Volume-53 | Issue-1(January-March)| Year 2021

Economic threshold concept for weed management in crops: Usefulness and limitation
T.K. Das, Suman Sen*, Rishi Raj, Sonaka Ghosh, Biswaranjan Behera and Arkaprava Roy

KEYWORDS:

Decision support system

Economic threshold

Herbicide

Hyperbolic regression model

Weed management

Abstract:

The economic threshold (ET) is one of the major decision-making frameworks for rationalizing herbicides use for better weed management while reducing environmental impacts. The ET is the density of weeds at which the cost of control equals the benefits obtained under particular weed control measure adopted. The ET rejects complete eradication of weeds, but advocates regulating weed populations at economically optimum levels. Control measure is adopted only when weed competition goes beyond a certain limit, thus, it uses certain damage levels for making cost-efficient weed management decisions. Several decision-making models on ET are available with high to low degree of precision. Despite potentials, the adoption of ET models as the major criterion for cost-effective herbicide use has been low. Limitations are building up of seed bank by residual weeds, complexity in estimating ET density, patchy weed distribution, and limited validity in cropping systems with multiple weed species. Yet, the ET-based decision has great potential in designing weed management under single weed dominance in crops. Information on weeds population dynamics in cropping system, biology, ecology and spatial heterogeneity would make determination of ET more precise and reliable, and managing weeds using integrated approach more successful.

Email

sumansen.agri@gmail.com

Address

Division of Agronomy, ICAR – Indian Agricultural Research Institute, New Delhi 110 012, India
Weeds as alternate and alternative hosts of crop pests
Sushil Kumar*, Malay K. Bhowmick1 and Puja Ray

KEYWORDS:

Alternate host, Alternative host, Insect pest, Mites, Nematode, Plant pathogen, Weed

Abstract:

Weeds pose a perpetual menace both in cropped and non–crop areas. They provide food, shelter and reproductive sites for various pest organisms (plant pathogens, insect pests, mites, nematodes, rodents and others), and thereby play a key role to serve as alternate as well as alternative hosts. Many plant pathogens (fungi, bacteria and viruses) may also have either narrow or wide host range on which they pass at least a part of their life cycle. Alternate hosts from plant families other than the family of main (primary) host help a crop pest not only to complete its life cycle, but also support the crop pest to survive under unfavourable conditions and non–availability of main host. Alternative (collateral) hosts of similar plant family as of primary host help a crop pest to survive during the periods when main hosts are not seasonally available, and while the pests subsequently migrate back onto the main host plants. Although there are some similarities, differences between alternate and alternative hosts are aptly justified, signifying the relative importance of alternative hosts over the alternate ones. There may also have the possibilities of an elevated weed status from its indirect role as alternate and alternative hosts to directly as the main host under certain circumstances. However, eliminating harmful weeds (alternate and alternative hosts) from the margins of crop fields as well as non–crop areas at the extent possible or feasible is imperative to preventing continued infection and infestation of crop plants from different pest organisms.

Email

sknrcws@gmail.com

Address

ICAR-Directorate of Weed Research, Maharajpur, Jabalpur, Madhya Pradesh 482004, India 1Directorate of Agriculture (Government of West Bengal), Kolkata, West Bengal 700001, India 2Department of Life Sciences, Presidency University, Kolkata, West Bengal 700073, India
Sesbania, Azolla and herbicide use for weed management and optimizing yield in direct-seeded rice
Suryendra Singh, S. Elamathi, Gautam Ghosh and N.S. Abeysingha

KEYWORDS:

Azolla

Direct-seeded rice

Grain yield

Sesbania

Weed smothering efficiency

Abstract:

 

