• Authors:
    • Lenssen, A.
    • Caesar-Thonthat, T.
    • Waddell, J.
    • Sainju, U. M.
  • Source: Journal of Environmental Quality
  • Volume: 35
  • Issue: 4
  • Year: 2006
  • Summary: Long-term use of conventional tillage and wheat (Triticum aestivum L.)-fallow systems in the northern Great Plains have resulted in low soil organic carbon (SOC) levels. We examined the effects of two tillage practices [conventional till (CT) and no-till (NT)], five crop rotations [continuous spring wheat (CW), spring wheat-fallow (W-F), spring wheat-lentil (Lens culinaris Medic.) (W-L), spring wheat-spring wheat-fallow (W-W-F), and spring wheat-pea (Pisum sativum L.)-fallow (W-P-F)], and Conservation Reserve Program (CRP) planting on plant C input, SOC, and particulate organic carbon (POC). A field experiment was conducted in a mixture of Scobey clay loam (fine-loamy, mixed, Aridic Argiborolls) and Kevin clay loam (fine, montmorillonitic, Aridic Argiborolls) from 1998 to 2003 in Havre, MT. Total plant biomass returned to the soil from 1998 to 2003 was greater in CW (15.5 Mg ha(-1)) than in other rotations. Residue cover, amount, and C content in 2004 were 33 to 86% greater in NT than in CT and greater in CRP than in crop rotations. Residue amount (2.47 Mg ha(-1)) and C content (0.96 Mg ha(-1)) were greater in NT with CW than in other treatments, except in CT with CRP and W-F and in NT with CRP and W-W-E The SOC at the 0- to 5-cm depth was 23% greater in NT (6.4 Mg ha(-1)) than in CT. The POC was not influenced by tillage and crop rotation, but POC to SOC ratio at the 0- to 20-cm depth was greater in NT with W-L (369 g kg(-1) SOC) than in CT with CW, W-F, and W-L. From 1998 to 2003, SOC at the 0- to 20-cm depth decreased by 4% in CT but increased by 3% in NT. Carbon can be sequestered in dryland soils and plant residue in areas previously under CRP using reduced tillage and increased cropping intensity, such as NT with CW, compared with traditional practice, such as CT with W-F system, and the content can be similar to that in CRP planting.
  • Authors:
    • Cassman, K. G.
    • Hergert, G. W.
    • Payero, J. O.
    • Tarkalson, D. D.
  • Source: Plant and Soil
  • Volume: 283
  • Issue: 1-2
  • Year: 2006
  • Summary: Soil pH is decreasing in many soils in the semiarid Great Plains of the United States under dry land no-till (NT) cropping systems. This study was conducted to determine the rate of acidification and the causes of the acidification of a soil cropped to a winter wheat (Triticum aestivum L.)-grain sorghum [Sorghum bicolor (L.) Moench]/corn (Zea mays L.)-fallow rotation (W-S/C-F) under NT. The study was conducted from 1989 to 2003 on soil with a long-term history of either continuous NT management [NT(LT)] (1962-2003) or conventional tillage (CT) (1962-1988) then converted to NT [NT(C)] (1989-2003). Nitrogen was applied as ammonium nitrate (AN) at a rate of 23 kg N ha(-1)supercript stop in 1989 and as urea ammonium nitrate (UAN) at an average annual rate of 50 kg N ha(-1) from 1990 to 2003 for both NT treatments. Soil samples were collected at depth increments of 0-5, 5-10, 10-15, and 15-30 cm in the spring of 1989 and 2003. Acidification rates for the NT(LT) and NT(C) treatments were 1.13 and 1.48 kmol H+ ha(-1) yr(-1) in the 0-30 cm depth, respectively. The amount of CaCO3 needed to neutralize the acidification is 57 and 74 kg ha(-1) yr(-1) for the NT(LT) and NT(C) treatments, respectively. A proton budget estimated by the Helyar and Porter [1989, Soil Acidity and Plant Growth, Academic Press] method indicated that NO3- leaching from the 30 cm depth was a primary cause of long-term acidification in this soil. Nitrate leaching accounted for 59 and 66% of the H+ from the acid causing factors for NT(LT) and NT(C) treatments, respectively. The addition of crop residues to the soil neutralized 62 and 47% of the acidity produced from the leaching of NO3-, and 37 and 31% of the acid resulting from NO3- leaching and the other acid-causing constituents for the NT(LT) and NT(C) treatments, respectively. These results document that surface soils in dry land W-S/C-F rotations under NT are acidifying under current management practices. Improved management to increase nitrogen uptake efficiency from applied fertilizer would help reduce the rate of acidification. The addition of lime materials to prevent negative impacts on grain yields may be necessary in the future under current management practices.
