Hand Weeding Research Articles

Efficacy of tank mixtures of post-emergence herbicides in common bean

In common bean, the occurrence of weeds can cause significant reductions in the final grain yield. This study aimed to evaluate the efficiency of different herbicide trials, applied individually or in a mixture, in the management of common bean weeds. A randomized complete block was used, arranged in subdivided plots. The main plots consisted of three types of beans (Carioca Pérola cultivar, Black cultivar IPR Tuiuiu and one Red Bean strain VR20) and the subplots of different control modes, in four replications: hand weeding, fomesafen (250 g per hectare of ingredient active (g ha-1 of a.i.)), fomesafen (375 g ha-1 of a.i.), imazamox + bentazon (0,23 + 0,6g ha-1 of a.i.), imazamox + bentazon + fomesafen (0.23 + 0.6 + 125 g ha-1 of a.i.) and imazamox + bentazon + fomesafen (0.23 + 0.6 + 83 g ha-1 of a.i.). The following traits were evaluated during three seasons: weeds present in the area, phytotoxicity symptoms, and common bean grain yield. The data were analyzed using a variance analysis (F test), the means obtained were grouped by the Scott Knott test at 5 % probability. Differences in grain yield performance were observed between cultivars and crops season due to herbicide application. The most efficacy treatment for weeds was imazamox + bentazon + fomesafen (230 + 600 + 125 g ha-1 of a.i.), resulting in improved control and greater efficiency in avoiding grain yield losses.

Bio-efficacy of sequential herbicide application for weed management in dry direct seeded rice

Weeds are the major biotic constraint in dry-direct seeded rice (DDSR), mainly due to the concurrent emergence and absence of water layer to suppress weeds. Therefore, strategy needs to be developed to get broad-spectrum weed control in DDSR. Experiments were conducted in rice (var. MTU 1010) during 2015-16 where sequential applications of pre- and post-emergence herbicides were evaluated for providing broad-spectrum weed management options in DDSR. Both the years, employing two-hand weedings at 15 and 30 DAS provided the lowest weed densities and weed dry weight at 75 DAS, whereas the maximum values of weeds were recorded in un-weeded plots. Among the herbicide-based weed management practices, application of pendimethalin 1000 g/ha fb bispyribac sodium 25 g/ha fb fenoxaprop 60 g/ha + chlorimuron + metsulfuron 4 g/ha at 30 DAS provided excellent weed control at 75 DAS, with 4.3% higher rice grain yield than two hand weedings at 15 and 30 DAS, pendimethalin 1000 g/ha fb bispyribac sodium 25 g/ha also provided good weed control and higher grain yield. Un-weeded plots noticed with considerable yield reduction of 79.5-83.3% over two hand weedings. Therefore, sequential application of pendimethalin 1000 g/ ha fb bispyribac sodium 25 g/ha is recommended along with need-based application of post-emergence herbicides (fenoxaprop 60 g/ha + chlorimuron + metsulfuron 4 g/ha) or one hand weeding to improve the weed control efficiency and provides economically higher productivity in DDSR.

Nutrients removal by crop and weeds under different weed and nutrient management practices in barley (Hordeum vulgare L.) and its associated weeds

A field experiment was conducted on sandy loam soil during 2015-16 and 2016-17 at Crop Research Center, Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut (U.P.). The treatments comprised five levels of nutrients viz.; 100% NPK, 75% N-PK + 25% N through FYM, 75% N-PK + 25% N through vermicompost, 50% N-PK + 50% N through FYM, 50% N-PK + 50% N through vermicompost as main plot and four levels of weed control measures viz; Control, Two hand weeding, Trisulfuron 15g a.i. ha-1 and Carfentrazone ethyl 15g a.i. ha-1 as sub plot and it was laid out in split-plot design with three replications. The results indicated that among different nutrient management practices, the maximum NPK uptake in barley and weeds were recorded with the treatment 75% N-PK + 25% N through vermicompost over rest of the other treatments. Among weed management practices, NPK content and uptake were recorded highest in two hand weeding followed by Trisulfuron 15g a.i. ha-1 and control. Therefore, nutrient uptake by crop, status of the soil also improved with the integration of organic and inorganic sources of plant nutrients. Thus 75% NPK + 25% N through vermicompost with Trisulfuron 15g a.i. ha-1 may be recommended for better weed control and higher barley yield.

