Hand-weeding Time Research Articles

Influence of Grass Pea Residues Extract on Weed Control Efficacy and Performance of Boro Rice

The agriculture sector is constantly adopting environmentally friendly and sustainable methods to reduce the harmful effects of herbicides on crop production. In this respect, an experiment was conducted at the Agronomy Field Laboratory (AFL), Bangladesh Agricultural University (BAU), Mymensingh to assess the allelopathic effects of grass pea crop residues on weed suppression and the growth performance of Boro rice from December 2021 to May 2022. The experiment consisted of four cultivars of Boro rice i.e. BAU dhan3, BRRI dhan28, BRRI dhan81, BRRI dhan96 along with four different treatments of weed control viz. no extract and no weeding (control), hot water extract of Grass pea residues as pre-emergence application at 3 DAT (days after transplanting), hot water extract of Grass pea residues as pre-emergence application at 3 DAT+ post- emergence at 10 DAT, hand weeding 3 times at 15, 30 and 45 DAT. The highest weed growth was noticed when no extract was added and the lowest was found when three times hand weeding was performed. The highest number of effective tillers (NET) hill-1, number of spikelets panicle-1 (NSP) and grain yield (GY), straw yield (SY) and biological yield (BY) were recorded from the rice variety BAU dhan3. The highest NET hill-1, NSP, 1000-grain weight (TGW), GY, SY and BY were recorded from three hand weeding which was followed by hot water extract of grass pea as pre-emergence application at 3 DAT+ post-emergence application at 10 DAT. From the interaction it is observed that the highest NET hill-1, NSP, SY and BY were obtained from BAU dhan3 with three hand weeding which was followed by BAU dhan3 with hot water extract of grass pea as pre-emergence application at 3 DAT+ post-emergence application at 10 DAT. The findings of this study reveal that hand weeding, followed by the application of grass pea crop residues, effectively suppresses weed growth. Our research suggested leveraging the allelopathy-weed inverse relationship to address weed problems. This approach holds significant promise for weed management in the twenty-first century. J Bangladesh Agril Univ 22(3):360-368, 2024

Effect of Chemical and Hand weeding Control Methods on Growth Yield Components and Yield of Field Pea in Bale Highlands, Southeastern Ethiopia

Afield experiment was conducted during bona season of 2019/2020 and 2021/2022 at two location Agarfa sub-site and Sinana on station to evaluate the integrated effects of pre-emergence herbicides and hand-weeding on weed control, yield components, yield, and their economic feasibility for cost effective weed control in field pea. The treatments consisted of three dual gold rates (1, 2 and 3 liter per hectares) and three times (0, 1and 2 times hand weeding). The experiment was laid out in a factorial arrangement of RBCD with three replications. Results indicated that Dual-gold 2 liter per hectare supplemented with hand weeding at 25-30 days after crop emergence resulted in the highest grain yield and economic benefit. However, in case labor is constraint and Pre-emergence herbicide is timely available, pre emergence application of Dual-gold 2 liter per hectare should be the alternative to prevent the yield loss and to ensure maximum net benefit for the producers. Thus, the result of this study, it can be tentatively concluded that herbicides application is an integral part of farmer’s pulse crop management in modern agricultural systems.

Soil solarization as a non-chemical weed control method in tree nursery production systems of the Pacific Northwest, USA

