Integrated Weed Management Practices Research Articles

Effect of integrated weed management practices on weed biomass, yield and economics of okra(Abelmoschus esculentus)

A field experiment was conducted during rainy season of 2011 at Gwalior (Madhya Pradesh), India to study the effect of integrated weed management practices on growth, seed yield and economics of okra (Abelmoschusesculentus L. Moench) under the soil of sandy clay loam. In the experimental field Cyperus rotundus, Parthenium hysterophorus, Commelina benghalensis, Digera arvensis, Phyllanthus niruri and Cynodon dactyl on were found as dominant weed flora and contributes about 90% of the total weed flora. Minimum weed dry weight was recorded under two hand weeding (HW) at 15 and 30 days after sowing (DAS) at all the growth stages, followed by under grass mulch (5 t ha−1) one week after germination. Maximum number of weed population was recorded under weedy check. Weed control efficiency ranged from 63.93 to 97.67% at 60 DAS. The highest weed control efficiency was observed in two HW at 15 and 30 DAS (97.67%), followed by grass mulch 5 t ha −1 (97.56%), pendimethalin 1 kg ha −1 pre-emergence (PE) + one HW at 30 DAS (90.34%) and pendimethalin 1 kg ha−1 PE (89.47%). The highest seed yield and stalk yield of okra was recorded from the weed free plot (1102 and 6056 kg ha−1, respectively), which was on par with grass mulch5 tha−1 (1046 and 5935 kg ha). However benefit: cost ratio was higher (7.00) in grass mulch 5 t ha−1, followed by two HW at 15 and 30 DAS (6.47).

Production potential and economics feasibility of buckwheat (Fagopyrum esculentum Moench) as influenced by integrated weed management practices under Terai rgion of West Bengal

A field experiment was conducted during the winter season of 2011-2012 and 2012-2013 at the Instructional Farm of Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, and West Bengal. The experimental field was laid out in Randomized Block Design, having seven (7) treatments with three (3) replications. The treatments consisted of preemergence application of fluchloralin @ 2.22 lit. ha -1 (T 1 ), post-emergence of application of glyphosate @ 2.50 lit. ha -1 (T 2 ), pre-emergence application of fluchloralin @ 2.22 lit. ha -1 + hand weeding (once at 35 DAS) (T 3 ), hoeing (Twice) 20 and 35 DAS (T 4 ), hand weeding (twice) at 20 and 35 DAS (T 5 ), pre-emergence application of fluchloralin @ 2.22 lit. ha -1 combined with postemergence application of glyphosate @ 2.50 lit. ha -1 (T 6 ) and unwedded control (T 7 ). The economics of buckwheat under seven varying weed management practices showed that the hand weeding twice at 20 and 35 DAS recorded highest net income, benefit cost ratio and lowest cost of producing per kg of seed over other weed control practices, this is environmentally sound, socially acceptable and economically viable. Among the weed management practices pre-emergence application of fluchloralin @ 2.22 lit. ha -1 and post-emergence application of glyphosate @ 2.50 lit. ha -1 at 20 DAS produced higher yield attributes and yield over unwedded control whereas pre-emergence application of fluchloralin @ 2.22 lit. ha -1 followed by one hand weeding at 35 DAS produced seed yield comparable to hand weeding treatment.

Sensitivity of imidazolinone-resistant red rice (Oryza sativa L.) to glyphosate and glufosinate

<p>Dose-response experiments were carried out to evaluate the sensitivity of imidazolinone-resistant red rice to nonselective herbicides currently used in rice-soybean rotation in Rio Grande do Sul. Two red rice biotypes previously identified as resistant and susceptible to the imidazolinone herbicides were treated with imazapic plus imazapic, glyphosate and glufosinate under nine herbicide rates. A non-linear log-logistic analysis was used to estimate the herbicide rate that provided 50% red rice control and dry weight reduction (GR<sub>50</sub>). Imidazolinone-resistant red rice exhibited greater GR<sub>50</sub> values than imidazolinone-susceptible biotype for imazapyr plus imazapic. In contrast, both imidazolinone-resistant and susceptible red rice showed similar GR<sub>50</sub>values for glyphosate and glufosinate. These results indicate that glyphosate and glufosinate effectively control imidazolinone-resistant red rice at similar herbicide rates used to control imidazolinone-susceptible; however, integrated weed management practices must be adopted in rice-soybean rotation to delay resistance evolution of red rice populations to glyphosate and glufosinate</p>

