Uncontrolled Weeds Research Articles

Impact assessment of front line demonstration of safflower on farmers’ fields

AICRP on Safflower, VNMKV, Parbhani conducted 160 demonstrations on safflowers during Five consecutive years from 2017–18 to 2021–22. The critical inputs were identified in existing production technology through meetings and discussions with farmers. Uncontrolled weeds, ignorance about fertilizers and lack of plant protection measures, were the predominant identified causes of low productivity of safflower. The average results of Five years study revealed that the Seed yield under demonstration plots was 1290 Kg/ha as compared to 994 kg /ha in traditional farmer practices plots. The results clearly indicate the positive effects of FLDs over the existing practices. Percentage increase Seed yield over farmer practice was found 30%.

Efficacy of p-hydroxy-phenyl-pyruvate dioxygenase (HPPD) enzyme-inhibitive tembotrione and topramezone herbicides for weed-management in rainy season grain sorghum (Sorghum bicolor)

A field experiment was conducted during the rainy season (kharif) of 2019 and 2020 at Maharana Pratap University of Agriculture and Technology, Udaipur, Rajasthan, to ascertain the weed-management efficacy of postemergence (PoE) tembotrione and topramezone at 25 days after sowing following pre-emergence (PE) atrazine in the kharif grain sorghum [Sorghum bicolor (L.) Moench]. Eight treatments (6 herbicidal along with weed-free and weedy check) were evaluated in randomized block design (RBD) with 3 replications. Results showed that, uncontrolled weeds have inflicted a grain, stover yield and net income penalty of 63.7, 55.5 and 69% over weed-free check (3.47, 12.34 t/ha and `135,216). Pre-emergence (PE) application of atrazine @ 0.5 kg a.i./ha was found to be the most promising herbicide in terms of benefit: cost ratio (5.76) despite having 12.4, 6.2, and 6.71% lower grain, stover and net income than weed-free treatment (5.03). Both PE and PoE application of atrazine did not bring any yield and profit gains over its PE application. Topramezone and tembotrione (PoE) controlled weeds as effective as weed-free treatment and their impacts persisted up to crop maturity. However, on account of crop phytotoxicity that is dependent on dose (2.83–5.17) severe yield losses (60 and 51.9% grain and stover) were recorded. Both tembotrione and topramezone at their higher dose (0.0242 and 0.0363 kg a.i./ha) resulted in at par grain yield (1.18 t/ha) as weedy check (1.26 t/ha).

Studying the Yield and Yield Parameters of Mungbean in Response to Different Weed-Crop Competition Periods

Impact of weed-crop competition periods on the yield and yield parameters of mungbean was investigated during the spring and summer season of 2018 at Agronomic Research Farm, Bahauddin Zakariya University, Multan. Treatments comprised of different weed-crop competition periods, weeds were allowed to compete for 15, 30, 45 and 60 days with mungbean after sowing. For comparison, weed free and weedy check plots were also maintained. Results revealed the importance of controlling weeds for getting better grain and other yield contributing traits during both the seasons. Uncontrolled weeds caused about 50 percent yield losses. Whereas similar results of grain yield and other yield related parameters were also recorded in weed free plots and weed-crop competition period for 15 days after sowing plots, while there is a gradual decline in yield and other yield related parameters if weed-crop competition periods were prolonged. These studies highlighted the importance of controlling weeds with further indication of controlling weeds till 15-30 days after sowing to get better yield of mungbean crop in both the spring and summer seasons.