IntroductionHerbicide application in tree nurseries is limited because of the potential for chemical injury to the large diversity of trees species grown, the lack of registered products, and increasing restrictions on herbicide use, necessitating the costly practice of hand weeding. Soil solarization can reduce the weed seedbank by trapping solar energy under clear plastic film, resulting in high soil temperatures lethal to imbibed weed seeds and seedlings. The objective of this study was to determine if soil solarization would be an effective weed management strategy in Pacific Northwest, USA, tree production systems.MethodsField studies were conducted at three commercial tree nurseries in Oregon and Washington over two years to test soil solarization in reducing the naturally occurring weed seedbank and the time required to hand weed fields. Further field and laboratory tests were conducted with five weed species: Poa annua, Polygonum pensylvanicum, Amaranthus retroflexus, Portulaca oleracea, and Cyperus esculentus. Weed seeds and tubers were buried in packets at 5 and 10 cm to determine their viability after 6 weeks of solarization. A laboratory study was conducted with all but C. esculentus to quantify the exposure time at 45, 50, and 55°C required for 90% death (T90).ResultsSoil solarization was particularly effective in reducing the emergence of naturally occurring weeds in the fall and winter, when weed emergence was reduced by 94-96%. Emergence was reduced 67-81% during the subsequent spring and early summer. Nine to ten months after solarization, solarized areas had a 52 – 69% reduction in hand weeding time compared to non-solarized areas. In field trials with buried seed and tuber packets, mortality differed by location and depth, with P. annua and P. pensylvanicum having the greatest percent seed mortality followed by A. retroflexus and variable results for P. oleracea and C. esculentus. In lab studies, seed mortality differed depending on species and temperature; however, at 55°C, there was a relatively rapid drop in seed viability for all species, and T90 values ranged from 1.2 to 41 h whereas at 45°C the range was 47 to > 3000 h. Similar to the field studies, P. annua and P. pensylvancium were more sensitive to heat, followed by A. retroflexus and P. oleracea.ConclusionSoil solarization can be an effective weed management tool in reducing the weed seedbank in Pacific Northwest tree nurseries and other fall-sown crops but may not work for certain, thermotolerant weed species such as C. esculentus.

Band Steaming for Weed and Disease Control in Leafy Greens and Carrots

Steam injected into the soil, raising soil temperatures to >70 °C for 15 to 20 minutes, will control weed seed and soilborne pathogens. The effect of this reduction in the weed seedbank viability results in weed control in the treated zone that can persist for several weeks or months. The effect of steam pasteurization of soil on weed seeds produces results similar to a preemergence herbicide. In our study, steam was applied to the soil to control weed seed and propagules of Sclerotinia minor and Pythium spp. Replicated field trials in carrot, lettuce, and spinach were conducted using two types of band steam applicators in 2020 and 2021. Data collected were soil temperatures after steam application, weed control, hand weeding times, diseased plant counts, pathogen populations in the soil, and crop yields. Post-steam soil temperature intervals >70 °C in the top 10 cm of the soil ranged from 67 to 176 minutes. Steam reduced weed densities by 64% to 100% and lowered hand weeding times by 23% to 91%. The reduction of S. minor sclerotia propagules after steaming was 69% to 95% compared with the no steam control. The percentage of lettuce plants infected with lettuce drop was reduced by 60% to 70% and the reduction of Pythium spp. propagules in the soil was reduced by 50% to 100% compared with the no steam control, respectively. Lettuce head diameters in steamed soils were 10% to 24% larger compared with the no steam control. Carrots grown in the steam-treated soil had a 10% greater root diameter than the no steam control. Steam increased lettuce yields in two of three trials 22% to 28% compared with the no steam control. Gross revenues for the steam-treated lettuce were $3231/ha higher than in the no steam control. The data suggest that band steam is a viable soil pest control treatment for vegetable crops.

Influence of Weed Control Techniques on Weeds, Yield, and Economics of Dry Direct-seeded-Drip-irrigated Rice under Philippine Conditions

The use of herbicides in combination with hand weeding has been shown to be effective against a variety of weeds in irrigated and rainfed wet direct-seeded rice in the Philippines. In the case of dry direct-seeded-drip-irrigated rice; however, these aspects are not known. A study was conducted to determine the influence of two weed control techniques on weeds, yield, and economics of dry direct-seeded-drip-irrigated rice under Philippine conditions. Four treatments – [T1] unweeded; [T2] application of pre-emergence herbicide using pretilachlor, followed by two times hand weeding; [T3] application of post-emergence herbicide using bispyribac-sodium, followed by two times hand weeding; and [T4] weed-free using the sequential application of pre- and post- emergence herbicides followed by six times hand weeding – were tested and arranged in RCBD with three repetitions. T1 has the highest weed density and biomass with lower grain yield (901.8 kg ha–1) but no net income. T2 and T3 had lower weed biomass than T1 but could not be compared with T4, where no weed density and biomass were recorded at 15, 30, and 45 DAS (days after seeding) in both dry and wet seasons. Grain yields at T2 (3,794.4 kg ha–1) were not significantly different from T3 (4,341.3 kg ha–1) except when compared with T4 (5,7245 kg ha–1). Net income in T2 was higher by PHP 20,575.1 over T1 and T3 by PHP 9,831.4 over T2. T4 had the highest grain yield among all treatments and achieved an advantage of PHP 45,272.1, 24,697.0, and 14,865.7 over T1, T2, and T3, respectively, in terms of net income. Herbicide application followed by hand weeding reduced weed growth and improved rice yield and net income. The combination of pre- and post-emergence herbicides followed by six times hand weeding was much more effective at suppressing weeds and achieving higher grain yield and net income.

