Reduction of nitrogen surplus by material circulation between dairy farms and arable crop farms in the mixed production area, Japan

The problematic of nitrogen surplus in mixed production areas might be reduced by exchanging nitrogen-containing material between dairy farms and arable crop farms, e.g. livestock manure and wheat straw as bedding material, respectively, or by temporary land exchange. Estimating the influence of the nitrogen surplus by material circulation between 133 dairy farms and 115 arable crop farms in a certain district, the nitrogen surplus decreased by 0.05 Gg N/year because 0.18 Gg N/year of nitrogen surplus was decreased at dairy farms even though 0.135 Gg N/year of nitrogen surplus was increased at arable crop farms. These results indicated that the material circulation between livestock farms and arable crop farms is effective to decrease the nitrogen surplus in the region.