Browsing by Author "Lötjönen, Sanna"

The aim of this study was to find out how crop rotations with legumes in comparison to monocultures affect nutrient runoff from cultivation and profitability. We looked at five period monocultures of wheat, barley and oats. In the rotations considered two periods were replaced by red clover-grass or pea-horse bean mixtures. Results from rotations were compared with the ones from monocultures. Rotations were studied in private and social optimum and the case of common agricultural policy. According to the results it is possible to reduce nitrogen runoff with the use of legumes in crop rotations. Reductions were achieved by two means: lower average nitrogen runoff of legumes and residual effect from biologically fixed nitrogen which allows reducing fertilization in the next period. The average reductions in nitrogen runoff were higher in rotations based on pea-horse bean due to its lower optimal fertilization rate compared to red clover-grass. However, average per grain runoff was reduced more with red clover-grass due to its greater residual effect. Average nitrogen runoff was reduced in all cases expect for red clovergrass based rotations in social optimum where the variation in buffer strips made the difference. Private and social profitability were the highest for red clover-grass and adding it to grain monocultures increased both private and social profits. If the demand as fodder was too low cultivation of red clover-grass was unprofitable. Pea-horse bean had the lowest profitability and adding it to grain monocultures reduced profits.