Influence of Integrated Weed Management Practices on Yield and Yield Components of Chickpea in Southeastern of Ethiopia

The experiment was conducted on research field of Sinana Agricultural Research center and Goro sub site in the highlands of Bale, south eastern Ethiopia under rain fed conditions during main cropping season of 2018 and 2019 to evaluate the integrated effects of pre-emergence (Dual gold 960 EC), post emergence (Gallant super) herbicides and hand weeding frequencies on yield and yield components of chick pea. The experiment consisted of eight weed management options; sole dual gold 960 EC, dual gold 960 EC + one time hand weeding at two weeks after crop emergence, and dual gold 960 EC at four weeks after crop emergence, sole gallant super, gallant super and one time hand weeding, weedy check, one time hand weeding at two weeks after crop emergence and two times hand weeding at two and four weeks after crop emergence along with two varieties (Dhera and Habru) laid out in randomized complete block (RCBD) with three replications. Analysis of variance showed that a significant difference in number of branches per plant, biological yield (kg ha^-1), and grain yield (kg ha^-1) were observed on different herbicidal treatments and hand weeding at Sinana while at Goro significant effects of integrated weed management were observed on dry matter, plant height, biological yield, grain yield and harvest index. The remains parameters studied at both locations were no significant for the treatments studied. The highest net return obtained from the application of 1.5 lit ha^-1 dual gold 960 EC integrated with hand weeding at four weeks after crop emergence while the highest net return at Goro was obtained from two times hand weeding at two and four weeks after crop emergence and hence can be recommended for the end users. Moreover, similar experiments should be carried out in different cold and warmer regions of chickpea potential areas of the zone to confirm the present findings.

Weeding Frequency to Increase Productivity of Sorghum in Gumara -Maksegnit Watershed

In the Amhara region, Ethiopia, sorghum production took 655,671 hectares of land, of which North Gondar zone accounts for one-third of it, 204, 686 ha. But its productivity is low, around 1.9 tons per hectare. Sorghum production has so many constraints, insect pest, disease, and weed infestation are the most known among them. Farmers in the Northwestern Ethiopia, Gumara-maksegnit watershed have no weeding habit of their sorghum at the right time and frequency because they believe that weed-free crops at the early stage of the crop will be infested with stalk borer damage and after at the beginning of September they start to weed their land and used the weed as a feed for their animal. Therefore the objective of this study was to determine the weeding frequency of sorghum in Gumara-maksegnit watershed, North Western Ethiopia in order to increase its productivity. The experiment was conducted in the Gumara- maksegnit watershed for two cropping seasons (2014-2015) in the main season at three sites. The experimental design was arranged in a randomized complete block design with three replications. Treatments like weed-free, unweeded, and farmers practice treatments, hand weeding once, two times hand weeding, three times hand weeding, and Shelshalo were studied. According to the combined analysis of variance of the two-year data showed that weed-free treatments gave the highest yield (3314 kg/ha) followed by two times and three times hand weeding. However, there was no significant difference between weed-free and two times hand weeding. Therefore, two times hand weeding is recommended for Gondar Zuria and similar agroecological areas.

