 1.35 ml each 9 m² and the second factor is the variety (V): Bisi-2 and Bisi-18. Based on the treatment of 12 plots with 3 repetitions times until there are 36 experimental units. Each treatment plot measures 300 cm x 300 cm with a planting distance of 75 cm x 25 cm so that the number of sample plants in each plot is 48 plants and the number of sample plants in each plot is 8 plants. The distance between plots is 50 cm and the distance between replications is 100 cm. The results obtained from observations are analyzed using the F test. If the results obtained from the variance are significantly different at the 5% level. The result of the research that has been carried out is that the most effective control technique in suppressing weed growth in corn plants is found at T5 (chemistry, topramezone + atrazine 1.35 ml each 9 m², at 21, 40, and 56 HST), followed by T2 (culture technique using rice husk charcoal), T4 (Chemical, nicosulfuron + atrazine 1.35 ml each 9 m², at 21, 40, and 56 HST) and T1 (manual, at 21, 40, and 56 HST) have the same position, then T3 (chemistry, atrazine + mesotrione 1.35ml each 9 m², at 21, 40 and 56 HST), and the last position in weed control techniques is WC (without control).

Theoretical and practical propositions for more sustainable livestock production

A brief review is made of theoretical and practical propositions for more sustainable livestock production (meat and milk). An Organic Livestock Conversion Index (OLCI) was developed to evaluate the level of approximation of Livestock Production Units (LPU) to the organic model. Organic practices such as crop rotation, use of cover crops, mechanical and manual weed control, and recycling of manure reduce soil erosion and pest problems and generally allow for avoiding the use of chemical fertilizers and pesticides, which - along with the substitution of nitrogen fertilizer with legumes and/or manure – reduces energy use in organic systems. Furthermore, practices by LPU contribute to sustainable livestock production by means of minimal use of chemical fertilizers in pastures; adding nutrients to the soil solely by cattle depositing manure during grazing, manual weed control, use of silvopastoral systems, and energy efficiency by the farmers. The approximation of the LPU to organic production, the use of organic practices, Silvopastoral Systems and more energy efficiency demonstrate the potential of organic livestock farms for contributing to more sustainable production as compared to conventional livestock production.

Weed Recognition at Soybean Seedling Stage Based on YOLOV8nGP + NExG Algorithm

The high cost of manual weed control and the overuse of herbicides restrict the yield and quality of soybean. Intelligent mechanical weeding and precise application of pesticides can be used as effective alternatives for weed control in the field, and these require accurate distinction between crops and weeds. In this paper, images of soybean seedlings and weeds in different growth areas are used as datasets. In the aspect of soybean recognition, this paper designs a YOLOv8nGP algorithm with a backbone network optimisation based on GhostNet and an unconstrained pruning method with a 60% pruning rate. Compared with the original YOLOv8n, the YOLOv8nGP improves the Precision (P), Recall (R), and F1 metrics by 1.1% each, reduces the model size by 3.6 mb, and the inference time was 2.2 ms, which could meet the real-time requirements of field operations. In terms of weed recognition, this study utilises an image segmentation method based on the Normalized Excess Green Index (NExG). After filtering the soybean seedlings, the green parts of the image are extracted for weed recognition, which reduces the dependence on the diversity of the weed datasets. This study combines deep learning with traditional algorithms, which provides a new solution for weed recognition of soybean seedlings.