Weed control technology to increase growth and yield of mungbean (Vigna radiata L.) in soils types

Mungbean is a plant that is cultivated by most of the people of Indonesia at the time before the dry season in the former paddy fields. The presence of weeds in crops that are not controlled by farmers caused the low yield of mungbean obtained by farmers. This study aims to determine the weed control technology to increase the growth and yield of mungbean in soil types. This experiment is a factorial experiment arranged in a completely randomized design (CRD) and repeated three times. The first factor is the weed control technology consisting of three kinds: weedy, hand weeding, and tool weeding. The second factor is the type of soil that consists of four types: coastal sand, latosol, volcanic, and regosol. The results showed that weed control at the age of 20 days after planting (DAP) could increase the growth and yield of mungbean in soil types, except in volcanic soils. Weed control with the hand weeding in coastal sand can give a higher production than tool weeding. Weed control technology with the hand and tool weeding way gives the results of mungbean relatively similar to latosol and regosol soils.

Effect of weed management practices on growth, yield and economics of chickpea

The field experiment conducted during Rabi season of the year 2017 at the Instructional Farm, Swami Vivekanand University, Sagar Madhya Pradesh. The nine weed control treatments comprising of three as pre-emergence viz., Pendimethalin @ 0.75 kg a.i. ha-1, Oxyfluorfen @ 0.100 kg a.i. ha-1 and Metribuzin @ 0.75 kg a.i. ha-1 and three as post–emergence viz., Imazethapyr @ 0.75 kg a.i. ha-1., Propaquizafop @ 0.75 kg a.i. ha-1 and Quizalofop-ethyl @ 0.40 kg a.i. ha-1, hand weeding twice at 30 and 45 DAS, weed free and weedy check, were laid out in randomized block design with 3 replications. The results indicated that among herbicides, application of Pendimethalin @ 0.75 kg a.i. ha-1 as pre-emergence recorded higher values of growth parameters viz., plant height, number of branches per plant, dry weight per plant, No. of nodules and weight of nodules, yield attributes viz., number of pods per plant, number of seeds per pod, test weight, biological yield/plot, seed yield/plot and straw yield/plot, straw yield (3205.60 kg ha-1), gross monetary returns (117667 Rs. ha-1), net Monetary returns (90902 Rs. ha-1) and benefit cost ratio (4.53) were recorded under application of Oxyfluorfen @ 0.100 kg a.i. ha-1 as compared to rest of the treatments.

Effect of encapsulated herbicides on weed control, productivity and nutrient uptake of rice (Oryza sativa)

Aim: To study the effect of season-long weed management using encapsulated herbicides on weed control, productivity and nutrient uptake of rice. Methodology: Field experiment was carried out with oxadiargyl encapsulated / loaded in zeolite, biochar, starch, water soluble polymer. It was compared with commercial formulation of oxadiargyl, butachlor, weed free check and weedy check. The experiments were laid out in randomized complete block design and replicated thrice. The physico-chemical properties of the experimental sites was sandy clay loam to clay loam in texture with pH ranging from 6.9 to 7.3, low organic carbon content, low available nitrogen, medium available phosphorus and potassium. Results: The lowest weed density and weed dry matter production of 47.3, 28.0 m-2 and 96.2, 32.8 kg ha-1 was observed in 2016 and 2017 respectively with the application of oxadiargyl loaded with zeolite at 20 DAT. Application of butachlor at 1.25 kg ha-1 fb hand weeding on 40 DAT and application of oxadiargyl loaded with zeolite recorded 86.7, 76.9 and 81.3, 72.8 percent higher grain yield in 2016 and 2017, respectively, as compared to weedy check. Higher N, P, K uptake was observed with application of butachlor at 1.25 kg ha-1 fb hand weeding on 40 DAT, which was comparable with oxadiargyl loaded with zeolite and oxadiargyl loaded with biochar during both the year. Interpretation: It can be concluded that oxadiargyl loaded with zeolite was more efficient in controlling weeds coupled with maximum growth and productivity under the constrained situation of manual weeding. Key words: Biochar, Encapsulation, Herbicides, Rice, Water soluble polymer, Zeolite

Effect of different weed management practices on growth and yield of okra (Abelmoschus esculentus (L.) Moench.)

