• Authors:
    • Wyse, D. L.
    • Buckley, D. H.
    • DeHaan, L. R.
    • Crews, T. E.
    • Mai, J. G.
    • Mangan, M. E.
    • Young, L.
    • Broussard, W.
    • DuPont, S. T.
    • Culman, S. W.
    • Glover, J. D.
    • Reynolds, H. L.
    • Turner, R. E.
    • Ferris, H.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 137
  • Issue: 1-2
  • Year: 2009
  • Summary: Perennial vegetation can provide multiple ecosystem services essential for sustainable production more effectively than production systems based on annual crops. However, the ability of annually harvested, unfertilized perennial systems to sustain long-term yields while also maintaining ecosystem services has not been widely studied. Here we compare the impacts of harvested perennial grass and annual crop fields on ecosystem functioning in KS, USA. Despite the lack of mineral fertilizer applications, the aboveground harvests of perennial fields yielded similar levels of N compared to those of conventional high-input wheat (Triticum aestivum) fields and at only 8% of the in-field energy costs. Their 75-yr cumulative N yield per ha was approximately 23% greater than that from the region's wheat fields. In terms of aboveground food webs, perennial fields harboured greater numbers and/or diversity of insect pollinators, herbivores and detritivores. Belowground, perennial grass fields maintained 43 Mg ha-1 more soil carbon and 4 Mg ha-1 more soil nitrogen than annual crop fields in the surface 1 m. Soil food webs in perennial fields, as indicated by nematode communities, exhibited greater food web complexity and stability than did those in annual crop fields. In surrounding watersheds, increased annual cropland was correlated with higher riverine nitrate-nitrogen levels. Given their benefits, harvested perennial grasslands provide valuable ecological benchmarks for agricultural sustainability.
  • Authors:
    • Alberta Environment
  • Year: 2009
  • Summary: The opportunity for generating carbon offsets with this protocol arises from the direct and indirect reductions of greenhouse gas (GHG) emissions through implementing no-till and reduced till systems on agricultural lands.
  • Authors:
    • Al-Kaisi, M. M.
    • Guzman, J. G.
  • Source: Journal of Environmental Quality
  • Volume: 39
  • Issue: 1
  • Year: 2009
  • Summary: In addition to their aesthetic and environmental qualities, reconstructed prairies can act as C sinks and potentially offset rising atmospheric CO2 concentration. The objective Of this Study was to quantify C budget components of newly established prairies on previously cultivated land. Net ecosystem production (NEP) was estimated using a C budgeting approach that assessed SOC content, soil surface CO2-C emission, and above- and belowground plant biomass. Study was conducted in southern Iowa, in 2005 to 2007. Results show that differences between sites for potential total C input were primarily due to root biomass contributions, which ranged from 0.8 to 5.4 Mg C ha(-1). Average potential aboveground biomass C input was 2.7 Mg C ha(-1) in 2006 and 5.5 Mg C ha(-1) in 2007. Total soil CO2-C emissions from heterotrophic respiration increased as prairie age increased from 2.9 to 4.0 Mg C ha(-1) and 3.1 to 4.7 Mg C ha(-1) in 2006 and 2007, respectively. Determination of NEP showed that the 1998 and 2003 reconstructed prairie sites had the greatest potential for soil C sequestration at 4.1 and 4.4 Mg C ha(-1). Increases in SOC content were only observed in the youngest established prairie site (2003) and the no-till site in 2003 at 2.1 and 2.6 Mg C ha(-1) yr(-1), respectively. Declines of SOC sequestration rates occurred when potential C equilibrium was reached (R-h = NPP) within 10 yr since prairie establishment.
  • Authors:
    • Bremer, E.