Dependence of table beet yield on different doses of compost in organic farming

The paper presents the experimental study results on the effect of different doses of BIAGUM compost on the yield of Dvusemiannaya TSHA table beet variety. The compost was produced from fermented poultry manure. The table beet was grown on sod-podzolic soil on carbonate loam in the frame work of a six-field biology-based crop rotation. No protective agents were used. Mechanical and manual weed control was applied instead. The precursor on the experimental plots was potatoes fertilized with BIAGUM compost in an amount of 4 t∙ha–1 (N = 80 kg∙ha–1) in 2021. The average biological yield of table beet roots in 2022 in the control variant without compost (variant 1) was 24.94 t∙ha–1, in the variant with the compost application dose of 4 t∙ha–1 (N = 80 kg∙ha–1) (variant 2) – 29.40 t∙ha–1, in the variant with the compost application dose of 8 t∙ha–1 (N = 160 kg∙ha–1) (variant 3) – 31.28 t∙ha–1. The study revealed that the compost application (variants 2 and 3) increased the average yield by 17.88 and 25.41 % compared to variant 1, respectively. There were statistically significant differences between the variant 1 and variants 2 and 3: the LSD for the 5 % significance level was 2.42 t∙ha–1. The compost application in variants 2 and 3 increased the average mass of table beet roots by 30.7 and 33 %, respectively, against the variant 1 (control). The share of substandard roots in the total yield for these variants also increased. In all experiment variants, the nitrate content in the table beet roots did not exceed the allowable value of 1400 mg/kg. The experiment findings indicate a positive effect of BIAGUM compost application in the set doses on the table beet yield cultivated in organic farming.

EFFECTIVENESS AND EFFICIENCY OF WEED CONTROL ON IMATURE PLANTS (TBM) II AT PT. SOCFINDO KEBUN SEUANGAN AFDILLING 1

There are so many problems found in the process of maintaining and increasing the production of oil palm plants. That is the benchmark for the success or failure of these plants. So far weeds are one of the most important problems because weeds interfere with the main crops during their growth and development.Many problems and losses are caused by the presence of weeds in an area if allowed to grow uncontrollably. Therefore, so that these weeds do not cause more serious problems, it is necessary to control weeds. This research is carried out. Every research is expected to be useful for all parties who read it and those who are directly involved in it.This study aims to determine the Effectiveness and Efficiency of weed control on immature plants both manually and chemically as seen from the comparison of control time, cost analysis, work performance, weed mortality rate and regrowth rate from manual and chemical weed control. The method used in this study is to use descriptive analysis method. FromThe results of this study indicate that chemical weed control is more effective and manual weed control is more efficient.

Identificación y caracterización de indicadores para evaluar la sustentabilidad ambiental en sistemas de producción agrícola en la zona del valle del municipio de Sinaloa

Agriculture has adopted practices to face the challenges of supply and the impacts of the growth of agricultural production, which generates the degradation of natural resources, the repercussions through climate change and the loss of knowledge of conservation practices. for production, so it has been essential to promote sustainable agriculture as set out in the 2030 agenda in its Sustainable Development Goals to ensure resilient food production based on the environmental, social and economic dimensions of sustainability. The objective of the study was to identify and characterize the indicators to evaluate environmental sustainability in part of the valley of the agricultural zone of the municipality of Sinaloa. The indicators that include the control of pests, diseases and weeds, agricultural diversity and biodiversity, water management and quality and health of the soil were worked on, the sub-indicators were standardized according to their importance with respect to sustainability. The traditional agroecosystems of the municipality of Sinaloa present a use in agricultural practices according to the values of the environmental sustainability indicator, sustainable and profitable agricultural practices have been implemented in the area, such as: manual weed control and organic or organic manufacturing fertilizers industrial, diversified establishments, with crop associations and natural vegetation, own sources of seeds and soil conservation. The application of these indicators facilitates the monitoring of agricultural conservation practices that are carried out in the study area in the environmental dimension, which will allow contributing to the management and sustainable production of agricultural systems. The indicators characterized in this study will serve as a basis for knowing long-term sustainability and identifying areas of opportunity, their strengths and weaknesses, and may contribute to improving the economic and social aspects of a production system.

