Critical Period Of Weed Competition Research Articles

Critical Period for Weed Competition in Sesame under Iraqi Irrigated Areas

Critical Period for Weed Competition in Sesame under Iraqi Irrigated Areas

Critical period of weed competition in cowpea

Weed competition is one of the factors that limit cowpea production in the world, causing losses of up to 90% of grain yield and quality. Knowledge of the critical period of weed competition (CPC) is important to prevent significant losses of grain and resources in the production process. The objective was to determine the critical period of weed competition in the cultivation of cowpea beans, Missouri cultivar, in two sowing seasons: dry (2022B) and rainy (2023A) of warm dry Colombian Caribbean. The randomized complete block design was used with eight treatments and four repetitions. The first four treatments corresponded to manual control of weeds in the intervals 0-10, 0-20, 0-30 and 0-50 days after emergence (DAE), the second four treatments corresponded to the crop-weed coexistence, in the same intervals. Cowpea grain yield, dry mass, cover and weed community composition were evaluated. The critical period of competition of weeds in the cowpea crop for the dry and rainy seasons was 14-33 and 14-29 days after emergence, respectively. The reduction in grain yield was 65.2% in the dry season and 80.46% in the rainy season. Rottboellia cochinchinensis had the highest occurrence rate with 30.3% and a density of 90 individuals per m2; which is important for the agronomic management of the crop in the humid Caribbean subregion.

Critical Period of Weed Competition in Curcuma Lanna Snow Field

The effects of weeds on crops can cause weed interference, which is the result of their competition with each other. The influence of weed interference periods on growth and inflorescence of Curcuma was investigated under field experiment. The critical period for weed control consists of the increased duration of weed competition period during the weed-infested treatment, and the increased duration of weed free period during the weed-free treatment. Weed-free and weed-infested treatments were used to identify the critical period for weed control with acceptable yield loss of 5 and 10%. The results revealed that weed infested periods at 10, 12, 14 and 16 weeks after planting and weed free periods at 0, 2 and 4 weeks after planting significantly reduced the leaf number, height of inflorescence, width of inflorescence and length of inflorescence of Curcuma, while plant height was slightly affected by weed-free treatment. In addition, the critical period for weed control with 5 and 10% acceptable yield loss was estimated to be between 6 to 10 weeks after planting and 5 to 8 weeks after planting, respectively. The critical period for weed control at 10% acceptable yield loss was shorter than the critical period for weed control at the level of 5%. However, the determination of appropriate critical period for weed control should be concerned to have better crop yield and reduce cost. Weed control estimation and recommendations can enhance more precise weed management, which is helpful in formulating appropriate weed-control strategies in Curcuma fields.

Effect of Herbicidal Weed Management on Productivity and Profitability of Summer Cowpea

Background: The presence of weeds in cowpea reduced the yield to the tune of 60-82% depending on the weed flora and density. The critical period of weed competition in cowpea was 20-25 DAS. Therefore it is essential to control weeds effectively to harness the maximum yield potential of the crop. To manage weeds in cowpea it is also important to determine the efficacy of pre and post-emergence herbicides. Sequential application of herbicides in a short duration crop not only increases the cost of production but also create cumbersome in its application. Therefore ready mix herbicides are now becoming popular among farming community. These new ready mix herbicides need to be tested for its bio-efficacy to manage weeds and its effect on crop productivity and symbiotic characters of cowpea. Therefore, a field experiment was carried out to evaluate the impact of herbicides on the productivity and profitability of summer cowpea (Vigna unguiculata L.) at Agronomy Main Research Farm, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha (India) during summer season. Methods: The experiment was laid out at Agronomy Main Research Farm, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha (India) during the summer season of 2021 and2022 in a randomized block design (RBD) comprised of eight treatment with three replications. Standard procedures were followed for the observations and statistical analysis of the data. Result: The experimental results revealed that ready mix of pendimethalin+imazethapyr-750 g/ha significantly control the mixed flora of weeds which resulted significant increase in growth and yield. Ready mix application of pendimethalin + imazethapyr 750 g/ha registered the highest benefit to cost ratio.

