Hand Weeding Research Articles

Effect of hand weeding and chemical treatments on weed flora in Potato crop

Effect of hand weeding and chemical treatments on weed flora in Potato crop

Control of Barley Weeds and its Reflection on the Growth Parameters

A field experiment was carried out to evaluate the efficiency of specific weed herbicides in controlling the weeds grown with cultivars of barley and their effect on some growth traits. The study was implemented using Randomized Complete Block Design (RCBD) with split plots arrangement by three replicates. The results showed the superiority of a herbicides combination (U 46 - Combifluid 1 L.ha-1) + (Axial 1.5 L.ha-1) (h1) by giving the best results as it reduced the weed dry weight to 0.00 g.m-2 with a 100% inhibition ratio. Furthermore, it gave the best results within growth parameters as it increased the flag leaf area and the growth rate of the crop, which reached 40.94 cm-2 and 59.14 g.m-2 day-1, respectively. In the same role, the results also showed the superiority of the cultivar IPA 265 (V3) by giving the best results for plant height, flag leaf area, and crop growth rate, which were 92.62 cm, 45.44 cm-2, and 61.02 g.m-2 day-1, respectively. The interaction was also significant, as the treatment with H1 herbicide and the treatment of hand weeding behaved similarly for almost all traits and with all cultivars by giving the best results for the interaction.

Influence of Integrated Nutrient and Weed Management on Growth, Yield and Quality of Soybean

A study was carried out at the experimental farm of School of Agricultural Sciences and Rural Development, Nagaland University, Medziphema campus, dist. Nagaland, India during the Kharif season (June to October) of 2017 and 2018 to assess the influence of integrated nutrient and weed management on soybean growth, yield and quality. The split-plot design was used with three replications: three nutrient management treatments and five weed management treatments in the main-plot and sub-plot, respectively. The pooled results revealed that the application of 50% RDF+50% organic through Rhizobium+Phosphate Solubilising Bacteria recorded significantly lower weed density and weed dry weight. Plant height (46.12 cm), plant dry matter (10.00 g plant-1), number of pods plant-1 (53.97), seed yield (16.28 q ha-1), straw yield (22.69 q ha-1), oil content (18.70%) and protein content (38.10%) were recorded highest under 75% RDF+25% organic through FYM+Phosphate Solubilising Bacteria. All of the weed treatments recorded lower weed density and dry weight over the weedy check significantly. Weed free treatment (hand weeding at 15, 30 and 45 DAS) gave highest seed yield (20.67 q ha-1) and straw yield (26.28 q ha-1). It was followed by propaquizafop @ 0.075 kg a.i. ha-1+hand weeding at 45 DAS and pendimethalin @ 1 kg a.i. ha-1+hand weeding at 30 DAS. Weed free registered highest oil content (19.38%) and protein content (38.97%) which was statistically at par with propaquizafop @ 0.075 kg a.i. ha-1+hand weeding at 45 DAS and pendimethalin @ 1 kg a.i. ha-1+hand weeding at 30 DAS.

AN AUTONOMOUS BRAKING CONTROL SYSTEM FOR A 2017 YAMAHA GRIZZLY 700

Weed control is an important issue for environmental protection all around the world. Traditional hand weed control is laborious whereas chemical control is costly and a threat to the atmosphere. A chemical patch weed control system is an optimized system but lacks cheap technical equipment. This research outlines a design process and test of a braking system that can be applied during the designing of an autonomous braking system for a 2017 Yamaha Grizzly 700. The system is intended to be used as an autonomous weed chemical spraying. A bolt-on approach that did not require any manipulation of the stock, an internal braking system was followed to reduce the complexity and installation time of multiple systems. Three different types of autonomous braking system solutions were initially investigated, with the linear actuator solution being decided on through the assistance of a weighted decision matrix. The system was designed around a 30 kg hand force; however, a spare actuator of approximately 20 kg of force was repurposed and used instead. Finite element analysis concluded that all major components within the proposed system were suitable for a lifetime of at least 1,000,000 cycles with a mild steel yield stress failure criterion of 370 MPa. A stationary test for the system was conducted to determine the success of the system, which pushed the brake lever approximately 25% of its disengaged handlebar to lever length. The resulting system met the requirements of the expectation and could be used to apply the ATV’s brakes autonomously while retracting the gear interlocking mechanism enough to change gears.