  • Authors:
    • McVay, K.
    • Langemeier, M.
    • Regehr, D.
    • Devlin, D.
    • Mankin, K.
    • Pierzynski, G.
    • Sweeney, D.
    • Janssen, K.
    • Zeimen, M.
  • Source: Journal of Soil and Water Conservation
  • Volume: 61
  • Issue: 5
  • Year: 2006
  • Summary: Best management practices have been recommended for controlling nutrient, herbicide, or sediment losses with surface runoff. This study was designed to determine the best overall combination of tillage and application practices to reduce surface losses from cropland. Runoff was collected from two Kansas sites in sorghum-soybean rotation during the 2001 to 2004 crop years and analysed for bioavailable phosphorus (P), soluble P, total P, ammonium, nitrate, total nitrogen (N), sediment, atrazine, and metolachlor concentrations. No-till treatments consistently experienced higher runoff water volumes than the chisel/disk tillage system used to warm and dry these clay soils in the spring. For this reason the no-till treatments also had higher nutrient and herbicide losses than chisel/disk tillage regardless of use of high or low application management techniques. The high included fertilizer and herbicide application practices intended to reduce losses with runoff while the standard application broadcast applied fertilizer and herbicide at planting. Few consistent differences were seen for pollutant loss between the high and standard application management. When average losses for all eight location-years were compared to chisel/disk low, soluble P losses were 3.0 and 2.1 times higher for no-till low and no-till high, respectively; metolachlor losses were 2.4 and 2.7 times higher for no-till low and no-till high, respectively; and atrazine losses were 4.8 and 6.1 times higher for no-till low and no-till high, respectively. The chisel/disk low did experience two times higher sediment losses compared with the no-till low or no-till high, when averaging over all eight location-years. However, tolerable soil loss was not exceeded, chisel/disk low generally had small losses for all tested pollutants and may be the best management combination to simultaneously reduce nutrient, herbicide, and sediment losses with cropland runoff for sites like those used in this study.
  • Authors:
    • Cantero-Martinez, C.
    • Westfall, D. G.
    • Sherrod, L. A.
    • Peterson, G. A.
  • Source: Journal of Soil and Water Conservation
  • Volume: 61
  • Issue: 2
  • Year: 2006
  • Summary: The presence of crop residue is an important component of dryland cropping systems management in the semiarid environment where soil erosion by wind is a major soil degradation process. Residue also affects precipitation capture and runoff. Long-term residue quantity dynamics of different cropping systems has not been studied in the semi-arid environment of the western Great Plains. Long-term studies were conducted in eastern Colorado, USA to determine the interaction of no-till cropping systems, soils, and climatic gradient on the production, retention, and disappearance of crop residue over a 12-year period. The cropping systems evaluated were winter wheat ( Triticum aestivum)-summer fallow (WF), winter wheat-maize ( Zea mays) or sorghum ( Sorghum bicolor)-summer fallow (WC/SF), winter wheat-maize/sorghum-millet ( Panicum miliaceum)-summer fallow (WC/SMF), and continuous cropping (CC). A soil surface residue base was achieved in a few years (four to five) and changed little over time. However, as cropping intensity increased the total crop residue retained on the soil surface increased as the proportion of fallow time decreased; a general trend was for residue levels to increase slowly. However, in the winter wheat-summer fallow system residue levels showed a trend to decrease after the initial base was achieved. Greater residue production and retention occurred on the toeslope soil position because these soils are deeper, have greater water holding capacity, and receive run-on water from upslope positions. Residue disappearance was less in the fallow period before maize planting compared to before wheat planting due to the greater fallow period, which included summer fallow in the wheat system. Residue loss was greater during the crop production periods as compared to the fallow periods. The levels of residue present on the soil surface in our intensive no-till cropping systems were generally adequate to control erosion by wind. However, at our high potential evapotranspiration site the residue levels were "marginal" for adequate wind erosion abatement, particularly in the winter wheat-summer fallow system. A combination of no-till management and increased cropping intensity (greater than winter wheat-summer fallow) is the key to sustainable production and soil conservation in this semi-arid environment.