Weed Smothering in Mustard (Brassica spp) by its High-Density Uniform Broadcast Sowing

Manual weed control in mustard is very expensive because of its high labour requirement i.e., 150-250 labourers/ha. Chemical weed control again imposes environmental hazards. Mechanical weed control in mustard is not still that popular till date. Due to severe weed competition, the yield reduction in Indian mustard may go as high as 70 per cent. Thus weed control in zero till mustard using its high-density sowing (HDS) was studied in different farmers’ field, at ICAR-CRIJAF, in North 24 PGS and Purulia, from 2018-2022. Fast growing and high- density uniform mustard canopy (100-200 m2) developed at early stages hinders sunlight penetration (up to 99.98 per cent) below its canopy (at 35- 40 days), leading to scanty and under developed growth of different composite weed species at harvest, those germinate or grow below mustard canopy. Weed population below mustard canopy was reduced by 92 to 97 per cent at mustard harvest. It was only 10-80/m2 at harvest over 350-1000/m2 in weedy situation at initial germination. The reduction of dicot weed biomass below matured mustard at harvest was 81-99 percent (5-150g/ m2) percent over weedy plots (500-800/ m2). Reduction of effective flowers/pods of different weeds under matured mustard canopy were up to 99.5 percent. Proper agronomic management practices of HDS mustard e.g., seed rate, date of sowing, uniformity of sowing, irrigation and fertiliser application will eliminate the herbicide application or manual weeding in mustard. Nearly 80 percent mustard plants remain active at harvest. It saves 150-250 labours /ha depending on weed species and its density of germination. Mustard grain yield ranged from 15-30 q/ha depending on management and varieties used. This weed smothering merit of mustard can be used for eco friendly weed control in other wide spaced field/horticultural crops using its dwarf variety (Toria).

The Profile of Bioactive Compounds in Two Tomato Lines (hp-2 and Atv_aft) When Grown under Low-Input Farming Conditions with or without Mulching and Intercropping

The work analyzed the effect of two types of low-input farming conditions on the yield components and on the bioactive compounds in the pulp and peel of tomato fruits. The first low-input (LI) system involved the application of cow manure and manual weed control; in the second (LIMI), the same system was integrated with mulching (the wood chips of eucalyptus) and intercropping (basil and cabbage plants). The study included the line 392, harboring the hp-2 gene that increases the pigments of plant and fruit; the line 446 with the atv and Aft genes which influence the content of polyphenols; and a commercial control (cv. Rio Grande). The experimental design was a split-plot where the farming system (LI and LIMI) was allocated in the main plot and the genotype was in the sub-plot. Within the main plot, each genotype was replicated three times in three randomized blocks. Mulching and intercropping led to a differentiation in the LIMI with respect to the LI system with higher values of the leaf greenness index (61.3 vs. 53.3 Spad units), the number of fruits (70 vs. 46), and the weight of fruits per plant (2716.6 vs. 2195.0 g). However, the LI system showed a higher content of polyphenols (+37.9%) and anthocyanins (+116.7%) in the peel and a higher content of vitamin C (+44.0%) and polyphenols (+11.1) in the pulp. The less complex LI system stimulated the plants to produce natural antioxidant systems to contrast biotic and abiotic offenders, while the introduction of mitigation elements in the LIMI system reduced the need for protective barriers against the environmental stress. The study also revealed that low-input systems can allow for satisfactory yields, minimizing the use of off-farm resources. Growers can combine factors of sustainable agriculture with specific genotypes to maximize the production of healthier foods.

