• Authors:
    • Cooke, F. T.,Jr.
    • Robinson, J. R. C.
    • Martin, S. W.
    • Parvin, D.
  • Source: Crop Management
  • Issue: April
  • Year: 2005
  • Summary: This study compared conventional, reduced tillage and no-till systems for cotton, maize, soyabean and sorghum in the Mississippi Delta. Most of the necessary parameters (e.g. yields, costs, equipment, field operations) were obtained from published budgets. The conventional systems typically involved subsoiling, discing, field cultivation, hipping and in-season cultivation. The reduced tillage systems substituted herbicides for heavy pre-plant soil preparation and in-season cultivation, while no-till systems substituted herbicides for all tillage operations. A whole-farm, mixed integer programming model was developed to determine the most profitable crop/tillage combinations at different acreage sizes, assess the actual economies of size (in dollars per acre) in row crop farming, determine the number of acres required to maximize economic viability, determine the best acreage size to minimize or optimize full-time labour, and evaluate profitability trade-offs, including farm programme eligibility, under different tillage systems.
  • Authors:
    • Van Acker, R. C.
    • Nazarko, O. M.
    • Entz, M. H.
  • Source: Canadian Journal of Plant Science
  • Volume: 85
  • Issue: 2
  • Year: 2005
  • Summary: There are many economic and health reasons for reducing pesticide use in Canada. Herbicide use on field crops is by far the most common pesticide use in Canada. This paper is a review of four topics related to herbicide use reduction on field crops in Canada: (1) broad strategies and (2) specific tactics for herbicide use reduction; (3) factors affecting adoption; and 4) research approaches for improving the implementation of herbicide use reduction. Numerous tactics exist to use herbicides more efficiently and herbicides can sometimes be replaced by non-chemical weed control methods. Many of these tactics and methods have been investigated and demonstrated for use on field crops in Canada. However, herbicide use reduction is fundamentally dependent upon preventative strategies designed to create robust cropping systems that maintain low weed densities. Diverse crop rotation forms the basis of preventative strategies as it inherently varies cropping system conditions to avoid weed adaptation. There is evidence that residual weed densities resulting from herbicide use reduction are manageable within competitive cropping systems. A great deal of research has been done on herbicide use reduction on field crops in Canada, and most projects report definite possibilities for herbicide use reduction in field crop production in Canada. Synthesizing and extending this information and customizing it for use on individual farms remain challenges. Collaboration between researchers and farmers can help to build successful strategies for herbicide use reduction which reflect the context of modem fanning, the will of farmers and the culture of technology adoption among farmers.
  • Authors:
    • Turkington, T. K.
    • Johnston, A. M.
    • Harker, K. N.
    • Clayton, G. W.
    • O'Donovan, J. T.
    • Kutcher, H. R.
    • Stevenson, F. C.
  • Source: Canadian Journal of Plant Science
  • Volume: 85
  • Issue: 1
  • Year: 2005
  • Summary: A field experiment was conducted at Lacombe and Beaverlodge, AB, and Melfort, SK, in 1999 and 2000 to evaluate the effect of seed placement and herbicide application timing on productivity of a general purpose (AC Lacombe) and hull-less (Falcon) barley (Hordeum vulgare L.) cultivars. Barley plant density was often less and dockage greater when seed was spread in a 20-cm band with 28-cm sweeps spaced 23 cm apart compared to seeding in distinct rows with hoe openers spaced 23 or 30 cm apart. Method of seed placement had little effect on barley grain yield or yield was significantly lower with the sweep compared to the distinct rows. Herbicide application timing effects were variable for barley grain yield. Grain yield was often greater and dockage less when herbicides were applied at the one- to two- or three- to four-leaf stage of barley compared to the five- to six-leaf stage. Method of seed placement did not influence barley responses to time of herbicide application with either cultivar. Barley silage yield was mainly higher with the distinct 23-cm row spacing than with the other seed placement methods. Herbicide application timing did not affect silage yield.
  • Authors:
    • Peterson, G. A.
    • Westfall, D. G.