The experiment was conducted at Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj (U.P.) during Kharif seasons of 2009 and 2010 to assess the performance of direct-seeded rice as influenced by Sesbania/ Azolla with nitrogen levels and herbicide use for managing weeds and optimizing the yield of direct-seeded rice (DSR). Weed density and dry weight were consistently lower with Azolla culture than with Sesbania during initial crop growth stages, however, they were similar at 90 days after sowing (DAS). Among weed management practices, pretilachlor (with safener) at 0.3 kg /ha at 2 DAS as pre-emergence application followed by (fb) hand weeding (HW) at 45 DAS was effective in controlling weeds and increasing the grain yield of DSR, which resulted in higher net returns and benefit cost ratio than HW twice at 20 and 45 DAS. The higher yields were recorded under Sesbania and Azolla than DSR (sole) crop. Sesbania Azolla + 100% recommended dose of nitrogen with pretilachlor (with safener) 0.3 kg /ha at 2 DAS as pre-emergence application fb HW at 45 DAS recorded lower weeds density, dry weight and higher economic returns in direct-seeded rice

 

Email

suryendra_aligarh@yahoo.com

Address

Department of Agronomy, Sam Higginbottom University of Agriculture, Technology and Sciences (SHUATS), Prayagraj, Uttar Pradesh 211007, India
Weed dynamics, crop growth and yield as affected by different weed management practices and plant growth-promoting rhizobacteria in direct-seeded upland rice
Jimni Phukan and Jayanta Deka

KEYWORDS:

Direct-seeded upland rice

Plant Growth-promoting Rhizobacteria

Pretilachlor

Pseudomonas fluorescens

Weed dynamics

Abstract:

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.

Email

jimniphukan2016@gmail.com

Address

College of Agriculture, Assam Agricultural University, Jorhat, Assam 785013, India
Herbicide combinations for management of resistance in Phalaris minor
Jeetendra Kumar Soni, Amarjeet, S.S. Punia and V.K. Choudhary

KEYWORDS:

Resistance

Phalaris minor

Herbicides

Grain yield

Regression

Correlation

Abstract:

Littleseed canarygrass (Phalaris minor Retz.) is a problematic weed of wheat under irrigated rice-wheat cropping system of Indo-Gangetic plains (IGP) of India. Due to its morphological similarity with wheat, herbicides are the best-suited method for its control. However, continuous use of same herbicide along with monocropping leads to development of multiple-herbicide resistance. To tackle this problem, an experiment was conducted at CCS Haryana Agricultural University, Hisar during 2016-17 and 2019-20 to find out the suitable herbicide combinations for management of resistance Phalaris minor, its regression and correlation studies with wheat. The finding revealed that increase in weed density and dry weight displayed a strong negative linear relationship with grain yield. Linear regression equation represented that increase in every one unit of density and dry weight of P. minor led to reduction in wheat yield by 0.027 and 0.0102 times, respectively. Among the herbicidal treatments, sequential application of pendimethalin + pyroxasulfone (tank-mix, TM) fb mesosulfuron + iodosulfuron (ready-mix, RM) (1500 + 102 g/ha) pre-emergence, (PE) fb 14.4 g/ha post-emergence, (PoE) or pendimethalin + metribuzin (TM) fb mesosulfuron + iodosulfuron (RM) (1000 + 175 g/ha) PE fb 14.4 g/ha PoE led to significantly control of P. minor, broad-leaved weeds (BLWs) and total weeds. This resulted in better crop growth, higher yield attributes, 37.6-51.9% higher grain yield and 80-81% higher net return as compared to unweeded control. However, PE or PoE herbicide applied alone recorded poor efficacy towards P. minor and other weeds and resulted in poor yield. Correlation studies indicated strong positive association of grain yield with visual weed control, crop dry weight and its height and negative association with weed density and dry weight. Therefore, for effective management of resistant P. minor along with other weed flora, herbicide combination with its sequential application is of prime importance for optimum yield in wheat.

