• Authors:
    • Dick, W.
    • Lal, R.
    • Kadono, A.
    • Kumar, S.
  • Source: SOIL SCIENCE SOCIETY OF AMERICA JOURNAL
  • Volume: 77
  • Issue: 2
  • Year: 2013
  • Authors:
    • Steinriede Jr., R. W.
    • Zablotowicz, R. M.
    • Locke, M. A.
    • Testa, S.
    • Reddy, K. N.
  • Source: SOIL SCIENCE SOCIETY OF AMERICA JOURNAL
  • Volume: 77
  • Issue: 3
  • Year: 2013
  • Summary: Conservation practices are increasingly important components of sustainable management systems, and information about their influence on soil characteristics is needed. Soil parameters were assessed in no-till (NT) or minimum tillage (MT) cotton (Gossypium hirsutum L.) production near Stoneville, MS, Mississippi Delta region, that included cover crop (rye [Secale cereal L.] or Balansa clover [Trifolium michelianum Savi var. balansae (Boiss.) Azn.]) vs. no cover crop. Soils (0-2, 2-5, and 5-15 cm) were sampled (2001-2006) before cotton planting. Independent of tillage, both cover crops accumulated more soil C than no cover, and N was greatest under clover. Soils (0-15 cm) under clover had greater aggregate stability than rye or no cover. The major factor influencing bulk density and infiltration was proximity to crop row bed and wheel traffic, but infiltration rates were sixfold greater under MT than NT (P rye or no cover). Moderate tillage slightly increased abundance of both reniform nematodes and earthworms, but neither was affected by cover crop. Fluorescein diacetate hydrolytic activity was higher in clover (50%) and rye (20%) in surface soil than with no cover. Soil microbial community structure (total fatty acid methyl ester analysis) (2005-2006) indicated a significant cover crop effect but no tillage effect. Mycorrhizal bioindicator (16:1 w5c) was greater in soil with rye than clover or no cover; however, cotton mycorrhizal infection was 40% greater in fibrous roots from rye or clover plots than roots from plots with no cover. Collectively, cotton production with a cover crop and reduced tillage resulted in soil conditions indicative of soil quality.
  • Authors:
    • Vigil, M. F.
    • Mikha, M. M.
    • Benjamin, J. G.
  • Source: SOIL SCIENCE SOCIETY OF AMERICA JOURNAL
  • Volume: 77
  • Issue: 2
  • Year: 2013
  • Summary: Long-term conservation tillage improves soil quality by enhancing soil structure, improving water availability, and reducing soil erosion. We investigated the effect of tillage intensity on soil organic carbon (SOC), organic carbon fractions, particulate organic matter (POM), and wet aggregate-size distribution after 39 yr of management. The data reported here were taken from a long-term tillage study initiated in 1967 near Akron, CO. Treatments sampled were conventional tillage (CT), moldboard plow (MP), no-tillage (NT), and reduced tillage (RT). In 2006, soil samples were collected from the 0- to 5-, 5- to 10-, 10- to 20-, 20- to 30-, and 30- to 60-cm depths in winter wheat (Triticum aestivum L.)-summer fallow (WF). Soils were fractionated for aggregate mass and POM-mineral-associated carbon (C) to evaluate the form and stability of SOC. On a fixed-depth basis, NT and RT had 21% more SOC, at the 0- to 30-cm depth than CT and MP. However, on equivalent mass basis (ESM), SOC was greater with NT, MP, and RT by 11% compared with CT. Conservation practices, NT and RT, had more macroaggregation and consequently greater soil stability compared with CT and MP. Tillage practices significantly impacted whole SOC distribution between POM-C and mineral-associated organic matter C (MAOM-C). The POM-C vs. MAOM-C component of the whole SOC was 23 vs. 77% at 0 to 5 cm and 10 vs. 90% at 5- to 20-cm depth. The POM-C associated with NT and RT, accounted for 17% of SOC where POM-C accounted for 12% of SOC with CT and MP at 0- to 20-cm depth. Redistribution and stratification of SOC, POM, and POM-C were observed especially with MP. Over all, we found the application of conservation tillage practices to be crucial for maintaining soil quality and soil C stock in the WF systems of the central Great Plains.
  • Authors:
    • Echeverría, H. E.
    • Vidaurreta, A.
    • Wyngaard, N.
    • Picone, L. I.