EFFECTS OF WEED CONTROL METHODS ON WEEDS AND PRODUCTIVITY OF RANGE GRASSES IN SEMI-ARID KENYA

<p><strong>Background:</strong> Weeds are a common occurrence and challenge in different crops eventually influencing crop development and yields. Weed control and management are key in enhancing the productivity of cultivated pastures. In semi-arid Kenyan drylands, the main methods employed for weed management are manual cultural practices and recently, the application of commercial herbicides. <strong>Objective:</strong> To evaluate the effects of two weed control methods on weed characteristics and productivity of four rangeland grasses commonly used in reseeding and pasture improvement in a semi-arid environment. <strong>Methodology:</strong> In a randomized complete block design in a field experiment, we determined the effects of two weed control methods (manual and herbicide use) in four rangeland cultivated grasses. These are Buffel grass (<em>Cenchrus ciliaris</em>), Horsetail grass (<em>Chloris roxburghiana</em>), Masaai love grass (<em>Eragrostis superba</em>) and Bush rye (<em>Enteropogon macrostachyus</em>). Weed characteristics (species, density, diversity and weed biomass,) were evaluated, as well as the effectiveness of the weed control methods in the grasses. <strong>Results:</strong> Broad-leaved weeds and annual grasses were prevalent in the established grasses. Generally, higher grass dry matter yields were obtained in <em>Cenchrus ciliaris</em> grasses (2.05 t h<sup>-1</sup>) while lowest yields were in <em>Chloris roxburghiana</em> (1.2 ton ha<sup>-1</sup>). Weed management interventions increased biomass production in the grasses by a mean of 19% in general. The mean yield increase varied with species and weed control method ranging from 8-39%. Weed control methods significantly reduced weed density, diversity and eventually weed biomass within the grass species. The efficacy of manual weed control and chemical application was in the range of 27-74%. <strong>Implications: </strong>Weed control is, therefore, necessary if one is to realize higher productivity and returns in cultivated pasture and fodder systems in semi-arid environments. <strong>Conclusion:</strong> Both chemical and manual control methods of weed control are important and effective approaches to manage weeds in pasture systems in semi-arid environments.<strong> </strong></p>

Bio-efficacy of different POE herbicides for broad spectrum weeds management in chickpea (Cicer arietinum L.)

A field experiment was conducted during 2020-21 and 2021-22 to study the effect of different post-emergence (POE) herbicides for broad spectrum weed management in chickpea. The experiment was laid out in a randomized block design with eight treatments and replicated thrice. Treatments comprises topramezone 20.6 g a.i. ha-1 at 14 DAS, topramezone 20.6 g a.i. ha-1 at 21 DAS, topramezone 25.7 g a.i. ha-1 at 14 DAS, topramezone 25.7 g a.i. ha-1 at 21 DAS, quizalofop-p-ethyl 100 g a.i. ha-1 at 21 DAS, unweeded control, weed free check (manual) and imazethapyr + manual weed control (MWC). Among the different herbicidal treatments, topramezone 20.6 g a.i. ha-1 at 21 DAS significantly higher seed yield (1377 kg ha-1) followed by topramezone 20.6 g a.i. ha-1 at 21 DAS (1265 kg ha-1), highest weed control efficiency and also recorded higher return (₹ 45,659 ha-1 ) and B: C ratio (2.73) during 2020-21.

Management of weed diversity through organic mulching and alternative weed suppression practices on ginger (Zingiber officinale)

A field experiment was conducted at the Regional Research Station (Hill Zone), Uttar Banga Krishi Viswavidyalaya, Kalimpong, Darjeeling, West Bengal, during 2019 and 2020 to study the effect of weed diversity, growth and yield of ginger (Zingiber officinale Rose) as influenced by organic mulching and alternative weed management practices. The randomized block design, having seven varying treatments with three replications was used. The treatments consisted of dry weed biomass mulch @ 5.0 t/ha (T1), paddy straw mulch @ 5.0 t/ha (T2), FYM Mulch @ 5.0 t/ha (T3), dry leaves of Schima wallichi@ 5.0 t/ha (T4), dry leaves of Artimesia sp. and Eupatorium sp. @ 5.0 t/ha (T5), hand weeding (twice) at 45 and 90 DAS (T6) and unweeded control (T7). The result showed that hand weeding twice at 45 and 90 DAS (T6) appreciably reduced the total weed population/m2 and total dry weight of weeds than unweeded control plot (T7) at all the stages of crop growth. The highest plant height (82.10 cm), number of leaves/clump (65.41), number of pseudo stem/clump (5.17), rhizome length (7.22 cm), rhizome width (5.50 cm), number of fingers/rhizome (6.42), yield/plant (0.268 kg/plant), yield (20.33 t/ha) and weed control efficiency were recorded under the hand weeding twice at 45 and 90 DAS (T6) compared to other treatments. The results showed that it is necessary to cover the soil surface with different mulch materials and manual weed control practices to achieve a good control of weeds along with enhanced yield attributes and yield.

