Soil Use and Management Supplement:

This Special Issue compares soil fertility in soils farmed organically and conventionally, and examines whether the current concept of soil fertility adequately encompasses both these systems. The papers presented are part of several DEFRA and SEERAD funded projects, involving scientists from a range of backgrounds. Organic Farming has been proposed as a solution to problems associated with inputs of chemical fertiliser and pesticide, taking an ecological approach to nutrient supply and crop protection. However, it too sets environmental, human health, economic andproduction challenges that require co-ordinated research to be fully addressed. Organic producers seek to manage the rotation as an integrated whole, and central tothis integration is informed management of soil fertility. But careful soil managementis not the sole preserve of organic farmers; so is there anything that is qualitativelydifferent about soil fertility on organic farms? The issue begins by describing the nature and practice of organic farming with the aid of a review, and an exploration into how organic growers use a range of management practices to maintain and improve soil fertility, follows. Subsequent papers examine the key components of soil fertility by combining comprehensive review with information from new or recent research. A comparative study of nitrate leaching from farms managed conventionally or organically is the subject of a further contribution. The final paper examines important aspects of nutrient pools and nutrient transformations, drawing together the findings of the previous papers in reaching a definitive answer to the question of the adequacy of the current concept of soil fertility.