The experiment was conducted during Kharif seasons of 2019-20 at AICRP (Vegetables) RHREC, Dharwad, Karnataka. The experiment was laid out in a randomized block design (RBD) with seven treatments with three replications. Significantly lowest dry weight of total weed biomass and Number of weeds per m2 area are registered under the treatment Pre-application of Pendimethalin @ 6 ml/L + one hand weeding of 7.43 g and 6.67 respectively at 60 DAS and also Higher gross return (Rs.175095), net return (Rs.108768) and B:C ration of 1.64.

Integrated Effect of Tillage and Herbicides on Wheat Crop

Combining tillage with herbicides is an economical and efficient method for weed management and yield improvement in wheat. A two-year study was conducted having three tillage levels viz. 2″ tillage (shallow tillage, ST), 4″ tillage (conventional tillage, CT) and 6″ tillage (deep tillage, DT). The weed control treatments were five including three herbicides i.e. bromoxynil + MCPA (a broad-leaf weed killer), fenoxaprop-p-ethyl (a grass killer) and isoproturon + carfentrazone (a broad-spectrum herbicide), along with a hand weeding (HW) and a weedy check (WC). Results showed that the recorded parameters were significantly affected by the varying tillage depths, herbicide applications and their interactions. The weed density and biomass were the highest in ST and the lowest in DT, while among the weed control treatments, the weed density and biomass were highest in WC and lowest in HW. On the other hand, the DT treatments resulted in highest number of spikes m−2, 1000-grain weight (TGW), biological yield and grain yield; while ST showed the lowest values. Among the weed control treatments, the number of spikes, TGW, biological and grain yields were the highest in HW and the lowest in WC treatments. The herbicide isoproturon + carfentrazone performed the best among the three applied herbicides in diminishing the weed population density and biomass, and improving the number of spikes, TGW, biological and grain yields. In conclusion, the combination of deep tillage and herbicide isoproturon + carfentrazone can prove to be the best option for optimum weed management in wheat at higher altitudes.

Resource conservation technology for sustainable productivity of intensive rice-based cropping pattern in Bangladesh

Exhaustive conventional tillage and removing residues of previous crops in the rice-based cropping system are labor intensive, costly, soil destructive and non-ecofriendly. In recent years, increased concerns for healthier food production and environmental quality, and increased emphasis on sustaining the productive capacity of soils, have raised concern in the maintenance and improvement of soil organic matter through appropriate land use and management practices. Strip tillage with the application of herbicides and crop residue mulching are being developed to overcome this challenge. A two-year experiment of the summer rice-mustard-winter rice (R-M-R) system was conducted at the farmers’ field in the northern Bangladesh during 2014-2016. Summer rice (BRRI hybrid dhan6), mustard (BARI Mustard 14) and winter rice (BRRI dhan28) were grown under, T1: Conventional tillage (CT) + three hand weeding (Control) and T2: Pre-plant herbicide (PRE) + strip tillage (ST) + pre-emergence herbicide (PE) + post-emergence herbicide (PO) with two levels of crop residue mulching, M0: no-mulch and M50: 50% standing mulch. The CT consisted of two primary tillage operations by a two-wheel tractor, and ST had done by a Versatile Multi-crop Planter in a single-pass process. The PRE (glyphosate) and PE (pendimethalin) in all crops and the PO (ethoxysulfuron-ethyl in rice and isoproturon in mustard) were applied at recommended dose and time. The combination of applied PRE, ST, followed by PE and PO herbicide and the retention of 50% mulch fetched the highest yield and economic returns of individual crop and the productivity of the summer rice-mustard-winter rice system.