Classification of Broadleaf Weeds Using a Combination of K-Nearest Neighbor (KNN) and Principal Component Analysis (PCA)

Palm oil is one of the leading commodities in Indonesia. Oil palm yields can be influenced by several factors, one of which is proper weed control. Uncontrolled weeds can damage oil palm plantations. To be able to manage and control weeds, especially large leaf weeds, it is necessary to know the types of weeds. However, not all farmers have knowledge about the types of weeds. For that we need a system that can help identify broadleaf weeds based on leaf images using image processing. So this study aims to build a large leaf weed classification system using a combination of the K-Nearest Neighbor (KNN) and Principal Component Analysis (PCA) algorithms. PCA is used as feature extraction based on the characteristics formed from each spatial property. PCA can be used to reduce and retain most of the relevant information from the original features according to the optimal criteria. The results of the information will then be used by KNN for learning by paying attention to the closest distance from the object. Based on the test results, the developed model is able to produce an accuracy of 90%. Principal Component Analysis (PCA) and K-Nearest Neighbor (KNN) algorithms can be used in the classification process properly. Accuracy results are strongly influenced by the amount of training data and test data as well as the quality of the image used.

Synergistic integration of crop residue mulch and cultural practices with herbicides for managing weed complex in turmeric in North-Western India

Turmeric being a wide spaced and long duration crop, weeds pose a serious problem due to its delayed emergence and slow initial growth which provide ideal environment for weeds to grow. This warrants for synergistic integration of residue mulch, cultural practices, and herbicides for effective weed management. Two field experiments were conducted during 2012-13 - 2013-14 and 2014-15 - 2015-16 at CCS Haryana Agricultural University, Regional Research Station, Karnal to evaluate different approaches involving integration of crop residue mulch and cultural practices with herbicides for effective and economical weed management in turmeric. The uncontrolled weeds caused 42-66% turmeric yield loss. Based on four years studies, it may be concluded that pre-emergence (PE) application of metribuzin 700 g/ha or pendimethalin 1000 g/ha or atrazine 750 g/ha integrated with rice straw mulching (10 t/ha) after herbicide application at 3 days after sowing (DAS) and hand weeding at 50 or 75 DAS provided effective control (86-100%) of complex weed flora in turmeric with improved rhizome yield (14.29 to18.60 t/ha), which was comparable to weed free, better economic returns without phyto-toxicity on the crop and detectable herbicidal residues in the turmeric rhizomes and soil at harvest. Integration of 2-hoeing with metribuzin 700 g/ha PE or pendimethalin 1000 g/ha PE were the two other viable options of integrated weed management (IWM) strategy. Among post-emergence (PoE) herbicides, fenoxaprop 67 g/ha 45 DAS, was safe to turmeric while metsulfuron 4 g/ha PoE was toxic. Glyphosate 0.3% PoE at 25 DAS could also be integrated with hoeing twice at 45 and 75 DAS for effective weed management in turmeric. Use of rice straw in IWM strategies in turmeric will also help in reducing herbicide dose, crop residue management without burning, conservation of soil moisture and other natural resources which will helps in long term sustainable and economical production system.

Efficacy of sequential application of pre- and post-emergence herbicides for weed management in sesame

A field experiment was conducted during rainy (Kharif) seasons of 2019 and 2020 to assess the efficacy of the sequential application of pre- and post-emergence herbicides for managing complex weed flora in line sown sesame (Sesamum indicum L.) at Agriculture Research Sub-Station, Sumerpur, Pali. There were nine weed control treatments replicated thrice in a randomized complete block design. Hand weeding twice recorded the highest values of growth parameters and seed yield (1.25 t/ha) which was at par with pre-emergence application (PE) of pendimethalin 750 g/ha followed by (fb) quizalofop-p-ethyl 40 g/ha at 20 days after seeding (DAS). The uncontrolled weeds in weedy check caused 50% sesame seed yield reduction. The post-emergence application (PoE) of quizalofop-p-ethyl 40 g/ha at 20 DAS and sequential application of pre-emergence application (PE) of pendimethalin 750 g/ha PE followed by (fb) quizalofop-p-ethyl 40 g/ha at 20 DAS recorded the highest weed control efficiency, sesame seed yield, net return and benefit cost ratio and were observed to be superior than the recommended practice of pendimethalin 1000 g/ha PE fb hand weeding at 25 DAS.