Effectiveness of napropamide herbicide controlling weeds on a golf course in Tropical Indonesia

Weeds existence interferes with the quality, aesthetics, and growth of golf course grass. Napropamide is a herbicide used to control broadleaf and grass weeds. Therefore, field experiments were employed during 2021 at Bandung Giri Gahana Golf Course, Jatinangor District, Sumedang Regency, West Java to determine effects of applying the herbicide in controlling weeds and on the growth of golf course grass. The experiment was laid out in randomized block design was used with six treatments, each of which was replicated four times. The treatments included manual hand weeding, a control, and different doses of Napropamide 50%, namely 6.75, 9, 11.25, and 13.5 kg/ha. The results showed that the herbicide Napropamide 50% with the dose of 6.75 kg/ha until 13.5 kg/ha were effectif to control grass weeds such as Eleusine indica, Panicum repens, Digitaria ciliaris and broad leaves weeds such as Cleome rutidosperma, Amaranthus viridis, Portulaca oleracea, up to 12 weeks after herbicide application without causing toxicity to golf course grass.

Influence of Nutrient and Weed Management on Zn and S Uptake by Crop and weeds in Mustard

A field experiment was conducted in rabi season 2018-2019 and 2019-2020 at Research farm of Bihar Agricultural College, Sabour to study the effect of nutrient levels and weed management on zinc and sulphur uptake by crop and weeds in mustard. This experiment consisted of three nutrient levels (N1-soil test-based recommended dose of fertilizer (RDF), N2-100 % RDF, N3-125 % RDF) in main plot; eight weed management practices (W1-Weedy, W2- Hand weeding (HW), W3-pendimethalin, W4-pendimethalin followed by (fb) quizalofop, W5-pendimethalin fb clodinafop, W6-oxyflourfen, W7-oxyflourfen fb quizalofop, W8-oxyflourfen fb clodinafop) in sub plots, was laid out in split plot design. Results indicated that in both the years 2018-19 and 2019-20, hand weeding at 25 and 50 DAS along with 125% RDF exhibited minimum Zn uptake by weeds. Among herbicides, application of pendimethalin 30 EC 1.0 kg a.i. ha-1 PE fb quizalofop 5 EC 60 g a.i. ha-1 PoE along with 125% RDF exhibited lowest Zn uptake by weeds. In both the years 2018-19 and 2019-20, hand weeding at 25 and 50 DAS along with 125% RDF recorded minimum S uptake by weeds. Lowest S uptake by weeds was noted under application of pendimethalin 30 EC 1.0 kg a.i. ha-1 PE fb quizalofop 5 EC 60 g a.i. ha-1 PoE along with 125% RDF. In 2018-2019, Zn uptake by mustard was maximum under 125% RDF being at par with soil test-based RDF and was superior over 100% RDF. Hand weeding at 25 and 50 DAS exhibited highest Zn uptake by mustard. Maximum Zn uptake by mustard was noted with pendimethalin 30 EC 1.0 kg a.i. ha-1 PE fb quizalofop 5 EC 60 g a.i. ha-1 PoE. In 2019-2020, hand weeding at 25 and 50 DAS along with 125% RDF exhibited highest Zn uptake by mustard. Among herbicides, application of pendimethalin 30 EC @ 1.0 kg a.i. ha-1 PE fb clodinafop 15 WP @ 60 g a.i. ha-1 PoE along with 125% RDF registered highest Zn uptake by mustard. In 2018-2019, hand weeding at 25 and 50 DAS exhibited highest S uptake by mustard. Maximum S uptake by mustard was recorded with pendimethalin 30 EC 1.0 kg a.i. ha-1 PE fb quizalofop 5 EC 60 g a.i. ha-1 PoE. In 2019-2020, although hand weeding at 25 and 50 DAS along with 125% RDF exhibited highest S uptake by mustard, however, pendimethalin 30 EC 1.0 kg a.i. ha-1 PE fb quizalofop 5 EC 60 g a.i. ha-1 PoE along with 125% RDF registered highest S uptake by mustard.

