Conservation Tillage Systems and Soil Productivity

This chapter reviews the benefits from conservation tillage (CT) systems, with emphasis on tillage goals and their consequent value to resource conservation. An understanding of causes and effects is necessary to clarify the relations, first, by quantifying the most important ends or goals of tillage, then by developing theoretical relations between these goals and their effects on runoff, water erosion, wind erosion, and other resource-related damages or benefits. The chapter then reviews existing schemes for guiding the use of CT technology as related to soils, climate, topography, and crop rotations. National soils and other data banks should be useful for expansion of these schemes. The chapter also gives a skeleton overview of crop yield trends for CT systems as compared to conventional tillage systems. It further suggests areas for research emphasis to assure that the national objective to achieve maximum adoption of CT systems is consistent with limiting natural and biological features.