  • Year: 2009
  • Summary: Native rangelands in Alberta contain large reservoirs of organic carbon and may be sequestering additional atmospheric CO2 through their response to elevated CO2 levels. Mitigation practices to increase atmospheric CO2 sequestration or otherwise reduce greenhouse gas (GHG) emissions were evaluated in this report. Improving range health through the effective application of rangeland management principles may increase C storage on rangelands that are currently rated as unhealthy or healthy with problems. However, the potential to reduce GHG emissions by this mechanism is small because most native rangelands in Alberta are healthy and the few estimates of C gain due to improved range health are small and inconsistent. Conversion of annual cropland to rangeland has the potential to increase C sequestration substantially, but this practice is most appropriately considered as a mitigation practice for annual cropland. Inclusion of legumes in seeding mixes and application of compost have good potential to increase C storage when annual cropland or degraded lands is converted to rangeland, but have limited potential to reduce GHG emissions on healthy rangelands. Overall, the potential to adopt practices that reduce GHG emissions on existing Alberta rangelands is small.
  • Authors:
    • Folley, J. A.
    • Kucharik, C. J.
    • Cahill, K. N.
  • Source: Ecological Applications
  • Volume: 19
  • Issue: 8
  • Year: 2009
  • Summary: We investigated carbon cycling and ecosystem characteristics among two prairie restoration treatments established in 1987 and adjacent cropland, all part of the Conservation Reserve Program in southwestern Wisconsin, USA. We hypothesized that different plant functional groups (cool-season C3 vs. warm-season C4 grasses) between the two prairie restoration treatments would lead to differences in soil and vegetation characteristics and amount of sequestered carbon, compared to the crop system. We found significant (P < 0.05) differences between the two prairie restoration treatments in soil CO2 respiration and above- and belowground productivity, but no significant differences in long-term (~16-year) carbon sequestration. We used a biometric approach aggregating short-term observations of above- and belowground productivity and CO2 respiration to estimate total net primary production (NPP) and net ecosystem production (NEP) using varied methods suggested in the literature. Net ecosystem production is important because it represents the ecosystem carbon sequestration, which is of interest to land managers and policymakers seeking or regulating credits for ecosystem carbon storage. Such a biometric approach would be attractive because it might offer the ability to rapidly assess the carbon source/sink status of an ecosystem. We concluded that large uncertainties in (1) estimating aboveground NPP, (2) determining belowground NPP, and (3) partitioning soil respiration into microbial and plant components strongly affect the magnitude, and even the sign, of NEP estimates made from aggregating its components. A comparison of these estimates across treatments could not distinguish differences in NEP, nor the absolute sign of the overall carbon balance. Longer-term quantification of carbon stocks in the soil, periodically linked to measurements of individual processes, may offer a more reliable measure of the carbon balance in grassland systems, suitable for assigning credits.
  • Authors:
    • Lu, Y.
    • Conklin, A. E.
    • Teasdale, J. R.
    • Hanson, J. C.
    • Hima, B. L.
    • Cavigelli, M. A.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 24
  • Issue: 2
  • Year: 2009
  • Summary: Interest in organic grain production is increasing in the United States but there is limited information regarding the economic performance of organic grain and forage production in the mid-Atlantic region. We present the results from enterprise budget analyses for individual crops and for complete rotations with and without organic price premiums for five cropping systems at the US Department of A(Agriculture-Agricultural Research Service (USDA-ARS) Beltsville Farming Systems Project (FSP) from 2000 to 2005. The FSP is a long-term cropping systems trial established in 1996 to evaluate the sustainability of organic and conventional grain crop production. The five FSP cropping systems include a conventional. three-year no-till corn (Zea mays L.)-rye (Secale cereale L.) cover crop/soybean (Glycine max (L.) Merr)-wheat (Triticum aestivum L.)/soybean rotation (no-till (NT)), a conventional, three-year chisel-till corn-rye/soybean-wheat/soybean rotation (chisel tillage (CT)), a two-year organic hairy vetch (Vicia villosa Roth)/corn-rye/soybean rotation (Org2), a three-year organic vetch/corn-rye/soybean-wheat rotation (Org3) and a four- to six-year organic corn-rye/soybean-wheat-red clover (Trifolium pratense L.)