Comparison of the effects of ammonium nonanoate and an essential oil herbicide on weed control efficacy and water use efficiency of pumpkin

AbstractWeed management is one of the major challenges responsible for growers’ reluctance to switch from conventional to organic vegetable production. Competition from uncontrolled weeds can significantly reduce the yield and water use efficiency (WUE) of vegetable crops. A field study was conducted during the summers of 2019 and 2020 at the Quaker Research Farm of Texas Tech University, in Lubbock, TX, to determine physiology, plant growth, yield, soil water depletion pattern, and WUE of pumpkin as affected by five weed control treatments: 1) ammonium nonanoate 5% ai, 2) ammonium nonanoate 6% ai, 3) clove oil + cinnamon oil 4.5% ai, 4) clove oil + cinnamon oil 9% ai, and 5) an untreated control. Each plot received the same herbicide treatment at 20 and 30 d after planting (DAP). The experiment was conducted in a randomized complete block design with four replications of each treatment. Both herbicides resulted in significant weed suppression compared to the untreated control and weed control was 88% to 98% with ammonium nonanoate and 39% to 69% with clove oil + cinnamon oil. Photosynthesis rate, stomatal conductance, shoot dry biomass, average fruit weight, total fruit yield, and WUE of pumpkin were significantly higher in plants that were treated with ammonium nonanoate compared to the untreated control. All the aforementioned parameters were not significantly different between clove oil + cinnamon oil and the untreated control. Use of higher active ingredient concentration did not improve the performance of either herbicide. Soil water depletion and evapotranspiration were comparable among all the treatments. Based on the results, ammonium nonanoate at its lower concentration could be an option for effective weed control, and for improving fruit yield and WUE of pumpkin.

Weed Control Using Paddy Straw Mulch in Integration with Herbicides in Autumn Potato in North-West India

Weeds are a major problem in potato production. Two years of trials were conducted to study the efficacy of herbicides and integrated use of mulch with herbicides in controlling weeds and for improving the growth and yield of autumn potato crop at Ludhiana, north-west India, during autumn 2016 and 2017. Each trial had a randomized complete block design with three replicates. There were 11 treatments including weed-free and weedy controls. Uncontrolled weeds caused a yield reduction of 49.7%. Metribuzin at 350 g/ha pre-emergence resulted in 82.4% weed control efficiency at 30 days after planting but this control was reduced to 23.9% at harvest. In contrast, metribuzin at 350 g/ha applied post-emergence controlled broadleaf weeds and grasses very effectively. Clodinafop at 60 g/ha post-emergence resulted in control of grasses only. The post-emergence application of pre-mix clodinafop plus metribuzin at 260 g/ha provided effective weed control and resulted in more tuber yield and economic returns and was significantly better than an application solely of metribuzin or clodinafop. The integrated weed control treatment of paddy straw mulch (PSM) at 6 t/ha with clodinafop plus metribuzin at 195 g/ha post-emergence resulted in the highest tuber yield with weed control efficiency of 95.3% at harvest. The next best one was an integrated treatment of PSM at 6 t/ha with metribuzin at 275 g/ha pre-emergence.

Performance of rice cultivars with weed management practices in dry direct-seeded rice

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.

Non suitability of tembotrione and topramezone for weed management in sorghum [Sorghum bicolor (L.) Moench