On-farm Evaluations of Wood-derived, Waste Paper, and Plastic Mulch Materials for Weed Control in Florida Container Nurseries

Mulches have been evaluated extensively as a weed management tool in container plant production, but most research has focused on loose-fill wood-derived mulch materials, such as pine bark or wood chips. In this experiment, pine (mixed Pinus sp.) bark (PB), shredded hardwood (HW), and pine sawdust were evaluated for weed control and crop response both alone and in combination with a guar gum tackifier alongside a plastic film mulch, a paper slurry mulch, and the paper slurry mulch + PB and compared with a nonmulched, nontreated control and a single application of preemergence herbicide (oxyfluorfen + pendimethalin). Mulch materials were applied to nursery containers ranging from 7 to 25 gal at two different nurseries and at two research centers in central Florida in 2017 and 2018. Results showed that the plastic mulch provided more than a 90% reduction in hand weeding time and weed weight over a 6-month period, and similar control was achieved with PB, paper slurry + PB, and the HW treatment (64% to 91% reduction in weeding time and weed weight). No growth differences were observed with any mulch treatment in any species evaluated including ligustrum (Ligustrum japonicum), Chinese elm (Ulmus parvifolia), or podocarpus (Podocarpus macrophyllum).

Crop signal markers facilitate crop detection and weed removal from lettuce and tomato by an intelligent cultivator

AbstractIncreasing weed control costs and limited herbicide options threaten vegetable crop profitability. Traditional interrow mechanical cultivation is very effective at removing weeds between crop rows. However, weed control within the crop rows is necessary to establish the crop and prevent yield loss. Currently, many vegetable crops require hand weeding to remove weeds within the row that remain after traditional cultivation and herbicide use. Intelligent cultivators have come into commercial use to remove intrarow weeds and reduce cost of hand weeding. Intelligent cultivators currently on the market such as the Robovator, use pattern recognition to detect the crop row. These cultivators do not differentiate crops and weeds and do not work well among high weed populations. One approach to differentiate weeds is to place a machine-detectable mark or signal on the crop (i.e., the crop has the mark and the weed does not), thereby facilitating weed/crop differentiation. Lettuce and tomato plants were marked with labels and topical markers, then cultivated with an intelligent cultivator programmed to identify the markers. Results from field trials in marked tomato and lettuce found that the intelligent cultivator removed 90% more weeds from tomato and 66% more weeds from lettuce than standard cultivators without reducing yields. Accurate crop and weed differentiation described here resulted in a 45% to 48% reduction in hand-weeding time per hectare.

Evaluation of post-emergence herbicides against major weed species in wheat in Bale highlands, South-eastern Ethiopia

A field experiment on weed control in wheat was conducted at Sinana agricultural research center and Robe area during the main bona season of 2016. Different post-emergence herbicides were evaluated together with the hand weeding and weedy check for weed control and yield and yield components of wheat. The experiment was laid out in randomized complete block design with three replications. Improved bread wheat variety ‘‘Mada walabu’’ with a seed rate of 150kgha -1 and different recommended agronomic practices was used in the experiment. The treatments consist of three post-emergence herbicides: Atlantis OD 37.5, Pallas 45 OD, and Topic plus and two times hand weeding and weedy check were used for comparison. The analysis result of the two locations showed that the yield and yield components of wheat were significantly responded to the applied treatments, except plant height, Biomass and HLW at Sinana on-station and plant height and spike length at Robe area. Maximum wheat grain yield was recorded (4622kgha -1 ) at Sinana on-station and (4645kgha-1) at Robe area in plots treated with Atlantis OD 37.5. The second maximum grain yield was recorded at both locations Sinana on-station and Robe area, 4311kgha -1 and 4289kgha -1 respectively, in plots treated with Pallas 45 OD. The third maximum grain yield at both locations was recorded in plots weeded twice. The lowest grain yield was recorded in weedy check plots at both locations Sinana on-station and Robe area, 2867kgha -1 and 2911kgha -1 respectively. The highest weed control efficacy at both locations for both grass and broad leaved weeds was recorded for Atlantis OD 37.5 followed by Pallas 45 OD. From one year result possible to conclude that if economically affordable and available Atlantis OD 37.5 is the best weed management option in wheat in Bale highlands.

