Soil Fertility Management and Grassland Renovation on Dairy Farms in Japan: Regional Differences between Hokkaido and Other Prefectures

抄録

In 2015-2016, we investigated the farmland management procedures used on dairy farms in Japan using a mail-back survey. In Hokkaido, 98% of the surveyed farms had meadows, 53% had pastures, and 49% had forage crop fields. In all other prefectures, 19% of farms had meadows, 10% had pastures, and 90% had forage crop fields. The median area of each field category per farm was greater in Hokkaido than in the other prefectures. In all places, the application rate of organic fertilizer decreased in the following order: forage crop field > meadow > pasture (37, 8.7, and 2.7 Mg-manure ha⁻¹ y⁻¹, respectively, in Hokkaido). In forage crop fields, organic fertilizer was applied at lower rates and inorganic fertilizer was applied at higher rates in Hokkaido than elsewhere (37 vs. 69 Mg-manure ha⁻¹ y⁻¹ and 42 vs. 22 kg-N ha⁻¹ y⁻¹ respectively). In meadows, organic fertilizer was applied at lower rates in Hokkaido (8.7 vs. 14 Mg-manure ha⁻¹ y⁻¹); however, inorganic fertilizer was applied at similar rates. The annual rate of grassland renovation with full-inversion tillage in 2006-2010 was 3.0% in Hokkaido and 1.3% in the other prefectures. In both regions, manure was intensively applied during grassland renovation.