• Authors:
    • Grignani, C.
    • Zavattaro, L.
    • Bertora, C.
    • Alluvione, F.
  • Source: Soil Science Society of America Journal
  • Volume: 74
  • Issue: 2
  • Year: 2010
  • Summary: Alternative N fertilizers that stimulate low greenhouse gas emissions from soil are needed to reduce the impact of agriculture on global warming. Corn (Zea mays L.) grown in a calcareous silt loam soil in northwestern Italy was fertilized with a municipal solid waste compost and vetch (Vicia villosa Roth.) green manure. Their potential to reduce N2O and CO2 emissions was compared with that of urea (130 kg N ha-1). Gaseous fluxes were measured for 2 yr in the spring (after soil incorporation of fertilizers) and in summer. In spring, the slow mineralization of compost reduced N2O emissions (0.11% of supplied N) relative to urea (3.4% of applied N), without an increase in CO2 fluxes. Nitrous oxide (2.31% of fixed N) and CO2 emissions from rapid vetch decomposition did not differ from urea. When N2O and CO2 fluxes were combined, compost reduced by 49% the CO2 equivalent emitted following urea application. Vetch did not show such an effect. In summer, no fertilizer effect was found on N2O and CO2 emissions. Compost proved to be potentially suitable to reduce the CO2 equivalent emitted after soil incorporation while vetch did not. For a thorough evaluation, net greenhouse gas emissions assessment should be extended to the entire N life cycle. Differences between calculated N2O emission factors and the default Tier 1 value of the Intergovernmental Panel on Climate Change (1%) confirmed the need for site- and fertilizer-specific estimations.
  • Authors:
    • Blanco-Canqui, H.
  • Source: Agronomy Journal
  • Volume: 102
  • Issue: 2
  • Year: 2010
  • Summary: Interest in producing cellulosic ethanol from renewable energy sources is growing. Potential energy crops include row crops such as corn (Zea mays L.), perennial warm-season grasses (WSGs), and short-rotation woody crops (SRWCs). However, impacts of growing dedicated energy crops as biofuel on soil and environment have not been well documented. This article reviews the (i) impacts of growing WSGs and SRWCs on soil properties, soil organic carbon (SOC) sequestration, and water quality, and (ii) performance of energy crops in marginal lands. Literature shows that excessive (>= 50%) crop residue removal adversely impacts sod and environmental quality as well as crop yields. Growing WSGs and SRWCs can be potential alternatives to crop residue removal as biofuel. Warm-season grasses and SRWCs can improve soil properties, reduce soil erosion, and sequester SOC. Crop residue removal reduces SOC concentration by 1 to 3 Mg ha(-1) yr(-1) in the top 10 cm, whereas growing WSGs and SRWCs increase SOC concentration while providing biofuel feedstocks. The WSGs can store SOC between 0 and 3 Mg C ha(-1) yr(-1) in the top 5 cm of soil, while the SRWCs can store between 0 and 1.6 Mg ha(-1) yr(-1) of SOC in the top 100 cm. The WSGs and SRWCs have more beneficial effects on soil and environment when grown in marginal lands than when grown in croplands or natural forests. Indeed, they can grow in nutrient-depleted, compacted, poorly drained, acid, and eroded soils. Development of sustainable systems of WSGs and SRWCs in marginal lands is a high priority.
  • Authors:
    • Huang, G.
    • Chai, Q.
    • Yang, C.
  • Source: Zhongguo Shengtai Nongye Xuebao / Chinese Journal of Eco-Agriculture
  • Volume: 18
  • Issue: 4
  • Year: 2010
  • Summary: A field experiment was carried out to investigate the effect of alternative irrigation on water consumption, yield and water use efficiency ( WUE) under wheat-maize intercropping in the oasis region of Shiyang River Basin, Gansu Province. The results indicate that evaporation for alternative irrigated intercropping system (AI) decreases by 44.0 mm compared to conventional irrigated intercropping system (CI). Water consumption under AI also increases by 15.4 mm while yield and WUE are respectively enhanced by 13.92% and 9.21% compared to CI. All these results show that alternative irrigation is an effective and practicable way to improve yield and WUE of wheat-maize intercropping. Although evaporation and water consumption in alternative irrigated intercropping system increase with increasing irrigation quota, overall WUE actually decreases.
