Soil resilience and nitrogen transformations in soils of three Kentucky organic farms

Organic farm management requires soil building practices such as cover cropping and does not allow chemical fertilizers. Enhanced soil biological activity is a goal of many organic farmers. The ability of three organically managed soils to resist change in or to recover biological functions after perturbation (soil resilience) was related to properties affected by management. Managing nitrogen (N) in organic farm systems is challenging. Partitioning of N among various forms was quantified. Because organic farmers' soil management practices are directed by knowledge and beliefs about soil, Kentucky organic farmers were interviewed.; Undisturbed soils on two organic farms had higher soil quality than cropped soils on those farms, as measured by organic matter content, light fraction organic matter, and selected physical properties. Cropped and undisturbed soils were similar in resilience to perturbation for soil enzymes measured. Organically cropped soils on a research farm did not differ in soil quality characteristics or resilience from undisturbed soil on that farm.; Cropped soils had more N in mineral forms at all times than undisturbed soils, but undisturbed soil had more potentially mineralizable N. Added N was not fully assimilated into organic forms over a brief incubation in any soil. Gross N-mineralization rates were similar for cropped and undisturbed soils over a 6-d incubation. If N-retention is a goal, management attention should be paid to light fraction organic matter, a strong sink for N.; Organic farmers are likely to concentrate on building soil organic matter rather than on managing N. They do not consider N-toss a problem. Organic matter is difficult to increase because most organic management practices are land- and labor-intensive. Attention to N-management as well as organic matter could benefit organic farms. The land grant university could best help organic farmers by encouraging the creation of markets and infrastructure appropriate to organic farming.