  • Source: SOIL SCIENCE SOCIETY OF AMERICA JOURNAL
  • Volume: 77
  • Issue: 5
  • Year: 2013
  • Summary: Phosphorus in the soil particulate fraction (PF, >53 μn) has been described to have a significant importance in P cycling. However, there is no information regarding the effect of management practices over P-PF and its association with soil organic carbon (SOC) dynamics. Changes in total phosphorus (Pt), inorganic phosphorus (Pi), organic phosphorus (Po), Bray-P, and SOC through time were evaluated in the whole soil, in the PF and in the associated fraction (AF, <53 μm). Two different tillage systems: conventional tillage (CT) and no-till (NT), and two fertilization treatments: N (no P fertilization) and NP (30 kg ha-1 yr-1) were evaluated. Tillage systems did not modify Pt, Pi, Po, or SOC in any fraction. A 0.32 g kg-1 yr-1 decrease in SOC-PF was observed, which was accompanied by a reduction of Po-PF (-0.87 mg kg-1 yr-1). This decrease was associated with the incorporation of soybean [Glycine max (L.) Merr.] and the elimination of pastures from the original crop rotation. The Pi in N plots diminished in PF, AF, and the whole soil (-0.35, -2.82, and -3.15 mg kg -1 yr-1, respectively), but it was not affected in NP plots due to the adsorption of P, which was limited in PF (41.47 mg kg -1). Bray-P concentration also decreased through time in N (2.2 mg kg-1 yr-1) but not in NP, indicating that even though P fertilization can replenish the available inorganic P pool in the soil, SOC, and Po-PF are still depleted by the use of intensive cropping rotations, consequently reducing soil fertility.
  • Authors:
    • Gramig, B. M.
    • Clawson, R. A.
    • Andrews, A. C.
    • Raymond, L.
  • Source: JOURNAL OF SOIL AND WATER CONSERVATION
  • Volume: 68
  • Issue: 6
  • Year: 2013
  • Summary: In this paper, framing effects are investigated in a new context: farmer decision making about conservation tillage practices. Primary hypotheses include the following: (1) frames (i.e., different arguments about or conceptions of an issue) portraying conservation tillage as "profitable" will generate more interest in the tillage technique among farmers than a control frame presenting only basic information; (2) frames discussing potential payments for "environmental benefits" will generate more positive attitudes than frames discussing payment for "storing carbon (C)" to limit climate change; and (3) framing effects will vary based on subjects' prior beliefs and experiences. These hypotheses were tested using a survey-based experiment administered to a national sample of row-crop farmers. Contrary to expectations, the profit frame and both payment frames had no effect on farmers' interest in conservation tillage across our entire sample. Consistent with the third hypothesis, however, a negative framing effect was found for the profit frame on nonadopters who reported no use of no-till in the past two years. These results support the argument regarding the importance of prior beliefs in reactions to frames. They also suggest the possibility of modest financial payments "crowding out" intrinsic motivations for contributions to public goods such as soil conservation. From a policy perspective, these findings also suggest the relative inefficacy of offers of modest conservation payments or profitability frames in promoting no-till farming, especially among nonadopters, and the need to find alternative frames that avoid reinforcing an argument that nonadopters appear to have already considered and rejected.
  • Authors:
    • Shaver, T. M.
    • Mamo, M.
    • Drijber, R. A.
    • Wortmann, C. S.
    • Shapiro, C. A.
    • Blanco-Canqui, H.
    • Ferguson, R. B.
  • Source: Web Of Knowledge
  • Volume: 68
  • Issue: 5
  • Year: 2013
  • Authors:
    • Labreuche, J.
    • Cohan, J. P.
    • Dimassi, B.
    • Mary, B.
  • Source: Agriculture Ecosystems and Envirtoment
  • Volume: 169
  • Year: 2013
  • Summary: Although continuous no-till (NT) is recommended for erosion control and carbon sequestration, it often has a limited duration since farmers alternate between NT and full inversion tillage (FIT) to control weed infestation and avoid soil compaction. In this paper, we evaluate the effect of continuous tillage and tillage conversion of NT to FIT and vice versa on SOC and SON stocks, in a long-term experiment at Boigneville in Northern France. Continuous NT (CNT) and FIT (CFIT) treatments were established in 1991 and maintained until 2011 while half of the plots were converted in 2005: from CNT to new FIT (NFIT) and CFIT to new NT (NNT). Bulk densities and organic C and N contents were determined in 2001 and 2011 down to the old ploughing depth ( opd) which was also measured. SOC and SON stocks were calculated at equivalent soil mass by correcting either bulk densities or the opd. Both methods produced very close results and similar conclusions. A typical gradient of SOC and SON concentrations vs depth was observed in CNT as opposed to a rather uniform distribution in CFIT. CNT resulted in SOC concentration in the top soil (0-5 cm) higher by 38% in 2001 and 53% in 2011 compared to CFIT. Conversely, it led to a SOC reduction in the deeper layer ( ca. 10-28 cm) by 14% in 2001 and 18% in 2011. The global effect was no significant change in SOC and SON stocks between treatments over the old ploughed layer (4060 t soil ha -1) in both years: 43.2 and 45.0 t C ha -1 in 2001 and 44.7 and 45.8 t C ha -1 in 2011, in CNT and CFIT, respectively. In 2011, six years after tillage conversion, the stratification of SOC and SON had disappeared in NFIT whereas a new one had appeared in NNT with a smaller gradient than in CNT. SOC or SON stocks over the old ploughed layer did not differ significantly between treatments after 6 years of conversion: SOC stocks were 45.8, 43.2, 44.7 and 43.1 t C ha -1 in the CFIT, NFIT, CNT and NNT treatments, respectively. Furthermore, SOC stocks below the old ploughed layer ( ca. 28-40 cm) were slightly greater in FIT than in NT treatment (10.9 vs 8.7 t C ha -1). In this experiment, continuous or conversion tillage did not result in any C sequestration benefit.
