Methods Of Seedbed Preparation Research Articles

Effect of Different Seedbed Preparation Methods on Potato Yields in Kabarole District, Uganda

Potato (Solanum tuberosum L) is one of the most important tuber crops produced in Uganda. However, the production and productivity of the crop are far below the world average due to poor crop seedbed preparation. An experiment for accessing the response of potato yields under different Seedbed preparation methods was conducted. Treatments consisted of two levels of seedbed preparation: Zero tillage and conventional tillage with and without NPK, laid out in Randomized Complete Block Design (RCBD) with three replications. Data was collected on growth parameters: average number of stems, estimated average plant height, estimated average plant width, and yield parameters: number of greened tubers, the weight of greened tubers, number of good tubers, and yield of potatoes. It was analysed using GenStat software. Results revealed that the proper seedbed preparation method was of paramount importance. Higher yields were observed in conventional tillage (14,744 Kg/ha) compared to zero-tillage (14,519 Kg/h). It was recommended that industrious seedbed preparation be encouraged among the farmers

Yields and weed management of sweet corn as influenced by seedbed preparation methods and wheat residues rates

One of the challenges to improve sweet corn [Zea mays var. Saccharata (Sturtev.) L. H. Bailey] production is finding a way to increase crop establishment and decrease weed infestation. Crop establishment and weed control are of prime importance in sweet corn production. Three methods of seedbed preparation including pre-planting irrigation before ridge-furrow preparation, pre-planting irrigation after ridge-furrow preparation and irrigation after planting, and four wheat (Triticum aestivum L.) residue rates (0, 250, 500 and 750 g/m2) were arranged in a split plot based on a randomized complete blocks design. Higher seedling emergence and weed control were significantly obtained in pre-planting irrigation than irrigation after planting treatments. Wheat residue mulching reduced soil moisture depletion, proline and soluble carbohydrates contents with decreasing weed biomass. The efficiency of weed management was found to be ensured using pre-planting irrigation coupled with wheat residues application. The grain yield was the highest (1433 g/m2) using pre-planting irrigation and wheat residue mulching (750 g/m2). Weed biomass decreased by 58% in pre-planting irrigation after ridge-furrow preparation and wheat residue mulching (750 g/m2) compared to irrigation after planting and no-mulching treatment. Therefore, pre-planting irrigation after ridge-furrow preparation and wheat residues application (500–750 g/m2) were optimal management practices for crop establishment and weed control to improve yields and water productivity of sweet corn in the region.

Weed Control Efficiencies, Grain Yield and Economics as Affected by Seedbed Preparation and Weed Management Practices in Central Terai, Nepal

Grain yield under dry direct seeded rice (DDSR) is primarily limited due to weeds. Therefore, a field experiment was conducted at Rampur, Chitwan during the monsoon season, of 2014. The treatments consisted of two methods of seedbed preparation in the main plot and six weed management methods in the sub-plot arranged in split plot design with four replications. Results revealed that the grain yield of dry-direct seeded rice did not vary due to seedbed preparation methods. However, weedy check treatments reduced more than 92.78 % of grain yield of dry-direct seeded rice compared to weed-free check. The herbicidal treatments were found to be superior for the benefit-cost ratio. Pendimethalin fb Bispyribac sodium recorded the highest net returns of NRs 68.73 thousand ha-1 and the benefit-cost ratio of 2.55. Sequential application of Pendimethalin followed by Bispyribac sodium was proved to be the most efficient weed management method for dry-direct seeded rice.

The Impact of the Renovation of Grassland on the Development of Segetal Weeds in Organic Farming

The intensive use or discontinuation of the use of swards can compromise biodiversity, yields, and feed quality; thus, leading to the degradation of permanent grasslands. Various methods of renovation are employed to restore the usability of degraded swards. In the years 2013–2016, a monofactorial field experiment was carried out on the Experimental Farm in Grabów (province of Mazowieckie, Poland). The experiment involved swards being reseeded after ploughing (P) and after disking with a compact harrow (H), with a non-renovated sward as the control treatment. The plots under renovation were reseeded with a lucerne–grass mixture. Both seedbed preparation methods for the renewed sward, ploughing (P) or shallow disking to a depth of 5 cm (H), were found to be effective for increasing sward yields, restricting weed growth, and reducing the number of weeds in the sward. The ploughing-based renovation method (P) had a strongly restrictive effect on biodiversity, as expressed by the H’ function value vis-à-vis the harrow method (H) and the non-renewed control (NR). Dicotyledonous species accounted for 92.3% of the weed population in the studied treatments. Of these, Taraxacum officinale, Achillea milefolium, Capsella bursa-pastoris, and Plantago maior occurred in the highest numbers.

