New means to assess manure management methods are presented using a global balance approach that consider environmental , agronomic and economical aspects. An important literature review was realized to evaluate the nutrients behavior of manure from the moment the manure is applied to soil. Certain aspects are well documented and can be used for a assessment of manure and they are: nitrogen volatilization, nitrogen (N) and phosphorus (P) run off, nitrogen availability during the first year and nutrients uptake by plants. However many other parameters needed to make the assessment are not documented or appropriate for Eastern Canadian conditions and they are: nitrogen denitrification, leaching (N, P, K) and N, P, K stocking and immobilization to soil particles. Considering those limits, it is difficult to elaborate a complete balance approach for nutrients in the farm manure from the first contact to soil at spreading through plant’s uptake. More research is needed to investigate those aspects of nutrients – soil interaction. As a result, the software, FECES, that was developed from the literature elements to help in nutrients (N,P, K) balance determination for specific cases, have to be used with caution. This software could be implemented as parameters are determined by research results. However the simulation helped pointing out that a vast majority of farmers put fertilizers in excess on their field: using mineral fertilizers and not really considering the nutrients contained in the manure they apply. Those excess outweighed the management practices they could use (ex: spring spreading rather than fall).

Better manure management practices have to be integrated in the whole nutrient balance of the farm considering the farm situation (crops, soils), the manure available and also the mineral fertilizers used. This report presenting an important literature review and software development is the result of a project founded by Quebec Environmental and Wildlife Ministry as part of special program of support of research and development in environment on better manure management practices.