Effect of Integrated Weed Management Practices on Weeds Infestation, Yield Components and Yield of Cowpea [Vigna unguiculata (L.) Walp.] in Eastern Wollo, Northern Ethiopia

Effect of Integrated Weed Management Practices on Weeds Infestation, Yield Components and Yield of Cowpea [Vigna unguiculata (L.) Walp.] in Eastern Wollo, Northern Ethiopia

Effect of crop establishment methods and weed management practices on weeds, growth and yield of direct-seeded rice

Field trials were conducted at Agricultural Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi during kharif seasons of 2011 and 2012 to study the effect of crop establishment methods and weed management practices on weeds, growth and yield of direct-seeded rice. Results indicated that bed planting of dry-seeded rice suppressed dry matter accumulation of weeds–grasses, sedges and broad leaf weeds most effectively among crop establishment methods, and as a consequence this crop establishment method had markedly higher growth rates, higher growth and yield attributes. Among different weed management practices, integrated weed management practices, namely, pre-emergence spray of pendimethalin 1 kg/ha followed by brown manuring of dhaincha by 2,4-D 0.50 kg/ha at 25 days after sowing (DAS) and combination of pre-emergence spray of pendimethalin 1 kg/ha followed by early post-emergence spray of bispyribac 0.025 kg/ha followed by brown manuring of dhaincha by 2,4-D 0.50 kg/ha at 25 DAS significantly lowered dry matter of all weeds than other weed management practices, thus improved growth and its rate and yield attributes of direct-seeded rice. Though crop establishment methods did not significantly influence grain yield of direct-seeded rice, protein content in grain and its yield were markedly improved by bed and no-till methods than conventional method. Integration of pendithalin application with brown manuring of dhaincha and pendimethalin followed by bispyribac followed by brown manuring of dhaincha registered significantly higher grain yield, protein content in grain and its yield than remaining weed management practices.

Effect of Integrated Weed Management Practices on Plant Height, Number of Tillers in Turmeric During kharif Season

Field experiments were conducted at the Agricultural Research Station, Bhavanisagar of Tamil Nadu Agricultural University, during kharif season of 2012 to evaluate the integrated weed management with pre and post emergence herbicides in turmeric. The experiments were laid out in Randomized block design and replicated thrice. The treatments comprised of different weed management practices wherein PE herbicides viz ., metribuzin 0.7 kg ha ‑1 , pendimethalin 1.0 kg ha ‑1 and atrazine 0.75 kg ha ‑1 followed by either POE fenoxaprop 67 g ha ‑1 + metsulfuron 4 g ha ‑1 (Tank mix) on 45 DAP or HW on 45 and 75 DAP or straw mulch 10 t ha ‑1 on 10 DAP + HW on 75 DAP, all PE oxyfluorfen 0.30 kg ha ‑1 , PE oxadiargyl 0.25 kg ha ‑1 , POE glyphosate 1.03 kg ha ‑1 and 1.54 kg ha ‑1 on 25 DAP followed by HW on 45 and 75 DAP, HW on25, 45 and 75 DAP and unweeded check were imposed. In both the experiments, observations were recorded on plant growth parameters like plant height and plant dry matter production and number of tillers were recorded in kharif season 2012. In the experimental fields, Echinochloa colonum and Digitaria bicornis among grasses, Cyperus rotundus in sedge, Eclipta prostrata and Boerhaavia diffusa under broad leaved weed were the predominant weeds. The grasses constituted the major proportion of the weed flora at all the growth stages of the crop. Slight to moderate phytotoxicity symptoms in turmeric were observed in glyphosate 1.03 and 1.54 kg ha -1 at the time of application of herbicides, however the crop recovered later. Among the weed management treatments imposed, PE metribuzin 0.7 kg ha ­-­1 + HW on 45 and 75 DAP registered higher uptake of nutrient by crop due to effective control of weeds which enhanced the availability of nutrients to crop leading to positive results in respective of growth parameters like plant height, dry matter production and number of tillers plant -1 , during 2012.

Integrated Weed Management in Turmeric: A Review

Weeds constitute a major component among the bottlenecks for successful crop production. Weeds are generally hardy species having vigorous, deep root system and compete very efficiently with cultivated crops for the nutrients available in the soil and for the much needed moisture and sunlight. Weeding is one of the important farm operations for agricultural crops. Different types of weeders are used in different parts of a country. Since, a major portion of labour input is spent on weeding operations; it was felt that the technology of weeding should be improved for the benefit of the farmers. For proper implementation of this, a few selected existing methods are need to be evaluated to formulate an efficient and economically viable integrated weed management practice. In this connection, the literature on various aspects related to the proposed study was collected and summarized in this chapter.