  • Authors:
    • Dong, G.
    • Chen, Z.
    • Wu, Z.
    • Sun, C.
    • Chen, L.
    • Zhang, Y.
  • Source: Plant Soil and Environment
  • Volume: 56
  • Issue: 11
  • Year: 2010
  • Summary: Agricultural practices that reduce soil degradation and improve agriculture sustainability are important particularly for dry hilly land of Chaoyang County in the Liaoning Province, North-east China, where cinnamon soils are widely distributed and mainly for wheat production. The impacts of 10-year cropping systems (wheat-cabbage sequential cropping, wheat-corn intercrop, wheat-sunflower rotation, wheat-soybean rotation) on soil enzyme properties of surface-soil (0-20 cm) were studied. Total carbon, nitrogen, phosphorus and sulfur, and nine soil hydrolases related to nutrient availabilities (beta-galactosidase, alpha-galactosidase, beta-glucosidase, alpha-glucosidase, urease, protease, phosphomonoesterase, phosphodiesterase, arylsulphatase) and five enzymes kinetic characters were examined. Wheat-corn intercrop systems had higher total C, total N, total P and total S concentrations than wheat-soybean and wheat-sunflower rotation systems. Most test enzyme activities (alpha-galactosidase, beta-galactosidase, alpha-glucosidase, beta-glucosidase, urease, protease, phosphomonoesterase and arylsulphatase) showed the highest activities under wheat-corn intercropping system. Urease, protease and phosphodiesterase activities of wheat-cabbage sequential cropping system were significantly higher than two rotation systems. The maximum reaction rates of enzymes ( Vmax) were higher than apparent enzyme activity, which suggests larger potential activity of enzymes, while not all kinetic parameters were adaptive as soil quality indicators in dry hilly cinnamon soil.
  • Authors:
    • Stone, L.
    • Kelley, K.
    • Sweeney, D.
    • Kluitenberg, G.
    • Buckley ,M.
  • Source: Soil Science Society of America Journal
  • Volume: 74
  • Issue: 6
  • Year: 2010
  • Summary: The midwestern United States has >4 million ha of claypan soils. These soils often require special management because of poor infiltration, drainage, and available water supply. This study was conducted to quantify the hydrologic balance of a claypan soil and determine the effect of tillage on water balance components. It was part of an ongoing project in Labette County, Kansas, in which no-till and chisel tillage plots had been maintained since 1995. A sorghum [ Sorghum bicolor (L.) Moench]-soybean [ Glycine max (L.) Merr.] rotation was initiated in 2003, with both crops grown each year in a randomized complete block design. The plots in sorghum were instrumented to measure water content throughout the profile. Precipitation and evapotranspiration (ET) were determined at the field scale. Soil hydraulic properties and water content data were used to estimate drainage. Runoff was determined as the residual in this water balance. Evaporation from chisel tillage was up to 1 mm d -1 greater than that from no-till during the early season. This resulted in differences in surface water content and runoff. These effects were limited to the early season, however, so that the water balance for the full growing season was not significantly affected by tillage. Drainage from the claypan soil was negligible. The 2006 crop year had 23.5 cm of ET, a value greater than the in-season precipitation. The 2007 crop year had 33.5 cm of ET, a value less than the in-season precipitation. With limited drainage and storage in the claypan, 37.5 cm of runoff occurred in 2007.
  • Authors:
    • Pierzynski, G.
    • Tuppad, P.
    • Janssen, K.
    • Maski, D.
    • Douglas-Mankin, K.