Control Recommendations for Black Medic (Medicago lupulina) Based on Growth and Development in Competition with Strawberry

Strawberries are an important horticultural crop in Florida. Black medic is among the most problematic weeds within the production system. To better coordinate control measures, black medic growth and development while in competition with strawberry was studied. Twelve plants were randomly selected at each of four field sites in Hillsborough County, FL, in 2014. Plants were repeatedly measured over the growing season for stem length and number of primary branches, flower buds, flowers, and seed clusters. Growing degree days (GDD) were calculated (Tbase=0 C) starting from the hole-punch application of the plastic mulch (October 8, 2014, to October 10, 2014) from weather station data generated from the Florida Automated Weather Network. Strawberry height and width increased consistently across all sites, but black medic growth and development varied considerably. Strawberry suppressed black medic growth up to 1,805 cumulative GDD at three of four sites where black medic remained beneath the strawberry canopy. After 1,805 GDD, the black medic stems still remained below but experienced exponential growth for total stem length and, in turn, flower buds, inflorescence, and immature seed clusters. Ideal clopyralid spray timing based on susceptible plant size was 890 to 1,152 GDD. Optimal hand-weeding time frames would likely occur as the plant stems expand beyond the strawberry canopy (to improve visibility) and before flower production to prevent seed return to the seedbank. First seed production was observed at 1,200 GDD at the earliest site and between 1,966 to 2,365 GDD across all the other sites. Overall, consistent trends were observed across sites, but between-site variability was observed that could not be accounted for by differences in temperature.

Effect of different weed management practices on growth, yield and yield components of Faba bean (Vicia faba L.) in Bale highland conditions, Southeastern Ethiopia

Weed is the major production constraints for Faba bean production in Bale Highlands. Its management is quite important to increase the production and productivity of the crop. Due to such gaps, The experiment was conducted at two locations: Sinana (on-station and on farmers field) during 2015 and 2016 “ Bona ” main cropping seasons to evaluate the effect of hoeing plus hand weeding frequencies on the yield of faba bean. The treatments consisted of eleven weed management options: weedy check, Hand weeding at 25-30 days after emergence (DAE) and then at 40-45 DAE, Hoeing at 7 DAE + hand weeding at 25-30 and then 40-45 DAE, Hoeing at 7 DAE + hand weeding at 25-30 DAE, Hoeing at 7 DAE + hand weeding at 40-45 DAE, Hoeing at 14 DAE + hand weeding at 25-30 DAE and then at 40-45 DAE, Hoeing at 14 DAE + hand weeding at 25-30 DAE, Hoeing at 14 DAE + hand weeding at 40-45 DAE, Hoeing at 21 DAE + hand weeding at 40-45 DAE, Hoeing at 28 DAE + hand weeding at 40-45 DAE, Weed removal at 50% pod setting stage. It was laid out in a randomized complete block design (RCBD) with three replications. Results indicate that Faba bean plant was flowered and matured early when infested with weeds as compared to well weed controlled treatments at both sites. The growth and yield attributes of Faba bean were significantly reduced when the crop was left unweeded. The result also showed there was 41% and 35% yield reduction were occurred due to total weed infestation of Faba bean as compared to the recommended two times hand weeding at on-station and on-farm respectively. Hoeing at 7 DAE plus twice hand weeding gave a yield advantage of 51% and 17% as compared to weedy check and the recommended two times hand weeding at on-station. There was 51% and 41% yield penalty while farmers remove weed at 50% pod setting stage for the purpose of feeding their livestock as compared to hoeing at 7 DAE plus twice hand weeding and the recommended two times hand weeding at on-station. Similarly, there was a yield loss of 17% while weed removal at 50% pod setting stage as compared to the recommended two times hand weeding and hoeing at 28 DAE plus once hand weeding at 40-45 DAE at on-farm. Thus, it was concluded that the use of weed management options as of hoeing at 7 DAE plus hand weeding at 25-30 DAE was more economically profitable and has an acceptable marginal rate of return at both locations.