Fabrication and field evaluation of a wheel weeder

In general human energy is used in small farms for doing fieldwork (tilling, aerating and weeding). But availability of skilled workers is less during the time of exigencies. Controlling the weeds is one of the laborious steps in crop cycle. With high labour charges and more time needed, complete hand weeding is uneconomical. In the present work comparative evaluation of an ergonomically designed wheel weeder was made with that of conventional weeding tools viz. trench hoe, spade and wheel weeder available in market. Travel speed, field efficiency, field capacity, working capacity, weeding efficiency and plant damage were calculated. Results indicate that ergonomically designed weeder is superior compared to trench hoe, spade and conventional wheel weeder. It reduces drudgery. It is economical and reduces drudgery as well. It operates up to a depth of 22 to 35 mm with a field capacity of 0.0038 ha/h. Hazard occurrence was also low.

Residual Effect of Weed Management Practices Executed in Preceding Maize on Succeeding Greengram

Background: Maize followed by summer pulses is the emerging cropping system in many places in India. Herbicides are the efficient tools for checking weed infestation and their usage is increasing throughout the globe due to increased labour cost and quick weed control. Some herbicides do not degrade quickly and may remain in the soil for weeks, months or years after application and may inhibit the growth of succeeding crops. Methods: Field experiment was conducted in a randomized block design (RBD) during rabi and summer seasons of 2017-18 and 2018-19 to know the residual effect of different herbicides applied in maize on succeeding greengram. Result: The present study revealed that lower density and dry weight of total weeds and higher yield attributes and yield was recorded with the practice of adopting two hand weedings at 15 and 30 DAS, which was however, at par with atrazine 1.0 kg ha-1 as PE fb one HW at 30 DAS, atrazine 1.0 kg ha-1 as PE fb topramezone 30 g ha-1 as PoE and atrazine 1.0 kg ha-1 as PE fb tembotrione 120 g ha-1 as PoE, without any significant disparity among them. Herbicides applied in maize did not alter statistically the enzyme activity and microbial count in the soil at harvest of succeeding greeengram.

Field evaluation of fluorochloridone for broad-spectrum weed control in carrot (Daucus carota L.) in north-west India

Weed management has been one of the major components of carrot production where the critical period of weed competition is longer as the development of a carrot canopy is very slow. Thus, hand weedings must be applied to control weeds. In this context, use of residual herbicides assumes greater significance in this important root vegetable. The field efficacy of fluorochloridone, a residual pre-emergence herbicide, was evaluated in carrot over two years at Ludhiana, India. Fluorochloridone at 625 and 750 g ha−1 provided >90% control of annual grasses [Digitaria sanguinalis (L.) Scop, Echinochloa colona (L.) Link, and Eleusine indica (L.) Gaertn.], and broad leaf weeds [Digera arvensis Forssk., Chenopodium album (L.), and Amaranthus viridis (L.)] until 60 days after application. Fluorochloridone at 625 and 750 g ha−1 gave the highest carrot root yield (28.4–31.7 t ha−1) which was similar to the hand weeded check (29.5–32.6 t ha−1) and 25.4–26.3% higher than the weedy check (23.1–25.1 t ha−1) in both years. Findings imply that application of fluorochloridone at 625 g ha−1 could be a suitable option for pre-emergence residual control of annual grass and broadleaved weeds in carrot.

