Environmental and economical sustainability of organic dairy farms

In the project titled - Environmental and economic sustainability of organic dairy farms - (Norwegian name: Miljømelk), we are investigating environmental effects and economy on 20 dairy farms, 10 organic and 10 conventional, in the county of Møre og Romsdal. The number of dairy cows on each farm varied from 13 to 69 cows (average 29). One cow produced on average 5800 kg milk on organic farms and 8200 kg on conventional. There are, however, large variations between the farms, with the largest variation among the organic ones. Less nitrogen was imported through fertilizers and fodder per kg produced milk and meat on organic than on conventional farms. Nitrogen surplus was calculated as nitrogen supplied (concentrates, fertilizers, roughage, livestock, biological nitrogen fixation) minus nitrogen sold from the farm (milk, meat, fodder and livestock). Large variation in nitrogen efficiency among the farms indicate that there is a potential for improved utilization of added nitrogen. The surplus of phosphorous varied also largely between the farms, mostly on conventional farms because some phosphorous also was used in mineral fertilizers. However, phosphorous in imported concentrates has the largest impact, resulting in a phosphorous surplus on most farms, even organic ones. Energy use per sold unit is an important environmental indicator. Energy is used in the form of fuel and electricity, but also indirect in fertilizers, plastic, concentrates, machines and buildings. Energy used to produce these agricultural inputs are included in the energy estimates. Most energy on organic farms was used for concentrates and fuel/electricity. On conventional farms, the energy to produce fertilizers increased the energy consumption. As there were no good data on the amount of energy bound in Norwegian agricultural buildings, we estimated the amount of energy that was used to produce the building materials used in the agricultural buildings on our 20 farms. The amount of energy used per cow place varied considerably. The amount of bound energy in the buildings increase with increased basal area per cow, insulation, and with concrete walls replacing wood. Preliminary results show that the amount of energy bound in agricultural buildings varies from 4 to 25 % of the total yearly energy consumption on the farms. The results will be valuable for recommendations on how to reduce the amount of energy required for construction of new agricultural buildings. Estimated greenhouse gas emissions, with all emissions from supply chain included, were in average 47 CO2 equivalents per ha on organic farms, and 192 on conventional farms. Estimated per unit product there were only minor differnces between the two production forms. There are no models adapted for Norwegian conditions, where emissions of greenhouse gases, use of energy, nitrogen, phosphorous and potassium are studied in coherence. We are developing such a model together with the Institute for Organic Farming, vTI, in Germany, to facilitate studying the coherences in our data. It is at the same time a model that has a large transfer value to other projects.

Environmental, economical and social sustainability is a fundamental goal for organic farming, but may be hampered by rapid farming structural changes. To analyze and evaluate the environmental and economical sustainability of organic dairy farms in Mør e og Romsdal County. Secondary objectives: A. To adapt existing tools to describe environmental effects of farm management on Norwegian dairy farms. B. To evaluate the environmental and economic sustainability of organic dairy farms. C. To evaluate the effect of farm size on the sustainability of organic dairy farms. D. To evaluate the effect of intensity on the sustainability of organic dairy farms. Accomplishment: A German model (REPRO) will be adapted to Norwegian conditions. The environmental effec ts of dairy farming will be estimated using these indicators: - Nutrient balances (N, P and K) on farm and field level. - Nutrient efficiency (N, P and K) per area of agricultural land and per produced kg of milk and meat. - Energy balance on farm level. - Emission of greenhouse gases on farm level (CO2, N2O and CH4). - Carbon balance. Environmental and economical sustainability will be studied on ten organic dairy farms in Møre og Romsdal County and ten conventional dairy farms as references. Emphasis w ill be put on effect of farm size (area and herd size) and intensity (produced milk per unit agricultural land and per cow, and ratio of purchased fodder per produced unit of milk and meat).