Establishment Methods and Weed Management Effects on Productivity and Soil Fertility in Wetland Rice (Oryza sativaL.)

Field experiments in 2010 and 2011 was conducted to evaluate the effect of integrated weed management practices on productivity, nutrient uptake, nutrient harvest index and residual soil fertility status in wetland rice (Oryza sativa L.) under different establishment methods. Wetland rice under system of rice intensification (SRI) method gave significantly higher grain productivity. However, hand weeding twice at 20 and 40 days after transplanting (DAT) was similar with butachlor 50 EC at 1.5 kg a.i. ha−1 at 3 DAT + cono-weeding at 20 DAT. Total uptake of N, P and K by wetland rice was recorded higher with SRI followed by integrated crop management and conventional rice culture. Hand weeding twice at 20 and 40 DAT recorded significantly higher N, P and K uptake in grain and straw followed by butachlor 50 EC at 1.5 kg a.i. ha−1 at 3 DAT + cono-weeding at 20 DAT. The highest nitrogen harvest index (NHI), phosphorus harvest index (PHI) and potassium harvest index (KHI) (79.8, 58.8 and 36.6%), respectively were recorded with cono-weeding twice at 20 and 40 DAT. The residual soil pH, OC, MBC and available N, P and K was significantly higher in SRI method with hand weeding twice at 20 and 40 DAT. Hence, integrated weed management with butachlor 50 EC at 1.5 kg a.i. ha−1 + cono-weeding at 20 DAT performed well under SRI method. However, hand weeding twice at 20 and 40 DAT performed better under ICM method in terms of productivity and better soil health in wetland rice ecosystem.

Physiological and morphological responses of Ischaemum rugosum Salisb. (wrinkled grass) to different nitrogen rates and rice seeding rates.

Ischaemum rugosum is a competitive weed in direct-seeded rice systems. Developing integrated weed management strategies that promote the suppression of weeds by crop density, cultivar selection, and nutrition requires better understanding of the extent to which rice interferes with the growth of this weed and how it responds to resource limitation due to rice interference. The growth of I. rugosum was studied when grown with four rice seeding rates (0, 25, 50, and 100 kg ha−1) and four nitrogen (N) rates (0, 50, 100, and 150 kg ha−1). Compared to the weed plants grown alone, weed tiller number was reduced by 63–80%, leaf number by 68–77%, leaf area by 69–77%, leaf biomass by 72–84%, and inflorescence biomass by 81–93% at the rice seeding rates of 25–100 kg ha−1. All these parameters increased with increasing rates of N from 0 to 150 kg ha−1. At weed maturity, I. rugosum plants were 100% taller than rice at 0 kg N ha−1, whereas, with added N, the weeds were only 50% taller than rice. Weed biomass increased by 82–160%, whereas rice biomass increased by 92–229%, with the application of 50–150 kg N ha−1. Added N favored rice biomass production more than it did the weed. Rice interference reduced the height and biomass of I. rugosum, but did not suppress its growth completely. I. rugosum showed the ability to reduce the effects of rice interference by increasing leaf area, leaf weight ratio, and specific leaf area, and by decreasing the root-shoot weight ratio in comparison to the weed plants grown alone. The results suggest that rice crop interference alone may reduce I. rugosum growth but may not provide complete control of this weed. The need for integrated weed management practices to effectively control this weed species is highlighted.

Influence of Integrated Weed Management Practices on Dynamics and Weed Control Efficiency in Dry Direct Seeded Rice

Field experiment under dry direct seeded rice(Oryza sativa L.) was conducted during rainy season of 2010 and 2011 at Regional Agriculture Research Station (RARS), Parwanipur, Bara to develop appropriate weed management practices for dry direct- seeded rice. The trial was laid-out in randomized complete block design (RCBD) and replicated thrice. Observations were taken on weed, plant growth and yield attributing, yield, and socio-economic parameters. The weed density, dry weed weight and weed control efficiency resulted significantly different as influenced by integrated weed management practices. Low weed population density, low weed index and highest weed control efficiency resulted by pendimethalin followed by 2, 4- D followed by one hand weeding were at par with weed free check. Highest yield resulted from weed free plot followed by pendimethalin followed by two hand weeding and pendimethalin followed by 2, 4- D followed by one hand weeding. However, the net return per unit investment resulted highest in pendimethalin followed by 2, 4- D followed by one hand weeding. This proved that amid increasing wage rate and labour scarcity integrated weed management through pendimethalin 30 EC (Stomp) @1 kg a. i. /ha as pre- emergence herbicide application followed by 2, 4- D sodium salt 80 WP @ 0.5 kg a. i. /ha followed by one hand weeding or stale seed bed followed by pendimethalin 30 EC (Stomp) @1 kg a. i. /ha followed by bispyribac (Nominee gold) @25 g a. i. /ha 10% @200 ml/ha at 20 days of seeding resulted best alternative for manual hand weeding practices giving higher net return per unit investment. DOI: http://dx.doi.org/10.3126/njst.v14i2.10413 Nepal Journal of Science and Technology Vol. 14, No. 2 (2013) 33-42