Email

jeetendra.soni@icar.gov.in

Address

Department of Agronomy, CCS Haryana Agricultural University, Hisar, Haryana 125004, India
Effect of post-emergence herbicides in chickpea
Indu Bala Sethi*, Harphool Singh, Suresh Kumar, Mahesh Jajoria, Lokesh Kumar Jat, Niranjan Kumar Braod, Suresh Muralia and Hans Ram Mali

KEYWORDS:

Chickpea

Herbicides

Weed management

Abstract:

A field experiment was conducted during two consecutive (Rabi) winter seasons (2018-19 and 2019-20) at Agricultural Research Station, Navgaon (Alwar), S.K.N. Agriculture University, Jobner, Jaipur (Rajasthan), India, to study the effect of weed management practices in chickpea. The experiment was laid out in a randomized block design with eight treatments and replicated thrice. The crop was sown as per the package of practices recommended for zone IIIB of Rajasthan. Treatments included application of pendimethalin 30% EC 1.0       kg/ha as pre-emergence, and quizalofop-p-ethyl 10% SL at 50g/ha, fenoxaprop p-butyl 10% EC at 100 g/ha, imazethapyr 10% EC at 75 g/ha, imazethapyr (35%) + imazamox (35%) at 100 g/ha, imazethapyr (2%) + pendimethalin (30%) at 2.5 litre/ha as post-emergence along with weedy and weed free checks. Among the different herbicidal treatments, imazethapyr (35%) + imazamox (35%) at 100 g/ha recorded significantly higher seed yield 2.22 t/ha in 2018-19 and 2.28 t/ha in 2019-20 with higher weed control efficiency and the lowest weed index. However, it remained at par with imazethapyr 10% EC 75 g/ha and, imazethapyr (2%) + pendimethalin (30%) at 1.0 kg/ha.

Email

indubalasethia2012@gmail.com

Address

Agricultural Research Station, Navgaon (Alwar), S.K.N. Agriculture University, Jobner, Jaipur, Rajasthan 303329, India
Bio-efficacy of weed management practices in rainfed potato
S.K. Yadav, T.K. Bag, A.K. Srivastava and V.P. Yadav

KEYWORDS:

Herbicide

Metribuzin

Potato

Tuber crop

Abstract:

A field experiment was conducted during 2013-14, 2014-15 and 2015-16 at ICAR-Central Potato Research Station, Shillong to evaluate the bio-efficacy of weed management practices in rainfed potato under North-Eastern hill region of India. Maximum potato tubers yield (21.3 t/ha) was recorded under weed free treatment followed by metribuzin application 0.75 kg/ha as a pre-emergence (PE). Reduction in crop yield due to presence of weeds was 54.0 per cent. Maximum uptake of nutrients, viz. nitrogen (113.2 kg/ha), phosphorus (14.5      kg/ha) and potassium (89.4 kg/ha) were recorded by the potato under weed free fb application of metribuzin 0.75 kg/ha as a PE. The highest net returns                       ( 176100/ha) and B:C ratio (2.3) were recorded under the metribuzin application 0.75 kg/ha. Thus, application of metribuzin 0.75 kg/ha as PE was found more effective in potato under the rainfed ecosystem of North-Eastern hill region of India.

Email

sanjaybhu05@rediffmail.com

Address

ICAR- Central Potato Research Station, Shillong, Meghalaya 793 009, India
Germination ecology of heteromorphic seeds of bur clover (Medicago denticulata willd.)
Renu Sethi and Navjyot Kaur

KEYWORDS:

Burial depth

Light

pH

Salinity

Seed coat colour

Temperature

Abstract:

 

Bur clover (Medicago denticulata Willd.) is a winter annual weed commonly found in wheat fields of Punjab, India. We observed it produces heteromorphic seeds varying in seed coat colour - cream and brownish-black. The information on germination ecology of M. denticulata seeds varying in seed coat colour is lacking. So, the present study was undertaken under laboratory conditions to study the effect of seed coat colour on germination characteristics of M. denticulata seeds in relation to various environmental variables. Germination of both cream and brownish-black seeds was independent of light. Cream seeds germinated in the wide temperature range of 15/5 to 30/20°C; while, brownish-black seeds germinated in a narrow temperature range of 15/5 to 25/15°C. Cream seeds were able to withstand greater salinity stress as some seeds (10%) were able to germinate under NaCl concentration of 200 mM; whereas germination of brownish-black seeds was completely inhibited at 200 mM NaCl. The NaCl concentration required for 50% inhibition of maximum germination for cream and brownish-black seeds was 100 and 70.6 mM NaCl, respectively. The osmotic potential required for 50% inhibition of the maximum germination of cream and brownish-black seeds was -0.37 and -0.32 MPa, respectively. These results indicated a greater ability of cream seeds to tolerate either salinity or osmotic stress. Both seeds germinated under acidic and alkaline pH with >40% germination in pH range 3-10. The highest emergence of cream and brownish-black seeds was recorded when seeds placed on the soil surface.