Determine the Competitive Ability of Some Sorghum Cultivars by the Effect of Weed Control Treatments

A field experiment was carried out in 2021 during the autumn season in soil with a mixture texture in Anbar Governorate, Ramadi District in research station of college of agriculture, university of Anbar in Al-Hamidiyah region. To study the effect of the competitive ability of some sorghum cultivars in the accompanying weeds with the impact of weed control treatments, The experiment was included three hoeings (hoeing once, hoeing twice, and hoeing three times) in addition to the control treatment with three cultivars of sorghum (Lilo, Angath and Rabeh). The experiment was designed according to a randomized complete block design (RCBD) and in the arrangement of split plots and three replications, as the hoes were at main plots while cultivars were at subplots. The results were as follows. Data showed a significant effect of the study factors in the studied traits, the number of weeds, and their dry weight, whether three times of hand weeding gave the highest plant height (194.87 cm), 500-grain weight (19.22 g), grain yield 8.85-ton hectare-1. As for the cultivars, the cultivar recorded the highest average of the leaf area (5900 cm2 plant-1) and the percentage of protein (8.48%).

N, P and K Uptake by Crop and Weed as Influenced by Nutrient Levels and Weed Management in Mustard

A field experiment was conducted in Rabi season of 2018-19 and 2019-20 at Research farm of Bihar Agricultural College, Sabour to assess the impact of nutrient and weed management on N, P and K uptake by crop and weed in mustard. This experiment with 3 nutrient levels (N1-soil test-based recommended dose of fertilizer (RDF), N2-100 % RDF, N3-125 % RDF) in main plot; 8 weed management (W1-Weedy, W2-Hand weeding (HW), W3-pendimethalin, W4-pendimethalin followed by (fb) quizalofop, W5-pendimethalin fb clodinafop, W6-oxyflourfen, W7-oxyflourfen fb quizalofop, W8-oxyflourfen fb clodinafop) in sub plots, laid in split plot design. Results indicated that in 2018-19, N, P and K uptake by mustard was found maximum under 125% RDF. Hand weeding exhibited highest N, P and K uptake by crop over weedy. Among herbicides, maximum N, P and K uptake by crop was noted with pendimethalin 30 EC 1.0 kg a.i. ha-1 PE fb quizalofop 5 EC 60 g a.i. ha-1 PoE. In 2019-20, hand weeding at 25 and 50 DAS along with 125% RDF exhibited highest N, P and K uptake by crop. Among herbicides, application of pendimethalin 30 EC 1.0 kg a.i. ha-1 PE fb quizalofop 5 EC 60 g a.i. ha-1 PoE along with 125% RDF exhibited highest N, P and K uptake by the crop. In both the years 2018-19 and 2019-20, hand weeding at 25 and 50 DAS along with 125% RDF exhibited N uptake by weeds, zero value being lower than weedy. In 2018-19, application of pendimethalin 30 EC 1.0 kg a.i. ha-1 PE fb quizalofop 5 EC 60 g a.i. ha-1 PoE along with 125% RDF exhibited the lowest N and K uptake by weeds. Among nutrient levels, application of 125% RDF exhibited the lowest P uptake by weeds, however, among herbicides; application of pendimethalin 30 EC 1.0 kg a.i. ha-1 PE fb quizalofop 5 EC 60 g a.i. ha-1 PoE registered the lowest P uptake by weeds. In 2019-20, application of pendimethalin 30 EC 1.0 kg a.i. ha-1 PE fb quizalofop 5 EC 60 g a.i. ha-1 PoE along with 125% RDF exhibited the lowest N, P and K uptake by weeds. Thus it was concluded that pendimethalin 1.0 kg a.i. ha-1 PE fb quizalofop 60 g a.i. ha-1 PoE along with 125% RDF (100:50:50:25:6.25 kg NPKSZn ha-1) enhanced N, P and K uptake by crop though hand weeding at 25 and 50 DAS along with 125% RDF (100:50:50:25:6.25 kg NPKSZn ha-1) exhibited significant improvement in nutrient uptake by crop.