Efficacy of Pre-emergence Herbicides for the Control of Major Weeds in Maize (<i>Zea mays</i> L.) at Bako, Western Oromia, Ethiopia

A field experiment was conducted to evaluate efficacy of pre-emergence herbicides against major weeds in maize at Bako during the main rainy season of 2016/17. The trial was laid out in randomized complete block design (RCBD) with three replication, and consisted of five treatments including pre-emergence application of Lunar 537.5 SE at 3L/ha, Venus 500 SC at 6L/ha and Prima gram dual Gold 660sc at 3 L/ha, and two times hand weeding at 25 and 40 DAS and weedy check for comparison. Application treatments boosted maize grain yield over weedy check plots there by reducing weed infestation. Analysis of variance showed statistically significance difference (P < 0.01) for total weed density (m^-2) and dry weight (gm. ^-2). Significantly the minimum density (8.5 m^-2) was observed in plots treated two times hand weeding which was statistically similar with evaluated herbicides. In contrary, the highest (39.1 m^-2) was observed in weedy check plots. All the herbicide treatments provided significant control of weeds causing significant reduction in density of target weed flora and also significantly improved the grain yield in comparison with the weedy check. However, no crop injury was observed in any of the herbicide treatments. The maximum grain yield (57.57 qt ha^-1) was obtained from Lunar 537.5 SE at 3L/ha followed by two times hand weeding (57.08 qt ha^-1) and Venus 500 SC at 6L/ha (54.03 qt ha^-1) having the yield advantage of 67.92, 67.64 and 65.82 respectively, whereas; the minimum (18.47 qt ha^-1) was from weedy check plots. In general application pre-emergence herbicides effectively control weeds in maize and reduce yield losses. Thus, the newly tested pre-emergence herbicides (Lunar 537.5 SE at 3L/ha and Venus 500 SC at 6L/ha) alone could be option to major weeds and increase maize grain yield.

Intrarow Weed Removal in Broccoli and Transplanted Lettuce with an Intelligent Cultivator

The performance of the Robovator (F. Poulsen Engineering ApS, Hvals⊘, Denmark), a commercial robotic intrarow cultivator, was evaluated in direct-seeded broccoli and transplanted lettuce during 2014 and 2015 in Salinas, CA, and Yuma, AZ. The main objective was to evaluate the crop stand after cultivation, crop yield, and weed control efficacy of the Robovator compared with a standard cultivator. A second objective was to compare hand weeding time after cultivation within a complete integrated weed management (IWM) system. Herbicides were included as a component of the IWM system. The Robovator did not reduce crop stand or marketable yield compared with the standard cultivator. The Robovator removed 18 to 41% more weeds at moderate to high weed densities and reduced hand-weeding times by 20 to 45% compared with the standard cultivator. At low weed densities there was little difference between the cultivators in terms of weed control and hand-weeding times. The lower-hand weeding time with the Robovator treatments suggest that robotic intrarow cultivators can reduce dependency on hand weeding compared with standard cultivators. Technological advancements and price reductions of these types of machines will likely improve their weed removal efficacy and the long-term viability of IWM programs that will use them.

Effects of Preemergence Herbicides on Bell Pepper, Crop Injury, and Weed Management in Irrigated Chilean Fields

Bell pepper is an economically important vegetable crop that is often impaired by weeds. Management of weeds in bell pepper is required to minimize yield loss because this crop does not tolerate weed competition. Several herbicides have been reported as selective for bell pepper, but research supporting their use for weed control in this crop is limited. Several herbicides were screened in a greenhouse to assess effects on plant biomass, and eight were selected that appeared to be safe for bell pepper. These herbicides, in addition to oxadiargyl, were then evaluated at two different Chilean locations, using different application timings. We measured the effects on plant injury, fruit yield, and the need for additional hand weeding on transplanted bell peppers. The herbicides clomazone, napropamide, pendimethalin, andS-metolachlor caused minimal foliar chlorosis and necrosis but did not affect fruit yield at either location. Pretransplant-incorporated application (PTI) caused no effect on fruit yield from the herbicides evaluated, whereas applications 2 wk (POST2) and 8 wk (POST8) after transplanting reduced fruit yield significantly. For weed management, the best combination was PTI + POST2 + POST8, which reduced the hand-weeding time by 30% compared to the control, at both locations. Based on our results, clomazone, pendimethalin, andS-metolachlor were the most effective treatments applied after transplanting, whereas all herbicides tested were selective for bell pepper when applied and incorporated before transplanting. Results presented here provide new insight into herbicides that can be used to manage weeds in bell pepper and shows that timing of herbicide application is critical to prevent injury to this crop.

