• Authors:
    • Taube, F.
    • Kluss, C.
    • Loges, R.
    • Claus, S.
    • Herrmann, A.
  • Source: CROP & PASTURE SCIENCE
  • Volume: 65
  • Issue: 6
  • Year: 2014
  • Summary: Greenhouse gas emissions (GHG) resulting from forage production contribute a major share to 'livestock's long shadow'. A 2-year field experiment was conducted at two sites in northern Germany to quantify and evaluate the carbon footprint of arable forage cropping systems (continuous silage maize, maize-wheat-grass rotation, perennial ryegrass ley) as affected by N-fertiliser type and N amount. Total GHG emissions showed a linear increase with N application, with mineral-N supply resulting in a steeper slope. Product carbon footprint (PCF) ranged between -66 and 119 kg CO(2)eq/(GJ net energy lactation) and revealed a quadratic or linear response to fertiliser N input, depending on the cropping system and site. Thus, exploitation of yield potential while mitigating PCF was not feasible for all tested cropping systems. When taking credits or debts for carbon sequestration into account, perennial ryegrass was characterised by a lower PCF than continuous maize or the maize-based rotation, at the N input required for achieving maximum energy yield, whereas similar or higher PCF was found when grassland was assumed to have achieved soil carbon equilibrium. The data indicate potential for sustainable intensification when cropping systems and crop management are adapted to increase resource-use efficiency.
  • Authors:
    • Smucker, A. J. M.
    • Basso, B.
    • Zhang, W.
    • Kavdir, Y.
  • Source: JOURNAL OF SOIL AND WATER CONSERVATION
  • Volume: 69
  • Issue: 5
  • Year: 2014
  • Authors:
    • Deichman, C. L.
    • Kremer, R. J.
  • Source: AGRONOMY JOURNAL
  • Volume: 106
  • Issue: 5
  • Year: 2014
  • Summary: The solar corridor crop system (SCCS) is designed for improved crop productivity based on highly efficient use of solar radiation by integrating row crops with drilled or solid-seeded crops in broad strips (corridors) that also facilitate establishment of cover crops for year-round soil cover. The SCCS is an agroecosystem with diverse system structure that should inherently provide many features to build soil quality. Management strategies include reduced tillage, intercropping, and soil conservation through crop residue retention, which are associated with improved soil quality attributes of enhanced C and N content, effective nutrient cycling, and high microbial activity. Our objective was to evaluate the effect of SCCS in 76- and 152-cm (corridor) row widths on selected soil quality indicators as an assessment of soil quality during establishment of SCCS. Microbial activity, measured as soil glucosidase activity, was highest in rhizosphere soils planted to corn ( Zea mays L.) hybrids at 74,000 plants ha -1 regardless of row width. However, soil glucosidase activity was strongly correlated ( r2=0.72) with active carbon (AC), and showed trends for increased contents in rows bordering the corridor. This suggested that increased carbon fixation by plants at the wide row spacing due to greater exposure to solar radiation also increased carbon substrates released into the rhizosphere for microbial metabolism. The limited soil quality assessment conducted in this study demonstrated that an integrated cropping system represented by the SCCS offers an effective management system for maintaining crop production while promoting soil quality and soil conservation.
  • Authors:
    • Schneider, D. A.
    • Lamb, D. W.
    • Stanley, J. N.
  • Source: PRECISION AGRICULTURE
  • Volume: 15
  • Issue: 5
  • Year: 2014
  • Summary: An integrated active optical, and passive thermal infrared sensing system was deployed on a low-level aircraft (50 m AGL) to record and map the simple ratio (SR) index and canopy temperature of a 230 ha cotton field. The SR map was found to closely resemble that created by a RapidEye satellite image, and the canopy temperature map yielded values consistent with on-ground measurements. The fact that both the SR and temperature measurements were spatially coincident facilitated the rapid and convenient generation of a direct correlation plot between the two parameters. The scatterplot exhibited the typical reflectance index-temperature profile generated by previous workers using complex analytical techniques and satellite imagery. This sensor offers a convenient and viable alternative to other forms of optical and thermal remote sensing for those interested in plant and soil moisture investigations using the 'reflectance index-temperature' space concept.
  • Authors:
    • Lehrsch, G. A.
    • Lentz, R. D.