  • Authors:
    • Gimeno, B. S.
    • Gattinger, A.
    • Lassaletta, L.
    • Aguilera, E.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 168
  • Year: 2013
  • Summary: Mediterranean croplands are seasonally dry agroecosystems with low soil organic carbon (SOC) content and high risk of land degradation and desertification. The increase in SOC is of special interest in these systems, as it can help to build resilience for climate change adaptation while contributing to mitigate global warming through the sequestration of atmospheric carbon (C). We compared SOC change and C sequestration under a number of recommended management practices (RMPs) with neighboring conventional plots under Mediterranean climate (174 data sets from 79 references). The highest response in C sequestration was achieved by those practices applying largest amounts of C inputs (land treatment and organic amendments). Conservation tillage practices (no-tillage and reduced tillage) induced lower effect sizes but significantly promoted C sequestration, whereas no effect and negative net sequestration rates were observed for slurry applications and unfertilized treatments, respectively. Practices combining external organic amendments with cover crops or conservation tillage (combined management practices and organic management) showed very good performance in C sequestration. We studied separately the changes in SOC under organic management, with 80 data sets from 30 references. The results also suggest that the degree of intensification in C input rate is the main driver behind the relative C accumulation in organic treatments. Thus, highest net C sequestration rates were observed in most eco-intensive groups, such as "irrigated", "horticulture" and controlled experiments ("plot scale"). (C) 2013 Elsevier B.V. All rights reserved.
  • Authors:
    • Blanco-Canqui, H.
  • Source: BioEnergy Research
  • Volume: 6
  • Issue: 1
  • Year: 2013
  • Summary: Crop residue removal for bioenergy can deplete soil organic carbon (SOC) pools. Management strategies to counteract the adverse effects of residue removal on SOC pools have not been, however, widely discussed. This paper reviews potential practices that can be used to offset the SOC lost with residue removal. Literature indicates that practices including no-till cover crops, manure and compost application, and return of biofuel co-products increase SOC pools and may thus be used to offset some SOC loss. No-till rotations that include semi-perennial grasses or legumes also offer a promise to promote soil-profile C sequestration and improve soil resilience after residue removal. No-till cover crops can sequester between 0.10 and 1 Mg ha(-1) per year of SOC relative to no-till without cover crops, depending on cover crop species, soil type, and precipitation input. Animal manure and compost contain about 15 % of C and thus their addition to soil can enhance SOC pools and boost soil biological activity. Similarly, application of biofuel co-products such as biochar, which contain between 45 % and 85 % of C depending on the feedstock source and processing method, can enhance long-term C sequestration. These mitigation strategies may maintain SOC pools under partial residue removal in no-till soils but are unlikely to replace all the SOC lost if residue is removed at excessive rates. More field research and modeling efforts are needed to assess the magnitude at which the different mitigation strategies can overcome SOC loss with crop residue removal.
  • Authors:
    • Jarosz, Z.
    • Faber, A.
    • Borzecka-Walker, M.
    • Syp, A.
    • Pudelko, R.
  • Source: Journal: Food, Agriculture and Environment (JFAE)
  • Volume: 11
  • Issue: 1
  • Year: 2013
  • Summary: The production of bio diesel from rape seed, in accordance with Directive 2009/28/EC (RED), requires estimation on greenhouse gas (GHG) emissions in the life cycle of bio fuels and reduction size in comparison to diesel as fossil fuel. The study sought a reduction in GHG emissions from agriculture, in the full life cycle of Fatty Acid Methyl Esters (FAME) by optimisation of nitrogen fertilisation of rape seed, the selection of fertilisers with lower emissions arising from their production and increased organic carbon sequestration in the soil by the use of reduced or no tillage (direct sowing). It was found that an optimisation of the nitrogen (N) dose and manipulations of fertiliser N type does not guarantee a 50% reduction in GHG emissions. The reduction of GHG emissions under reduced tillage, which increases the organic carbon sequestration in the soil, is achievable only at a dose of 150 kg N ha(-1) in the form of a urea ammonium nitrate (UAN) solution or mixture of ammonium nitrate + ammonium sulphate. The increase of organic carbon sequestration in the soil through the conversion of conventional oilseed rape cultivation to a no tillage system increases the reduction of GHG emissions by 58-63% at a dose of 150 kg N ha(-1) and 54-59% at a dose of 180 kg N ha(-1).