Estimation of farmyard manure application levels in nitrogen base by using the 2000 census of agriculture and forestry.

摘要

A new method to evaluate farming households' behaviours concerning farmyard manure application to fields and to estimate the distribution diversity of manure application levels in nitrogen base per unit area for agricultural land in Kyushu and Okinawa regions (8 local governments), Japan, was developed by using the personal questionnaire data of the 2000 Census of Agriculture and Forestry (Permission for Personal Data Use, No. Sohtohshin-333, dated on 6 September 2002). Livestock farming households were hypothesized to treat excess production of livestock manure after standard application to their fields as follows. The livestock farming households, who used their own or common treatment facilities and who exchanged raw manure for litter, would move their excess production to crop farming households, who applied manure to their fields at standard application levels. The livestock farming households, who did dig-and-throw or field-heaping, would apply all their excess products to one field. Other livestock farming households would equally apply their excess products to their grasslands. This simulation gave several manure application levels in nitrogen base; Standard (210 kg N ha-1 for grassland, 140 kg N ha-1 for upland, 70 kg N ha-1 for paddy field), overplus to grassland and extreme excess to one dig-and-throw field. The area ratios of fields with overplus application (more than 400 kg N ha-1) to total agricultural land were estimated as follows; 6.7% (Fukuoka Prefecture), 8.0% (Saga Prefecture), 20.8% (Nagasaki Prefecture), 18.2% (Kumamoto Prefecture), 16.3% (Ohita Prefecture), 31.1% (Miyazaki Prefecture), 23.5% (Kagoshima Prefecture), and 18.6% (Okinawa Prefecture). The volume ratios of the applied overplus farmyard manure to total production in nitrogen base were estimated as follows; 55.9% (Fukuoka Prefecture), 73.2% (Saga Prefecture), 78.1% (Nagasaki Prefecture), 72.5% (Kumamoto Prefecture), 65.0% (Ohita Prefecture), 83.0% (Miyazaki Prefecture), 74.4% (Kagoshima Prefecture), and 71.5% (Okinawa Prefecture).