Integrated weed management in sorghum [Sorghum bicolor(L.) moench] – A review

Sorghum is affected by weeds and the loss due to weeds account for 33 per cent of the potential production and 30 to 45 per cent of the plant nutrients from the soil. Traditional hand weeding is the most efficient and widely adopted practice of weed management but it is labour intensive, time consuming and not economical due to high wage rates. Mechanical equipment can be time saving during peak operation, resulting in higher output per worker and reduction in the cost of weeding. Chemical weed control is a better supplement to conventional method however the weed emergence pattern, application timing and stage of crop are important in chemical control. Continuous use of herbicides over a prolonged time leads to development of resistance in weeds making them difficult to control. Integrated weed management (IWM), the process of combining several single management strategies together to suppress weeds has been developed. Hence, various components of integrated weed management are to be blended in a systematic way to achieve the acceptable level of weed control. So there is a need to review different weed management techniques in sorghum, which should be efficient, cost effective and environmentally safe. Keeping these facts in view, a comprehensive review on different integrated weed management practices has been attempted.

Influence of integrated weed management practices on weeds and yield ofBtcotton

Field experiment was conducted during kharif seasons of the years 2010, 2011 and 2012 at DWSR-Anand Centre, B. A. College of Agriculture, Anand Agricultural University, Anand (Gujarat) to study the performance of different weed management practices on weeds and yield of Bt cotton. Results revealed that inter-culturing and hand weeding carried out at 15, 30 and 45 DAS recorded the minimum weed dry weight of monocot, dicot and total weeds at 25 DAS and at harvest with maximum weed control efficiency. The said treatment also recorded maximum seed cotton yield (3127 kg/ha) as well as additional profit over control (46367 kg/ha). The next best treatments were T1 (pendimethalin @ 900 g/ha fb IC+HW at 30 and 60 DAS), T2 (quizalofop-ethyl 50 g/ha POE fb IC+HW at 30 DAS) and T5 (fenoxaprop-p-ethyl 50 g/ha POE fb IC+HW at 30 DAS) which were found efficient and economical for weed management in Bt cotton.

Effect of integrated weed management practices on yield, nutrient uptake and economics of baby corn

A field experiment was conducted during rabi, 2009 on sandyloam soils to study the effect of integrated weed management practices on yield, nutrient uptake and economics of baby corn. Results revealed that the cob green fodder yield, uptake of nutrients, net returns and benefit cost:ratio were highest with pre-emergence application of atrazine + one intercultivation at 30 DAS. The weedy check registered highest nitrogen, phosphorus and potassium uptake by weeds.

Impact of integrated package of agrotechniques on growth and yield of aerobic rice

A field experiment was conducted during Kharif, 2011-2012 and 2012-2013 at GKVK, Bengaluru, Karnataka to study the effect of integrated package of agrotechniques on growth and yield of aerobic rice. The predominant weed flora observed in the experimental field were, Eleusine indica, Digitaria marginata L., Dactyloctenium aegyptium L., Alternanthera sessilis, Mollugo distica L., Celosia argentia and Borreria hispida. Treatments receiving integrated weed management practices recorded significantly lower weed population and weed dry weight as compared to pre-emergence application of pyrazosulfuron ethyl alone. Application of RDF + FYM + Biofertilizers + FeSO4 +IWM practices (T8) recorded significantly higher growth, yield parameters and yield as compared to RDF + FYM + IWM practices and was being on par with RDF + FYM + Biofertilizers + IWM practices (T5).

