A primary goal in developing environmentally sound and profitable farming systems has been to prevent soil degradation and erosion loss, and wherever possible, enhance soil quality through organic matter management. Conventional tillage practices currently used for vegetable production in the Willamette Valley involve from 5-8 passes over the field. For the past four years we have been working with vegetable growers in the Willamette Valley to develop an integrated system of vegetable production using winter annual cover crops and rotary strip- tillage.
Winter rye (Secale cereale L.) is an outstanding cover crop in its suppression of early season weeds. This suppression has been largely attributed to allelopathy; ryeís allelochemicals inhibit weed germination and growth. However, its lack of suppression of late season weeds and its inconsistent results between years and regions hinder the use of rye as a cover crop. This study, which is Part I of a 2-year project, explores a management method that may be used to increase weed suppression of rye by manipulating its allelopathic activity.
The production of organic processing tomatoes requires large inputs of organic sources of nitrogen. Besides the addition of compost, manure, and other organic amendments, leguminous cover crops, grown during the winter, are important sources of nitrogen for a subsequent tomato crop. Present management of cover crops for tomato production generally requires significant amounts of tillage that may retard the improvement of physical and chemical properties of the soil.