Soil can be conserved at any degree or level between zero and approximately 100 percent. Also, in conserving soil at a given level (say at a level that permits an average soil loss of 7 tons per acre annually), various methods or combinations of methods are usually ·available. Intertilled, small grain and forage crops can be combined in varying proportions. The mechanical practices of contouring, strip cropping or terracing can be substituted for years of legumes and grasses in the crop rotation. Since there is a choice in level of soil conservation and in methods by which a given level can be achieved, these questions arise: What is the most profitable level of soil conservation over time? What is the least-cost or most profitable method of attaining this level?

One of the major farm management problems in western Iowa is that of adjusting farming systems to control erosion. The erosive nature of Ida-Monona soils arises out of their vertical structure and their steep and long slopes. Past farming practices have given rise to a large amount of gullying. Three to four large gullies per farm are not uncommon in the area. The soils are inherently productive, but the problem is the extent to which they can be maintained through the use of erosion control systems of farming. Our questions are these: Will shifting from soil-exploitive to soil-conserving farming systems increase farm income for tenants and for landlords? What are the costs, capital requirements and returns for tenants and landlords? Are conventional lease arrangements obstacles to either tenants or landlords in making the shift? Are some lease arrangements obstacles while others are not? How can leases be altered to facilitate shifts to soil-conserving farming systems?