Production potential of transplanted rice as influenced by pre and post emergence herbicides

A study was designed on the way to evaluate and identify the pre and post emergence herbicide combinations in transplanted rice variety ‘ASD 16’ during February-May 2020 at the Experimental Farm, Department of Agronomy, Annamalai University, Tamil Nadu, India. The experiment was laid out in randomized block design with three replications and fourteen treatments. The treatment details includes sequential application of pre and post emergence herbicide viz., pre-emergence herbicides (butachlor, pretilachor and pyrazosulfuron ethyl) and post emergence herbicides (bispyribac sodium, metsulfuron methyl + chlorimuron ethyl, fenoxaprop-p-ethyl and triafamone + ethoxysulfuron), hand weeding twice (20 and 40 DAT) and unweeded control plot. All the weed management practices were found to be significantly influenced the weed biometrics, growth attributes, grain and straw yields of transplanted rice. The result of the study clearly showed that hand weeding twice at 20 and 40 days after transplanting (DAT) significantly registered lesser weed dry matter production, weed index, maximum weed control index (WCI), higher growth attributes viz., plant height, number of tillers hill-1, DMP, grain and straw yields.

Influence of Nitrogen Levels and Weed Management Practices on Soil Quality of Wetland Rice

Rice (Oryza sativa L.) is one of the most popular cereal crops serves as the staple food for world’s half of the population. Nutrients and weeds are two important factors that determine the productivity of wetland rice. Nitrogen (N) is major nutrient that contributes in rice production. Weeds are the major constraint limiting high productivity of rice. Weeds may remove considerable quantity of nutrients besides competing for light; space and moisture thus become a major constraint in wetland rice. Considering these, a field experiment was conducted for two successive kharif seasons of 2018 and 2019 at Agricultural Research Farm, B.H.U., Varanasi, UP (India). The study included influence of nitrogen levels and weeds management practices (WMP) post harvest soil quality of wetland rice. The experiment was laid out in split plot design involving five nitrogen levels viz. control, 60 kg N ha-1 through inorganic, 60 kg N ha-1 as farmyard manure (FYM), 90 kg N ha-1 & 120 kg N ha-1 in main plots and four weed management practices viz. Azolla 2 t ha-1, BGA 1.25 kg ha-1, two hand weeding (2HW) at 20 & 40 days after transplanting (DAT) along with weedy in sub plots and replicated thrice. The results showed that the FYM treated plots exhibited maximum residual NPK and organic carbon with comparatively less pH in post harvest soil of wetland rice. Post harvest soil studies indicated that among weed management practices Azolla facilitated higher residual NPK and organic carbon and least pH in wetland rice field.

Growth and Productivity of Black Gram (Vigna mungo L.) as Influenced by Residual Effect of Triafamone Herbicide Applied for Transplanted Rice (Oryza sativa L.)