The Effectiveness of Mixing Herbicides and Manual Weed Control on Corn (Zea mays L)

Field trials were conducted in Januay 2021 cropping seasons to evaluate some herbicide mixtures and manual weed control method in the maize production. The experiment consisted of 10 treatments as follows: Metolachlor + atrazine (1.0 + 2.0 kg a.i./ha), metolachlor + atrazine (2.0 + 2.5 kg a.i./ha), metolachlor + atrazine (3.0 + 3.0 kg a.i./ha), pendimethlin + atrazine ( 1.0 + 2.0 kg a.i./ha), pendimethlin + atrazine (2.0 + 2.5 kg a.i./ha), pendimethlin + atrazine (3.0 + 3.0 kg a.i./ha), metolachlor + atrazine (1.0 + 2.0 kg a.i./ha) plus one supplementary hoe weeding (SHW) at 6 weeks after sowing (WAS) and pendimethlin + atrazine (1.0 + 2.0 kg a.i./ha) plus one SHW at 6 WAS, hand weeding at 3 and 6 WAS and a weedy check. These treatments used in randomized complete block design with three replicates. The rsults showed that metolachlor + atrazine and pendimethalin + atrazine at 1.0 + 2.0 kg a.i./ha plus one SHW at 6 WAS significantly reduced weed infestation and gave higher maize grain yield and economic returns. These methods are therefore recommended to farmers as alternative to two hand weeding at 3 and 6 WAS.

Weed management and tillage effect on rainfed maize production in three agro‐ecologies in Mexico

AbstractMaize (Zea mays L.) is grown in a wide range of agro‐ecological environments and production systems across Mexico. Weeds are a major constraint on maize grain yield, but knowledge regarding the best weed management methods is lacking. In many production systems, reducing tillage could lessen land degradation and production costs, but changes in tillage might require changes in weed management. This study evaluated weed dynamics and rainfed maize yield under five weed management treatments (pre‐emergence herbicide, post‐emergence herbicide, pre‐emergence + post‐emergence herbicide, manual weed control, and no control) and three tillage methods (conventional, minimum and zero tillage) in three agro‐ecologically distinct regions of the state of Oaxaca, Mexico, in 2016 and 2017. In the temperate Mixteca region, weeds reduced maize grain yields by as much as 92% and the long‐growing season required post‐emergence weed control, which gave significantly higher yields. In the hot, humid Papaloapan region, weeds reduced maize yields up to 63% and pre‐emergence weed control resulted in significantly higher yields than treatments with post‐emergence control only. In the semi‐arid Valles Centrales region, weeds reduced maize yields by as much as 65%, but weed management was not always effective in increasing maize yield or net profitability. The most effective weed management treatments tended to be similar for the three tillage systems at each site, although weed pressure and the potential yield reduction by weeds tended to be higher under zero tillage than minimum or conventional tillage. No single best option for weed management was found across sites or tillage systems. More research, in which non‐chemical methods should not be overlooked, is thus needed to determine the most effective weed management methods for the diverse maize production systems across Mexico.

Herbicides and family farming, a marriage of convenience?