Nutrient Availability and Nutrient Uptake by Crop and Weed as Influenced by Stale Seedbed, Mulching and Mechanical Weeding in Okra

Background: Weeds are the major biological constraint in okra due to its slow initial growth and wider row spacing. Due to severe crop weed competition, weeds removed considerable amount of nutrients from the soil. Competition exists between the crop and weed for nutrients results in nutrient deficiencies in crop. Hence the present experiment is formulated to assess the effect of stale seedbed, mulching and mechanical weeding on nutrient availability, nutrient uptake by crop and weed in okra. Methods: Experiment was conducted at Coconut Research Station, Balaramapuram, Thiruvananthapuram, Kerala during Rabi 2020-21. Design adopted for the study was RBD with two factors. The first factor was seedbed preparation (S) and the second factor was weed management (W). Stale seedbed (S1) and normal seedbed (S2) were the two different seedbed preparation methods and dried banana leaf mulch @10 t ha-1 alone (W1), dried banana leaf mulch @10 t ha-1 fb wheel hoe weeding at 30 and 45 DAS (W2), dried banana leaf mulch @10 t ha-1 fb hand weeding at 30 and 45 DAS (W3), wheel hoe weeding at 15, 30 and 45 DAS (W4), hand weeding at 15, 30 and 45 DAS (W5) and weedy check (W6) were the six different weed management options tried. Soil samples were collected after the harvest of the crop to determine the nutrient availability. Weed samples at 30 and 60 DAS and plant samples at harvest were analyzed to determine the NPK content and respective uptake of nutrients were calculated by multiplying the nutrient content with DMP. Result: Stale seedbed significantly enhanced the dry matter production and nutrient uptake by okra at harvest and lowered the nutrient removal by weeds at 30 and 60 DAS. Compared to non-stale, stale seedbed recorded significantly higher fruit yield. Among the weed management, wheel hoe weeding at 15, 30 and 45 DAS, recorded the lowest total weed dry weight at 30 and 60 DAS and resulted in the highest NPK uptake by crop and fruit yield. Uncontrolled weed growth resulted in a loss of 81.33, 18.16 and 50.84 kg N:P:K ha-1 at 30 DAS and 102.09, 57.90 and 55.31 kg N:P:K ha-1 at 60 DAS, respectively. Nutrient removal by weeds was the lowest in wheel hoe weeding at 15, 30 and 45 DAS and the highest in weedy check. It could be concluded that, wheel hoe weeding at 15, 30 and 45 DAS was the best option for the management of weeds, higher nutrient availability and uptake and yield in okra.

Effect Of Seedbed Preparation Methods And Herbicide Application On Yield And Economics Of Dry Direct-Seeded Rice At Parwanipur, Nepal

Field experiments were conducted during the 2016 and 2017 normal season (June-November) dry direct[1]seeded rice (DDSR) at RARS Parwanipur to assess the effect of various combinations of herbicides mixture under seedbed preparation to evaluate different attributes of weed control efficiencies (WCE) coupled with grain yield and economics of DDSR. The experiment was laid out in two factors factorial strip plot design with four replications. Treatments consisted of nine levels of weed management practices that include weed free, weedy check, Pendimethalin, Bispyribac sodium, Ethoxysulfuron, Pendimethalin followed by (fb) Bispyribac sodium, Pendimethalin fb Ethoxysulfuron, Bispyribac sodium tank mix with Ethoxysulfuron and Pendimethalin fb tank mixture of Bispyribac sodium and Ethoxysulfuron as horizontal factor whereas two levels of seedbed preparation methods (stale seedbed and normal seedbed) as the vertical factor. The result of the experiments revealed lower weed intensity (WI) and higher weed control efficiency (WCE), net return and benefit-cost (B:C) ratio with Pendimethalin fb tank mixture of Bispyribac sodium and Ethoxysulfuron in both the years 2016 and 2017. Grain yield was significantly higher with weed free treatment followed by Pendimethalin fb tank mixture of Bispyribac sodium and Ethoxysulfuron in both the years due to higher WCE and lower WI which resulted in better growth and development of DDSR. Therefore, the Pendimethalin fb tank mixture of Bispyribac sodium and Ethoxysulfuron is a better option for DDSR under Parwanipur condition during main season rice DDSR rice production.

