Soil Fertility Management for Organic Crops

Abstract

Organic vegetable production systems are guided byan overriding philosophy of “feed the soil to feed theplant.” This basic precept is implemented through aseries of approved practices designed to increase soilorganic matter, biological activity, and nutrient availability.Over time, adding organic materials such asgreen manure, crop residues, and composts to cultivatedsoils builds levels of soil organic matter. As soilorganic matter increases, the ability of the soil to supplynutrients to crops also increases. The ultimate goal is ahealthy, fertile, biologically active soil with improvedstructure and enhanced nutrient availability.Many soil amendments and fertilizers commonlyapproved for organic production systems have appreciableamounts of nutrients, but only a portion of thesenutrients are available to the current crop. Organic soilfertility programs are designed to maintain adequatelevels of nutrients in the soil nutrient pool and to augmentthe pool as needed. Management practices striveto optimize diverse biological processes in the soil tocreate a complex environment that ensures adequatenutrition to the crop. For a discussion of related soilmanagement practices, see Soil Management and SoilQuality for Organic Crops (UC ANR Publication 7248).