A prototype band-steaming machine: Design and field application

Soil steaming is a preventive non-chemical weed control method. We designed and studied a new prototype band-steaming machine. Tests were conducted during the growing cycle of organically cultivated carrot in real-field conditions, in order to study the effect of different steam doses on crops and a natural weed seedbank, throughout the whole growth cycle. The prototype has a 3265 MJ h −1 steam generator, which applies steam in 12 soil bands, 180 mm wide. The steam was mixed with the soil by mean of an apposite rotary cultivator. Four biological steam doses (0, 1.11, 1.59, and 2.78 kg m −2 ) were applied in combination with 4000 kg ha −1 of CaO prior to sowing the crop. Log-logistic models were used to describe the responses of temperatures, weed density, time required for hand weeding, weed dry biomass at harvest, and carrot yield to the band-steaming application. Based on the experimental data, an economic margin was evaluated to find the optimum application dose. Overall responses were influenced by steam dose. The results showed that a maximum temperature of 63 °C at a 25 mm depth was observed with a steam dose of 2.78 kg m −2 . With a 2.78 kg m −2 dose, the operative time was approximately 14 h ha −1 and total fuel consumption was 768 kg ha −1 . An estimated mean steam dose of 2.3 kg m −2 could be able to provide similar yield and hand weeding times responses to the highest steam dose applied, thus reducing both the operative time and fuel consumption of the machine.

Comparative Efficacy of White Mustard (Sinapis alba L.) and Soybean (Glycine max L. Merr.) Seed Meals as Bioherbicides in Organic Broccoli (Brassica oleracea Var. Botrytis) and Spinach (Spinacea oleracea) Production

White mustard and soybean seed meals were compared for weed control and yield of organically grown broccoli and spinach. The meals were incorporated into the soil 2 weeks before crop planting at two rates (1.24 and 4.48 t ha−1). Weed densities and hand-weeding time were recorded twice during the growing seasons and weed biomass was measured at crop harvest. Compared to the 1.24 t ha−1 soybean treatment, weed densities were 52 to 95% and 41 to 45% less at 3 and 6 weeks after planting, respectively, in both crops with the 4.48 t ha−1 white mustard seed meal treatment. Time required for hand weeding at these times was also reduced by up to 82% and 48%, respectively. Broccoli yield was similar in all the treatments, but spinach yield was greatest in the 4.48 t ha−1 treatments for both seed meals. Petiole nitrate and nutrient concentrations in both crops were generally similar in all the treatments.

The effect of the treatment weeds in some thickness plantcharacteristics of growth and production and its containers of sesame

Afield experiment had been performed in Zngura field /Ramdi/ ALAnbar at width line 38◦ North and length line 43◦ east in summer season in 2013. It is clay- garnet texture to know the effect of treatment on weeds and thickness plants in some characteristics of growth ,production and its containers of sesame The system of split spot had been used in performing the experiment according to randomizing complete blocks with three replications. The results are the three main blocks have three thickness of plants (D3,D2,D1) which led to(66667,80000,100000)plants.H-1 The secondary blocks have five treatments of weeds .They are once, twice and three times hand weeding for addition, tow comparative treatments ( weeds and absence of weeds). The results show the significant effects of the weeds treatments in characteristics that are still studied. Three times hand weeding (W4) led to dry weight weeds (40,6g) which increased the constriction percentage to( 93.27% )also the treatment for absence of weeds led to increased most of characteristics of growth and production and its containers which have no significant dereferences with( W4) treatments for three times hand weed . The effects are :the length of plant(164,172 c) .area of leaves ( 0.64 , 0.65 )m ,number of branches (7.83,848),numbers of capsules in every plant (244.8,300.2) .the whole production is( 24 82 , 2652 ) kg .H-1 for each treatments sequence. according to weeds treatment which record lest percentage for all these characteristics . Also the results record that no significant differences of plant thickness effects to decreased the dry weight of weeds and the constriction percentage which effects on most of plant characteristics of sesame and its production. The results record there are no differences in height of plant, the average of leave area , numbers of capsules in every plant , numbers of seeds in every capsule with, thousand seeds. So the thickness of plants(D2) records highest average numbers of branches (74) that effects on whole production which records the same thickness, the highest average is (1931kg) mixture between the three times (W4) and plant thickness (D3) record lest dry weight of weeds, so this mixture records (31.7 g), the treatment of twice hand weeding with plant thickness (D3) records the highest constriction percentage (%94.61) and this treatment isn’t significant different with the treatment of three times hand weeding with tow plants thickness (D2,D1) which is (%92.84,92.38)so this effects positively led to improve all characteristics of growth and production and its containers. we conclusion from this studying is that the treatment of three times hand weeding led to constriction of thickness of weeds and their dry weights which effects on improvement of characteristics of growth and production and its contianers.