  • Authors:
    • Waddell, J.
    • Caesar-Tonthat, T.
    • Lenssen, A.
    • Sainju, U. M.
  • Source: Soil Science Society of America Journal
  • Volume: 70
  • Issue: 2
  • Year: 2006
  • Summary: Sustainable management practices are needed to enhance soil productivity in degraded dryland soils in the northern Great Plains. We examined the effects of two tillage practices [conventional till (CT) and no-till (NT)], five crop rotations [continuous spring wheat (Triticum aestivum L.) (CW), spring wheat-fallow (W-F), spring wheat-lentil (Lens culinaris Medic.) (W-L), spring wheat-spring wheat-fallow (W-W-F), and spring wheat-pea (Pisum sativum L.)-fallow (W-P-F)], and a Conservation Reserve Program (CRP) on plant biomass returned to the soil, residue C and N, and soil organic C (SOC), soil total N (STN), and particulate organic C and N (POC and PON) at the 0- to 20-cm depth. A field experiment was conducted in a mixture of Scobey clay loam (fine, smectitic, frigid Aridic Argiustolls) and Kevin clay loam (fine-loamy, mixed, superactive, frigid Aridic Argiustolls) from 1998 to 2003 near Havre, MT. Mean annualized plant biomass returned to the soil from 1998 to 2003 was greater in W-F (2.02 Mg ha-1) than in W-L and W-W-F, regardless of tillage. In 2004, residue cover was greater in CW (60%) than in other rotations, except in W-W-F. Residue amount and C and N contents were greater in NT with CW (2.47 Mg ha-1 and 963 and 22 kg ha-1, respectively) than in NT with W-L and CT with other crop rotations. The POC at 0 to 5 cm was greater in W-W-F and W-P-F (2.1-2.2 Mg ha-1) than in W-L. Similarly, STN at 5 to 20 cm was greater in CT with W-L (2.21 Mg ha-1) than in other treatments, except in NT with W-W-F. Reduced tillage and increased cropping intensity, such as NT with CW and W-L, conserved C and N in dryland soils and crop residue better than the traditional practice, CT with W-F, and their contents were similar to or better than in CRP planting.
  • Authors:
    • Hons, F.
    • Dou, F.
  • Source: Soil Science Society of America Journal
  • Volume: 70
  • Issue: 6
  • Year: 2006
  • Summary: Management practices that alter plant residue production and distribution influence SOC (soil organic carbon) dynamics. The objectives of this study were to investigate the impacts of tillage, cropping system, and N fertilizer application on SOC and soil N pools through physical fractionation of a central Texas soil after 20 years. Nitrogen fertilizer application and no-tillage (NT) significantly increased wheat ( Triticum aestivum) straw yield. Compared with conventional tillage (CT), SOC under NT in surface (0-5 cm) samples was 38, 69, and 68% greater for continuous wheat (CW), wheat-soyabean ( Glycine max)-sorghum ( Sorghum bicolor) rotation (SWS), and double-cropped wheat-soyabean (WS), respectively. The greatest SOC was observed in WS under NT with N fertilizer application, and the lowest occurred in CW under CT without N. Increased cropping intensity increased SOC compared with monoculture. Nitrogen fertilizer application only significantly increased SOC sequestration under NT. No-tillage increased SOC concentration in all physical size fractions compared with CT. Increased cropping intensity and N fertilizer application significantly increased SOC sequestration in most size fractions only under NT. Intraparticulate organic matter C (IPOM-C) was proportionally more affected by tillage than total SOC, indicating that this fraction was more sensitive to management. Carbon concentrations in all size fractions were significantly correlated with each other as well as SOC. Our results indicated that NT associated with enhanced cropping intensity and N fertilizer application sequestered greater SOC and soil total N.
