Comparative assessment of soil properties and economic return of alternative farming systems

Trivendhiran Pillai

Agricultural intensification has resulted in a number of environmental and social concerns that threaten the sustainability of current farming systems, including reliance on nonrenewable resources, reduced biodiversity, water and air pollution, soil degradation, chemical residues in food, and health risks to farm workers handling pesticides. In order for a farm to be sustainable, it must demonstrate the capacity to (1) raise sufficient yields of high quality; (2) be profitable; (3) protect the environment and conserve natural resources; and (4) be socially responsible. During 2001 to 2002, five alternative agroecosystems were established at the USDA Palouse Conservation Field Station (PCFS) near Pullman, WA, in order to compare and contrast how diverse farming systems performed with respect to sustainability criteria. The five agroecosystems consisted of two continuous no-till, annual cropping systems, one with continuous cereals (NTC) and one with a grain legume (NTL); two perennial-based systems, one a native prairie grass system that would qualify as a Conservation Reserve Program planting (NAT) and one a perennial wheat-based system using advanced, but unreleased lines of perennial wheat (PAT); and one low soil disturbance organic agroecosystem (OAT) that would qualify as certified organic. The objectives of the project were to (1) compare and assess rates of change soil organic carbon (SOC) and nitrogen (SON), soil pH, measures of soil biological activity, and soil bulk density after five years of farming system establishment; (2) determine the financial performance of the five alternative farming systems after five years; and (3) use these data to inform any recommendations for future farming system modifications required to meet sustainability goals. During the four years, SOC and SON increased at surface depths for all farming systems, but overall stocks (0-20 cm) changed more slowly. Particulate organic carbon (POC) and particulate organic nitrogen (PON) increased at all depths across all farming systems and POC/SOC was approaching levels found in native Palouse soils in the surface 0-5 cm. Soil pH was less acidic and biological activity [(dehydrogenase enzyme activity (DH) and substrateinduced respiration (SIR)] was greater in surface soil of OAT and NAT compared to NTC, NTL, and PAT. Comparative economic analysis indicates the order of profitability as follows: NTL > NTC > NAT > NTW > PAT > OAT. PAT and OAT had negative net returns, which resulted in redesigning the two systems for future trials.

Comparative assessment of soil properties and economic return of alternative farming systems

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