Basal Fertilizer Effects on Weed Occurrence and Rice Yield in Acid Upland Soil of West Africa at Bénin

Fertilizers application is required in order to improve rice production in low fertile soils of West Africa. This practice can also increase weed pressure in rice field, thereby reducing yield significantly. Chemotropism of weed was hypothesized to identify nutrient effects on weed abundance and biomass production as well as rice yield for suitable recommendation of basal fertilizer in terre de barre soil agro-ecology. Two years (2005 and 2006) fertilizer omission trial including nitrogen (N), potassium (K), phosphorus (P), calcium (Ca), magnesium (Mg) and zinc (Zn) was conducted in a randomized completed block design, with 4 replications at the Africa Rice Center experiment station, in Benin. The New Rice for Africa named NERICA 4 was sown. Weed dominance-abundance indices and biomass, as well as, rice grain yield were assessed. Results show that Digitaria horizontalis Wild and Mariscus cylindristachyus Steudel were the most dominant weed species in rainfed rice fields on terre de barre soils and the omission of Zn has ability to discriminate among weeds. Base on weed biomass (60.11 – 129.26 g m-2) reduction by 36 – 53% in treatments with Ca, Mg and P omission, the application of N, K and Zn was recommendable for basal fertilizer as integrated weed management practice for boosting rice production on terre de barre soils in West Africa.

Effect of integrated weed management practices on performance of dry direct seeded rice (Oryza sativa L.)

Weeds are serious problem in dry direct seeded rice (DDSR). A field experiment was conducted during rainy seasons of 2010 and 2011 at research farm of the Regional Agricultural Research Station (RARS) Parwanipur, to study the effect of integrated weed management practices on the performance of dry direct seeded rice. Ten treatment combinations viz; weedy, weed free (weekly), Pendimethalin fb (followed by) Bispyribac, Pendimethalin fb two hand weeding, Stale seedbed fb Bispyribac, Stale seedbed fb Pendimethalin fb Bispyribac, Mulch 4 t/ha fb Bispyribac fb one hand weeding, Stale seedbed fb mulch 4 t/ha fb Bispyribac, Pendimethalin and Sesbania co-culture fb 2,4-D Na salt fb one hand weeding and Pendimethalin fb 2,4-D fb one hand weeding were tested in a randomized complete block design and replicated thrice. Observations were taken on weed, plant growth and yield attributes, yield, and socio-economic parameters. All weed control treatments significantly reduced the weed density and dry weight of weed resulting significant increase in yield of DSR over weedy check in both years. Weed free treatment resulted the highest yield, however, it was not economical due to high cost of cultivation. The use of Pendimethalin fb 2,4-D fb one hand weeding produced yield (5161 in 2010 and 6160 kg/ha in 2011) which were statistically at par with yield (5305 in 2010 and 6319 kg/ha in 2011) obtained under the weed free treatment. Further, the highest benefit cost ratio (CBR) 1.77 and 2.22 and net return Rs 47700 and 75084/ha during 2010 and 2011, respectively, were obtained under this treatment indicating its superiority over other treatments. The grain yield, yield attributing characters viz. panicles per m2, panicle weight, filled grain per panicle, thousand grain weight as influenced by different weed management practices revealed that higher yield resulted from weed free plot followed by Pendimethalin followed by two hand weeding and Pendimethalin followed by 2,4-D followed by one hand weeding. However, the net return per unit investment resulted highest in Pendimethalin followed by 2,4-D followed by one hand weeding. This proved that amid increasing wage rate and labor scarcity integrated weed management through Pendimethalin 30 EC (stomp) @ 1 kg a. i./ha as pre- emergence herbicide application followed by 2,4-D sodium salt 80 WP @ 0.5 kg a.i./ha followed by one hand weeding or stale seed bed followed by Pendimethalin 30 EC (stomp) @ 1 kg a. i./ha followed by Bispyribac (nominee gold) @ 25 g a. i./ha 10 % @ 200 ml/ha at 20 days of seeding resulted best alternative for manual hand weeding practices giving higher net return per unit investment. Agronomy Journal of Nepal (Agron JN) Vol. 3. 2013, Page 53-63 DOI: http://dx.doi.org/10.3126/ajn.v3i0.9006

An Environmental and Economic Perspective on Integrated Weed Management in Iran

Inputs, including herbicides, used in crop production may create negative environmental impacts. One solution to minimize these adverse effects is the adoption of integrated weed management (IWM) with the intention of reducing herbicide use. This study, conducted in 2010, estimates the willingness of farmers to pay for the adoption of more effective weed management methods. Results suggest that the willingness to pay (WTP) for IWM is greater than the WTP for other weed management methods, including chemical weed management and chemical and mechanical weed management. This study also identified a number of factors that influence the adoption of IWM on wheat farms in Iran using a multinomial logit model. Total annual income, area under irrigated wheat, wheat yield loss due to weeds, perennial nature of the weeds, and having awareness of weed resistance to herbicides had a positive effect on the adoption of IWM practices. However, having rain-fed (dryland) wheat cultivation and a larger number of plots on the farm had a negative influence on the choice of IWM.