Effect of different single herbicide doses on sugar beet yield, quality and associated weeds

BackgroundThe objective of this work is to identify the most proper herbicidal treatment on sugar beet to compare different single weed control herbicide doses on sugar beet traits and associated weeds as well as yield and quality under sandy soil conditions. Therefore, two field experiments were conducted during the winter seasons of 2017/2018 and 2018/2019 at the Experimental Farm of the National Research Centre, El-Beheira Governorate. Tigro at 1.0 and 0.750 l fed−1, Betasana-Trio at 0.675 and at 0.9 l fed−1, Select Super at 0.5 and 0.375 l fed−1 and Betanal MaxxPro at 0.5 l fed−1 besides the unweeded and hand weeded twice were used.ResultsThe results showed that the herbicides Betasana-Trio at 0.9 l fed−1, Tigro at 1.0 l fed−1 and Betasana-Trio at 0.675 l fed−1 when sprayed twice could effectively and/or completely eliminate the broadleaved weeds associated with sugar beet plants. Moreover, the results indicated and confirmed that Tigro and Betasana-Trio herbicides are effective in controlling broadleaved weeds. Similar tendency was recorded for the narrow-leaved weeds, where Select Super or Betanal MaxxPro at 0.5 l fed−1 as well as Select Super at 0.375 l fed−1 could completely eliminate or minimize the narrow-leaved weeds associated with sugar beet plants. The greatest significant root length, root diameters and root yield plant−1 were recorded when hand weeding twice followed by Betanal MaxxPro at 0.5 l fed−1 without significant differences. Gross sugar % ranged between 12.08 and 15 .7% and extractable sugar % ranged between 8.97 and 13.8% for Betasana-Trio at 0.09 l fed−1 and Betanal MaxxPro at 0.5 l fed−1.ConclusionBetanal MaxxPro gave the highest values of root and biological yield ton fed−1. Betanal MaxxPro followed by hand weeding treatment twice resulted in the greatest sugar yield fed−1. The highest sugar yield resulted from the herbicidal treatment with Betanal MaxxPro or Tigro at 1.0 l fed−1, which gave the greatest gross and extractable sugar yield fed−1 and exceeded the hand weeding treatment by 10.4 and 7.8%.

Efficiency of Certain Herbicides and Adjuvants Combinations Against Weeds in Wheat Fields

Two field experiments were carried out at El-Dalangat district, El-Beheira Governorate, Egypt during two successive winter seasons of 2017-2018 and 2018-2019, to evaluate the efficiency of post-emergence herbicides: Clodimex (clodinafop-propargyl 24% EC),Pallas (pyroxsulam 4.5% OD), Skylla (tribenuron-methyl 75% WG) at their recommended rates or at reduced rates without adjuvants or in combination with Argal at 0.2% v/v and Techno oil at 0.3% v/v adjuvants in combination with clodinafop-propargyl + tribenuron-methyl at half recommended rate combined with Argal or Techno oil adjuvants and hand weeding at 25 and 40 days after sowing (DAS) for controlling predominant weeds in wheat crop compared to unweeded check. The results indicated that the dominant weed species in the experimental wheat field were, two grassy weeds, Phalaris minor and Eragrostis ciliagensis, and six broad-leaved weeds: Malva parviflora, Sonchus oleraceus, Coronopus squamatus, Rumex dentatus, Anagallis arvensis and Medicago polymorpha during the both seasons. In addition, Eclipta alba weed was found only in the second season. Results also showed that all herbicidal treatments significantly decreased the total weed biomass compared to the unweeded check 60 and 90 DAS. Among herbicidal treatments applied, pyroxsulam herbicide at ¾ of recommended rate with Argal recorded the highest weed control efficiency against grassy and broad-leaved weeds followed by pyroxsulam treated plots at ¾ of recommended rate combined with Techno oil 60 and 90 DAS throughout the two studiedseasons. On the other hand, regardless of application rates or adjuvants, tribenuron-methyl and clodinafop-propargyl seemed to be the least effective treatments against the total weeds 60 and 90 DAS during the both seasons in comparison with unweeded plots. The maximum increase in wheat grain yield was observed in pyroxsulam treated plots at ¾ recommended rate with Argal or Techno oil combinations. It could be concluded that the addition of Argal or Techno oil to herbicides spray solutions at reduced rates especially at ¾ of the recommended rate resulted in enhancing the herbicidal activity against weeds and increasing wheat grain yield.

