19802015
  • Authors:
    • Licht, M. A.
    • Yin, X.
    • Al-Kaisi, M. M.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 105
  • Issue: 4
  • Year: 2005
  • Summary: Soil organic C (SOC) and total N (TN) contents play a crucial role in sustaining agricultural production systems. Short-term (<=10-year) management effects on SOC and TN dynamics are often complex and variable. Three experiments were conducted to evaluate short-term tillage and cropping system effects on SOC and TN within the 0-30 cm soil depth across Iowa. The first experiment with no-tillage and chisel plowing treatments was established in 1994 on Clarion-Nicollet-Webster (CNW), Galva-Primghar-Sac (GPS), Kenyon-Floyd-Clyde (KFC), Marshall (M), and Otley-Mahaska-Taintor (OMT) soil associations under a corn (Zea mays L.)-soybean (Glycine max (L.) Merr.) rotation. The second experiment with no-tillage, strip-tillage, chisel plowing, deep ripping, and moldboard plowing treatments was initiated in 1998 on the CNW soil association in a corn-soybean rotation. The third experiment consisting of smooth bromegrass (Bromus inermis Leyss.), switchgrass (Panicum virgatum L.) and corn-soybean-alfalfa (Medicago sativa L.) treatments was established in 1991 on Monona-Ida-Hamburg (MIH) soil association under no-tillage management. Short-term tillage effects on SOC and TN occurred primarily at the 0-15 cm soil depth. Tillage effects did not vary significantly with soil association. No-tillage resulted in greater SOC and TN contents than chisel plowing at the end of 7 years of tillage practices averaged over the CNW, GPS, KFC, M, and OMT soil associations. The increase in SOC and TN with no-tillage was not related to SOC and TN stratification in the soil profile or annual C and N inputs from crop residue, but most likely due to decreased mineralization rate of soil organic matter. However, tillage effects on SOC and TN were negligible at the end of only 3 years of tillage practices on the CNW soil association. Smooth bromegrass and switchgrass systems resulted in greater SOC and TN contents at both 0-15 cm and 15-30 cm soil depths than a corn-soybean-alfalfa rotation after 10 years of management on the MIH soil association. Smooth bromegrass and switchgrass systems increased SOC by 2.3 and 1.2 Mg ha-1 yr-1 at the 0-15 cm soil depth, respectively. We conclude from these short-term experiments that reducing tillage intensity and increasing crop diversity to include perennial grasses could be effective in improving C and N sequestration in Midwest soils.
  • Authors:
    • Sweeney, D.
    • Kelley, K.
  • Source: Agronomy Journal
  • Volume: 97
  • Issue: 3
  • Year: 2005
  • Summary: In the eastern Great Plains, winter wheat ( Triticum aestivum L.) is often rotated with other crops to diversify cropping systems. In these multicropping systems, wheat typically is planted with conservation tillage methods, but previous crop residues influence fertilizer N management. This field study was conducted from 1992 through 2001 in southeastern Kansas on a Parsons silt loam soil (fine, mixed, thermic, Mollic Albaqualf). The objectives were to determine effects and interactions of previous crop {grain sorghum [ Sorghum bicolor (L.) Moench] and soybean [ Glycine max (L.) Merr.]}, tillage system [reduced tillage (RT) and no-tillage (NT)], N rate (67 and 134 kg ha -1), and preplant placement (surface-broadcast and subsurface-knife) of urea ammonium nitrate solution (UAN, 280 g kg -1) on wheat grain yield, yield components, and plant N uptake in a 2-yr cropping rotation. Wheat yields averaged 3.39 Mg ha -1 following soybean compared with 2.90 Mg ha -1 following grain sorghum. Tillage effects on grain yield were smaller than other treatment factors, averaging 3.23 Mg ha -1 for RT and 3.06 Mg ha -1 for NT. Grain yields were greatest in all cropping systems for the high-N-rate subsurface-knife treatment. Plant N uptake responses indicated that grain yield differences were primarily related to greater immobilization of both fertilizer and soil N following grain sorghum, compared with soybean, and to better utilization of subsurface-knifed N than surface-broadcast N. Results indicate that wheat yield potential is more strongly influenced by previous crop, fertilizer N rate, and N placement method than tillage system.
  • Authors:
    • Johnston, A.
    • Turkington, T.
    • Harker, K.
    • Clayton, G.
    • Lupwayi, N.