  • Authors:
    • Lampurlanés, J.
    • Cantero-Martínez, C.
  • Source: Soil & Tillage Research
  • Volume: 85
  • Issue: 1-2
  • Year: 2006
  • Summary: The objective of this study was to investigate the effect of tillage and cropping system on near-saturated hydraulic conductivity, residue cover and surface roughness to improve soil management for moisture conservation under semiarid Mediterranean conditions. Three tillage systems were compared (subsoil tillage, minimum tillage and no-tillage) under three field situations (continuous crop, fallow and crop after fallow) on two soils (Fluventic Xerochrept and Lithic Xeric Torriorthent). Soil under no-tillage had lower hydraulic conductivity (5.0 cm day(-1)) than under subsoil tillage (15.5 cm day(-1)) or minimum tillage (14.3 cm day(-1)) during 1 of 2 years in continuous crop due to a reduction of soil porosity. Residue cover at sowing was greater under no-tillage (60%) than under subsoil or minimum tillage (
  • Authors:
    • Franzluebbers, A. J.
    • Causarano, H. J.
    • Reeves, D. W.
    • Shaw, J. N.
  • Source: Journal of Environmental Quality
  • Volume: 35
  • Issue: 4
  • Year: 2006
  • Summary: Past agricultural management practices have contributed to the loss of soil organic carbon (SOC) and emission of greenhouse gases (e.g., carbon dioxide and nitrous oxide). Fortunately, however, conservation-oriented agricultural management systems can be, and have been, developed to sequester SOC, improve soil quality, and increase crop productivity. Our objectives were to (i) review literature related to SOC sequestration in cotton (Gossypium hirsutum L.) production systems, (ii) recommend best management practices to sequester SOC, and (iii) outline the current political scenario and future probabilities for cotton producers to benefit from SOC sequestration. From a review of 20 studies in the region, SOC increased with no tillage compared with conventional tillage by 0.48 +/- 0.56 Mg C ha(-1) yr(-1) (H(0): no change,p
  • Authors:
    • Cook, R. J.
  • Source: PNAS, Proceedings of the National Academy of Sciences
  • Volume: 103
  • Issue: 49
  • Year: 2006
  • Summary: The defining features of any cropping system are (i) the crop rotation and (ii) the kind or intensity of tillage. The trend worldwide starting in the late 20th century has been (i) to specialize competitively in the production of two, three, a single, or closely related crops such as different market classes of wheat and barley, and (ii) to use direct seeding, also known as no-till, to cut costs and save soil, time, and fuel. The availability of glyphosate- and insect-resistant varieties of soybeans, corn, cotton, and canola has helped greatly to address weed and insect pest pressures favored by direct seeding these crops. However, little has been done through genetics and breeding to address diseases caused by residue- and soil-inhabiting pathogens that remain major obstacles to wider adoption of these potentially more productive and sustainable systems. Instead, the gains have been due largely to innovations in management, including enhancement of root defence by antibiotic-producing rhizosphere-inhabiting bacteria inhibitory to root pathogens. Historically, new varieties have facilitated wider adoption of new management, and changes in management have facilitated wider adoption of new varieties. Although actual yields may be lower in direct-seed compared with conventional cropping systems, largely due to diseases, the yield potential is higher because of more available water and increases in soil organic matter. Achieving the full production potential of these more-sustainable cropping systems must now await the development of varieties adapted to or resistant to the hazards shown to account for the yield depressions associated with direct seeding.
  • 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.