Sustainable Organic Corn Production with the Use of Flame Weeding as the Most Sustainable Economical Solution

Flame weeding is an alternative method of weed control. Essentially, it is a supplement to other physical and mechanical processes used in organic production. Weed control costs have a large share of the total cost of crop production. This study aimed to investigate hand weed hoeing’s cost-effectiveness, accompanied by inter-row cultivation and flame weeding applied in organic maize production using two different machines to determine the economically best solution. For this purpose, the prototype flame weeder and commercial flame-weeding machinery were used. Designed primarily for smaller fields, the prototype flame weeder was equipped with a cultivator and a 70 kg propane bottle. Commercial Red Dragon flame weeder, fitted with an 800 kg propane tank and featuring no cultivation implements, is designed for larger areas. The analysis has shown that hand hoeing produced a higher yield (8.3 t/ha in total), but it contributed significantly to the production costs. The costs per hectare decreased when the prototype flame weeder and the commercial Red Dragon flame weeder were used compared to hand hoeing. More beneficial economic impacts were recorded when the prototype flame weeder was used (489.39 €/ha) than in applying the Red Dragon flame weeder (456.47 €/ha). The efficacy of flame weeding is somewhat limited and could be enhanced by additional hand hoeing, if the effect of the machine in terms of weeding is observed. However, the analysis has shown that, in this case, investments in additional hand hoeing are not economically justified because the operating costs incurred therein (168 €/ha) were not met by a yield increase of 500 kg/ha, i.e., a surplus revenue of 100 €/ha. Moreover, the economic impacts of flame weeding would be considerably more significant in larger fields.

Aqueous Extract of Mustard Crop Residues on Weed Management and Crop Performance of Wheat

Allelopathy is expected to be an important mechanism in the plant invasion process. The experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh to evaluate the effect of aqueous extract of mustard crop residues on weed management and crop performance of wheat. The experiment consisted of three cultivars of wheat viz., BARI Gom 19, BARI Gom 21, BARI Gom 24 and five levels of aqueous extract such as no crop residues (C0), mustard crop residues: chaffed leaves soaked in water in 1:20 ratio (w/v) (C1), 1:30 ratio (w/v) (C2), 1:40 ratio (w/v) (C3), hand weeding (C4). The maximum weed growth was noticed with the cultivar BARI Gom 19 and the minimum was found in the cultivar BARI Gom 21. The grain yield as well as the other yield contributing characters produced by BARI Gom 21was the highest among the studied varieties. The highest percent inhibition of all weed species was caused by hand weeding. The highest numbers of tillers hill-1, numbers of grains spike-1, 1000 grain weight, grain yield and straw yield were observed where hand weeding is done and followed by the application of aqueous extract in 1:20 ratio (w/v). BARI Gom 21 cultivar with all treatments produced the highest grain and straw yield among the treatment combination. The results indicate that different amount of aqueous extract of mustard crop residues showed potential activity to suppress weed growth and it has a significant effect on the yield of wheat. Therefore, mustard crop residues might be used as an alternative way for weed management in effective and sustainable crop production.
 SAARC J. Agri., 18(2): 17-26 (2020)

Weed dynamics, crop growth and yield as affected by different weed management practices and plant growth-promoting rhizobacteria in direct-seeded upland rice

Effect of different weed management practices and plant growth-promoting rhizobacteria (PGPR) were evaluated in Jorhat (Assam) on weed dynamics, crop growth and yield in direct-seeded upland rice during 2018 and 2019. Results revealed that density and dry weight of weeds were the lowest with Pseudomonas fluorescens among PGPR treatments. The growth and yield attributing characters were significantly improved due to P fluorescens contributing to the highest grain and straw yield of rice. Single application of pretilachlor pre-emergence 0.75 kg/ha or application of pretilachlor pre-emergence 0.75 kg/ha followed by one hand weeding at 30 DAS resulted in least density and dry weight of weeds at initial stages of crop growth. The lowest values were recorded in three hand weedings done at 15, 30 and 45 DAS. Better growth and yield attributing characters of rice with three hand weedings at 15, 30 and 45 DAS resulted in the highest grain and straw yields. Combination of P fluorescens with either three hand weedings at 15, 30 and 45 DAS or pretilachlor pre-emergence 0.75 kg/ha followed by one hand weeding at 30 DAS was found to be superior with grain and straw yields along with similar trend in gross and net returns. However, the benefit: cost ratio was the highest in the combination of P fluorescens with pretilachlor pre-emergence at 0.75 kg/ha followed by one hand weeding at 30 DAS.