  • Source: Better Crops with Plant Food
  • Volume: 89
  • Issue: 3
  • Year: 2005
  • Summary: A field experiment was conducted at Fort Vermilion in northwestern Alberta, Canada, during 1998-99 and 1999-2000 to determine the amount of potassium (K) released from crop residues of four different crop rotations that included red clover [ Trifolium pratense] green manure, field pea, canola [rape] and spring wheat, under conventional and no-till seeding systems. Crops were grown on soils that had soil test levels of 150 ppm K (0.5M NaHCO 3-extractable), and no fertilizer K was added. Crop residues dry matter returned to the soil by the different crops were considerably higher in 1999-2000 relative to 1998-1999, reflecting the higher crop production during the 1999 growing season. Crop residue yield showed a large difference between the two study periods in the amount of total K being returned to the field. The results illustrate that all crop residues considered released more than 90% of their accumulated K in the 52-week period. The tillage system had no effect on the release of K from the crop residues.
  • Authors:
    • Arshad, M.
    • Soon, Y.
  • Source: Soil & Tillage Research
  • Volume: 80
  • Issue: 1/2
  • Year: 2005
  • Summary: Limited information is available on soil management effects on crop production and nitrogen (N) cycling in acid soils. The effects of conventional tillage (CT) versus no-till (NT) and liming (0 versus 7.5 Mg ha -1), and their interaction, on labile N pools in an acid soil were evaluated during the 7th to 10th year of a 3-course small grain rotation. Crop production and N uptake, N 2 fixation by pea ( Pisum sativum L.), and labile soil N were determined. Liming increased the pH from 5.3 to 6.0 in the top 10 cm of soil and had no influence below 10 cm depth. No-till increased average crop yield and N uptake by 12 and 14%, respectively, compared to CT. The corresponding increases due to lime application were 13 and 20%. There was no treatment effect on N concentrations in plant tissues (probably because of adequate N fertilizer application), or on N 2 fixation in pea. The percent N derived from the atmosphere varied from 12% in one dry year to 68% in a moister year. Soil NO 3 in spring and autumn was significantly higher where the preceding crop was field pea, particularly in the surface soil layer. Soil inorganic N was little influenced by tillage and liming. In contrast, soil microbial biomass N concentration was consistently greater with liming than without (30-64% difference) and with NT than with CT (7-36% difference), but little affected by crop sequence. Liming enhanced the positive effect of NT on soil microbial biomass N. Crop total N uptake was significantly correlated with microbial biomass N ( r=0.69* for barley ( Hordeum vulgare L.), and 0.70** for canola ( Brassica rapa L.)). Liming with NT can be effective in increasing N turnover and crop growth in acid soils.
  • Authors:
    • Arshad, M.
    • Klein-Gebbinck, H.
    • Soon, Y.
  • Source: Canadian Journal of Plant Science
  • Volume: 85
  • Issue: 1
  • Year: 2005
  • Summary: Brown girdling root rot (BGRR) is a serious and widespread disease of canola ( Brassica rapa L.) in the Peace River region of northwestern Canada. There is no chemical control treatment for the pathogen, and farmers have observed that the disease is more severe when canola follows red fescue ( Festuca rubra L.) or clover ( Trifolium spp.) compared to summer fallow. A field study was conducted to determine how crop sequences following red fescue termination can be combined with residue and tillage management to reduce BGRR infection and increase canola yield. The five treatments consisted of rotations of: continuous canola (CCC) and oat ( Avena sativa L.)-oat-canola (OOC), both managed using reduced tillage (RT), and wheat ( Triticum aestivum L.)-wheat-canola (WWC), managed using RT, conventional tillage (CT) or no-till (NT). Canola yield followed the trend: OOC(RT)=WWC(RT) > WWC(CT) > CCC(RT)=WWC(NT). BGRR infection increased with tillage intensity: WWC(CT) > CCC(RT)=WWC(RT)=OOC(RT) > WWC(NT), and was reduced when canola followed two cereal break crops. Yield was highest when canola was preceded by a cereal crop and lowest without a break crop. The low yield with NT was attributed to poor crop emergence from a hard seed bed with unbroken turf and to competition from re-emerged fescue in the third year after fescue breaking. This study demonstrated that the cropping sequence and tillage system used influenced canola yield to a greater extent than did BGRR infection.
  • Authors:
    • Dille, J. A.
    • Stahlman, P. W.
    • Bensch, C. N.
    • Al-Khatib, K.
    • Liphadzi, K. B.
    • Todd, T.
    • Rice, C. W.
    • Horak, M. J.
    • Head, G.