 

Email

sethirenu6@gmail.com

Address

Department of Botany, Punjab Agricultural University, Ludhiana, Punjab 141004, India
Dissipation kinetics and harvest time residues of pyrazosulfuron-ethyl + pretilachlor in rice
Ambily Paul and Thomas George

KEYWORDS:

Dissipation 

Half-life

Pretilachlor

Pyrazosulfuron-ethyl

Residues

Rice

Abstract:

The study on dissipation and harvest time residues of pyrazosulfuron-ethyl 0.75% and pretilachlor 30% WG after foliar application at seedling stage in rice at two doses 2000 g/ha (15 + 600 g/ha) and 4000 g/ha (30.0 + 1200 g/ha) was conducted at Integrated Farming System Research Station, Kerala Agricultural University, Thiruvananthapuram, Kerala. The pyrazosulfuron-ethyl and pretilachlor residues were estimated using LCMS/MS. The mean initial deposit of pyrazosulfuron-ethyl at recommended and double the recommended doses were 0.18 and 0.48 mg/kg, respectively. The residue dissipated with time and reached below limit of quantification (LOQ) of 0.01 mg/kg after 5 days in the recommended dose and 7 days in double the recommended dose. The mean initial deposit of pretilachlor at recommended and double the recommended dose were 8.84 and 15.50 mg/kg, respectively. The residue dissipated with time and reached below LOQ of 0.05 mg/kg within 15 days both in the recommended and double the recommended dose. The half-life values (days) were 1.29 and 1.80 for pyrazosulfuron-ethyl and 1.88, 1.37 for pretilachlor at recommended and double the recommended doses, respectively. In addition, the harvest time residues of pyrazosulfuron-ethyl 0.75% + pretilachlor 30% WG were estimated in samples of rice grain, husk, straw and cropped soil and were found below LOQ.

Email

ambily.paul@kau.in

Address

College of Agriculture, Vellayani, Thiruvananthapuram, Kerala Agricultural University, Kerala 695 522, India
Farmers’ knowledge level and constraints faced in the adoption of weed management technologies
Yogita Gharde and P.K. Singh

KEYWORDS:

Adoption

Chemical weed control

Factor analysis

Herbicide

Weed management 

Abstract:

One common problem for the organizations and individuals involved in the transfer of the agricultural technologies is how to accelerate the adoption rate of technologies; which is mainly influenced by many factors such as simplicity of the technology, relative advantages, etc. Further, after the adoption of technology, the question arises that for how many years the farmers practiced the technology. In the present work, knowledge and awareness level of farmers on weed management technologies and constraints faced in the adoption of these technologies were studied. Primary data were collected from the farmers of different parts of India selected by random sampling using detailed pre-tested interview schedule and comprising a total of 412 farmers in the sample. Awareness level of farmers on weed management including chemical method were checked using statistical methods such as descriptive statistics. Parameters explaining the awareness level of the farmers on weed management, in general and chemical weed management, in particular, were subjected to factor analysis. Varimax rotation technique was used as solution pertaining to different factors. Two factors were selected for further interpretation which explained 72.6 and 84.3% variability in the level of awareness among farmers on weed management and chemical method of weed control, respectively. Study showed that the risk associated with the use of herbicides was the major constraint for non-adoption of this technology. Further, other major constraints were lack of technical knowledge about herbicides; lack of awareness about improved weed management technologies and lack of knowledge about the precautions during spray of herbicides.

Email

yogita_iasri@rediffmail.com

Address

ICAR-Directorate of Weed Research, Jabalpur, Madhya Pradesh 482004, India
Efficacy of fenoxaprop-p-ethyl and penoxsulam for weed management with special emphasis on Echinochloa spp. in transplanted summer rice
Subhaprada Dash1, B. Duary* and K. Sar

KEYWORDS:

Echinochloa spp.