Efficacy of weed control treatments on weeds and productivity of chickpea under Jatropha based agroforestry

A field experiment was conducted at Research Farm, Department of Forestry, JNKVV, Jabalpur during Rabi season 2019-20 to find out the effect of weed management on weeds and productivity of Chickpea under Jatropha based Agroforestry. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications and 12 herbicidal treatments consisted of Pendimethalin (1000 g ha-1), Imazathaper (900 g ha-1), Atrazine (1000 g ha-1), Metribuzin (300 g ha-1), Oxyflorfen (100 g ha-1), Pendimethalin (500 g ha-1) fb Imazathaper (450 g ha-1), Pendimethalin (500 g ha-1) fb Oxyflorfen (50 g ha-1), Metribuzin (150 g ha-1) fb Oxyflorfen (50 g ha-1), Atrazine (500 g ha-1) fb Metribuzin (150 g ha-1), Imazathaper (450 g ha-1) fb Atrazine (500 g ha-1), hand weeding (30 DAS) and Weedy check (control). The field was infested with 4 major weed species Medicago denticulata Willd., Vicia sativa L., Cynodon dactylon L., and Cyperus rotundus L. Minimum weed density per m2 (7.53) and weed dry weight (5.42 q ha-1), was found under hand weeding 30DAS over weedy check. Minimum dry weight of weeds was found under hand weeding (30 DAS) 5.42q ha-1 as compare to weedy check (control) 16.84q ha-1). The highest weed control efficiency was found in hand weeding (30DAS) 89.75%, Pendimethalin (1000 g ha-1) 78.50 %, Atrazine (1000 g ha-1) 67.67 %, Oxyflorfen (100 g ha-1) 66.83 %, and Metribuzin (150 g ha-1) fb Oxyflorfen (50 g ha-1) 65.41%. The loss of grain yield was significantly reduced where weeds were control by Pendimethalin (1000 g ha-1) 11.16 %, and Metribuzin (150 g ha-1) fb Oxyflorfen (50 g ha-1) 11.19 %. Amongst the different herbicidal treatments higher seed yield was found under Pendimethalin (1000 g ha-1) 12.54 q ha-1, higher stover yield was found under Pendimethalin (1000 g ha-1) 37.46 q ha-1, higher crop biomass was found under Pendimethalin (1000 g ha-1) 50.00 q ha-1 and higher harvest index was found under Pendimethalin (1000 g ha-1) 24.99 % as compared to other treatments. The perusal data showed that higher harvest index was found under hand weeding (30DAS) 25.06 % which was significantly superior over weedy check (control) 18.74 % and rest of the weed control treatments. Pre emergence herbicides and hand weeding can further enhance the weed suppressive effect of the crop under Jatropha based Agroforestry.

Effect of weed management on nutrient utilization by chickpea and weeds under Jatropha based agroforestry