A field experiment was conducted during rainy (Kharif) seasons of 2019 and 2020 at Hagari, Karnataka, India to assess the efficacy of post-emergence application (PoE) of two HPPD (p-hydroxy-phenyl-pyruvate dioxygenase) enzyme inhibitive herbicides, viz. tembotrione and topramezone in combination with pre-emergence application (PE) of atrazine. Among the 10 treatments tested, atrazine 1000 g/ha PE followed by fb) atrazine 1000 g/ha PoE or 2,4-D Na salt 937.5 g/ha PoE or 2, 4-D Ethyl Ester 2368 g/ha PoE at 20 days after sowing (DAS) proved as effective as weed free treatment (hand weeding twice) in increasing the sorghum grain yield and net returns. The topramezone 37.5 and 56.3 g/ha PoE though provided effective weed control, caused phytotoxicity to sorghum resulting in 21 and 39% grain yield reduction and 32 and 74% net return reduction, respectively when compared to atrazine PE applied alone which recorded grain yield of 2.31 t/ha and net return of ^45,007 but it was better than weedy check. The tembotrione 70.3 and 105.5 g/ha PoE also caused reduction of 2.1 and 3.3% in biological yield, 18.6 and 26.1 in grain yield and 19.2 and 63.9% in net returns, respectively and was significantly inferior to weedy check. The crop phytotoxicity of tembotrione resulted in negative herbicide efficiency index (−0.09 to -0.78) and high weed index values (37.32 to 51.7) indicating its non-suitability for use in sorghum. The uncontrolled weeds (weedy check) on an average have caused 32.1, 42.7 and 32.5% reduction in biological yield, grain yield and net returns, respectively when compared to weed free check.

Wild marigold (Tagetes minuta L.) biomass and essential oil composition modulated by weed management techniques

Weed management system plays an important role in reducing the yield losses brought by uncontrolled weeds in the agricultural production system. Moreover, the weed management studies on aromatic crops, particularly Tagetes minuta L. are not well documented. Thus a study was carried out at CSIR-Institute of Himalayan Bioresource Technology Palampur, India, during 2018 and 2019. Nine treatments of herbicides viz., pendimethalin at 1.50 kg a.i./ha (P), imazethapyr at 0.10 kg a.i./ha (I), carfentrazone-ethyl at 0.02 kg a.i./ha (C), P + HW, I + HW, C + HW (integration of all herbicide treatments with hand weeding) and hand weeding alone (HW). Lowest weed density (16.69 and 15.61 m−2), weed biomass (9.10 and 10.09 g m−2) at 75 and 105 days after sowing (DAS), respectively, and the highest total above ground biomass (17925 kg ha-1), essential oil (EO) yield (103.11 kg ha-1) was recorded in imazethapyr + hand weeding (I + HW) amongst all weed control treatments. Herbicide integrated with hand weeding lead to the reduction of the number and dry weight of weeds, with a significant increase in T. minuta total aboveground biomass and EO yield. Essential oil analysis found Z-β-ocimene, dihydrotagetone, tagetone, and ocimenone as the main constituents which were differently influenced by different weed control treatments. Treatment I + HW may therefore be recommended as weed control method for aromatic plant growers, especially in T. minuta production.

Weed management in direct seeded rice: A review

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

Mechanical weed control in onion seed production

Two field experiments with onion (Allium cepa L.) cultivated by the “seed-to-seed” and “bulb-to-seed” methods for the organic seed production were carried out in central Italy in order to evaluate the effects of some mechanical methods (harrowing, hoeing, hoeing-ridging, split-hoeing, finger-weeding, manual weeding) on: i) weed control; ii) selectivity to the onion; iii) onion seed production. The results showed that the choice of the seed production method and then the mechanical treatments require to be managed very carefully in order to maximize the weed control, reducing seed yield losses. The seed-to-seed method seemed to be not advisable in the Mediterranean areas, because there were great difficulties to control weeds by mechanical method mainly owing to the long crop cycle with more fluxes of weed emergence, the very low competitiveness of onion at the early growth stages and the weather conditions during the crop cycle that has greatly affected the timeliness, repeatability and effectiveness of mechanical control. In these conditions, competition of uncontrolled weeds caused heavy seed yield losses or the crop failure and only manual weeding ensured a satisfactory weed control and seed yield, although with a very high hand labour. The bulb-to-seed method was the only advisable for onion seed production because allowed to control weeds by mechanical methods, obtaining good levels of seed yield. In particular, combined intra and inter-row methods, such as hoeing-ridging or split-hoeing + finger-weeding, allowed a high effectiveness against weeds (ranged from 63% to 92%) and a good selectivity to the crop, reducing weed-crop competition and assuring satisfactory onion seed production. Unlike seed yield, seed quality was not affected by weed competition: weight, moisture and germinability of onion seeds were always over of the standard levels required for commercialization, regardless of weed competition levels.