Lignocellulosic Biomass Production and Persistence of Perennial Grass Species Grown in Mediterranean Marginal Lands

Biomass production in marginal lands represents one of the most challenging and promising alternatives to sustainably produce biofuels. Native species seem to be the most adequate option to obtain a profitable output when low-input techniques are applied, and biomass is grown in depleted soils and harsh climatic conditions. In this study, a 5-year field trial in the island of Majorca served to investigate different autochthonous and naturalized Mediterranean perennial grasses as novel candidate lignocellulosic bioenergy crops for the semi-arid Mediterranean area and compare them with commercial ones (both Mediterranean and non-Mediterranean). Species and growing season had a significant effect on biomass production, perennialism and biomass quality. Arundo donax (winter crops) and Piptatherum miliaceum (autumn crops) performed better than the commercial species tested (Panicum virgatum for winter crops and Festuca arundinacea for autumn crops) in biomass production and perennialism. In terms of biomass quality, Panicum virgatum was the best species, having high structural content (mainly cellulose and hemicellulose), low non-structural content and the lowest ash. However, Ampelodesmos mauritanicus and Arundo donax rendered similar results, with no significant difference in terms of cellulose production for this latter but with higher lignin content. For the autumn species, Festuca arundinacea was the species with the best biomass quality but with the highest ash production for all the species considered. Hence, both for winter or autumn regimes, native or naturalized plants seem to be better suited than the commercial commonly used for biomass production with energy-producing purposes. Further research must be conducted in terms of seed biology and physiology, seedbed preparation methods, sowing time, seedling density and weed control before they can firmly be proposed as adequate alternatives for energy purposes.

Weed density and productivity of dry direct seeded rice in relation to weed management practices and seedbed preparation methods

Effective weed management practice is important for successful dry direct seeded rice (DDSR) cultivation. Field experiments were conducted during rainy seasons of 2016 and 2017 to assess the effect of herbicides, or herbicides mixture, and seedbeds preparation methods on weed density and grain yield of DDSR. The experiments were done by using two factors factorial strip plot design with four replications. The treatments consisted of nine weed management practices (weed free; weedy check; spraying Pendimethalin; Bispyribac sodium; Ethoxysulfuron; Pendimethalin followed by Bispyribac sodium; Pendimethalin followed by Ethoxysulfuron; Bispyribac sodium tank mix with Ethoxysulfuron, and Pendimethalin followed by Bispyribac sodium tank mix with Ethoxysulfuron) as horizontal factor whereas two seedbed preparation methods (stale, and normal seedbed) were considered as the vertical factor. The data were collected and analyzed using MSTAT-C statistical software. Total density and dry matter of weeds were significantly (p<0.05) lower in weed free treatment followed by Pendimethalin spray and Bispyribac sodium tank mix with Ethoxysulfuron spray at all the growth stages of rice in both the years. Similarly, rice grain yield was significantly higher (p<0.05) in weed free treatment followed by Pendimethalin spray and Bispyribac sodium tank mix with Ethoxysulfuron spray in both the years. Effect of seedbed preparation methods on weed density and dry matter, yield attributes and yield of rice were non-significant. Therefore, Pendimethalin spray followed by Bispyribac sodium tank mix with Ethoxysulfuron spray seems better option for managing weeds in DDSR.