Integrated weed management-A strategy for sustainable wheat production - A review

Wheat is one of the important cereals contributing approximately 30–35% to total food grain basket of the country. Wheat infested by multifarious weed flora comprising both grassy as well as broad leaf weeds causing yield reduction of 15–40% depending upon type and intensity of their infestation. Herbicides continue to be the most powerful, economically effective and reliable way to control weeds in wheat. Over the years, the efficacy of herbicides has started declining and there is possibility of development of cross resistance. An integrated approach, where herbicide plays a pivotal role isthe only way ahead for effective weed management. Use of weed free seed, use of well rotten farm yard manure, method of sowing, seed rate, sowing time, varietal selection, amount of fertilizer application, proper herbicide selection, proper dose, time and method of herbicide application, herbicide rotation and mixture, use of adjuvant, mechanical weeding and crop rotation are the major constituents of integrated weed management. Thus, integrated weed management practices should belocation and time specificby considering the weeds in a broader ecological and management context.

Herbicide and Cover Crop Residue Integration forAmaranthusControl in Conservation Agriculture Cotton and Implications for Resistance Management

Conservation agriculture (CA) practices are threatened by glyphosate-resistant Palmer amaranth. Integrated control practices including PRE herbicides and high-residue CA systems can decreaseAmaranthusemergence. Field experiments were conducted from autumn 2006 through crop harvest in 2009 at two sites in Alabama to evaluate the effect of integrated weed management practices onAmaranthuspopulation density and biomass, cotton yield, and economics in glyphosate-resistant cotton. Horizontal strips included four CA systems with three cereal rye cover crop seeding dates and a winter fallow (WF) CA system compared to a conventional tillage (CT) system. Additionally, vertical strips of four herbicide regimes consisted of: broadcast, banded, or no PRE applications ofS-metolachlor (1.12 kg ai ha−1) followed by (fb) glyphosate (1.12 kg ae ha−1) applied POST fb layby applications of diuron (1.12 kg ai ha−1) plus MSMA (2.24 kg ai ha−1) or the LAYBY application alone. Early-seasonAmaranthusdensity was reduced in high-residue CA in comparison to the CA WF systems in 2 of 3 yr.Amaranthusdensities in herbicide treatments that included a broadcast PRE application were lower at three of five sampling dates compared to banding early-season PRE applications; however, the differences were not significant during the late season and cotton yields were not affected by PRE placement. High-residue conservation tillage yields were 577 to 899 kg ha−1more than CT, except at one site in 1 yr when CT treatment yields were higher. CA utilizing high-residue cover crops increased net returns over CT by $100 ha−1or more 2 out of 3 yr at both locations. High-residue cover crop integration into a CA system reducedAmaranthusdensity and increased yield over WF systems; the inclusion of a broadcast PRE application can increase early-seasonAmaranthuscontrol and might provide additional control when glyphosate-resistantAmaranthuspopulations are present.

Comparative Performance of Different Weed Management Practices in System of Rice Intensification

A field study was conducted at Agricultural Research Station, Kampasagar, Andhra Pradesh during kharif 2008-09 to evaluate the best weed management practice in System of Rice Intensification. The experiment was laid out in randomized block design with eight weed management treatments (T 1 - Pre emergence application of butachlor @ 1.5 kg a.i ha -1 , T2 - cono weeding (CW) thrice at 15 days interval, T3 – T1 +T 2 , T 4 - T 1 + hand weeding (HW) at 20 and 40 days after planting (DAP), T 5 - T 2 + HW at 20 and 40 DAP, T 6 - T 3 + HW at 20 and 40 DAP, T 7 - un weeded check and T 8 - weed free). Weed density and weed dry matter were higher in un weeded check followed by Butachlor application and cono weeding alone practices. Integrated weed management practice of butachlor @ 1.5 kg a.i ha -1 combined with cono weeding thrice at 15 days interval and hand weeding at 20 and 40 DAP recorded significantly higher yield attributes and grain yield than the weedy check, butachlor @ 1.5 kg a.i ha -1 alone and cono weeding thrice at 15 days interval alone practices. Combination of weed management practices, integrated weed management practices and weed free check were comparable with each other with respect to grain yield and yield attributes.