Efficacy of pre-emergence and post-emergence herbicides for weed management in groundnut (Arachis hypogaea L.) production in Guinea Savannah

Groundnut or peanut (Arachis hypogaea L.) has gained prominence as food and cash crop both in the domestic and export markets. In Ghana, the bulk of groundnut is produced in the Guinea savannah zone where it is vulnerable to weed infestation that results in average yields of about 800 kg/ha compared to developed countries of more than 3,000 kg/ha. This experiment was conducted in Tolon during the 2012 farming season to determine the most suitable combination of pre-emergence and post-emergence herbicides and/or hand weeding that could enhance efficient weed control and to assess the treatments that could promote yield and yield components of groundnut. Some local available herbicides and recommended rates used included: Pendimethalin at 0.15 kg a.i./ha, gallant super at 0.03 kg a.i./ha, agil at 0.02 kg a.i./ha, basagran at 0.14 kg a.i./ha. The study was laid out in RCBD with four replications. Results showed Pendimethalin at 0.15 kg a.i./ha plus gallant super at 0.03 kg a.i/ha at 4 weeks after planting (WAP) recorded the highest pod yield of 2436 kg/ha. All treatments recorded significantly high yield over the Weedy check. Weed biomass correlated negatively (r= -0.5074) with nodulation count while haulm yield showed a positive correlation coefficient of (r=0.4575*) with pod yield. Weed control efficiency of 94.8% showed pendimethalin at 0.15 kg a.i/ha plus agil at 0.02 kg a.i/ha at 4WAP was most effective in weed control. Herbicide application reduced weed index. Basagran at 0.14 kg a.i/ha at 4WAP plus one hand weeding at 7WAP recorded least weed index of 24%. The most dominant weeds were broadleaves such as Ageratum conyzoides (L), Corchorus olitorius (Linn) and Ludwigia abyssinica (A. Rich). Plots with uncontrolled weeds resulted in 69% loss of pod yield. In order of decreasing weed control, yield components and pod yield; Pendimethalin at 0.15 kg a.i./ha plus gallant super at 0.03 kg a.i/ha applied at 4 WAP was more effective than basagran at 0.14 kg a.i/ha at 4WAP plus 1HW at 7WAP and gallant super at 0.03 kg a.i/ha at 4 WAP plus 1HW at 7 WAP; and are recommended in that order to groundnut farmers in the Guinea savanna zone of Ghana.

Effect of different weed management options on weed flora, rice grain yield and economics in dry direct-seeded rice

The shift in the method of rice establishment from traditional manual transplanting of seedlings to direct seeding has occurred in many Asian countries including India. Weeds are the most important biotic constraint in dry direct-seeded rice (dry-DSR) production. Field experiments were carried out during 2015–16 and 2016–17 at Pandit Jawaharlal Nehru College of Agriculture & Research Institute, Karaikal, and Puducherry UT, India to study the effect of different weed management options on the diverse weed flora, rice grain yield and economics in dry-DSR under unpuddled condition. The grassy weeds dominated the weed flora, with 86.12% relative density of Echinochloa colona (L). Link. The sequential application of pendimethalin and bispyribac-sodium herbicides (1000 fb 25 g/ha) with a manual weeding in 40 days after sowing (DAS) reduced total weed density (14.4/m2) and biomass (37 g/m2), resulted in better rice growth (plant height and tillers/m2), yield parameters (panicle weight and 1000 grain weight) and higher rice grain yield (3.86 t/ha). Negative linear relationship was observed between rice grain yield and total weed biomass at 80 DAS. Uncontrolled weeds caused 68.3% dry-DSR yield loss. Pre-emergence pendimethalin 1.0 kg/ha application integrated with manual weeding with or without bispyribac-sodium application and manual weeding thrice recorded higher B: C ratio in deltaic coastal ecosystem of Karaikal, Puducherry UT.