Effects of crop residue mulch and seedbed preparation methods on soil properties and rainfed groundnut production in Alfisols of semi‐arid India

AbstractDecreased frequency but greater intensity of rainfall in semi‐arid India severely affects growth and the yield of rainfed annual food crops, where there is no other source of water, leading to moisture stress during protracted dry spells. As Indian farmers growing rainfed crops are small landholders, their better option is in situ rainwater harvesting. This ensures moisture storage and increases soil moisture available to rainfed crops with less‐costly investment. Accordingly, a field investigation was established over 2011, 2012 and 2013 at the Dryland Agricultural Research Station, Chettinad, India. We studied the effects of seedbed preparation method (SBPM) and mulching with crop residues (CRM) on soil physicochemical properties, growth, yield and yield attributes of groundnut. Greater soil moisture content was measured under compartmental bunding (CB) and raised bed (RB) with CRM than under flatbed (FB). Soil bulk density was considerably smaller under CB and RB with CRM (1.36 and 1.37 Mg m−3) compared with FB (1.39 Mg m−3). Soil microbial biomass carbon (SMBC) was larger under CB and RB with CRM (563 and 542 mg kg−1 soil, respectively) than FB with and without CRM. RB with CRM application contained more soil organic carbon (SOC) stock (3.1 Mg ha−1) than FB. CB with CRM resulted in larger groundnut yield (1,604 kg ha−1) and rainwater use efficiency (5.8 kg ha−1 mm−1) than the FB with and without CRM; RB and RF with CRM were intermediate. The ideal seedbed preparation for groundnut crop in Alfisol under semi‐arid conditions was compartmental bunding (CB) and raised bed (RB) along with CRM.

Trials Evaluating Solarization and Tarping for Improved Stale Seedbed Preparation in the Northeast USA

Stale seedbeds are commonly used by organic vegetable farmers to reduce in-season weed density. The primary purpose of this study was to evaluate the efficacy of soil solarization (clear plastic) with subsequent flaming for stale seedbed preparation. A secondary objective was to compare the efficacy of solarization with tarping (black plastic). Solarization is an established weed management practice in warmer climates, but its efficacy in the humid continental Northeast USA was unknown. We hypothesized that solarization during May-June in Maine, USA would increase weed emergence, and could thereby contribute to depletion of the germinable weed seedbank and, with subsequent flaming, creation of an improved stale seedbed. We expected that firming soil with a roller prior to solarization would further increase weed emergence. Across four site-years of replicated field experiments and two on-farm trials we found that, contrary to expectations, 2 weeks of solarization reduced apparent weed emergence (density) in comparison to nonsolarized controls by 83% during treatment, and 78% after 2 weeks of observation following plastic removal and flaming. Rolling did not significantly affect weed density. Soil temperatures were elevated in solarized plots, reaching a maximum of 47◦ C at 5 cm soil depth, compared to 38◦ C in controls. Weed community analyses suggested that solarization might act as an ecological filter limiting some species. Addressing our secondary objective, two replicated field experiments compared the efficacy of solarization with tarping applied for periods of 2, 4, and 6 weeks beginning in July. Across treatment durations, solarization was more effective than tarping in one site-year, but tarping outperformed solarization in the other; this discrepancy may be explained by differences in weed species and soil temperatures between experiments. Overall, solarization and tarping are promising stale seedbed preparation methods for humid continental climates, but more work is needed to compare their relative efficacy.

Pollinator Habitat Establishment after Organic and No-till Seedbed Preparation Methods

