Mixed crop-livestock systems and conservation tillage: Farm profitability, adoption potential, and environmental impacts.

摘要

This research focused on two types of mixed crop-livestock systems: i) a sodbased rotation (SBR) in Southeastern US that incorporates bahiagrass (Paspalum notatum Fluegge) and conservation tillage (CT) in the conventional cotton-peanut rotation; and ii) a potato-pasture rotation (Solanum tuberosum - Lolium perenne) in Colombia that incorporates CT to reduce water pollution with plant nutrients. The objectives of this study were: 1) to assess the adoption potential of SBR in Southeastern US; 2) to analyze SBR's profitability relative to those of the conventional rotation; and 3) to evaluate the effect of conservation and conventional tillage in the trial system in Colombia on nutrient losses and concentrations in runoff.;For the first objective, response to surveys disseminated by mail, were used to build an empirical model to test what characteristics might be associated with willingness to adopt the SBR. Results indicate that 45% of respondents were willing to practice SBR and that the probability of a positive response of adoption is higher for farmers that: a) feed animals with products other than hay and grazed pastures; (b) first heard about SBR through an extension visit to their farm; (c) do not receive government payments; (d) use intensive tillage methods; (e) are growing peanuts and cotton; (f) have farm sales per year in the range of US;For the second objective, a linear programming model was used to determine the SBR's profitability. The results show that for peanut-cotton producers, SBR can generate important increases in net revenues (over US;The third objective achieved by performing a field experiment, between 2011 and 2013 found that impacts of CT vary in accordance with soil type and precipitation variability between cropping cycles. In general, CT reduced nutrient losses in Inceptisols while it did not do so in Andosols. P concentrations in runoff water in all rotations and of nitrate-N in potato with CT and oats were above the recommended limits.