The Role of Soil Management in Crop Nutritional Quality and Susceptibility to Pests
Proponents of organic farming have long contended that their methods of soil management lead to healthy crops with higher nutritional value and greater resistance to insects and disease than crops grown using high-chemical fertility. These reports have been largely anecdotal, but recent studies support the idea of lower pest susceptibility in organic crops. The effects of different soil-management systems on crop nutritional quality remain largely unexplored. Although mineral nutrients are recognized to play an essential role in plant health, it is usually measured by plant yield. When soil-fertility recommendations are based on avoiding nutrient deficiencies that limit yield, there is strong incentive to apply more fertilizer than necessary since the only perceived trade-off is cost of fertilizer. The primary objective of the proposed research is to establish a more holistic view of soil management, requiring an expanded concept of plant health, "inclusive plant health," which includes nutritional quality and resistance to insects and disease.
To understand the interaction of soil management and inclusive plant health, we shall use on-farm research and controlled greenhouse experimentation. Initial whole-farm and greenhouse studies will demonstrate how nutritional quality and pest susceptibility differ between crops grown under organic and conventional management, while subsequent empirical studies will help to establish the mechanisms underlying this interaction. The project represents a collaboration between an interdisciplinary team of researchers and farmers who use different fertility management practices. Farmers will provide soil for greenhouse experiments, will provide records of fertility and pesticide inputs, and will allow surveys of pests on their farm. In addition, they will provide experiential knowledge for management variables to be tested and will act as scouts for pest outbreaks in fields other than those being surveyed.
In the broad sense, the work should: 1) contribute to reintegrating production systems, with a systems view of soil management and inclusive plant health; and 2) provide an economic incentive for adopting LISA practices through a reduced need for pesticide. More specifically, we expect the work to lead to: 1) reduced dependence on pesticide; 2) reduced use of inorganic fertilizers and increased use of plant/animal manures; 3) easier transition to LISA with regard to pests; 4) lower off-farm purchased inputs; and 5) potentially improved crop nutritional value and herd health. By both comparing organic and chemical fertility management and measuring the effects of mineral-nutrient balance, the proposed work will benefit the full spectrum of American farmers.
Findings will be disseminated through statewide farmer organizations and publications of the OSU Sustainable Ag Program. Results will also be used to assist farmers in conducting their own experiments. In so doing, farmers will become part of our outreach program, as their experiences increase the interest and confidence of other farmers in changing their soil management.