• Authors:
    • Licht, M. A.
    • Yin, X.
    • Al-Kaisi, M. M.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 105
  • Issue: 4
  • Year: 2005
  • Summary: Soil organic C (SOC) and total N (TN) contents play a crucial role in sustaining agricultural production systems. Short-term (<=10-year) management effects on SOC and TN dynamics are often complex and variable. Three experiments were conducted to evaluate short-term tillage and cropping system effects on SOC and TN within the 0-30 cm soil depth across Iowa. The first experiment with no-tillage and chisel plowing treatments was established in 1994 on Clarion-Nicollet-Webster (CNW), Galva-Primghar-Sac (GPS), Kenyon-Floyd-Clyde (KFC), Marshall (M), and Otley-Mahaska-Taintor (OMT) soil associations under a corn (Zea mays L.)-soybean (Glycine max (L.) Merr.) rotation. The second experiment with no-tillage, strip-tillage, chisel plowing, deep ripping, and moldboard plowing treatments was initiated in 1998 on the CNW soil association in a corn-soybean rotation. The third experiment consisting of smooth bromegrass (Bromus inermis Leyss.), switchgrass (Panicum virgatum L.) and corn-soybean-alfalfa (Medicago sativa L.) treatments was established in 1991 on Monona-Ida-Hamburg (MIH) soil association under no-tillage management. Short-term tillage effects on SOC and TN occurred primarily at the 0-15 cm soil depth. Tillage effects did not vary significantly with soil association. No-tillage resulted in greater SOC and TN contents than chisel plowing at the end of 7 years of tillage practices averaged over the CNW, GPS, KFC, M, and OMT soil associations. The increase in SOC and TN with no-tillage was not related to SOC and TN stratification in the soil profile or annual C and N inputs from crop residue, but most likely due to decreased mineralization rate of soil organic matter. However, tillage effects on SOC and TN were negligible at the end of only 3 years of tillage practices on the CNW soil association. Smooth bromegrass and switchgrass systems resulted in greater SOC and TN contents at both 0-15 cm and 15-30 cm soil depths than a corn-soybean-alfalfa rotation after 10 years of management on the MIH soil association. Smooth bromegrass and switchgrass systems increased SOC by 2.3 and 1.2 Mg ha-1 yr-1 at the 0-15 cm soil depth, respectively. We conclude from these short-term experiments that reducing tillage intensity and increasing crop diversity to include perennial grasses could be effective in improving C and N sequestration in Midwest soils.
  • Authors:
    • Hadatsch, S.
    • Milestad, R.
  • Source: Conservation Ecology
  • Volume: 8
  • Issue: 1
  • Year: 2003
  • Summary: Farming in the Austrian Alps is small in scale and involves a high degree of manual labor. In the face of structural changes in agriculture, alpine farms are finding it increasingly difficult to remain economically viable. Organic farming presents a promising alternative for alpine farmers because it receives considerable financial support under the Common Agricultural Policy of the European Union. Recent years have seen an increase in the number of organic farms in Austria in general, and in alpine areas in particular. Using data from an empirical study carried out in the alpine area of Solktaler, Austria, this paper examines the issues of how closely the regulations and principles of organic farming match farmers' perspectives on sustainable agriculture and whether or not organic farming is capable of building social-ecological resilience for local farms. Qualitative interviews and a series of workshops were used to learn about farmers' "desired system state" with regard to their region, disturbances to this system, and their perspectives on organic farming. The desired system in Solktaler as formulated by the farmers depicts a vivid farming community that manages a diverse traditional agricultural landscape and performs a number of ecological services. The desired system and the principles of organic farming have several aspects in common, and many management practices and features of the social system support social-ecological resilience. The vulnerability of farms increases, however, when farmers must deal with structural changes in agriculture, the erosion of traditional ecological knowledge, and societal transformation. In conclusion, organic farming is a tool that can be used to build social-ecological resilience for Solktaler farms, because it secures economic funding for the area and makes it possible to sustain environmentally benign practices. What remains is the question of whether the farming community is capable of reorganizing the social system under the pressures of modernization so that the desired system state can be reached.
  • Authors:
    • McCarl, B. A.
    • Adams, D. M.
    • Alig, R. J.
  • Source: Journal of Agricultural and Applied Economics
  • Volume: 30
  • Issue: 2
  • Year: 1998
  • Summary: The forest and agriculture sectors are linked by having a portion of their land bases suitable for use in either sector. A substantial part of the southern land base is suitable for either forestry or agriculture use, with most of forestation on U.S. agriculture land in the South. We examine how land exchanges between forestry and agriculture are influenced by specific federal conservation and farm support policies, including changes in the Conservation Reserve Program. Reallocation of land is a significant part of the sectors' responses to the policies, along with intensification of timber management on existing southern forests.