Establishing on-farm pollinator habitat can mitigate native pollinator and pollination ecosystem service declines, and federal programs are available to provide technical and financial assistance to farmers interested in habitat installation. Although sufficient seedbed preparation to limit weed competition is thought to be the most important step toward achieving good pollinator habitat establishment, preparation recommendations vary and studies have not investigated seedbed preparation techniques in the context of the U.S. Department of Agriculture (USDA) Farm Bill programs for pollinator conservation. To address this, we assessed the effects of two seedbed preparation methods, conventional inversion tillage and no-till with herbicide, on wildflower establishment and weed competition during the first year after planting. Experiments were conducted in Blacksburg, VA, and were replicated in 2015 and 2016. In addition, we tracked seedbed preparation methods and pollinator habitat establishment on seven farms located on the Eastern Shore of Virginia and Maryland in 2016. The wildflower mix consisted of nine species of forbs and two species of grasses: the forbs were black-eyed Susan (Rudbeckia hirta L.), partridge pea [Chamaecrista fasciculata (Michx.) Greene], plains coreopsis (Coreopsis tinctoria Nutt.), lanceleaf coreopsis (Coreopsis lanceolata L.), purple coneflower [Echinacea purpurea (L.) Moench], narrowleaf mountain mint (Pycnanthemum tenuifolium Schrad.), wild bergamot (Monarda fistulosa L.), Maximilian sunflower (Helianthus maximiliani Schrad.), and showy tickseed [Bidens aristosa (Michx.) Britton] or Indian blanket (Gaillardia pulchella Foug.); the grasses were splitbeard bluestem (Andropogon ternarius Michx.) and little bluestem [Schizachyrium scoparium (Michx.) Nash]. In the experiments, wildflower establishment was greater after no-till with herbicide than after tillage preparation (2015: P = 0.09; 2016: P = 0.002). Predominating weed species varied by study, with more common lambsquarters (Chenopodium album L.) and hairy galinsoga [Galinsoga ciliata (Raf.) S.F. Blake] growth after tillage treatments, and more hairy vetch (Vicia villosa Roth) growth after no-till preparation. On-farm pollinator habitat establishment on the Eastern Shore was highly variable, but more wildflower forbs established after tillage-plus-herbicide than tillage-only seedbed preparations (P = 0.01). Across sites, we found a large degree of site-specific variation in wildflower establishment and predominant weed species.

Switchgrass Stand Density and Yield as Influenced by Seedbed Preparation Methods in a Sandy Loam Soil

Successful establishment of switchgrass (Panicum virgatum L.) remains a challenge. It is reported that increasing seed-soil contact using a roller could improve switchgrass establishment in silt-loam soils. However, use of rollers is not common among growers and operating them could be difficult. The objective of this study was to assess whether rolling could improve switchgrass stand establishment in sandy-loam soils by increasing seed-soil contact through compacting the soil, and to evaluate the use of cultipacker as a more user-friendly alternative to roller. An experiment was conducted in 2012 and repeated in the 2013 growing season at the University of Massachusetts Agricultural Experiment Station farm in Deerfield. The soil type at the experimental site was Hadley fine sandy loam (nonacid, mesic Typic Udifluvent). The experimental design was a randomized complete block design with four replicates. There were eight treatments including disking-planting (D-P), disking-cultipacking-planting (D-C-P), disking-cultipacking-planting-cultipacking (D-C-P-C), disking-cultipacking-planting-cultipacking-cultipacking (D-C-P-C-C), disking-rolling-planting (D-R-P), disking-rolling-planting-rolling (D-R-P-R), disking-rolling-planting-rolling-rolling (D-R-P-R-R), and disking-rolling-planting-rolling-rolling-rolling (D-R-P-R-R-R). Tiller density was influenced rolling and cultipacking frequency but not by the compaction equipment. Tiller density increased by cultipacking or rolling the soil once (D-C-P-C; D-R-P-R) and two times after planting (D-C-P-C-C; D-R-P-R-R). Disking-planting had the lowest tiller density with 188 and 110 plants (m−2) in 2012 and 2013 growing seasons, respectively. Similar to tiller density, biomass yield was not influenced by compaction equipment but by compaction frequency. Higher biomass yield was obtained from soils that were firmed once before and at least once after planting (D-C-P-C; D-R-P-R) compared with seedbed firming only once before planting (D-C-P; D-R-P). In a dry season (2012), a twofold yield increase (1.06 Mg ha−1) was obtained from D-C-P-C compared with D-C-P (0.55 Mg ha−1). However, two times rolling (D-R-P-R-R-) or cultipacking (D-C-P-C-C) after planting was needed in 2013 to increase the yield compared with D-C-P by 41 %. Our results indicated that using cultipacker as an alternative to roller can be a solution to improve switchgrass establishment. We conclude that D-C-P-C-C could ensure switchgrass establishment and improve switchgrass biomass production in the establishment year in a sandy-loam soil.