Determination of Critical Period for Sustainable Weed Management and Yield of Jute (Corchorus olitorius L.) under Sub-Tropical Condition

A field investigation was run to ascertain the critical period of weed control in jute (Corchorus olitorius). The study consisted of two distinct sets of treatments, with one set of weeds being left to invade the crop for a longer period of time, specifically, for 15, 30, 45 and 60 days after sowing (DAS) and up to harvest. In the other set of treatments, the plants remained weed-free for progressively longer periods, i.e., 15, 30, 45 and 60 DAS, and until harvest. The reduction in fibre yield (FY) was recorded as 53.39% when weed interference was permitted from the beginning to harvest, as opposed to the season-long weed-free period. The critical period for weed competition (CPWC) of jute was calculated as being 11 to 68 DAS and 19 to 59 DAS, based on results of 5% and 10% yield loss, respectively. Under the 5% yield loss condition, although yield was higher (3.36 t ha−1), the benefit cost ratio (BCR) was lower (1.65), whereas yield was slightly lower (3.19 t ha−1) but BCR was higher (1.73) with respect to 10% yield loss. Therefore, jute fields should be kept weed free from 19 to 59 days after sowing, and a weed management strategy should be undertaken accordingly.

Date of Transplanting and Integrated Weed Management Effects on Growth and Yield of Black Rice (Oryza sativa L.) under SRI

Background: The date of transplanting which is related to the climatic condition is one of the major factor affecting the growth and yield of black rice. Weeds also pose serious threat to rice in SRI condition if not controlled during critical period of weed competition. Therefore, efficient integrated weed management practices are required in SRI. The experiment was carried out to assess the effect of date of transplanting and integrated weed management on black rice. Methods: The experiment was conducted in the experimental farm of SASRD, NU, Medziphema campus during kharif season of 2019 and 2020. The experiment was laid out in split plot design with three dates of transplanting in the main plots and five integrated weed management treatments in the sub-plots with 15 treatment combinations and three replications. Result: Minimum weed population and dry weight were recorded with transplanting black rice on 15th June. It also gave significantly highest growth attributes and yield of black rice. Among the integrated weed management, Pretilachlor 0.75 kg/ha t 3 DAT fb handweeding at 40 DAT recorded significantly lowest weed population and dry weight and highest plant height, number of green leaves plant-1, dry matter accumulation and yield of black rice.

Assessing critical period of weed competition in direct seeded rice (Oryza sativa L.)

Assessing critical period of weed competition in direct seeded rice (Oryza sativa L.)

Determination of critical period of weed competition in Sugarcane (Saccharum officinarum L.) at Arjo Didessa sugar estate, western Ethiopia

Weeds limit sugar cane production. A field experiment employing cultivar NCO334 and Randomized Complete Block Design (RCBD) was done to assess weed competition crucial period. After planting, experimental plots were either weed-free or weedy (0, 25, 50, 75, 100, 125, and 150 DAP). Weed density, weed dry weight, sugarcane sprout, tiller number, cane height, millable cane number, girth, weight, and predicted cane and sugar production traits were evaluated. For different periods, weed competition affects tiller number, cane height, girth, weight, millable cane number, and cane and sugar yield. Tiller production, cane height, girth, weight, millable canes, and cane and sugar output rose with more extended weed-free periods. Weeds in sugarcane caused 90. 5% and 94.6% cane and sugar yield losses, respectively. Cane girth, height, weight, tiller number, cane, and sugar production correlated positively and negatively with weed density and dry weight. weed crop competition begins between 17 and 131 DAP. To limit the impact of weeds on sugar cane yield, weed management measures should be implemented in sugarcane plantations during this important period.

Weed competition affecting growth and yield in ajwain (Trachyspermum ammi)

Weeds compete with crop plants throughput the plant growth period and causes significant losses in quality, productivity and profitability. Seed spices are more sensitive to crop weed competition as they are grown under arid conditions where moisture is the limiting factor. A study was carried out to identify the critical period of weed competition in ajwain (Trachyspermum ammi Sprague) during 2012-13 to 2014-2015 at ICAR-National Research Centre on Seed Spices, Ajmer, Rajasthan. Treatments included weedy and weed-free condition for different growth periods, i.e. 15, 30, 45, 60, 75, 90, 105, 120 days after sowing (DAS) along with weed free throughout growth period and weedy throughout growth period. Weedy period up to 30, 45, 60, 75, 90, 105, 120 DAS and weedy throughout growth period reduced the seed yield significantly to the tune of 321.4, 463.0, 607.7, 705.9, 852.9, 950.4, 1072.9 and 1162.4 kg/ha respectively as compared with the weed free throughout growth period. Weed free up to 15 DAS to 120 DAS decreased the seed yield from 1039.4 to 99.0 kg/ha as compared to the weed free throughout growth period. Weedy period up to 75 DAS gave tough competition to the crop for growth which was reflected in yield attributes and seed yield of ajwain. The maximum yield of 1244.5 kg/ha was obtained with the treatment weed free throughout growth period, this was also found economically viable which resulted in highest gross return of ` 136891/ha, net returns ` 102953/ha and B: C ratio of 3.03. Critical period for weed competition in ajwain was found to be 54 days after sowing.