For situations and crops as diverse as sugarcane in Réunion (a French overseas department), grown in systems close to monoculture, and cotton in Cameroon, grown in rotation with food crops, the gruelling manual weed control operations using hoes (the daba in Cameroon and the mattock in Réunion), traditionally inherent to family farming, have been considerably alleviated by the emergence then widespread implementation of chemical weed control, manual in Cameroon and partially motorised in Réunion. Based on these two examples taken from his experience as a tropical agronomist in Northern Cameroon and in Réunion, the author concludes that in just a few decades, family farming and chemical weed control have forged very strong links, which are now difficult to undo.

COVER CROPS AS A WEED CONTROL METHOD AND THEIR EFFECT ON THE INITIAL GROWTH OF A Tectona grandis L.f. PLANTATION

Tectona grandis L.f. (teak), is one of the most used tropical species in commercial reforestation projects. Weed control is a common activity within these plantations. The objective of the study was to evaluate the effect of cover crops in weed control and the initial growth of a young teak stand in the southern part of Costa Rica. We used a randomized complete blocks design with three replications and seven treatments: a) control (without weed control), b) chemical weed control, c) manual weed control, d) cover crop Canavalia ensiformis , e) cover crop Vigna radiata , f) mix between Vigna radiata and Pueraria phaseloides, g) cover crop Crotalaria juncea . In addition, we calculated total costs for all treatments. All species exceeded 60% ground coverage, with C. juncea and V. radiata being the best performers. Although all cover crops had higher height values than the other treatments, only C. ensiformis had a significant effect on height growth at 6 months of age. Manual weed control was the most economical treatment. Based on the results obtained, we concluded that the cover crops can be used as an alternative method of weed control without affecting the growth of the trees.

ANALISIS BIAYA PENGENDALIAN GULMA MANUAL PADA TANAMAN BELUM MENGHASILKAN (TBM) DI PT. SENTOSA KALIMANTAN JAYA

This research is based on the background that weeds in oil palm plantations must be controlled so that economically it does not affect production. The implementation of manual weed control on immature plants (TBM) must have used costs that must be incurred by the company.This study aims to analyze the cost of controlling weeds manually and to identify the factors that affect the cost of controlling weeds in immature plants (TBM).
 The implementation of this research uses quantitative methods in analyzing costs at 2 work units (Afdeling) by using data on the implementation / realization of work for February-April 2019 and descriptive methods in identifying factors that affect costs by conducting field analysis. The results of the cost analysis in 2 afdeling get results in the form of the average Afdeling cost, namely: The cost of manually controlling weeds in the gawangan at Afdeling 1 is Rp. 254,756 / ha and the gawangan at Afdeling 2 is Rp. 261,242 / ha. Meanwhile, the cost of controlling weeds manually on the plate at Afdeling 1 is Rp. 254,483 / ha and the plate at Afdeling 2 Rp. 238,787 / ha. Factors that influence the cost of controlling weeds manually in immature plants (TBM), especially in the dish and in the fields are more due to factors of land topography, weed density, and the types of weeds that are controlled.

MULCHING AND WEED MANAGEMENT EFFECTS ON THE PERFORMANCE OF RICE (ORYZA SATIVA L.) TRANSPLANTED IN NON-PUDDLED SOIL

Labour shortage is pushing the smallholder farms to seek for labour saving strategies for planting and weed control. With this point of view, this study was undertaken to determine the effectiveness of mulching from previous crop relative to herbicides and hand weeding on weed control and grain yield of rice transplanted in non-puddled soil after mustard in the northern Bangladesh during January to May in 2014 and 2015. Rice cv. BRRI dhan28 was transplanted with a combination of six weed control practices [Conventional tillage (CT)+3 hand weeding (HW) (Control); Glyphosate (Gly)+strip tillage (ST)+1HW; Gly+ST+pre-emergence (PE) herbicide (pendimethalin); Gly+ST+post-emergence (PO) herbicide (Ethoxysulfuron-ethyl); Gly+ST+PE+PO; and Gly+ST+weed-free (WF)], and two levels mulch of previous mustard [M0: no mulch and M50: 50% mulch (875 kg ha-1). Over the two years, CT produced 30% higher weed density and 40% higher weed biomass than ST. Spraying herbicides at PE followed by at PO in ST reduced weed density by 45% and weed biomass by 70%. Retention of 50% mulch reduced weed density by 20% and biomass by 34%. The combination of applied glyphosate, ST, followed by sequential application of PE and PO herbicides and the retention of 50% mulch achieved the highest weed control efficacy. Furthermore, this practice produced the 12% higher yield and 47% higher economic returns relative to manual weed control in conventional tillage. These results demonstrate the value of mulch integrated with pre-plant, PE and PO herbicides in controlling weeds and improving grain yield and return of rice transplanted in a non-puddled soil.