English

An on-station study at Fumesua and Ejura in Ghana with two yam varieties (Pona and Dente), seedbed option (ridge and mound) and NPK fertilizer rates (0, 45-45-60, 60-60-60 and 60-60-80 kg ha-1 N-P205-K20) revealed significant (p < 0.05) increases in soil carbon and phosphorus with fertilizer application to yam. Fertilized yam had acceptable culinary qualities. Another study on staking options using a promising non-staked yam line TDR95/19177 showed that non-staked yam resulted in a high (32.5%) yield reduction, suggesting the need for further plant breeding work. On–farm studies showed significant (P £ 0.05) interaction between fertilizer rate and seedbed preparation method on continuously cropped lands, with mechanised and manual ridging having significantly (p < 0.05) higher yam plant population (5,503-7,483 plants ha-1) than farmers’ mounding (4,219-4,579 plants ha-1), and a greater yield response to fertilizer. Benefit Cost Ratio (BCR) was highest (2.7:1) when 45-45-60 kg ha-1 N-P205-K20 was applied to yam on ridges. On newly cleared fields, yam planted on ridges with trellis/minimum staking gave highest tuber yields and BCR of 3.8:1. Mechanised ridging for yam seedbed preparation fertilizer application and the significant reduction in the use of stakes will reduce drudgery and the contribution of yam production to deforestation and climate change.   Key words: Continuously cropped fields, ridging, staking, yam.

Seedbed Preparation Techniques and Weed Control Strategies for Strip‐Planting Rhizoma Peanut into Warm‐Season Grass Pastures

ABSTRACTPlanting rhizoma peanut (Arachis glabrata Benth.; RP) in strips into bahiagrass (Paspalum notatum Flüggé) pastures can reduce establishment cost relative to conventional techniques, but research is needed to determine the best seedbed preparation methods. The objectives were to quantify the effects of four seedbed preparation techniques: glyphosate + tillage, tillage only, glyphosate + no‐till, and sod removal; and four postemergence weed control strategies: control (no herbicides, no mowing), mowing (every 28 d to 10‐cm stubble height), imazapic (0.29 L ha–1), and imazapic + 2,4‐D amine (0.29 and 0.58 L ha–1, respectively). Sprout emergence ranged from 90 to 119 m2 in treatments where tillage occurred compared with 54 to 58 m–2 in no‐till and sod removal. Nevertheless, by season end RP canopy cover and frequency of occurrence favored no‐till (21% cover and 70% frequency) compared with the other treatments (≤14% cover and 53% frequency). Weed control strategy after planting had a greater effect on establishment success than seedbed preparation. By season end, RP cover and frequency were greater for imazapic (25 and 64%, respectively) and imazapic + 2,4‐D (23 and 64%, respectively) than for the control (10 and 42%, respectively) and mowing treatments (7 and 36%, respectively). Glyphosate followed by no‐till planting and postemergence use of imazapic with or without 2,4‐D is a viable option for reduced‐cost establishment of RP in strips into bahiagrass pastures.

Effect of different methods of seedbed preparation on irrigated canola yield after corn in North West Iran

One of the major problems that farmers in the Northwest of Iran contend with after the corn harvest for mechanized cultivation of canola is lack of time and soil moisture over prepared seedbed. Consequently, the effects of five different seedbed preparation methods were analyzed, namely; T1: moldboard plows (conventional tillage), T2: stalk shredder followed by chisel and disk, T3: stalk shredder followed by double-disc, T4: chisel followed by disk and T5: two heavy disk tillage using a randomized complete block design (RCBD) with four replications. Results showed that the soil bulk density in the 0 to 10 cm layer had nosignificant effect, but the 10 to 20 cm depth was significantly higher than the conventional tillage. However,penetration resistance in 10 to 30 cm under T5 was significantly higher than others. Thus, comparison of the soil bulk density, penetration resistance, and plant establishment showed that reduced tillage in canola seedbed preparation was effective. Besides, the surveys indicated that there was significant difference between mean weight diameter (MWD) after primary and secondary tillage and the MWD’s under T2, T3 and T5 were 1.18, 1.01 and 1.22, respectively lower than T1 with 2.06. Maximum plant height and grain yield were obtained under T2, 117.12 cm and 2941.50 kg ha-1, respectively. Therefore, T2 was recommended as the time limitation on rapeseed bed preparation after corn, due to higher speed of operation and lower cost. Key words: Corn residues, cone index, reduce tillage and yield of canola.