Fenoxaprop-p-ethyl

Penoxsulam

Summer rice

Weed management

Abstract:

An on-farm experiment was conducted during summer (boro) season of 2016-17 at farmer’s field (Borah village of Nanoor Block) in Birbhum district, West Bengal to study the efficacy of fenoxaprop-p-ethyl and penoxsulam against composite weed flora with special emphasis on Echinochloa spp. in transplanted rice. The experiment comprising of eight treatments was laid out in a randomized block design with three replications. The experimental field was dominated with Echinochloa glabrescens, E. crus-galli, Panicum sp. (grasses), Cyperus iria (sedge) and Jussiaea repens (broad-leaved) throughout the crop growing period. Of these predominant weeds, there was severe infestation of grassy weeds. Among herbicidal treatments, fenoxaprop-p-ethyl 90 and 100 g/ha at 20 days after transplanting (DAT) and penoxsulam 25 g/ha at 20 DAT effectively controlled the Echinochloa spp. at 50 DAT. Application of penoxsulam 25 g/ha at 20 DAT exhibited effective management of composite weed flora as well as higher grain yield in summer rice. Lower values of weed density and weed dry weight along with improved weed control efficiency and higher grain yield were registered with penoxsulam 25 g/ha at 20 DAT, which was statistically at par with two rounds of hand weeding at 20 and 40 DAT in summer rice.

Email

bduary@yahoo.co.in

Address

Department of Agronomy, (Institute of Agriculture), Visva-Bharati, Sriniketan, West Bengal 731236, India
In situ green manuring and herbicide on weed biomass, productivity and profitability of upland rice
Y. Basila, S. Anitha, Meera V. Menon, K. Sreelakshmi and V.I. Beena

KEYWORDS:

Brown manuring

In situ green manuring

Oxyfluorfen and pyrazosulfuron-ethyl

Upland rice

Weed management

Abstract:

Field experiment was conducted at Agronomy Farm, College of Horticulture, Vellanikkara during Kharif (rainy season) 2019 to develop cost-effective weed management strategy for upland rice in Kerala. Treatments consisted of brown manuring (cowpea) by application of 2,4-D 1.0 kg/ha at 25 days after sowing (DAS); in situ green manuring (cowpea) at 25 DAS; oxyfluorfen 0.15 kg/ha on the day of sowing fb hand weeding (HW) at 30 DAS; oxyfluorfen 0.15 kg/ha on the day of sowing fb bispyribac-sodium 0.025 kg/ha at 20 DAS; pyrazosulfuron-ethyl 0.03 kg/ha at 6 DAS fb HW at 30 DAS; pyrazosulfuron-ethyl 0.03 kg/ha at 6 DAS fb bispyribac-sodium 0.025 kg/ha at 20 DAS. Hand weeded control and unweeded control were also maintained. Results revealed that application of oxyfluorfen at 0.15 kg/ha on the day of sowing fb hand weeding at 30 DAS recorded lesser weed density and dry matter production, higher grain (2.74 t/ha) and straw (5.89 t/ha) yields and net monetary returns. It was at par with pyrazosulfuron-ethyl 0.03 kg/ha at 6 DAS fb hand weeding at 30 DAS. 

Email

basilayoosaf1234@gmail.com

Address

Department of Agronomy, College of Horticulture, Vellanikkara, Thrissur, Kerala 680 656
Weed management in aerobic rice with sequential application of pendimethalin and bispyribac-sodium under coastal deltaic ecosystem
M. Pavithra, R. Poonguzhalan, A.L. Narayanan and P. Saravanane

KEYWORDS:

Aerobic rice,  Pendimethalin, Bispyribac-sodium, Weed management 

Abstract:

A field experiment was conducted at Pandit Jawaharlal Nehru College of Agriculture and Research Institute (PAJANCOA&RI), Karaikal during September 2013 - January 2014 with ten treatments replicated thrice in a randomized block design to evaluate the weed management efficacy of sequential application of pendimethalin and bispyribac-sodium in aerobic rice. Echinochloa colona (28.1%), Ludwigia abyssinica (28%) and Cyperus difformis (19.8%) among grasses, broad-leaved weeds and sedges, respectively were the predominant in the experimental field. Among the weed control treatments, pendimethalin 1.0 kg/ha at 3 days after seeding (DAS) fb bispyribac-sodium 30 g/ha at 30 DAS was found to be effective recording lowest weed density and biomass and superior growth attributes, yield attributes and yield of rice (4.86 t/ha).

Email

pavimuthukumar@gmail.com

Address

Department of Agronomy, Pandit Jawaharlal Nehru College of Agriculture & Research Institute, Karaikal, Puducherry 609 603, India
Efficacy of pre- and post-emergence ready-mix herbicides in rainfed lowland wet-seeded rice
M.S.S. Reddy and M. Ameena

KEYWORDS:

Early post-emergence, Pre-emergence, Rainfed lowland rice, Ready mix herbicides, Weed management, Wet-seeded rice 

Abstract:

The experiment was conducted during Kharif (rainy) season of 2019 to assess comparative efficacy of low dose high efficiency herbicides in providing season-long weed control in direct wet-seeded rainfed lowland rice at Integrated Farming System Research Station (IFSRS), Karamana, Kerala. The rice yield reduction due to unmanaged weeds in unweeded control in rainfed lowland rice was estimated to be 59.75%. Rice grain yield obtained was 159.9% higher in bensulfuron-methyl + pretilachlor fb HW at 40 DAS (5.46 t/ha) compared to weedy check with a B: C ratio of 1.83 and was at par with penoxsulam + cyhalofop-butyl fb HW at 40 DAS (5.35 t/ha) with a B:C ratio of 1.77. Application of ready mix of either bensulfuron-methyl + pretilachlor 60 + 600 g/ha at 3 DAS or penoxsulam + cyhalofop-butyl 150 g/ha at 20 DAS both fb HW at 40 DAS was observed as the most effective weed management strategy in wet-seeded lowland rainfed rice.

Email

drameenaubaid@gmail.com

Address

Department of Agronomy, College of Agriculture, Vellayani, Thiruvananthapuram, Kerala 695522, India
Performance of rice cultivars with weed management practices in dry direct-seeded rice
K. Pooja and P. Saravanane

KEYWORDS:

Dry direct-seeded rice

Grain yield

Rice cultivars

Weed management

Abstract:

Weeds are the most important biotic constraint in direct-seeded rice (DSR) production. A field experiment was carried out in split plot design replicated thrice during September 2019 to evaluate the performance of different cultivars integrated with weed management practices under DSR at Pandit Jawaharlal Nehru College of Agriculture & Research Institute, Karaikal, Puducherry UT, India. The treatment combination consisted of three cultivars in main plot (ADT 46, CO 52 and White Ponni) and five levels of weed management practices in the sub-plots (application of pendimethalin 1.0 kg/ha as pre-emergence herbicide at 3 DAS, bispyribac-sodium 0.02 kg/ha as post-emergence herbicide at 20 DAS, sequential application of pendimethalin 1.0 kg/ha followed by bispyribac-sodium 0.02 kg/ha, hand weeding twice at 20 and 40 days after sowing (DAS) and unweeded control. Results revealed that rice cultivar ADT 46 integrated with sequential application of pendimethalin fb bispyribac-sodium (1.0 kg/ha fb 0.02 kg/ha) reduced the weed density and weed dry weight, and increased the growth, yield attributes and rice grain yield. Uncontrolled weeds caused 51.9 % yield loss in dry-DSR under coastal deltaic ecosystem.