Development of Test and Measurement of Knowledge Level of Sunflower Farmers

A test was constructed to measure the farmers’ knowledge level on sunflower cultivation during 2021-22. Relevant items were collected from review of literature and discussed with scientists. For relevancy test, 39 items were sent to 320 experts for their judgement. Based on 45 experts judgement, 18 items (overall mean score > 2.57) were selected for item analysis and administrated to 60 farmers of Chinnakoduru village of Siddipet district. Item analysis was done by item difficulty index, item discrimination index and point biserial correlation and 15 items were finalized for knowledge test. Reliability (Cronbach alpha, Spearman brown coefficient and Guttman split-half) and validity (point biserial correlation) were estimated for standardization of the test and found to be highly significant. The test was administered to 140 respondents in Andhra Pradesh and Telangana states. In Andhra Pradesh, 78.8 per cent and in Telangana 85.0 per cent of respondents were in medium level of knowledge category. The item analysis indicated significant differences in knowledge level of farmers pertaining to most suitable period of sowing sunflower crop during Rabi, suitable sunflower hybrids, optimum seed rate, critical period of weed competition, application of fertilizers and bee keeping in sunflower in two states.

Competition of Weeds Dominated by Wild Oat (Avena sterilis L.) in Wheat (Triticum durum Desf.) in Jordan

Wheat is the main field crop grown in Jordan. Productivity is low due to different factors, including erratic rainfall, poor soil fertility and weed competition. A field experiment was carried out at the University of Jordan Research Station for two growing seasons to determine the effect of weed competition on growth and yield of wheat (Triticum durum Cv. “Hourani”). Treatments consisted of either allowing weeds to infest the crop or maintaining the crop weed-free for increasing durations after emergence. Results showed that, the longer the periods of weed competition, the greater the loss in crop growth and yield. Average reductions in grain and straw yields were 41% and 37%, respectively. The highest grain yield obtained was from weed-free, and the lowest was in weed-infested plots for the entire growing season. Average grain yield was not significantly different at 14 to 49 days of weed-infested periods, while none of the weed-free periods produced a yield similar to that of the weed-free control. However, maintaining a weed-free crop for three weeks after emergence significantly increased grain yield compared with the weed-infested control. High rainfall in the first season almost doubled weed growth and greatly reduced wheat growth and yield compared with the second season. To determine the critical period of weed competition and the influence of weed infestation on wheat grain yield, Gompertz and logistic equations were fitted to data representing increasing duration of weed-free and weed-infested periods, respectively. Based upon an arbitrary 5% level of average grain yield loss in the two years, the critical period of weed competition occurred at 0–49 days after wheat emergence, which corresponded with the rapid increase in weed biomass.

Review on critical period of weed competition and management in maize (Zea mays L.)

Review on critical period of weed competition and management in maize (Zea mays L.)

Evaluation of critical period for weed crop competition in growing broccoli crop

To standardize the existing approach of single weeding in cole crops practiced by most of the vegetable growers, a two-year field trial was designed to figure out the critical period for weed competition in broccoli (Brassica oleraceae L. var. italica). Two broccoli varieties “Rocco” and “Galabrease” were used with weeding intervals of 15, 30, 45, and 60 days after transplantation (DAT) along with a weedy check (control). Ten-gram (10 g) seed of various weed species was sown in each plot to get sufficient weed influx. Growth and yield parameters of broccoli including head diameter, number of axillary shoots, the weight of axillary shoots, total yield, and marketable yield, while weed parameters viz. weed density and fresh weed biomass were recorded during experimentation. Results revealed that Rocco a hybrid variety of broccoli performed significantly better than Galabrease for various growth and yield parameters at all weeding intervals. As regards the effect of various weeding treatments, the best treatment was hoeing 15 DAT followed by 30 DAT. Delayed hoeing beyond this critical period of 15 to 30 DAT correspondingly decreased all the growth and yield parameters, the untreated control showing the lowest value. Weed infestation had a strong negative correlation with the yield parameters of broccoli. It is concluded from the present study that weed density of 1 plant m−2 would result in a loss of 0.062 t ha−1 of marketable yield in broccoli, which warrants timely management of weeds to obtain the optimum yield of broccoli.