Ridging, a Mechanized Alternative to Mounding for Yam and Cassava Production

A cassava seedbed preparation field study was established at Fumesua in the forest and Ejura in the forest-savanna transition agroecologies of Ghana in 2004/2005. The experimental design was split plot with three seed bed preparation methods as the main plots and three nitrogen rates as sub plots, with basal application of 45-90 kg ha-1 P205 - K20 on the fertilized plots. A similar study was conducted on yam seedbed preparation in 2003/2004, with a 23 factorial design. Cassava and yams on ridges resulted in highest root and tuber yields, on both Lixisols in the coastal and forest-savanna transition and Acrisols in the forest agro-ecologies. However, yam tuber yield on mounds was not statistically different from yields on ridges. Number of roots per plant was identified as a major contributory factor to the yield increase of cassava on ridges. Seed bed preparation method was, however, not an important determinant of cassava root yield at high rates of fertilizer application of 90-45-90 kg ha-1 N-P205-K20. Planting on mounds resulted in slender, cylindrically shaped cassava roots and yam tubers, while ridging produced oblong shaped roots and tubers. Weeding and fertilizer application were easier on manual ridging than on manual mounds. The study points to ridging as a potential option to mounding for cassava and yam production, with the feasibility of mechanization of ridges to reduce drudgery associated with roots and tuber crop production in the West African sub-region.

(157) Weed Control in Organic Edamame Soybean Production

Weed control is a major challenge confronting growers transitioning to organic vegetable production. Organic standards require that growers manage weeds without synthetic herbicides while maintaining or enhancing soil quality. In 2005, we evaluated the effects of two seedbed preparation methods and six weed management tactics, compatible with organic standards, on soil quality indicators, weed pressure, and yield of edamame soybean [Glycine max (L.) Merrill]. Seedbed preparation was conducted with either a moldboard plow and roto-tiller or a spading machine. Weeds were managed by a) regular hand weeding, b) pre-emergent flaming, c) post-emergent incorporation of 100 g of corn gluten meal/m2, or weekly passes from crop emergence until row closure with d) a spring-tine weeder, e) a rolling cultivator, or f) a between-row flame weeder. Dominant weeds were smooth pigweed [Amaranthus hybridus (L.)], goosegrass [Eleusine indica (L.) Gaertn.], and giant crabgrass [Digitaria sanguinalis (L.) Scop.]. Smooth pigweed dominated in the corn gluten meal and spring-tine weeder treatments; goosegrass and giant crabgrass dominated in the two flamed treatments. Weed pressure was lowest, and crop yield highest, in the hand-weeded control and rolling cultivator treatments. Relative to these, crop yield was severely depressed by weed pressure in other treatments. The labile carbon concentration and enzymatic activity of soils was tested midseason, and at harvest, showed no significant treatment effects. Results suggest that the rolling cultivator offered the best weed control among the tactics tested, without adversely affecting soil quality.

Tillage and Phosphorus Management Effects on Crop Production in Soils with Phosphorus Stratification

Reduced‐ and no‐tillage seedbed preparation methods coupled with broadcast P applications lead to an accumulation of available P in the surface 0‐ to 5‐cm soil layer and a depletion of available P deeper in the profile. A 3‐yr study determined the effects of tillage and fertilizer P management on P uptake and grain yield for P‐stratified soils. Tillage practices were moldboard plow (once at the start of the study followed by reduced tillage), reduced tillage (disk followed by field cultivation), and no‐tillage. Four P management methods were imposed: (i) no P; (ii) 20 kg P ha−1 applied as a surface broadcast; (iii) 20 kg ha−1 applied as a banded starter, 5 cm to the side and 5 cm below the seed; or (iv) 20 kg ha−1 applied in a deep placed band, 13 to 15 cm on 0.7‐m centers. The one‐time moldboard plowing produced higher early season dry matter yields for corn (Zea mays L.), wheat (Triticum aestivum L.), and soybean [Glycine max (L.) Merr.] compared with the no‐tillage system, but tillage effects on final grain yield were inconsistent. Subsurface placement of P generally increased P uptake and grain yield of corn and sorghum [Sorghum bicolor (L.) Moench], but had little effect on grain yield of soybean. Results indicate that subsurface applications of P fertilizers should be considered if soil test P is highly stratified within the surface 0‐ to 15‐cm layer and the 15‐cm composite is medium or below for available P.