    • Ortega, R. A.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 36
  • Issue: 19/20
  • Year: 2005
  • Summary: In the West Central Great Plains of the United States, no-till management has allowed for increased cropping intensity under dryland conditions. This, in turn, has affected the carbon (C) and nitrogen (N) mineralization dynamics of these systems. In this region, moisture stress increases from north to south due to an increase in evapotranspiration (ET), resulting in a climatic gradient that affects cropping system management. The objectives of this study were to determine the interaction of cropping system intensification and climatic gradient (ET) on C and N mineralization and to determine if the presence or absence of crop residue on the soil surface affects C and net N mineralization. Two cropping systems, winter wheat-fallow (WF) ( Triticum aestivium L.) and winter wheat-corn (sorghum)-millet-fallow (WCMF) [ Zea mays (L.), Sorghum bicolor (L.) Moench, Panicum milaceum (L.)] were studied at three locations across this aforementioned ET gradient. The treatments had been in place for 8 yrs prior to sampling in the study. These results showed that the more intense cropping system (WCMF) had a higher laboratory C mineralization rate at two of the three locations, which the study concluded resulted from larger residue biomass additions and larger quantities of surface residue and soil residue at these locations (Soil residue is defined as recognizable crop residue in the soil that is retained on a 0.6 mm screen). However, no differences in N mineralization occurred. This is most likely due to more N immobilization under WCMF as compared to WF. Presence or absence of crop residue on the surface of undisturbed soil cores during incubation affected potential C and net N mineralization more than either cropping system or location. Soil cores with the surface residue intact mineralized as much as 270% more C than the same soils where the surface crop residue had been removed. In laboratory studies evaluating the relative differences in cropping systems effects on C and N mineralization, the retention of crop residue on the soil surface may more accurately access the cropping system effects.
  • Authors:
    • Whitehead, W. F.
    • Sainju, U. M.
    • Singh, B. P.
  • Source: Plant and Soil
  • Volume: 273
  • Issue: 1-2
  • Year: 2005
  • Summary: Soil and crop management practices may influence biomass growth and yields of cotton (Gossypium hirsutum L.) and sorghum (Sorghum bicolor L.) and sequester significant amount of atmospheric CO, in plant biomass and underlying soil, thereby helping to mitigate the undesirable effects of global warming. This study examined the effects of three tillage practices [no-till (NT), strip till (ST), and chisel till (CT)],. four cover crops [legume (hairy vetch) (Vicia villosa Roth), nonlegume (rye) (Secale cereale L), hairy vetch/rye mixture, and winter weeds or no cover crop], and three N fertilization rates (0, 60-65, and 120-130 kg N ha(-1)) on the amount of C sequestered in cotton lint (lint + seed), sorghum grain. their stalks (stems + leaves) and roots, and underlying soil from 2000 to 2002 In central Georgia, USA. A field experiment was conducted on a Dothan sandy loam (fine-loamy, kaolinitic, thermic. Plinthic Kandiudults). In 2000, C accumulation in cotton lint was greater in NT with rye or vetch/rye mixture but in stalks, it was greater in ST with vetch or vetch/rye mixture than in CT with or without cover crops. Similarly, C accumulation in lint was greater in NT with 60 kg N ha(-1) but in stalks, it was greater in ST with 60 and 120 kg N ha(-1) than in CT with 0 kg N ha(-1). In 2001, C accumulation in sorghum grains and stalks was greater in vetch and vetch/rye mixture with or without N rate than in rye without N rate. In 2002, C accumulation in cotton lint was greater in CT with or without N rate but in stalks, it was greater in ST with 60 and 120 kg N ha(-1) than in NT with or without N rate. Total C accumulation in the above- and belowground biomass in cotton ranged from 1.7 to 5.6 Mg ha(-1) and in sorghum ranged from 3.4 to 7.2 Mg ha(-1). Carbon accumulation in cotton and sorghum roots ranged from 1 to 14% of the total C accumulation in above- and belowground biomass. In NT, soil organic C at 0-10 cm depth was greater in vetch with 0 kg N ha(-1) or in vetch/rye with 120-130 kg N ha(-1) than in weeds with 0 and 60 kg N ha(-1) but at 10-30 cm, it was greater in rye with 120-130 kg N ha(-1) than in weeds with or without rate. In ST, soil organic C at 0-10 cm was greater in rye with 120-130 kg N ha(-1) than in rye, vetch, vetch/rye and weeds with 0 and 60 kg N ha(-1). Soil organic C at 0-10 and 10-30 cm was also greater in NT and ST than in CT. Since 5 to 24% of C accumulation in lint and grain were harvested, C sequestered in cotton and sorghum stalks and roots can be significant in the terrestrial ecosystem and can significantly increase C storage in the soil if these residues are left after lint or grain harvest, thereby helping to mitigate the effects of global warming. Conservation tillage, such as ST, with hairy vetch/rye mixture cover crops and 6065 kg N ha(-1) can sustain C accumulation in cotton lint and sorghum grain and increase C storage soil compared with conventional tillage, such as CT, with no cover crop and N fertilization, thereby maintaining crop yields, improving soil quality, and reducing erosion.