Optimum weeding and agronomic traits of five varieties of Sesame indicum L.

Field experiments were conducted during 2015–16 at the Teaching and Research Farm, Ladoke Akintola University of Technology, Ogbomoso, Nigeria to determine the appropriate weeding regimes and agronomic traits in five selected varieties of sesame. Five weeding regimes: no weeding (control), weeding once (at 3 weeks after planting), two weedings (at 3 and 6 weeks after planting), three weedings (at 3, 6 and 9 weeks after planting) and weed free were imposed on five sesame varieties, namely, NCRI BEN-01M (01M), NCRI BEN-02M (02M), NCRI BEN-03L (03L), E-8 and Exotic-sudan (EX) in a split plot arrangement laid out in randomized complete block design (RCBD) and replicated three times. Weeding regime significantly affected the plant growth parameters, number of pods and seed yield of the sesame varieties. Across the five sesame varieties, uncontrolled weeds led to an average of 49% yield reduction, however, 02 M variety exhibited the least tolerance to weed infestation (60% reduction), while other varieties had almost similar values. Seed yield under treatment of two weedings (350.86 kg/ha) or three weedings (413.41 kg/ha) was comparable to those of weed free (411.28 kg/ha) across the varieties in two years. In conclusion, weeding two times was adequate for optimum seed yield production. Growers can successfully cultivate sesame varieties NCRI BEN-01M, NCRI BEN-03L or E-8.

Potential Yield Loss in Dry Bean Crops Due to Weeds in the United States and Canada

AbstractEarlier reports have summarized crop yield losses throughout various North American regions if weeds were left uncontrolled. Offered here is a report from the current WSSA Weed Loss Committee on potential yield losses due to weeds based on data collected from various regions of the United States and Canada. Dry bean yield loss estimates were made by comparing dry bean yield in the weedy control with plots that had >95% weed control from research studies conducted in dry bean growing regions of the United States and Canada over a 10-year period (2007 to 2016). Results from these field studies showed that dry bean growers in Idaho, Michigan, Montana, Nebraska, North Dakota, South Dakota, Wyoming, Ontario, and Manitoba would potentially lose an average of 50%, 31%, 36%, 59%, 94%, 31%, 71%, 56%, and 71% of their dry bean yield, respectively. This equates to a monetary loss of US $36, 40, 6, 56, 421, 2, 18, 44, and 44 million, respectively, if the best agronomic practices are used without any weed management tactics. Based on 2016 census data, at an average yield loss of 71.4% for North America due to uncontrolled weeds, dry bean production in the United States and Canada would be reduced by 941,000,000 and 184,000,000 kg, valued at approximately US $622 and US $100 million, respectively. This study documents the dramatic yield and monetary losses in dry beans due to weed interference and the importance of continued funding for weed management research to minimize dry bean yield losses.

Optimization rate of pinoxaden + clodinafop-propargyl for weed control in wheat

A field experiment was conducted during 2011–12 and 2012–13 at GB. Pant University of Agriculture & Technology, Pantnagar to study the effect of different rates of pre-mix of pinoxaden 2.53% + clodinafop-propargyl 2.53% on population and growth of weeds and grain yield of wheat. Major weed species identified in the experiment were Phalaris minor, Avena spp., Chenopodium album, Anagallis arvensis, Polygonum plebeium, Melilotus indica, Coronopus didymus during both the years. The lowest density and biomass of grassy weeds were recorded with pinoxaden 2.53% + clodinafop- propargyl 2.53% at 60 g/ha. However, it was ineffective against broad-leaf weeds. Maximum grassy weed control efficiency (100%) was observed with pinoxaden + clodinafop-propargyl at 60 g/ha closely followed by its lower dose applied at 50 g/ha and pinoxaden at 50 g/ha. Pre-mix of pinoxaden 2.53% + clodinafop-propargyl 2.53% at 60 g/ha produced highest grain yield (4.5–4.6 t/ha). Uncontrolled weeds caused 55.7 and 52.2% reduction in grain yield of wheat when compared with weed free conditions during 2011–12 and 2012–13.