  • Source: Transactions of the ASABE
  • Volume: 53
  • Issue: 5
  • Year: 2010
  • Summary: Cropland best management practice recommendations often combine tillage and nutrient application improvements to reduce nutrient losses with surface runoff. This study used the Soil and Water Assessment Tool (SWAT) model to evaluate nutrient runoff yields from conventional-till and no-till management practices with surface and deep-banded fertilizer application in a sorghum-soybean rotation. The model was calibrated for three field plots (0.39 to 1.46 ha) with different combinations of practices and validated for three field plots (0.40 to 0.56 ha) during 2001 to 2004. Daily performance of the calibrated SWAT model in simulating total N for all treatments was satisfactory for median-based Nash-Sutcliffe model efficiency (E f* of 0.54 to 0.64), good to very good for percent bias (PBIAS of 31% to 7%), and satisfactory to good for median-based root mean square error to observations standard deviation ratio (RSR* of 0.72 to 0.62). Performance was slightly lower and more variable for total P calibration (E f* of 0.42 to 0.62, PBIAS of -48% to 2%, and RSR* of 0.76 to 0.62). Monthly statistics improved for total P runoff yield compared to daily performance, but changed little for total N runoff yields, probably due to the stronger influence of outliers in the N data. Based on validation results, SWAT was more robust in simulating total N runoff yields from the treatment with less soil disturbance (NT/SB) and total P for the two treatments with more soil disturbance (NT/DB and TILL). A major concern was that SWAT predicted greater annual average total N runoff yields for no-till treatments than for tilled treatments, which was contrary to measured values at the study site. This reinforces a fundamental research issue that tillage system effects on nutrient losses are still very much uncertain and thus may not be properly modeled. The SWAT model generally underpredicted monthly total N yields for all treatments in the higher-precipitation months of May and June and overpredicted total N and total P yields from September through November. Calibration for N and P resulted in identical calibration parameters for NPERCO (1.0), RSDCO (0.05), BIOMIX (0.2), PPERCO (10), PHOSKD (175), and UBP (50) regardless of tillage practice or fertilizer application method. Together with results that calibrated parameters for runoff (CN, K sat, AWC) and erosion (C min) differed among the treatments, this study found that differences in nutrient yields among tillage and fertilizer management may be adequately modeled with SWAT by calibrating runoff and sediment yields only, and that further calibration of nutrient parameters may not improve model results.
  • Authors:
    • Sweeney, D.
    • Kelley, K.
  • Source: Crop Management
  • Issue: July
  • Year: 2010
  • Summary: Field studies were conducted from 1996 through 2006 in southeastern Kansas to evaluate the influence of previous crop [corn, Zea mays L.; grain sorghum, Sorghum bicolor (L.); and soybean, Glycine max (L.) Merr.] and tillage system (conventional versus no-till) on grain yield of hard red winter wheat ( Triticum aestivum L.) and double-crop soybean in a 2-year rotation. On average, wheat yield was greater following corn or soybean than following grain sorghum. Yield of double-crop soybean averaged 20% greater when wheat followed corn or grain sorghum than when wheat followed full-season soybean. Tillage system influenced grain yield of double-crop soybean more than it influenced wheat yield. Double-crop soybean yield often was greater for continuous no-till than for conventional or one-time no-till per cropping cycle. Soil analyses at the end of the study showed that total C and total N were greater for no-till than for conventional in the 0- to 3-inch depth, but total C and total N were greater for conventional than no-till in the 3- to 6-inch depth. In the multi-cropping systems of the eastern Great Plains, both crop rotation and tillage system can significantly influence grain yield and selected soil properties.
  • Authors:
    • Stone, L.
    • Schlegel, A.
    • Klocke, N.
    • Blanco-Canqui, H.
    • Rice, C.
