The Swedish Parliament, the government and the authorities have been working on measures to reduce eutrophication since the 1980s. The Board of Agriculture has designed computer software as an aid for plant nutrient extension services focused on environmental issues. This software, called VERA, can for instance be used to evaluate how various ways of handling manure affect the use of plant nutrient materials, or for calculating plant nutrient balances on the farm. Starting from 2001, advisors began to provide advice on the results of nutrient balances on individual farms.
‘Focus on Nutrients’ offers free advice to farmers. At the initial advisory visit on the farm, the farmer and the advisor discuss the need for additional advice and establish a nutrient balance for the farm. The nutrient balance shows the starting position of the farm, and the balance calculation is repeated once or several times during future visits. After seven advisory farm visits there is a follow-up, where the farmer and the advisor establish a new nutrient balance and evaluate actions carried out in different areas on the farm.
Focus on Nutrients has designed a system that compares balances before and after advisory services. Farms selected for inclusion in the analysis are those where the farmer has received at least four advisory visits, and at least two that include balance calculations. On average, six years have passed from the first to the most recent balance. The latest report of results include data from year 2000 to 2016. A total number of 3,428 conventional farms comprising 388,000 hectare and 572 organic farms with a total of 65,000 hectares were included in the calculations. Surpluses of nitrogen and phosphorus have declined significantly on most types of farm.
This long lasting work with nutrient balances in Sweden has proved to be a relevant tool for visualising nitrogen efficiency. Together with other tools such as field trials on optimum fertilisation rates, measurement of nitrogen plant uptake in field by sensors, soil tests and maps, it has shown that the surpluses have decreased on all type of farms. The Focus of Nutrient database is a valuable source of information when it comes to identifying the trends in nutrient efficiency in agriculture.
Stina Olofsson, Emma Hjelm and Hans Nilsson, Swedish Board of Agriculture, Elevenborgsvägen 4, Alnarp, Sweden
16 pages, 7 figures, 2 tables, 3 references