Book of Abstracts
11th IFOAM Scientific Conference
11-15 August 1996, Copenhagen, Denmark
Research Station for Ecological Agriculture, Agricultural Research Centre, FIN-51900 Juva
The nutrient management of six cattle farms was studied during five years in the South-Savo district of Finland by means of farm gate balances of nitrogen, phosphorus and potassium. Two of the farms were conventionally cultivated, but they used clover-grass leys, two converted during the study period to ecological farming and the other two had been cultivating according to ecological or almost similar methods for a few years. The study material was based mainly on taxation book keeping and milk records.
The changes in the nutrient management were clearly a consequence of the agricultural environmental policy of the Finnish government. The use of fertilizer phosphorus on conventional farms decreased after the phosphorus tax had come into force, and the compulsory fallowing increased the nutrient surplus on the farms due to increased fodder purchase. On farms under conversion and on ecological farms the use of rock powders biotite and apatite increased due to the conversion subsidy. The dairy farms converting to ecological farming suffered from lack of forage, which resulted in purchase from neighbouring farms. This increased remarkably the input of potassium and nitrogen to the farms.
The relation of farm gate balances and the soil analyses of soluble nutrients in the study was rather weak. The content of soluble phosphorus in the soils of almost every farm decreased independently from the phosphorus surplus in the phosphorus balance. However, the increased use of biotite contributed to the increase of exchangeable potassium in the soils. The nutrient farm gate balance is a good tool for planning nutrient management on ecological farms where nutrient economy is based on recycling. The use of rock powders should not be included in the balances because of their long-lasting nutrient effects. The mineralization rhythm of nutrients from rock powders is still under study.