Evaluation of herbicides and manual weed control methods in the establishment of Theobroma cacao L. in Cross River State of Nigeria

Evaluation of herbicides and manual weed control methods in the establishment of Theobroma cacao L. in Cross River State of Nigeria

Evaluation of herbicides and manual weed control methods in the establishment of Theobroma cacao L. in Cross River State of Nigeria

Field trial was conducted at the Cocoa Research Institute of Nigeria (CRIN), Ajassor substation, Cross River State, Nigeria between 2015 and 2017 to evaluate the effect of different weed control methods on the growth and yield of cocoa during their early years of establishment. Glyphosate and paraquat were applied at 480, 720, 960 and 1440 gram of active ingredient per hectare using very low volume (g a.i. ha-1 vlv) while manual weeding (i.e. slashing with cutlass) was used as the control. A Nigeria commercial cocoa variety Tc series, also known as 18-month cocoa, was established at a CRIN recommended spacing of 3 x 3 m, laid out in a Complete Randomized Block Design with four replications. All young cocoa stands were ring weeded at 50 cm diameter and covered with black polythene bags before the spraying of herbicides during the first six months of establishment to reduce injury that could result from the drifting of herbicide solution to plants during their early growth stage. Data was collected on the plant height, stem girth and number of leaves of cocoa plants while the cocoa dry beans weight and labour cost for each treatment were determined. The results showed that 960 g a.i. ha-1 vlv was the best herbicide application rate while plots under glyphosate at 960 g a.i. ha-1 vlv produced significantly higher values of plant height, stem girth and number of leaves at (p=0.05) than both paraquat at 960 g a.i. ha-1 vlv and manual weeding. Labour cost for controlling weeds with either glyphosate or paraquat at all application rates were considerably lower than cost for control (manual weeding). Glyphosate at 960 g a.i. ha-1 vlv is recommended for weed control in cocoa plantation because it encouraged higher growth and yield performance of cocoa than other treatments, had considerably cheaper cost of application than paraquat at 960 g a.i. ha-1 vlv and manual weeding, and it also ensured a weed-free environment over a longer period of time than the other treatments.

Weed management in direct seeded rice: A review

Direct seeding is done by sowing of pre-germinated rice seeds under puddled condition either manually or by drum seeding methods. Direct seeded rice (DSR) cultivation needs only 34 per cent of the total labour requirement and saves 29 per cent of the total cost of the transplanted rice. Weed infestation and competition are severe in direct wet seeded rice as compared to transplanted rice, because of the simultaneous growth of both crops and weeds. Uncontrolled weeds decreased the yield by 96 per cent in dry DSR and 61 per cent in wet DSR. The yield loss due to weeds varies from 40 to 100 per cent in direct seeded rice. Any delay in weeding will lead to increased weed biomass which has a negative correlation with yield. Though manual weeding is considered to be the best, undependable labour availability and escalating labour cost in many cases have given impetus to the development and use of new chemicals for weed control. In contrast to this, chemical weed control offers economic and efficient weed control if applied at proper dose and stage. The combination of chemical, manual and mechanical weed control is an efficient integrated weed management strategy for effective weed control in direct seeded rice.