  • Source: SOIL SCIENCE SOCIETY OF AMERICA JOURNAL
  • Volume: 78
  • Issue: 3
  • Year: 2014
  • Summary: Little is known about inorganic fertilizer or manure effects on organic C (OC) and inorganic C (IC) losses from a furrow irrigated field, particularly in the context of other system C gains or losses. In 2003 and 2004, we measured dissolved organic and inorganic C (DOC, DIC) and particulate OC and IC (POC, PIC) concentrations in irrigation inflow, runoff, and percolation waters (six to seven irrigations per year); C inputs from soil amendments and crop biomass; harvested C; and gaseous C emissions from field plots cropped to silage corn (Zea mays L.) in southern Idaho. Annual treatments included: manure treatment (M) 13 (Year 1) and 34 (Year 2) Mg ha-1 stockpiled dairy manure; inorganic fertilizer treatment (F) 78 (Year 1) and 195 (Year 2) kg N ha-1 inorganic N fertilizer; or no amendment treatment (NA) as a control. The mean annual total C input was 15.7, 10.8, and 10.4 Mg ha-1 for M, F, and NA, respectively, while total C outputs for the three treatments were similar, averaging 12.2 Mg ha-1. Manure plots ended each growing season with a mean net gain of 3.3 Mg C ha-1 (a positive net C flux) vs. a net loss for F and NA (-1.6 and -1.5 Mg C ha-1, respectively). The C added to M was ∼1.5 × that added to F or NA, yet relative to F, M increased gaseous C emissions only 1.18×, increased runoff DOC losses only 1.04×, decreased particulate runoff total C 19%, and decreased percolate DOC 32%. Increased C gas emissions from manure (relative to fertilizer) were less when silage was removed than when retained (1.18× vs. 2× reported in other studies). This suggests a means by which manure applications to corn crops can be managed to minimize C emissions. Amendments had both direct and indirect influences on individual C components, e.g., the losses of DIC and POC in runoff and DOC in percolation water, producing temporally complex outcomes, which may depend on environmental conditions external to the field. © Soil Science Society of America.
  • Authors:
    • Turner, N. C.
    • Fu, T. T
    • Wang, Y. P.
    • Hai, L.
    • Li, X. G.
    • Liu, X. E.
    • Li, F. M.
  • Source: SOIL SCIENCE SOCIETY OF AMERICA JOURNAL
  • Volume: 78
  • Issue: 4
  • Year: 2014
  • Summary: Alleviating the hydrothermal limitations to growth, clear film fully mulched ridge-furrow (FMRF) cropping significantly improves maize (Zea mays L.) grain yield on the Loess Plateau of China. Major concerns for FMRF cropping are the stability of maize productivity and whether the system is detrimental to the soil organic C (SOC) balance under changed hydrothermal conditions. We investigated the effects of maize production with FMRF and its effect on SOC concentration for five consecutive years from 2008 to 2012. Three treatments were imposed: no mulch (narrow ridges with the crop sown beside the ridges), half mulch (the same as no mulch, except the narrow ridges were mulched), and full mulch (i.e., FMRF; alternate narrow and wide ridges, all mulched, with maize in furrows). The 5-yr average of the grain yield was 3.8 Mg ha -1 under no mulch. Half and full mulch increased the grain yield by 68 and 102%, respectively, relative to no mulch. Root biomass was 69 and 104% greater under half and full mulch, respectively, than no mulch. The maize yield and biomass differed among years depending on the growingseason precipitation and its distribution, but the increased yield and biomass from mulching was consistent in all years. The mulch stimulated SOC mineralization and enzymatic activity but had no effect on light (density <1.8 gcm-3) and total SOC concentrations compared with no mulch. We conclude that increased SOC mineralization under FMRF was offset by increased SOC addition; FMRF cropping increased maize productivity without detriment to the SOC balance. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA All rights reserved.
  • Authors:
    • Venterea, R. T.
    • Maharjan, B.
  • Source: JOURNAL OF ENVIRONMENTAL QUALITY Pages:
  • Volume: 43
  • Issue: 5
  • Year: 2014
  • Summary: Anhydrous ammonia (AA) is a major fertilizer source in North America that can promote greater emissions of nitrous oxide (N 2O) than other nitrogen (N) fertilizers. Previous studies found that injection of AA at a shallow depth (0.1 m) decreased N 2O in a rainfed clay loam but increased N 2O in an irrigated loamy sand compared with the standard injection depth of 0.2 m. The objective of this study was to evaluate the effects of AA injection depth in a silt loam soil used for corn ( Zea mays L.) production and managed under two contrasting tillage regimes over two consecutive growing seasons (2010 and 2011) in Minnesota. In contrast with previous studies, AA placement depth did not affect N 2O emissions in either tillage system or in either growing season. Tillage by itself affected N 2O emissions only in the drier of two seasons, during which N 2O emissions under no tillage (NT) exceeded those under conventional tillage (CT) by 55%. Soil moisture content under NT was also greater than under CT only in the drier of the two seasons. Effects of AA placement depth and long-term tillage regime on N 2O emissions exhibit intersite as well as interannual variation, which should be considered when developing N 2O mitigation strategies. Further study is needed to identify specific soil, climate, or other factors that mediate the contrasting responses to management practices across sites.
  • Authors:
    • Gregorutti, V. C.
    • Novelli, L. E.
