Nutrient flows are calculated for dairy farms in three countries: The Netherlands, Spain and Poland. Incoming flows are compared with outgoing flows, where a distinction is made between nutrients that leave the farm in the form of farm products and other flows. Non-product flows are considered as undesirable although they may contain storage of nutrients in the soil. Efficiency of farm production is expressed as total amount of unutilized nutrients per hectare (nutrient surplus) or as part of available nutrients that are recovered in the products (nutrient efficiency). This allows comparison of efficiency rates in the countries that were studied. 

Nutrient efficiency is calculated for the use of nitrogen, phosphorus and potassium, being the most important nutrients in agriculture. Specific data for dairy farming were lacking for Spain and Poland. In these cases, general data were used. 

Large differences are found between the countries. Nutrient surplus is very high in The Netherlands, where efficiency is low: about 20% of the available nitrogen and 35% of phosphorus and potassium is recovered in farm products. Surplus of nutrients in Spain is limited to 65kg of nitrogen and less than 10kg of phosphorus and potassium. Polish agriculture fully utilizes available phosphate and potassium while nitrogen surplus is less than 30kg per hectare. Efficiency rates in this country are very high (50 to 100%). They are about double of those in Spain. 

Differences that are found between countries reflect differences in production background. They refer to other farm styles, where production takes place under specific policy or economic conditions. Figures on The Netherlands apply to intensive and specialized in dairy farms, while data for Spain and Poland refer to general and mixed farming conditions. Using comparable, average data for The Netherlands does not change the outcome. This is due to the high animal density (number of animals per hectare) and general intensive farming practices in this country. 

The influence of policy environment on nutrient applications and efficiency is demonstrated by a comparison of efficiency rates in Dutch dairy farming during different years. It appears that policy measures like production quotation has lead to a steady improvement of nutrient efficiency (efficiency increased with 40%). Likewise, economic changes in Poland have lead to a strong decline in fertilizer and feed purchases per farm. This has had however limited effect on nutrient efficiency. 

Comparison of efficiency rates should be accompanied by an analysis of farming conditions. While most figures relate to averages of large numbers of farms in different areas, little is known of the effect this has on the outcome of the calculations. Nutrient efficiency can vary enormously between farm types or regions. Studies reveal that these differences probably are related to animal density, fertilizer application and production of animal feed. 

Notwithstanding the use of average and general data it is felt that the outcome of this study sheds some light on different production practices in Europe and the efficiency of nutrient use in The Netherlands, Spain and Poland. The outcome, however, is general and not applicable to specific local production situations.