Email

psaravanane@rediffmail.com

Address

Department of Agronomy, Pandit Jawaharlal Nehru College of Agriculture & Research Institute, Karaikal, Puducherry 609603, India
Weed dynamics in pulses cultivated in summer-fallows of double cropped lowland rice fields of Northern Kerala
S. Adarsh and Jacob John

KEYWORDS:

Pulse

Summer-fallow

Rice

Weed dynamics

Abstract:

A field study was undertaken to find the weed dynamics in different pulse crops in summer-fallows of lowland rice fields under varying nitrogen doses during summer 2018. Among grasses, sedge and broad-leaved weeds Oryza sativa, Cyperus rotundus and Boerhavia diffusa, respectively were dominant in the field where pulses are grown. Absolute density of weeds was lesser in plots where red gram was cultivated with 75% and 50% of the recommended dose of nitrogen (RDN). Blackgram (50% RDN) was effective in smothering weeds. The dry matter production of weeds was the highest in fallows. The N removal by weeds was higher in fallow and that of P and K were at par in all treatments. The leaf area index (LAI) (100 and 50% RDN), crop growth rate (CGR) (50% RDN), yield (50% RDN) were significant for cowpea. Cowpea and red gram performed better among the different pulses in terms of yield. There was no significant difference in yield of pulses under varying levels of N, indicating that the lower level of N (50% RDN) will be sufficient.

Email

sssadarshsss@gmail.com

Address

Department of Agronomy, College of Agriculture, Kerala Agricultural University, Padannakkad, Kasaragod, Kerala 671314, India
Assessment of bioefficacy of novel pyroxasulfone for controlling weeds in summer maize
R. Mohan Kumar, Yamanura and B. Boraiah

KEYWORDS:

Herbicide

Pyroxasulfone

Summer maize

Weed control

Abstract:

An experiment was conducted during summer 2020 at Zonal Agricultural Research Station, UAS, GKVK, Bangalore to study the bio-efficacy of pyroxasulfone for controlling weeds in summer maize. Treatment consisted of pre-emergence application of pyroxasulfone 85% WG at 125, 150, 175 and 300 g/ha and was compared with atrazine 50% WP at 2000 g/ha along with unweeded control and weed-free treatment. Treatments were arranged under randomised complete block design with 3 replications. Weeds caused yield reduction to the tune of 32% in summer maize. Results revealed that application of pyroxasulfone reduced weed-crop interference effectively which was significantly superior over atrazine. The per cent increase in maize yield due to pyroxasulfone treatment in its corresponding doses of 125, 150, 175 and 300 g/ha was 21, 18, 14 and 7%, respectively over unweeded control treatment. Increasing the dose of pyroxasulfone beyond 125 kg/ha reduced the yield of maize.

Email

mohankumarr@uasbangalore.edu.in

Address

Zonal Agricultural Research Station, University of Agricultural Sciences, GKVK, Bangalore, Karnataka 560 065, India
Performance of ready-mix herbicides for weed control in blackgram
N. Ram Mohan Reddy, D. Subramanyam, V. Sumathi, V. Umamahesh and G. Karuna Sagar

KEYWORDS:

Diclosulam, Economics, Ready-mix herbicides, Weed growth, Yield 

Abstract:

A field experiment was conducted during Kharif (rainy season), 2019 at S.V. Agricultural College, Tirupati, Andhra Pradesh to find out the best chemical weed management practice for blackgram. Results revealed that pre-emergence application of diclosulam 20 g/ha supplemented with HW at 30 DAS resulted in lower density and dry weight of weeds with higher weed control efficiency, and it was closely followed by pre-emergence application of pendimethalin + imazethapyr 1000 g/ha supplemented with HW at 30 DAS. Heavy weed infestation of weeds in unweeded check reduced the seed yield by 58.4% compared to pre-emergence application of pendimethalin + imazethapyr 1000 g/ha supplemented with HW. All the pre-and post-emergence herbicides did not show inhibitory effect on succeeding fodder sorghum.

