ECONOMIC ANALYSIS APPROACHES TO POTATO-BASED INTEGRATED CROP SYSTEMS: ISSUES AND METHOD
In response to stagnating yields and mounting pest problems, Michigan potato growers are investigating ways to bring manure and cover crops back into potato production systems. The alternative systems bring benefits and costs for monetary net returns, the variability of net returns, and environmental impacts. This paper reviews the likely yield and biological system effects of alternative potato production systems that incorporate manure and cover crops. After briefly considering research designs for gathering experimental versus farm field data, it reviews four economic analysis methods for evaluating alternative systems. All methods are illustrated with examples. First, for evaluating comparative average profitability, it reviews a) enterprise budgets, b) partial budgets, and c) break-even analysis. Second, for integrating environmental impacts into profitability analysis by using monetary measures of environmental effects, it introduces "green" budgets. Third, for evaluating efficiency trade-offs between profitability and environmental impacts, it covers trade-off frontiers. Finally, for comparing the variability of returns across systems (including for risk-averse decision makers), it introduces analysis of variance and stochastic dominance. These methods provide a basic set of tools for the economic analysis of changes in potato-based crop systems that should be adequate for most static comparisons of annual crop management practices.
Cover crops as a means of ecological weed management in agroecosystems
Weeds cause an estimated crop yield loss of about 43% world-wide. The heavy use of herbicides in weed management has several environmental and health risks. Therefore, systems-oriented approaches to weed management that make better use of alternative weed management tactics need to be developed. One of these approaches is the use of plants with strong weed-suppressing abilities as a component of integrated crop management. Cover crops are well-suited in such a holistic approach as they provide many other agroecosystem services besides suppressing weeds. However, compared to the use of herbicides, the use of cover crops as a weed management tool needs careful follow-up throughout the intended period to maximize the agroecosystem services they provide, minimize the disservices they exert, and optimize their selectivity between weed and crop suppression. Although there are many review papers that address the contribution of cover crops for managing weed problems in agroecosystems, few systematically address the difficulties that are encountered in fitting in the cover crops in the different cropping systems and the methods how to overcome these difficulties. Therefore, this paper is to examine how to maximize weed suppressive effects of cover crops and minimize the negative side effects of introducing cover crops into annual and perennial cropping systems and how to optimize selectivity between weeds and crops. We suggest further research regarding the selection of cover crops that are compatible with annual and perennial cropping systems under different climatic conditions and identify the traits responsible for adaptation in various cropping systems and environments.
Net returns from 12 cropping systems containing sugarbeet and navy bean
Considerable research has been conducted evaluating yield relationships among crops in various rotations and cropping systems. To compare cropping systems of different lengths of rotation and with different crops, however, a common measurement is needed. This paper evaluates annual net return to land and unallocated resources (ANR) from various cropping systems containing sugarbeet (Beta vulgaris L.), navy bean (Phaseolus vulgaris L.), corn (Zea mays L.), oat (Avena sativa L.), and alfalfa (Medicago sativa L.). Gross returns using representative crop prices are calculated for each cropping system for yield data from a 15-yr cropping systems study conducted on a Misteguay silty clay soil in the Saginaw Valley of Michigan. Costs in 1991 dollars of agricultural inputs, machinery ownership, repairs, maintenance, fuel, and wages are used to calculate expenses. ANR is calculated by subtracting pre- and postharvest operating costs plus machinery ownership costs from gross income for two farm sizes and two sugarbeet prices. With sugarbeet priced at $36/ton, systems with the greatest proportion of sugarbeet and also including navy bean have the highest ANR. The relative ranking of a cropping system's ANR did not change appreciably when farm size increased from 600 to 1000 acres. A sensitivity analysis shows that sugarbeet priced at or below $18/ton caused the relative ranking of the systems to shift and navy bean to become a more dominant factor in the ANR of these systems. While short rotations for sugarbeet and navy bean production may result in lower crop yields, the high economic return of these crops is probably the major reason growers do not employ longer rotations