  • Authors:
    • Wang, X. B.
    • Cai, D. X.
  • Source: Transactions of the Chinese Society of Agricultural Engineering
  • Volume: 21
  • Issue: 6
  • Year: 2005
  • Summary: Field experiments on surface soil mulch with emulsified bituminous materials and fertilizer management based on conservation tillage practices for spring maize were conducted in dry farmland of Shouyang in Shanxi Province (China), to determine the impacts of tillage, surface mulch with emulsified bituminous materials and fertilizer rate on soil temperature, soil water, and crop seedling emergence and yields, and to evaluate the integrated management of conservation tillage, emulsified bituminous mulch and fertilizer application in dry farming for promoting agricultural production. Compared with the conventional tillage methods, using emulsified bituminous mulch under no-tillage soils caused the increases of 0.5-2degreesC for surface temperature during the seedling stage, above 18% for the number of maize seedling emergence, approximately 5% for maize yields, 21 mm for the 0-200 cm soil moisture contents, and 12 mm for water use during the growing season. The study provides information for improving tillage-mulching-fertilizer application management of dry farming.
  • Authors:
    • Sturny, W. G.
    • Ramseier, L.
    • Chervet, A.
    • Tschannen, S.
  • Source: Revue Suisse d'Agriculture
  • Volume: 12
  • Issue: 5
  • Year: 2005
  • Summary: Over the last ten years, conventional plough tillage has been compared to no-tillage on six crop rotation plots in the long-term field trial Oberacker at the Inforama Ruetti in Zollikofen, Switzerland. The deep cambisol of the trial plots contains 15% clay and 3% organic matter. The absence of tillage operations in no-tillage makes a more complex strategy for weed control necessary. Options such as a balanced crop rotation, permanent soil cover, adapted crop residue management and immediate seeding of subsequent crops are used alongside chemical, mechanical, and thermal strategies of weed control. Land use is sustainable in the no-tillage system: No-tilled soil has a higher structural stability and load capacity while being markedly less prone to erosion; less machine usage and traffic reduce (fuel) costs. After seven years of no-tillage, continuous release of soil-borne nitrogen leads to crop yields and qualities at least equal to those obtained with conventional tillage. Two challenges remain only partly solved: (a) the greater dependence on herbicides such as glyphosate and (b) the greater risk of mycotoxin formation in no-tilled winter cereal crops that follow maize. Remedies include adaptations of the crop rotation, chopping of residual maize straw/stalks and cropping of cereal varieties less susceptible to fusarium. In conclusion, no-tillage contributes substantially to maintaining soil fertility on a long-term basis.
  • Authors:
    • Mehuys, G. R.
    • Madramootoo, C. A.
    • Burgess, M. S. E.
    • Mehdi, B. B.
    • Dam, R. F.
    • Callum, I. R.
  • Source: Soil & Tillage Research
  • Volume: 84
  • Issue: 1
  • Year: 2005
  • Summary: Different tillage and residue practices could potentially lead to significant differences in both crop production and soil properties, especially if both practices are implemented over a long time period and on continuous monoculture corn (Zea mays L.). The objective of this research was to determine how differing tillage practices and corn residues affected soil bulk density, corn emergence rates and crop yields over an 11-year period. The experimental site consisted of three tillage practices (no-till, NT; reduced tillage, RT; and conventional tillage, CT) and two residue practices (with grain corn residue, R; without residue (corn crop harvested for silage), NR). Bulk density was 10% higher in NT (1.37 Mg m(-3)) than in CT (1.23 Mg m(-3)), particularly at the 0-0.10 m depth. Spring corn emergence in NTR was slower by 14-63% than all other treatments in 1992-1994. In 1996, corn emergence in the NTR treatment was 18-30% slower, and NTNR was 5-30% faster than all other treatments. No-till with residue (NTR) possibly had the slowest overall emergence due to the higher surface residue cover (8.5 Mg ha(-1) in 1996) and higher bulk density (1.37 Mg m(-3) over the 11 years). Long-term mean dry matter corn yields were not affected by tillage and residue practices during the course of this study; rather climatic-related differences seemed to have a greater influence on the variation in dry matter yields. The long-term cropping of corn under different tillage and residue practices can change bulk density in the surface soil layer, vary the corn emergence without affecting yields, and produce comparable yields between all the tillage and residue practices. (C) 2004 Elsevier B.V. All rights reserved.