/orchard grass (Dactylis glomerata L.) or alfalfa (Medicago sativa L.) rotation (Org4+). Economic returns were calculated for rotations present from 2000 to 2005, which included some slight changes in crop rotation sequences due to weather conditions and management changes additional analyses were conducted for 2000 to 2002 when all crops described above were present in all organic rotations. Production costs were, in general, greatest for CT, while those for the organic systems were lower than or similar to those for NT for all crops. Present value of net returns for individual crops and for full rotations were greater and risks were lower for NT than for CT. When price premiums for organic crops were included in the analysis, cumulative present value of net returns for organic systems (US$3933 to 5446 ha(-1), 2000 to 2005. US$2653 to 2869 ha(-1), 2000 to 2002) were always Substantially greater than for the conventional systems (US$1309 to 1909 ha(-1),2000 to 2005; US$634 to 869 ha(-1), 2000 to 2002). With price premiums, Org2 had greater net returns but also greater variability of returns and economic risk across all years than all other systems, primarily because economic Success of this short rotation was highly dependent on the success of soybean, the crop with the highest returns. Soybean yield variability was high due to the impact of weather on the success of weed control in the organic systems. The longer, more diverse Org4+ rotation had the lowest variability of returns among organic systems and lower economic risk than Org2. With no organic price premiums, economic returns for corn and soybean in the organic systems were generally lower than those for the conventional systems due to lower grain yields in the organic systems. An exception to this pattern is that returns for corn in Org4+ were equal to or greater than those in NT in four of six years due to both lower production costs and greater revenue than for Org2 and Org3. With no organic premiums, present value of net returns for the full rotations was greatest for NT in 4 of 6 years and greatest for Org4+ the other 2 years, when returns for hay crops were high. Returns for individual crops and for full rotations were, in general, among the lowest and economic risk was, in general, among the highest for Org2 and Org3. Results indicte that Org4+, the longest and most diverse rotation, had the most stable economic returns among organic systems but that short-term returns could be greatest with Org2. This result likely explains, at least in part, why some organic farmers in the mid-Atlantic region, especially those recently converting to organic methods, have adopted this relatively short rotation. The greater stability of the longer rotation, by contrast, may explain why farmers who have used organic methods for longer periods of time tend to favor rotations that include perennial forages.
  • Authors:
    • Lal, R.
    • Chatterjee, A.
  • Source: Soil & Tillage Research
  • Volume: 104
  • Issue: 2
  • Year: 2009
  • Summary: No-tillage (NT) farming offers innumerable benefits to soil and water conservation, however, its potential to sequester soil organic carbon (SOC) and related soil properties varies widely. Thus, the impact of long-term (>4 yr) NT-based cropping systems on SOC sequestration and selected soil physical and chemical parameters were assessed across soils within five Major land Resource Areas (MLRAs: 99 and 111 in Michigan; 124 and 139 in Ohio; and 127 in Pennsylvania) in eastern U.S.A. Soil samples were collected from paired fields of NT and plow tillage (PT) based cropping systems and an adjacent woodlot (WL). The SOC concentration, bulk density (rho(b)), texture, pH, electrical conductivity (EC), soil N, coarse particulate organic matter (CPOM) C and N, and nitrate N (NO3-N) concentrations were determined. Conversion from NT to PT practice increased surface soil pH from 5.97,6.56 and 6.02 to 6.62, 6.91 and 7.09 under MLRAs 127, 111 and 99, respectively. NT soils had higher SOC concentration soils by 30,50 and 67% over PT soils at 0-5 cm depth under MLRAs 99, 111 and 127, respectively. Considering the whole soil profile SOC, WL had higher SOC pool than NT and PT practices under MLRAs 99, 111 and 124, however, there was no significant difference (P < 0.05) between NT and PT practices across five soils. Almost the same trend was observed in the case of depthwise soil N content. NT soil had higher N content than PT soils by 27,44 and 54% under MLRAs 99,127 and 111, respectively. However, whole soil profile N content of NT soil was significantly higher by 12% than PT soil under MLRA 99. Concentrations of CPOM associated C and N of NT soil was higher than PT soil under MLRAs 99. 111 and 127 at 0-5 soil depth. These results indicated that impact of tillage on soil C and associated soil quality parameters is confined within specific soil types. (C) 2009 Elsevier B.V. All rights reserved.