Background: The major area under black gram are cultivated as rice fallow crop to harness the available soil moisture and other resources without application of any inputs as that of other input intensive crops. Weeds are one of the important biotic factors which affect the growth and yield of black gram. The weeds can be effectively managed in black gram by the herbicide applied in the previous crop viz., transplanted rice. Since, the black gram has quick ground cover, hence initial weed management is very much important. In order to manage the weeds in rice fallow black gram crop evaluation of Triafamone herbicide applied to the transplanted rice crop was carried out in succeeding black gram crop in terms of the growth and yield of black gram. Methods: Field experiments were conducted during Kharif, 2019 (July to August) and Rabi 2019-20 (November to January) at Wetland farm of Tamil Nadu Agricultural University, Coimbatore to study the residual effect of herbicides applied in transplanted rice on succeeding black gram growth and productivity. The experiment was laid out in a randomized complete block design with three replications. The treatments consisted of four doses (30, 40, 50 and 100 g/ha) of new rice herbicide Triafamone 20% SC each as pre emergence and early post emergence, along with check herbicides Pretilachlor 50% EC 750 ml/ha and Pyrazosulfuron ethyl 10% WP 15 ml/ha as early post-emergence along with farmers practice (two hand weedings), weed free and weedy checks. Result: The weed flora of the experimental field consisted of weed complex including grasses, sedges and broad leaved weeds. Among the different dose of herbicides applied, Triafamone 20% SC at 100 g/ha markedly suppressed the weeds growth. There were no phytotoxic effects of herbicides on succeeding black gram. Different doses and time herbicides applied in transplanted rice did not affect the germination of succeeding black gram. Higher weed control efficiency, growth and yield component and yield of black gram were recorded with the Triafamone at 40 g/ha as pre emergence and early post emergence application.

Financial Return from Weed and Disease Management Practices in Peanut (Arachis hypogaea L.) in Southern Ghana

Peanut (Arachis hypogaea L.) yield and financial return can be negatively affected by weeds and the combination of early leaf spot disease [ Passalora arachidicola (Hori) U. Braun] and late leaf spot disease [ Nothopassalora personata (Berk. & M.A. Curtis) U. Braun, C. Nakash., Videira & Crous] in Ghana. Research was conducted in southern Ghana to evaluate hand-weeding, herbicide applied preemergence (PRE) or herbicide applied postemergence (POST), a combination of PRE and POST herbicides, and PRE or POST herbicides supplemented with hand-weeding and disease management practices (i.e., no fungicide or a two sequential fungicide applications 45 and 60 days after planting). Although some differences in leaf spot severity were observed based on weed management, peanut pod yield and financial return based on yield and cost of pest management practices were affected by weed management and disease management practices individually but not the interaction of these treatment factors. The weed management practices with the highest financial return included a POST herbicide with or without hand weeding and a PRE herbicide followed by hand-weeding or a POST herbicide.

Impact of Various Types of Mulch Materials on Plant Growth, Yield and Quality Attributes of Kinnow Mandarin

Background: Among Citrus fruits, Kinnow mandarin is one of the significantly important fruit crops commercially grown in North-Western parts of India. However, due to climate change scarcity of water and soil degradation are the challenging problems, which can cause economic loss to growers. Thus, use of mulching is the one of the appropriate practice for sustainable fruit production. Methods: The experiment consisted of six different types of mulch materials including inorganic and organic mulches like polyethylene (bicolour), bio-mulch (dried local weeds/grasses), mustard straw mulch, sugarcane trash mulch, control (no mulching+no weeding) and hand weeding were applied under Kinnow mandarin trees. The experiment was laid out in randomized block design with three replications. Result: The findings of the study revealed that maximum canopy volume (5.62 m3), number of fruits (485.30 tree-1), fruit yield (95.44 kg tree-1) fruit length, fruit width, fruit weight, total soluble solids, ascorbic acid and juice content (6.51 cm, 8.07 cm, 196.74 g, 12.47°Brix, 46.89 mg/100 ml and 51.37%, respectively) with minimum peel thickness (2.10 mm) and acidity (1.03%) were recorded with bicolour polyethylene mulch followed by sugarcane trash mulch and were the lowest in control. The highest B:C ratio of 2.49 was obtained from the bicolour polyethylene mulch followed by sugarcane trash mulch (2.45) as compared to control (1.96).