    • Melchiori, R. J. M.
    • Caviglia, O. P.
  • Source: AGRONOMY JOURNAL
  • Volume: 106
  • Issue: 5
  • Year: 2014
  • Summary: Nitrogen fertilization often increases maize ( Zea mays L.) grain yield but reduces the C/N ratio of stover returned to the soil, which may affect the soil organic carbon (SOC) balance. This study evaluated the long-term effect of N fertilization on maize grain yield, stover quality in terms of its C/N ratio, and its effect on SOC. In addition, a simulation approach was used to account for the effect of stover quality on its mineralization and SOC balance. Maize grain yield, stover production and quality, and SOC stock were measured during a 6-yr period (2006-2012) in a long-term N fertilization experiment under continuous maize since 1994 in Parana, Argentina. On average, grain yield ranged from 5.06 in 2011 to 9.10 Mg ha -1in 2009. The N effect on grain yield, significant in all seasons, was more important than the effect on C stover production. In contrast, stover C/N ratio showed a linear decrease as a function of N fertilization. Changes in the stover C/N ratio were inversely proportional to the difference between the N rate and the agronomical optimum nitrogen rate (AONR). Although N fertilization increased stover C inputs in 3 out of 6 yr, SOC stock remained unchanged. Simulation results indicate that the required stover amount to maintain the SOC stock increased as the C/N ratio decreased. Our results contribute to better understanding of the previous, controversial results of the N effect on SOC and provide useful insights to develop or improve simulation models for SOC dynamics.
  • Authors:
    • Kaspar, T. C.
    • Wiedenhoeft, M. H.
    • Moore, E. B.
    • Cambardella, C. A.
  • Source: SOIL SCIENCE SOCIETY OF AMERICA JOURNAL
  • Volume: 78
  • Issue: 3
  • Year: 2014
  • Summary: Corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] farmers in the upper Midwest are showing increasing interest in winter cover crops. The effects of winter cover crops on soil quality in this region, however, have not been investigated extensively. The objective of this experiment was to determine the effects of a cereal rye (Secale cereale L.) winter cover crop after more than 9 yr in a corn silage-soybean rotation. Four cereal rye winter cover crop treatments were established in 2001: no cover crop, rye after soybean, rye after silage, and rye after both. Soil organic matter (SOM), particulate organic matter (POM), and potentially mineralizable N (PMN) were measured in 2010 and 2011 for two depth layers (0-5 and 5-10 cm) in both the corn silage and soybean phases of the rotation. In the 0- to 5-cm depth layer, a rye cover crop grown after both main crops had 15% greater SOM, 44% greater POM, and 38% greater PMN than the treatment with no cover crops. In general, the treatments that had a rye cover crop after both crops or after corn silage had a positive effect on the soil quality indicators relative to treatments without a cover crop or a cover crop only after soybean. Apparently, a rye cover crop grown only after soybean did not add enough residues to the soil to cause measureable changes in SOM, POM, or PMN. In general, rye cover crop effects were most pronounced in the top 5 cm of soil.
  • Authors:
    • Kadžiuliene, Ž.
    • Venslauskas, K.
    • Navickas, K.
    • Nekrošius, A.
    • Tilvikiene, V.
  • Source: ZEMDIRBYSTE-AGRICULTURE
  • Volume: 101
  • Issue: 3
  • Year: 2014
  • Summary: The research was aimed to investigate the energy biomass productivity and biogas production from silage of different perennial grasses with evaluation of greenhouse gas emissions through the entire process from biomass cultivation to processing. The experiments with perennial grasses-cocksfoot (Dactylis glomerata L.), tall fescue (Festuca arundinacea Scherb.) and reed canary grass (Phalaris arundinacea L.) were carried out at Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry in 2008-2010. The swards were grown in an Endocalcari-Endohypogleyic Cambisol (CMg-n-w-can), which contained: organic carbon-1.61-1.75%, available P-145-224 mg kg-1and K-128-158 mg kg-1, soil pH ranging between 6.7-7.0. The three perennial grass species with varying yields of biomass were used to ensure a steady operation of the selected biogas plant of 500 kWeelectric power. The different quantities of biomass feedstock and varying energy input are required for such biogas plant. Therefore all data correspond to a biogas cogeneration plant of 500 kWe electric power. Required land area for the same amount of energy produced depends on species of perennial grasses, rates of fertilization and number of cuts. These results mainly depended on the biomass productivity and biogas yield from dry mass. Biomass yield from dry matter in the first year of use of tall fescue cut twice per vegetation season was higher compared to that cut three times, while cocksfoot and reed canary grass yielded better cut three times compared to cut twice. The highest yield was obtained in tall fescue swards cut twice and fertilized with N180. The total balance of greenhouse gas emissions showed their mitigation and ranged from 0.206 to 0.298 kg CO2eq kWh-1.