  • Source: Weed Science
  • Volume: 53
  • Issue: 4
  • Year: 2005
  • Summary: Field experiments were conducted at Ashland Bottoms in northeastern Kansas and at Hays in western Kansas in 2001, 2002, and 2003 to determine the response of soil microbial and nematode communities to different herbicides and tillage practices under a glyphosate-resistant cropping system. Conventional herbicide treatments were a tank mixture of cloransulam plus S metolachlor plus sulfentrazone for soybean and a commercially available mixture of acetochlor and atrazine for corn. Glyphosate was applied at 1.12 kg ai ha(-1) when weeds were 10 or 20 cm tall in both corn and soybean. Soil samples were collected monthly at Ashland Bottoms during the growing period for soil microbial biomass (SMB) carbon determination. In addition, substrate-induced respiration (SIR) and BIOLOG substrate utilization were determined at the end of the growing season each year at Ashland Bottoms, and nematode populations were determined at the beginning and the end of the growing season at both sites. Direct effects of glyphosate rates on soil microbial and nematode communities were also studied in a controlled environment. Values for SMB carbon, SIR, and BIOLOG substrate utilization were not altered by glyphosate. Nematode community response to the glyphosate treatment was similar under both conventional tillage and no-till environments. Total nematode densities were similar with the glyphosate and conventional herbicide treatments. SMB carbon and BIOLOG substrate utilization did not differ between tillage treatments. Nematode densities were greater under conventional tillage than in the no-till system. This study showed that soil health when glyphosate was applied in a glyphosate-resistant cropping system was similar to that of cropping systems that used conventional herbicides.
  • Authors:
    • Quine, T. A.
    • Djurhuus, J.
    • Heckrath, G.
    • Van Oost, K.
    • Govers, G.
    • Zhang, Y.
  • Source: Journal of Environmental Quality
  • Volume: 34
  • Issue: 1
  • Year: 2005
  • Summary: Tillage erosion had been identified as a major process of soil redistribution on sloping arable land. The objectives of our study were to investigate the extent of tillage erosion and its effect on soil quality and productivity under Danish conditions. Soil samples were collected to a 0.45-m depth on a regular grid from a 1.9-ha site and analyzed for Cs-137 inventories, as a measure of soil redistribution, soil texture, soil organic carbon (SOC) contents, and phosphorus (P) contents. Grain yield was determined at the same sampling points. Substantial soil redistribution had occurred during the past decades, mainly due to tillage. Average tillage erosion rates of 2.7 kg m(-2) yr(-1) occurred on the shoulderslopes, while deposition amounted to 1.2 kg m(-2) yr(-1) on foot- and toeslopes. The pattern of soil redistribution could not be explained by water erosion. Soil organic carbon and P contents in soil profiles increased from the shoulder- toward the toeslopes. Tillage translocation rates were strongly correlated with SOC contents, A-horizon depth, and P contents. Thus, tillage erosion had led to truncated soils on shoulderslopes and deep, colluvial soils on the foot- and toeslopes, substantially affecting within-field variability of soil properties. We concluded that tillage erosion has important implications for SOC dynamics on hummocky land and increases the risk for nutrient losses by overland flow and leaching. Despite the occurrence of deep soils across the study area, evidence suggested that crop productivity was affected by tillage-induced soil redistribution. However, tillage erosion effects on crop yield were confounded by topography-yield relationships.
  • Authors:
    • Álvaro-Fuentes, J.
    • Arrúe, J. L.
    • López, M. V.
    • Moret, D.
  • Source: European Journal of Agronomy
  • Volume: 23
  • Issue: 1
  • Year: 2005
  • Summary: Most of the benefits from conservation tillage are attained by maintaining crop residues on the soil surface. However, the effectiveness of crop residues depends on their persistence in time and maintenance of sufficient residue cover can become difficult, especially when a long-fallow period is involved. In this study, we evaluate the effects of conventional tillage (CT) and two conservation tillage systems (reduced tillage, RT, and no-tillage, NT), under both continuous cropping (CC) and cereal-fallow rotation (CF), on the dynamics of surface barley residues during four fallow periods in a dryland field of semiarid Aragon. The CC system involves a summer fallow period of 5-6 months and the CF rotation a long-fallow of 17-18 months. Results indicate that the lack of residue-disturbing operations in NT makes this practice the best strategy for fallow management. With this tillage system, the soil surface still conserved a residue cover of 10-15% after long-fallowing and percentages of standing residues ranging from 20 to 40% of the total mass after the first 11-12 months. In both CT and RT, primary tillage operations had the major influence on residue incorporation, with percentages of cover reduction of 90-100% after mouldboard ploughing (CT) and 50-70% after chiselling (RT). Two decomposition models were tested, the Douglas-Rickman and the Steiner models. Our data indicate that the Steiner model described more accurately the decline of surface residue mass over the long-fallow period in the NT plots. Measured and predicted data indicate that, under NT, 80-90% of the initial residue mass is lost at the end of fallow and that 60-75% of this loss occurs during the first 9-10 months. Finally, the mass-to-cover relationship established in this study for barley residues could be used to predict soil cover from flat residue mass through the fallow period by using a single A(m) coefficient (0.00208 ha kg(-1)). (C) 2004 Elsevier B.V. All rights reserved.
  • 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.