Objective:
i) Evaluate the effectiveness of alternative forage production systems utilizing animal manures on long-term P and K nutrient budgets, N leaching losses and soil organic carbon dynamics; ii) evaluate alternative rotations that open windows for application of manure, and increase feed production for dairy operations; and iii) design improved organic grain rotations that include manure inputs and produce feed for organic dairy operations.

Approach:
Improved management of dairy farms requires successful management of nutrient flows, both to maximize nutrient use by animals and crops in order to optimize profit, and to minimize nutrient loss to the environment in order to optimize sustainability. This SCA will continue to monitor long-term cropping systems trials (established 1990) that include three grain- and three forage-production systems. Of particular interest in this study, which includes the use of animal manures, is the comprehensive performance of these production systems. Specifically, participating scientists are not only interested in traditional agronomic measures of forage and grain production, but also in long-term P and K nutrient budgets, N leaching losses, and soil organic C dynamics. Another aspect of these studies seeks to develop conventional and organic crop-management strategies to facilitate the exchange of N, P, and K as manure and feed between neighboring dairy and cash-grain farms. This will be accomplished via on-station and on-farm trials. Finally, a grass ley concept that provides sites for summer manure applications onto perennial-forage sods will be evaluated in replicated plot trials, as well as through assessment of voluntary intake by replacement dairy heifers.