Rolled–Crimped Winter Rye Cover Effects on Hand-Weeding Times and Fruit Yield and Quality of Cucurbits

Pesticide-free vegetables are in demand at farmers’ markets featuring locally grown products. Weeds often are deleterious in such crops, and managing them without herbicides is difficult. Stale seedbeds and rolled–crimped winter rye (Secale cereale L.) cover crops are nonchemical methods that may help manage weeds effectively. These methods were compared over two growing seasons as they affected fruit yield, fruit quality, and hand-weeding times in west-central Minnesota for transplanted cucumber (Cucumis sativus L.), pumpkin (Cucurbita pepo L.), and watermelon (Citrullus lanatus [Thunb.] Matsum. & Nakai). Cumulative hand-weeding times were 82–85 h·ha−1 in stale seedbed systems but 5–18 h·ha−1 in rolled–crimped rye mulch systems. Even without hand-weeding, cucumber yields and quality scores in rye mulch were similar to those in stale seedbeds augmented with preemergence herbicide and hand-weeded. Pumpkin yields were reduced by 25% in rye mulch systems, but quality was not affected. Watermelon had yield reductions up to 75% in rye mulch compared to stale seedbeds with weed control. Cucumber, pumpkin, and watermelon have high, moderate, and low potential, respectively, for herbicide-free production in rolled–crimped winter rye mulch in cold–temperate growing regions.

Interactive Effects of Hand Weeding, Tine and Sweep Cultivation for Weed Control in Organic Peanut Production

ABSTRACT Previous research has shown that mechanical cultivation is the most effective and affordable method of weed control in organic peanut production. However, growers are in need of more information on specific integrated cultivation regimes for effective season-long weed control with minimal hand-weeding requirements. Therefore, field trials were conducted in 2010–2012 to evaluate the effects of various tine and sweep cultivation treatments combined with or without hand-weeding on season-long weed control, stand establishment, and yield and grade of an organically-managed peanut crop. Tine cultivation treatments consisted of no cultivation or weekly cultivations for 5 wks after planting (WAP). Sweep treatments consisted of no cultivation, weekly cultivations (for 5 WAP), cultivations at 2 and 5 WAP only, or cultivation at 5 WAP only. Hand-weeding treatments were no hand-weeding or hand-weeding of the entire plot. There were numerous significant interactions among tine and sweep treatments on weed control. Initial weed species composition greatly affected cultivation effects on overall weed control. Tine cultivation was most effective at controlling annual grass weeds. Sweep cultivation was effective at reducing weeds (Amaranthus spp., southern crabgrass, and Florida pusley), but primarily when tine cultivation was absent. Hand-weeding significantly improved weed control for every weed species every year. Additionally, inclusion of certain cultivation regimes significantly reduced the hand-weeding time requirement over the control. However, cultivation treatments did not improve pod yield or grade in any year. The most significant benefit in cultivation from these data is in the reduction in hand-weeding requirements. Based on this research, a regime consisting of weekly tine cultivations for 5 WAP, combined with two timely sweep cultivations provided the best overall balance of weed control and minimization of hand-weeding. Hand-weeding is the most critical weed control method, followed by tine cultivation, and finally sweep cultivation, which primarily served as an aid in the event of missed tine cultivations or failure.