Email

subbuagro37@gmail.com

Address

Department of Agronomy, S. V. Agricultural College, Tirupati, Andhra Pradesh 517 502, India
Bio-efficacy of new post-emergent herbicides on growth and yield of blackgram
S. Harisha, C. Seenappa, B.S. Lalitha, Gurunath Raddy and U. Pandu

KEYWORDS:

Blackgram, Fomesafen + propaquizafop, phytotoxicity, nutrient uptake and economics, yield

Abstract:

A field experiment was conducted during Kharif 2018 Gandhi Krishi Vigyan Kendra, University of Agricultural Sciences, Bangalore, Karnataka. to evaluate the bio-efficacy of new herbicides with pre-mix formulations in blackgram. Major weeds were Achyranthes aspera, Ageratum conyzoides, Alternanthra sessilis, Borreria articularis, Cynodon dactylon, Dactyloctenium aegyptium, Echinochloa colona, Eleusine indica and Cyperus rotundus.  Post-emergence application of fomesafen 18.8% SL + propaquizafop (5.83% EC) 252 + 78 g/ha recoded better crop growth seed yield (1.29 t/ha) along with higher net returns ( 50,106/ha) and benefit:cost ratio (3.27) without any phytotoxic effect on crop and was found comparable with two hand weeding at 15 and 30 days after sowing (seed yield 1.348 t/ha)

Email

harishs27666@gmail.com

Address

Department of Agronomy, University of Agricultural Sciences, GKVK, Bengaluru, Karnataka 560065, India
Weed management in groundnut
Satyanarayan Regar, S.P. Singh, Hansraj Shivran, R.C. Bairwa, Vimal Khinchi

KEYWORDS:

Groundnut

Pendimethalin 

Weed management

Abstract:

A field experiment was conducted on groundnut (Arachis hypogaea L.) during Kharif (rainy season) 2016 at College of Agriculture, SKRAU, Bikaner (Rajasthan). The soil was loamy sand, low in organic carbon (0.08%) and available N (78 kg/ha) and medium in available P (22 kg/ha) and available K (210 kg/ha) with pH 8.3. Significantly the lowest density and dry matter of weeds and the highest haulm and pod yield were recorded with application of pendimethalin + imazethapyr (30+2) 800 g/ha(PE) followed by pendimethalin 1.0 kg/ha as PE, imazethapyr + imazamox (35:35) 70 g/ha at 20 DAS as PoE (at 3-4 leaf stage), pendimethalin + imazethapyr (30 + 2) premix 800 g/ha(PPI), imazethapyr + imazamox (35:35) 50 g/ha at 20 DAS as PoE (at 3-4 leaf stage), imazethapyr 70        g/ha at 20 DAS as PoE and pendimethalin + imazethapyr (30 + 2) 800 g/ha (Dry). Maximum net returns of  223016 /ha was realized under the weed free treatment and it was closely followed by pendimethalin + imazethapyr (30+2) 800 g/ha (PE), pendimethalin 1.0 kg/ha (PE) and pendimethalin 1.0 kg/ha (PPI) as  185045,  9177813 and  175462 /ha, respectively.

Email

spbhakar2010@gmail.com

Address

Department of Agronomy, College of Agriculture, Bikaner Rajasthan 334006, India
Effect of weed management treatments on growth and yield of tomato
M.P. Kavitha, M. Uma Maheswari, K. Krishna, G. Balaji, R. Yuavaraj, R. Sachin and S. Kissan Kumar

KEYWORDS:

Black polythene mulch, Herbicides, Rice straw mulch, Tomato

Abstract:

A field experiment was conducted to study the effect of weed management treatments on growth and yield of tomato (Lycopersicon esculentum L) at Western block, Horticultural College and Research Institute, Periyakulam during summer season of the year 2019. The experiment was carried out in randomized block design with eight treatments and replicated thrice. Application of black polythene mulch (60% 6000 m2/ha) gave maximum control of weed by lowering the weed density, weed biomass and higher weed control efficiency (98.9%). This was followed by rice straw mulch 5 t/ha which recorded weed control efficiency of 98.5 %. Black polythene mulch recorded significantly higher fruit yield (28.1 t/ha) and recorded higher net returns ( 1, 90,630/-) and the BC ratio (3.11).

Email

kavimaruthu@rediffmail.com

Address

Horticultural College and Research Institute, Periyakulam, Tamil Nadu 625 604, India

Indexing Indexing & Abstracting Services