Effect of Nutrient and Weed Management Practices on Growth, Yield Parameters and Yield of Semi Dry Rice in Central Telangana One

A field experiment was carried out at College Farm, Agril. College, Aswaraopet, Bhadradri Kothagudem Dist. The experimental site was sandy clay loam soil. The experiment was laid out in a split plot design with three replications comprising of three nutrient (chemical fertilizer alone and integration of fertilizers with organic manures) and four weed management practices (Control, combination of pre/early post-emergence and post-emergence herbicides along with hand weedings) in semi dry rice during kharif 2016 and 2017.Application of integrated nutrient and weed management recorded significantly superior growth and yield parameters and yield compared to sole application of herbicides or control. Plant height, dry matter production, no. of panicles m-2, no. of filled grains panicle-1, test weight, grain and straw yield and harvest index were higher with 75% RDF+25% N through vermicompost and Bispyribac sodium 10% SC @25 g ha-1 (Pre-Emg.) fb (Pyrazosulfuron ethyl 10 % WP @ 25 g ha-1 + 2, 4-D 80% WP @ 0.5 kg a.i ha-1) + HW @ 50 DASat par with 75% RDF + 25% N through FYM and Bispyribac sodium 10% SC @25 g ha-1 (Pre-Emg.) fb Hand weeding @ 20, 40 DASas compared to 100% RDF and control.

Effect of Planting Methods and Weed Management Practices on Growth and Yield of Paddy (Oryza sativa L.)

The trial was conducted at Crop Research Farm, Department of Agronomy of Naini Agricultural Institute, SHUATS, Prayagraj (U.P), during Kharif 2021.The experiment was bifactorial (two factors) which consists of three different planting methods i.e., Direct seeded rice, Transplanted rice and SRI method, and three different weed management practices i.e., Hand weeding (twice), Oxadiazon 25 EC (as Pre emergence) at 250g/L (2L/ha) and Pyrazosulfuron ethyl 10% WP at 20g/ha (as Post Emergence) and a control plot laid out in randomized block design with ten different treatment combinations which is replicated thrice. The results revealed that at harvest significantly, higher growth attributes like plant height (117.28 cm), Number of tillers (38), plant dry weight (56.36 g/hill) at harvest is recorded in treatment number 7 with a combination of SRI method of planting and Hand weeding twice at critical crop weed competition. Significantly, higher yield attributes like number of effective tillers/ hill (35), number of panicles/ plant (44), number of grains per panicle (216.6), test weight (25 g), grain yield (5.1 t/ha) and straw yield (8.1 t/ha) was highest in the same treatment. From the experiment it can be concluded that treatment 7 where SRI method of planting and hand weeding twice during critical crop weed competition was considered as best treatment combination with maximum effective tillers/hill, number of panicles/plant, number of grains per panicle, test weight, grain yield and straw yield i.e., all the yield attributes.
 

​​Improved Herbicide Efficacy through Sole and Sequential Application of Herbicides for Higher Productivity of Urdbean (Vigna mungo) in Indian Semi-arid Tropics

Background: Weeds are major factor that leads to increase crop-weed competition and adversely effects of on growth, quality and yield of urdbean during kharif season. In urdbean the critical period for crop weed competition was the first 25-30 days; yields can be reduced by 50-90%, if weeds were not controlled during this period. As a result, successful weed management strategies to achieve increased growth and yield. Due to the ease, lower cost, timeliness and success controlling weeds, the progressive transformation of agriculture involving intensive use of herbicides has gained traction in recent years. Methods: During kharif season 2019, a field experiment was undertaken at the Agricultural Research Station of Ummedganj, Kota, comprising ten weed management strategies, laid out in a randomised complete block design with three replications. Result: Two hand weedings at 20 and 40 DAS recorded significantly lower weeds dry matter, higher weed control efficacy, ultimately culminating in improved yield attributes and yield, compared to weedy check. This treatment was at par with pendimethalin 30% EC @ 1 kg a.i. ha-1 fb propaquizafop 2.5% w w-1 @ 33.3 g a.i. ha-1 + imazethapyr 3.75% w w-1 (pre mix) ME @ 50 g a.i. ha-1 at 20 DAS resulting in significantly higher pods plant-1 (13.67), seeds pod-1 (6.33), test weight (28.47 g), grain (827 kg ha-1), straw (1393 kg ha-1), biological (2221 kg ha-1) and harvest index (37.26%) of urdbean over the other chemical based treatment.