  • Authors:
    • Prado A., R. del
    • Diaz S., J.
    • Espinoza N., N.
  • Source: XVII Congreso de la Asociación Latinoamericana de Malezas (ALAM) I Congreso Iberoamericano de Ciencia de las Malezas, IV Congreso Nacional de Ciencia de Malezas, Matanzas, Cuba, 8 al 11 de noviembre del 2005, pp. 326
  • Year: 2005
  • Summary: Eight biotypes of herbicide-resistant weeds have been described in Chile. All belong to grass weeds, specifically wild oat ( Avena fatua), ryegrass ( Lolium rigidum), Italian ryegrass ( L. multiflorum) and crested dogtailgrass ( Cynosurus echinatus), which are the most common in the main wheat, barley, oats, lupin and canola producing area (36degreesS to 39degreesS). The biotypes have shown resistance to ACCasa, ALS and EPSP inhibitors. Most biotypes have appeared in farm fields subjected to intensive land use, with annual crops, with a trend to wheat monoculture in some cases, and with intense use of no-till and herbicides with similar mode of action. Herbicides most frequently used have been glyphosate (EPSP), diclofop-methyl and clodinafop-propargyl (ACCasa). Cross-resistance to ACCasa was found in some biotypes of wild oat and ryegrass, with greater resistance to aryloxyphenoxypropionates than to cyclohexanediones. All ACCasaresistant biotypes were susceptible to iodosulfuron and flucarbazone Na (ALS). These two herbicides are recommended for wheat and began to be used just recently in the country. Two biotypes of Italian ryegrass were found resistant to glyphosate. One of these biotypes showed, in addition, resistance to ALS; that is to say, showed multiple resistance. Also the crested dogtailgrass biotype showed multiple resistance to ACCasa and ALS.
  • Authors:
    • Sayre, K. D.
    • Govaerts, B.
    • Deckers, J.
  • Source: Field Crops Research
  • Volume: 94
  • Issue: 1
  • Year: 2005
  • Summary: Subtropical highlands of the world have been densely populated and intensively cropped. Agricultural sustainability problems resulting from soil erosion and fertility decline have arisen throughout this agro-ecological zone. This article considers practices that would sustain higher and stable yields for wheat and maize in such region. A long-term field experiment under rainfed conditions was started at El Batan, Mexico (2240 m a.s.l.; 19.31 degrees N, 98.50 degrees W;fine, mixed, thermic, Cumulic Haplustoll) in 1991. It included treatments varying in: (1) rotation (continuous maize (Zea mays) or wheat (Triticum aestivum) and the rotation of both); (2) tillage (conventional, zero and permanent beds); (3) crop residue management (full, partial or no retention). Small-scale maize and wheat farmers may expect yield improvements through zero tillage, appropriate rotations and retention of sufficient residues (average maize and wheat yield of 5285 and 5591 kg ha(-1)), compared to the common practices of heavy tillage before seeding, monocropping and crop residue removal (average maize and wheat yield of 3570 and 4414 kg ha(-1)). Leaving residue on the field is critical for zero tillage practices. However, it can take some time-roughly 5 years-before the benefits are evident. After that, zero tillage with residue retention resulted in higher and more stable yields than alternative management. Conventional tillage with or without residue incorporation resulted in intermediate yields. Zero tillage without residue drastically reduced yields, except in the case of continuous wheat which, although not high yielding, still performed better than the other treatments with zero tillage and residue removal. Zero tillage treatments with partial residue removal gave yields equivalent to treatments with full residue retention (average maize and wheat yield of 5868 and 5250 kg ha(-1)). There may be scope to remove part of the residues for fodder and still retain adequate amounts to provide the necessary ground cover. This could make the adoption of zero tillage more acceptable for the small-scale, subsistence farmer whose livelihood strategies include livestock as a key component. Raised-bed cultivation systems allow both dramatic reductions in tillage and opportunities to retain crop residues on the soil surface. Permanent bed treatments combined with rotation and residue retention yielded the same as the zero tillage treatments, with the advantage that more varied weeding and fertilizer application practices are possible. It is important small-scale farmers have access to, and are trained in the use of these technologies. (c) 2004 Elsevier B.V. All rights reserved.