Effect of Critical Period of Weed Competition and Its Management Option in Sweet Corn [Zea mays (L.) var. saccharata strut] Production: A Review

Sweet corn [Zea mays (L.) var. saccharata strut] is the most important variety of maize with high sugar content. It contains a glossy sweetish endosperm and primarily grown for human food. It requires moderately high temperature from 22oC up to 33oC, high light intensity and adequate and well distributed rainfall of not less than 200mm during growing season. It can be grown on the wide range of soils. However, it performs best on neutral, well drained, well aerated and moderately heavy, deep fertile soils. Sweet corn is not so much competing with weeds like other crops. Avoid the influence of weed competition on the growth and development of sweet corn produce maximum yield and the economic importance of sweet corn used for conception and health benefits. By so far it is good in health and as medicinal uses it should be managed without affecting by weeds. The weed management option properly controls by the method of mechanical, biological, chemical and integrated weed management. In general, it is significant that properly controlling critical period weed competition in sweet corn reducing the competition of light, water, nutrient and space and maximizing the yield of sweet corn.

Yield Losses Due to Weeds, Critical Period for Weed-crop Competition in Fenugreek (Trigonella foenum-graecum L.)

Background: Weed populations reduce crop yields by influencing the pattern of crop growth and development throughout the season and by directly competing with the crop for limiting precious resources, like light, water or nutrients. A number of the factors that influence magnitude of crop yield losses from weed interference include the timing of weed emergence relative to the crop, weed density, pattern of weed growth and development. Weed management is one among the foremost critical factors influencing crop yield. By providing a window of weed-free growth early within the season, the size advantage that crop seedlings have over weeds can be utilized to reduce the intensity of direct competition for resources at the stages of crop development when yield is being determined. Weeds are identified as a significance drawback since they create biotic stress in realizing the genetic yield potential of this valuable crop.Methods: A field experiment was carried out during the rabi season of 2010-11 to 2014-15 at ICAR- National Research Centre on Seed Spices, Ajmer, Rajasthan to estimate the yield losses because of weed infestation and to work out the critical period for weed control (CPWC) in fenugreek (Trigonella foenum-graecum L.). There were 14 treatments comprising of initial weedy periods of 15, 30, 45, 60, 75, 90 days after sowing (DAS) and weed free period upto 15, 30, 45, 60, 75, 90 DAS along with weedy till harvest (un-weeded check) and weed free till harvest (weed free check). The treatments were replicated three times in a randomized block design.Result: Maximum pod length (cm), number of pods/plant, number of seed/pod, test weight (g), seed yield (kg/ha), straw yield (kg/ha) and harvesting index (%) to the tune of 9.47, 41.2, 16.67, 12.60, 2297, 4954 and 31.73 were recorded at weed free throughout growth period. Weed infestation up to 30, 45, 60, 75, 90 DAS and weedy throughout growth period reduced the seed yield significantly to the magnitude of 567.3, 801.7, 913.3, 1253.3, 1393.7 and 1736.3 kg/ha. Yield losses in fenugreek increase from 2.95 kg/ha/day at 15 days weed infestation to 12.31 kg/ha/day at 135 days weed infestation. Maximum gross return (`104248/ha), net return (`67018/ha) were obtained at weed free throughout growth period with the B:C ratio 2.80 among the weed free treatments. The employment of response curves with weed free or weed competition period showed that seed yield of fenugreek were the highest with the field free from weeds throughout the growth period and the critical period of weed/fenugreek competition was 32 days after sowing and lies between 30-45 days after sowing. In regression approach for fenugreek seed yield and weed free or weed competition period the quadratic function was fitted to estimate the expected yields which had the high significant with the data recorded and have the highest values of R2. If we predict the seed yield losses based on the quadratic model for weed free period model, it declined from 42.04 at 0 DAS to 0.0% at 135 days. Similarly, weed infestation period model predicted the seed yield losses increased from 0.00 at 0 days weed infestation to 73.42% at 135 days. Critical period for weed competition in fenugreek was found to be 32 days after sowing. The CPWC is helpful for making decisions on the necessity for and timing of weed control.