Conservation Agriculture- Based Planting Techniques and Weed Management Practices Influence on Nutrient Content and Their Uptake in Dry Direct-Seeded Rice (Oryza sativa L.)

Conventionally established rice leads to major challenges in crop production like soil health degradation, water table declination and labour scarcity which ultimately increases the cost of production. To address these issues of transplanted rice, different conservation agriculture (CA) based crop establishment practices in combination with suitable weed management options were incorporated to sustain rice productivity. The field trial was conducted for two years during kharif season of 2018 and 2019 at Research Farm, Banaras Hindu University, Varanasi, Uttar Pradesh (India). The experiment was laid out in split plot design having four planting techniques in main plots viz., farmer’s practice (Conventional Transplanting), zero-till direct seeded rice (ZT-DSR), reduced-till direct seeded rice (RT-DSR) (Rotavator single pass) and conventional-till direct seeded rice (CT-DSR) and five weed management practices viz., pendimethalin 1 kg ha-1 pre-emergence (PE) followed by (fb) chlorimuron + metsulfuron (4g + 4g ha-1) at 20 days after sowing (DAS), pendimethalin 1 kg ha-1 PE fb pyrazosulfuron (30 g ha-1) at 20 DAS, bispyribac-sodium + chlorimuron + metsulfuron (25g + 4g + 4g ha-1) at 20 DAS, hand weeding at 20 and 40 DAS and Weedy check in sub-plots and replicated thrice. The results showed that Nitrogen (N), Phosphorus (P) and Potassium (K) content in grain and straw were not significantly influenced by planting techniques and weed management practices. However, among various crop establishment methods CT-DSR recorded significantly higher N, P and K uptake by both grain and straw over rest of the treatments except ZT-DSR during both the years. Similarly, two hands weeding (at 20 DAS and 40 DAS) recorded the highest N, P and K uptake by the crop. With respect to herbicidal treatments, higher N, P and K uptake by crop was found with the application of pendimethalin 1 kg ha-1 (pre-em) fb chlorimuron + metsulfuron (4g + 4g ha-1) at 20 DAS compared to others during both the years of experimentation. Based on the results, it is concluded that application of pendimethalin 1 kg ha-1 PE fb chlorimuron + metsulfuron (4g + 4g ha-1) at 20 DAS to CT-DSR was registered maximum N, P and K uptake by both grain and straw of rice.

Weed Management and Crop Establishment Methods in Rice (Oryza sativa L.) Influence the Soil Microbial and Enzymatic Activity in Sub-Tropical Environment.