Evaluation of efficacy of different herbicides on weed dynamics and performance of dwarf fieldpea in Tarai soils of Uttarakhand, India

A field experiment was conducted during rabi season of 2010-2011 and 2011-12 at Pantnagar in tarai soil of Uttarakhand to study the effect of different herbicides on plant growth, weed dynamics, nutrient uptake and yield of dwarf fieldpea. Results revealed that uncontrolled weeds caused 27.3 and 39.4 per cent reduction in grain yield of dwarf fieldpea during first and second year, respectively as compared to two hand weedings done at 20 and 40 days after sowing (DAS). Among the chemical treatments, minimum nutrient removal of 3.0 kg N,0.5 kg P and 3.3 kg K ha-1by weeds was recorded under pendimethalin 1.0kg ha-1 (PE)+ imazethapyr 0.05 kg ha-1 (POE,30 DAS) as against 11.4 kg N, 1.96 kg P and 12.6 kg K ha-1, respectively in weedy check Two hand weedings done at 20 and 40 DAS, which remained at par with pendimethalin1.0 kg ha-1 (PE) + imazethapyr 0.05 kg ha-1 (POE, 30 DAS) and pendimethalin 1.0kg ha-1(PE) + quizalofop ethyl 0.05kg ha-1(POE, 30 DAS) caused significant reduction in weed dry weight and increased the value of plant height, number of leaves per plant and dry matter accumulation per plant as compared to weedy check. These treatments produced 27.1, 23.1 and 16.0 per cent more number of pods/plant and yielded 50, 40 and 35.7 per cent higher grain yield, respectively over weedy check. The maximum weed control efficiency was computed under two hand weedings followed by pendimethalin 1.0 kg ha-1 (PE)+ imazethapyr 0.05kg ha-1 (POE, 30 DAS) and pendimethalin 1.0kg ha-1 (PE)+ quizalofop ethyl 0.05 kg ha-1 (POE, 30 DAS).

Economics and Yield Gap Analysis of Front Line Demonstrations Regarding Scientific Practices of Indian Mustard in Punjab

The Front Line Demonstration (FLD) is an applied approach to accelerate the dissemination of proven technologies at farmers ’fields in a participatory mode with an objective to explore the maximum available resources of crop production and also to bridge the productivity gaps by enhancing the production in national basket. Krishi Vigyan Kendra, Amritsar, Punjab conducted 82 demonstrations on Indian mustard variety GSC 6 during five consecutive years from 2010–11 to 2014–15. The critical inputs were identified in existing production technology through meetings and discussions with farmers. Delayed sowing, use of higher seed rate resulting into dense plant population, uneven plant population, uncontrolled weeds, ignorance about fertilizers and lack of plant protection measures were the predominant identified causes of low productivity of oilseeds in district Amritsar. In the same sequence the other parameters like technology gap, extension gap and technology index were analyzed for assessment of technology adoption rate with extension activities and feasibility of demonstrated technologies at grass root levels. The results of five years study revealed that the yield under demonstration plots was 12.62 q ha'1 as compared to 9.02 q ha'1 in traditional practices plots. This additional yield of 3.60 q ha'1 and the increase in average mustard productivity by 40.35 per cent may contribute to present oilseed requirement on national basis. The average of technology gap and technological index were found to be 2.55 q ha'1 and 16.81 per cent respectively. The results clearly indicate the positive effects of FLDs over the existing practices. Benefit: cost ratio was recorded to be higher under demonstrations against control treatments during all the years of experimentation.