  • Authors:
    • Mishra, U.
    • Lal, R.
    • Christopher, S. F.
  • Source: Soil Science Society of America Journal
  • Volume: 73
  • Issue: 1
  • Year: 2009
  • Summary: No-till (NT) agriculture has been promoted as one of the optimal management practices that preserves soil and water, and increases soil organic C (SOC) compared with conventional tillage (CT) practices. Information on SOC sequestration in NT systems, however, has been based on measurements from the surface soil (<30 cm) and little is known about the extent of SOC sequestration in NT across the entire 0- to 60-cm soil profile. We conducted a regional study of NT farming to assess the extent of SOC sequestration in the whole soil profile across 12 contrasting but representative soils in the Midwestern United States, each within a Major Land Resource Area (MLRA: 98, 111C, 114B, 122 in Indiana; 111A, 111B, 111D, 124, and 126 in Ohio; and 127 and 147 in Pennsylvania). Soils on gentle terrain were sampled in paired NT and CT fields as well as in an adjacent woodlot in each MLRA. The SOC and N concentrations were greater in the surface 0- to 5-cm soil in NT than CT in MLRA 124. The SOC concentration in CT soil was greater than in NT soil at 10 to 30 cm in MLRAs 98 and 126. The total SOC pool for the whole soil profile did not differ between NT and CT in eight of the 12 MLRAs and the total profile SOC was actually greater under CT in MLRAs 98, 127, and 126, resulting in negative C sequestration rates on conversion from CT to NT in these three MLRAs. This regional study suggests that the entire soil profile must be examined and ecosystem C budget assessed when elucidating SOC sequestration in NT vs. CT fields.
  • Authors:
    • Climate Change Central
  • Source: ClimateCHECK
  • Year: 2009
  • Summary: From exec summary: This Consultation Report describes the development to date of the Nitrous Oxide Emissions Reduction Protocol ("NERP"), designed on the framework provided by the Right Product @ Right Rate, Right Time, Right Place™ stewardship model of the Canadian Fertilizer Institute. The process for development includes a Technical Background Document, a Science Discussion document, and a Consultation Workshop. Following the decisions of the Consultation Workshop, the main elements of the NERP are determined. The eligibility requirements of the NERP are designed according to the criteria of the Alberta Offsets System and Canada's Offset System. The GHG emissions for the baseline scenario and project condition are calculated using the country-specific methodology used in Canada's National Inventory Report. The scope of the NERP is limited to (1) on-farm reductions of (2) emissions associated with quantification categories fertilizer, manure, residues, and irrigation. The baseline is determined according to three years of farm-level data. The essential component for participation in the NERP is defined as the implementation of a 4R N stewardship plan, as assured by (1) general guidance in the NERP confirmed by third party verification, (2) detailed design instructions in the NERP, (3) conformity with a recommended predictive model, or (4) retaining services of an approved consulting professional. The fertilizer management practices comprising the Basic, Intermediate, and Advanced levels of the NERP are listed. And, the reduction modifiers associated with the levels of the NERP are proposed.
  • Authors:
    • Benbrook, C.
  • Source: Critical Issue Report: The First Thirteen Years
  • Year: 2009
  • Summary: Th is report explores the impact of the adoption of genetically engineered (GE) corn, soybean, and cotton on pesticide use in the United States, drawing principally on data from the United States Department of Agriculture. Th e most striking finding is that GE crops have been responsible for an increase of 383 million pounds of herbicide use in the U.S. over the first 13 years of commercial use of GE crops (1996-2008).