  • Source: Soil Science Society of America Journal
  • Volume: 74
  • Issue: 4
  • Year: 2010
  • Summary: Deficit irrigation is an important strategy to manage water, but its impacts on soil C sequestration and physical properties have not been well documented. We assessed changes in soil organic C (SOC) and soil inorganic C (SIC) concentrations and selected soil physical properties at two no-till experiments on Ulysses silt loam (a fine-silty, mixed, superactive, mesic Aridic Haplustoll) with <1% slope under six irrigation treatments (66, 86, 117, 152, 182, and 217 mm of water applied) at Garden City and three (127, 254, and 381 mm of water applied) at Tribune in western Kansas after 5 and 8 yr of management, respectively. For the 0- to 10-cm depth, SOC concentration and wet aggregate stability increased with an increase in irrigation amount, but bulk density, particle-size distribution, and SIC concentration were unaffected. At Garden City, the SOC pool in the 0- to 10-cm depth increased by 46% (11.2 vs. 16.4 Mg ha -1) from the lowest (66 mm) to the highest (217 mm) irrigation amount. At Tribune, the SOC concentration in the 5- to 10-cm soil depth increased by 30% when the irrigation amount increased from 127 (7.8 g kg -1) to 254 (10.2 g kg -1) mm. The amount of macroaggregates increased with an increase in the irrigation amount, particularly in the 5- to 10-cm depth. At Garden City, irrigation-induced increase in SOC concentration increased the mean weight diameter of aggregates ( r=0.66; P<0.001). Overall, deficit irrigation affected SOC concentration and soil structural development near the soil surface, but the magnitude of impacts was site specific.
  • Authors:
    • Sundermeier, A.
    • Diedrick, K. A.
    • Dygert, C. E.
    • Mullen, R. W.
    • Henry, D. C.
  • Source: Agronomy Journal
  • Volume: 102
  • Issue: 1
  • Year: 2010
  • Summary: Inclusion of a winter legume cover crop into a crop rotation has been suggested as a method to provide a substantial portion of the N requirement of the following crop. While the benefits of winter cover crops such as reduced soil erosion, increased soil organic matter, and increased mulch cover have been well documented, the N contribution to the subsequent crop has shown to be variable. The objective of this study was to determine the N contribution from a red clover (Trifolium pratense L.) cover crop following wheat (Triticum aestivum L.) to a subsequent corn (Zea mays L.) crop. The experiment was conducted at two western Ohio locations over 3 yr. At both locations, red clover was either interseeded into wheat or seeded after harvest, the red clover cover crop was eliminated with tillage or herbicide application, and corn was planted with three N rates (0, 90, and 180 kg N ha(-1)). The data revealed that for three of the four site years (when the cover crop was successfully established) there was no N contribution attributable to the presence of red clover. The one site that did show a N contribution revealed that the amount of N contributed was less than 90 kg N ha(-1). However, even when no N benefit was found, yields were improved by non-N-related rotational effects. Significant reductions in N fertilization rates following a red clover cover crop are likely to result in lost corn yield opportunities in western Ohio.
  • Authors:
    • Yang, D. W.
    • Lei, H. M.
  • Source: Global Change Biology
  • Volume: 16
  • Issue: 11
  • Year: 2010
  • Summary: In China, croplands account for a relatively large form of vegetation cover. Quantifying carbon dioxide exchange and understanding the environmental controls on carbon fluxes over croplands are critical in understanding regional carbon budgets and ecosystem behaviors. In this study, the net ecosystem exchange (NEE) at a winter wheat/summer maize rotation cropping site, representative of the main cropping system in the North China Plain, was continuously measured using the eddy covariance technique from 2005 to 2009. In order to interpret the abiotic factors regulating NEE, NEE was partitioned into gross primary production (GPP) and ecosystem respiration (R(eco)). Daytime R(eco) was extrapolated from the relationship between nighttime NEE and soil temperature under high turbulent conditions. GPP was then estimated by subtracting daytime NEE from the daytime estimates of R(eco). Results show that the seasonal patterns of the temperature responses of R(eco) and light-response parameters are closely related to the crop phenology. Daily R(eco) was highly dependent on both daily GPP and air temperature. Interannual variability showed that GPP and R(eco) were mainly controlled by temperature. Water availability also exerted a limit on R(eco). The annual NEE was -585 and -533 g C m-2 for two seasons of 2006-2007 and 2007-2008, respectively, and the wheat field absorbed more carbon than the maize field. Thus, we concluded that this cropland was a strong carbon sink. However, when the grain harvest was taken into account, the wheat field was diminished into a weak carbon sink, whereas the maize field was converted into a weak carbon source. The observations showed that severe drought occurring during winter did not reduce wheat yield (or integrated NEE) when sufficient irrigation was carried out during spring.