Weed seedbank response to planted fallow and tillage in southwest Nigeria

Planted fallows are an alternative to the unsustainable bush fallow for improved soil and weed management in the tropics. However, the interactive effects of planted fallows and tillage on the weed seedbank are not well documented in the tropical environment. The effect of fallow type and tillage on the weed seedbank in the soil was assessed in 1995 and 1996 at Ibadan, southwest Nigeria. The planted fallow species consisted of a herbaceous legume (Pueraria phaseoloides) and three woody legumes (Acacia auriculiformis, Leucaena leucocephala, and Senna siamea). Natural bush fallow and continuous cassava/maize plots were controls. Tillage treatments were minimum tillage and mounding. Continuous maize/cassava plots had the largest weed seedbank in both years. After six years of continuous fallow, the weed seedbank was 86% lower in A. auriculiformis, 79% in P. phaseoloides, 68% in S. siamea, 53% in L. leucocephala, and 35% in natural bush fallow plots than in continuously cultivated plots. Compared to minimum tillage, mounding reduced the seedbank by 47% in 1995 and 66% in 1996. Redundancy analysis showed that tillage contributed significantly to the variance in species composition. Euphorbia hyssopifolia, E. heterophylla, and Cynodon dactylon showed no preference in terms of tillage. Perennial and annual grasses (Digitaria horizontalis, Eleusine indica, Paspalum orbiculare, Cynodon dactylon) with Cyathula prostrata and Desmodium scorpiurus, an annual and perennial broadleaf, respectively, were most abundant in the seedbank of continuously cultivated plots. There were more annual broadleaf weeds in the seedbank of planted fallow plots than in the control plots. Species diversity of the seedbank was greatest in plots under minimum tillage. Mounding as a seedbed preparation method, especially within the improved fallow system, could reduce the high weed pressure experienced by smallholder farmers in southwest Nigeria.

Comparison of Sugar Beet Cropping Systems with Dead and Living Mulch using a Glyphosate‐resistant Hybrid

AbstractThe aim of this study was to evaluate new options for sugar beet mulch systems, using a glyphosate‐resistant hybrid. In four field trials – conducted in 2002 and 2003 at two sites in a major sugar beet‐growing region in the central Germany – three different mulch systems (straw, non‐winterhardy and winterhardy cover crop) and an alternative seedbed preparation method (rotary band tillage) have been tested in comparison with a control treatment (plough, no mulch, broadcast seedbed preparation) representing the common German practice. In all systems, a set of eight different weed control programmes, including two reference treatments, one with selective conventional herbicides and five exclusively using glyphosate, has been evaluated for efficacy. It could be shown that the integration of winterhardy cover crops into sugar beet mulch systems reduced the risk of nitrogen loss by leaching. The changes in the nitrogen dynamics neither influence the yield nor the technical quality of the sugar beet. The field emergence of sugar beet decreased while using a winterhardy cover crop, but was not altered by the seedbed preparation method. Compared with the conventional broadcast seedbed preparation, the rotary band tillage did reduce the weed density. The lowest weed density was observed in the straw mulch system. It was not possible to control the remaining plants of the winterhardy cover crops completely with selective herbicides. If glyphosate was used until the four‐leaf stage of the sugar beet, a regulation of the winterhardy cover crop was achievable. With glyphosate it was also feasible to control older weeds together with the newly emerging ones with post‐emergence applications only. For most of the mulch systems tested, the sugar beet was very sensitive to weed competition between the four‐ and 10‐leaf stage. If the weeds within the sugar beet rows were controlled during this sensitive period with an early glyphosate band application, the remaining weeds between the rows could be left uncontrolled until the 10‐leaf stage of the sugar beet without any yield loss. Only in the combination of winterhardy cover crop × rotary band seedbed preparation, the weeds and cover crop had to be controlled directly after emergence of the sugar beet.