Weed management has become the most important and inevitable aspect of crop management for achieving a higher rice yield. Nowadays, chemical herbicide application has become a popular practice for managing weeds in different rice cultures. However, herbicide application can have qualitative and quantitative impacts on soil microorganisms and soil enzymes, particularly in the case of new herbicide molecules and their indiscriminate use for a longer period. Further, different rice establishment methods also play a significant role in soil microbial population dynamics as well as soil biological properties. Keeping these in view, a field experiment was conducted at the Agronomy Main Research Farm, Orissa University of Agriculture and Technology (OUAT), India, during the kharif season of 2016 and 2017, on the impact of crop establishment methods and weed management practices on soil microbial and enzymatic status. The field experiment was laid out in a split-plot design with three replications with four crop establishment methods in the main plot, viz., M1, Direct Seeded Rice (DSR); M2, Wet Seeded Rice (WSR); M3,Unpuddled Transplanted Rice (NPTR); M4, Puddled Transplanted Rice (PTR), and six weed management practices in the sub-plot, viz., W1, Weedy check; W2, Bensulfuron methyl 0.6% + Pretilachlor 6% (pre-emergence (PE)) 0.660 kg ha−1 + Hand weeding (HW) at 30 days after sowing/transplanting (days after sowing/transplanting (DAS/T)); W3, Bensulfuron methyl 0.6% + Pretilachlor 6% (PE) 0.495 kg ha−1 + HW at 30 DAS/T; W4, Bensulfuron methyl 0.6% + Pretilachlor 6% (PE) 0.495 kg ha−1 + Bispyribac-Sodium (post-emergence(POE)) 0.025 kg ha−1 at 15 DAS/T; W5, Cono weeding (CW) at 15 DAS/T + hand weeding 30 DAS/T, and W6, Brown manuring/Green manuring. The initial decline in the microbial population was observed due to herbicide application in NPTR and PTR up to 7 DAS/T and then it increased up to 28 DAS/T. There was a reduction in soil microbial and enzymatic status after the application of herbicides Bensulfuron methyl 0.6% + Pretilachlor 6% (PE) and Bispyribac-Sodium (POE) that again followed an upward graph with crop age. Significant variation in enzymatic activity and the microbial count was also observed among treatments involving crop establishment methods. The study revealed that improved microbial population and enzyme activity were noted in unpuddled transplanted rice under organic weed management due to favorable conditions, and chemical weed control initially affected microbial population and activities.

Effect of Weed Management Practices on Nutrient Uptake and Removal in Transplanted Rice

Different pre and post emergence herbicides, herbicide mixtures along with hand weeding in transplanted rice were evaluated at PJTSAU, Rajendranagar during Kharif season of 2019 in a randomized block design with three replications. Higher nutrient uptake by grain and straw were recorded with application of flopyrauxifen-benzyl 2.7% + cyhalofop-butyl 10% EC 150 g ha -1(PoE) fb hand weeding at 40 DAT and lower nutrient removal by weeds were recorded with application of herbicide mixtures along with hand weeding than single herbicide application followed by hand weeding. Where as in case of unweeded control lower nutrient uptake and higher nutrient removal by weeds over all the treatments.

Competitiveness of swamp rice against Echinochloa crus-galli and Monochoria vaginalis weeds

Weed competition, especially with Echinochloa crus-galli and Monochoria vaginalis, is a major constraint in rice production as they reduce yield by competing with crops for resources such as light, nutrients, and water. Therefore, this study aims to determine rice competitiveness against Echinochloa crus-galli and Monochoria vaginalis weeds. The experimental design was a split-plot with four replications, with the main plot being weed-free, E. crus-galli, and M. vaginalis treatments, while the subplot was rice varieties namely Inpara 3, 4, 7, and 8. The result showed that existence of weeds reduced the plant height, tillers, photosynthetic rate, leaf area, biomass, percentage of filled grain, and yield of rice due to competition, with losses up to 15%. Furthermore, the rice varieties differed in their yield performances and weed competitiveness. The grain yield ranged from 7.75 t ha-1 to 5.96 t ha-1 for Inpara 4 and 8, respectively, under the weed-free condition. A low weed tolerance and suppress ability was found in Inpara 7, both for E. crus-galli and M. vaginalis. Inpara 8 had a low weed tolerance in E. crus-galli, but high in M. vaginalis, while Inpara 4 produced the highest yield in a weedy condition, along with high weed tolerance and suppress ability. Traits related to the leaf area and rice dry weight at grain filling stage are associated with rice competitiveness. Based on the results, competitive rice can be an important strategy for reducing hand weeding and herbicide inputs in rice production