A field experiment was conducted at Research Farm, Department of Forestry, JNKVV, Jabalpur during Rabi season 2019-20 to find out the effect of weed management on nutrient utilization by Chickpea and weeds under Jatropha based Agroforestry. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications and 12 herbicidal treatments consisted of Pendimethalin 1000 g ha-1, Imazathaper 900 g ha-1, Atrazin 1000 g ha-1, Metribuzin 300 g ha-1, Oxyflorfen 100 g ha-1, Pendimethalin 500 g ha-1 fb Imazathaper 450 g ha-1, Pendimethalin 500 g ha-1 fb Oxyflorfen 50 g ha-1, Metribuzin 150 g ha-1 fb Oxyflorfen 50 g ha-1, Atrazin 500 g ha-1 fb Metribuzin 150 g ha-1, Imazathaper 450 g ha-1 fb Atrazin 500 g ha-1, hand weeding (30 DAS) and Weedy check (control). The nutrient absorption by crop and weeds is significantly influence by different herbicidal treatments. The result revealed that there were different variations in nutrients absorption by weeds. The highest nutrient absorption by chickpea seed was observed in hand weeding (42.6: 9.22: 19.2) and minimum was in weedy check (14.3: 2.22: 7.25). The highest nutrient absorption by stover was observed in hand weeding (44.4: 10.6: 32.8) and minimum was in weedy check (23.7: 2.93: 18.2). The maximum nutrient absorption of hand weeding (87.07: 19.85: 50.48) and minimum was in weedy check (38.15: 5.16: 24.85) of total (seed + stover). Among different herbicidal treatments application of Pendimethalin 1000 g ha-1 was found the highest (66.37: 13.85: 42.29) and lowest was in Imazathaper 900 g ha-1 (49.12: 7.06: 29.:39) of total (seed + stover). Weedy check recorded significantly higher nutrient absorption of weeds viz., Cynodon dactylon (4.52: 2.40: 3.46 NPK kg ha-1), Cyperus rotundus (3.03: 1.41: 7.41), Medicago arabica (24.23: 3.34: 31.33), and Vicia sativa (15.77: 2.57: 24.37). Hand weeding (30DAS) recorded significantly lower nutrient absorption by weeds viz., Cynodon dactylon (0.59: 0.28: 1.78), Cyperus rotundus (0.29: 0.11: 0.77), Medicago arabica (2.14: 0.30: 2.86), and Vicia sativa (1.46: 0.21: 2.27 K) Lower absorption of nutrient in these treatments attributed to lower weeds density and dry weight. The maximum nutrient absorption of total weeds in weedy check (47.60: 9.72: 76.67) and minimum was in hand weeding (4.48: 0.91: 7.65). Among different herbicidal treatments application of application of Imazathaper 450 g ha-1 fb Atrazin 500 g ha-1 was found the highest (21.31: 4.20: 36.51) and lowest was in Metribuzin 150 g ha-1 fb Oxyflorfen 50 g ha-1 (13.44: 3.09: 24.80).

Effects of Conservation Agricultural Practices on Soil Microbial Population and Yield of Cotton

Field investigations were conducted to assess the effect of conservation agricultural practices on soil biological properties and yield of cotton during the kharif season of 2018 and 2019. The experiments were laid out in a split plot design with four main factors viz., conventional tillage with irrigation schedule of 0.8 IW/CPE ratio (M1), conventional tillage with irrigation schedule of 0.6 IW/CPE ratio (M2), minimum tillage with irrigation schedule of 0.8 IW/CPE ratio (M3) and minimum tillage with irrigation schedule of 0.6 IW/CPE ratio (M4). Sub plot had six treatments of weed and nutrient management viz., crop residue mulch with 100% RDF (S1), crop residue mulch with 75% RDF (S2), pre-emergence application of pendimethalin fb one hand weeding with 100% RDF (S3), pre-emergence application of pendimethalin fb one hand weeding with 75% RDF (S4), mechanical weeding twice with 100% RDF (S5) and mechanical weeding twice with 75% RDF (S6). Total microbial populations viz., bacteria, fungal, and actinobacteria were higher in cotton rhizosphere soil with the minimum tillage of irrigation at 0.8 IW/CPE ratio (M3) in the main plot treatments. Cotton rhizosphere soil with crop residue mulch with 100% RDF (S1) recorded a higher microbial population and it was statistically similar with pre-emergence application of pendimethalin fb one hand weeding with 100% RDF (S3) in the sub plot treatments. Among the treatment combination, minimum tillage with irrigation at 0.8 IW/CPE ratio (M3) and crop residue mulch with 100% RDF (S1) recorded a higher microbial population. Similarly, a higher seed yield of cotton was also recorded with minimum tillage and irrigating the crop at 0.8 IW/CPE ratio and pre-emergence application of pendimethalin fb one hand weeding along with application of 100% RDF (M3S3)