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

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

Weed management in finger millet in India- an overview

Eleusine coracana (L.) Gaertn (finger millet) is one of the most nutritious and major staple food in some states of India. Finger millet is cultivated by using broadcast seeding, row (drill) seeding, and transplanting. In this review, the weeds associated with finger millet in different parts of India are listed, information on reported weed management options in finger millet is synthesized and future weed management research needs are enumerated. Weeds smother the finger millet resulting in significant reduction in the yield by 5 to 70%. The critical period for weed competition in finger millet is the first 4–6 weeks from planting/seeding. Physical/mechanical methods such as hand weeding at 20 and 30 days after planting (DAP) or passing wheal hoe twice with one manual weeding were found to be equally effective. In majority of the studies, inter-cropping was found helpful in reducing weed population substantially. Pre-emergence application of bensulfuron-methyl + pretilachlor, butachlor, isoproturon and post-emergence application of 2,4-D, chlorimuron-ethyl either alone or in combination with other methods were found effective in managing weeds in finger millet. Future research needs are: continuous monitoring of weeds and their shifts, understanding weed ecology and biology, developing improved mechanical tools and weed competitive cultivars along with location specific cost-effective and eco-friendly weed management strategies.

Effects of Irrigation Regimes and Duration of Weed Interference on Grain Yield of Wheat (Triticum aestivum L.) in Middle Egypt

TWO EXPERIMENTS were performed at Farm of Faculty of Agriculture, El-Minia University Egypt, during two consecutive winter seasons 2017-2018 and 2018-2019 to evaluate the impact of weed removal period and different irrigation regimes on weeds, critical period of weed competition and yield and its components on wheat crop. A strip-plot design with three replications was used. Four irrigation regimes were in the horizontal plots and eight treatments of weed competition (4 weed-free periods and 4 weed competition periods) were in vertical plots. Results showed that omitting two irrigation (IR4) significantly decreased total density and dry weight of weeds, wheat traits, i.e. plant height, spike length, number of grains spike-1, 1000-grain weight, number of spikes m-2, grain yield and grain ability. Weed infestation for whole season significantly decreased all studied traits compared with weed removal even once after wheat sowing (DAS). Maximum yield losses of wheat due to weed infestation in whole season were 28.52 and 28.17% compared with weed-free treatment in the 1st and 2nd seasons, respectively. Cubic model was the best model for weed-free and weed competition over all treatments of the two seasons. The critical periods for weed control were 28 to 52 and 28 to 67 DAS in the two seasons, respectively.

Weed Management Practices in Maize (Zea mays L.): A Review

In India the highest loss (33%) is caused by weeds, followed by pathogens (26%), insects (20%), storage pests (7%), rodents (6%) and others (8%). Weeds compete with the crop for both above and below ground resources. Critical period of weed competition starts from 17 to 29 days after planting of corn, at an acceptable yield loss of 5 to 10 per cent. Herbicides are efficient tools for checking weed infestation and its usage is increasing throughout the globe due to increasing labour cost and quick weed control in various situations. The common weed management practice for Maize is pre-emergence application of selective herbicides like atrazine or pendimethalin followed by one hand weeding. Managing weeds through pre-emergence, post-emergence and sequential use of herbicides will be an ideal means for controlling the weeds in the view of economics and effectiveness in maize.

Weed Management in Pulses: A Review

Pulses are the important crop after cereals and is the cheapest source of dietary protein. After the Green revolution, the production of pulses in India remain stagnant over the years due to various biotic and abiotic stresses. Among the various biotic stresses, weeds are the major one which causes severe yield loss in pulses. Due to initial slow growth of pulses, weeds emerge first and gain competitive advantage over the crop and exhibit smothering effect on crop. Moreover, major area of pulses (84 per cent) are under rainfed condition and grown in combination with non-legume crop. As a result, pulses are subjected to various types of biotic and abiotic stresses. Weeds besides causing direct loss in yield also hinder farm activities and serve as alternate host to many pests. Weed management in pulses is essential to bring the weeds below the threshold level to maximize the seed yield and quality. The literature regarding the importance of weed management in pulses, weed flora, critical period of crop weed competition and different weed management methods of weed control are collected and presented in this paper.Weeds are the predominant biological constraint in pulse production due to the slow initial growth of the crop. Strategies’ of weed management depends on the weed competition, types of weeds present and weed control method adopted. In general, critical period of weed competition for short duration pulses is up to 30 days and for long duration pulse crops it is up to 60 days. The major three types of weeds viz., grasses, broad leaved weeds and sedges were found in association with pulses. Intensity of weed infestation varies with agroecological conditions and crop management practices followed. A system approach is necessary to maintain the weed population below the economic threshold level thereby reducing the yield loss. Integrated weed management (IWM) which has been proved to be more effective than any single method in alleviating the buildup of weeds in pulse crop.