Characteristics of Nitrogen Balances of Large-scale Stock Farms and Reduction of Environmental Nitrogen Loads

Abstract

We calculated nitrogen balances on farm gate and soil surface on large-scale stock farms and discussed methods for reducing environmental nitrogen loads. Four different types of public stock farms (organic beef, calf supply and daily cows) were surveyed in Aomori Prefecture.
(1) Farm gate and soil surface nitrogen inflows were both larger than the respective outflows on all types of farms. Farm gate nitrogen balance for beef farms were worse than that for dairy farms.
(2) Soil surface nitrogen outflows and soil nitrogen retention were in proportion to soil surface nitrogen inflows.
(3) Reductions in soil surface nitrogen retention were influenced by soil surface nitrogen inflows.
(4) In order to reduce farm gate nitrogen retention, inflows of formula feed and chemical fertilizer need to be reduced.
(5) In order to reduce soil surface nitrogen retention, inflows of fertilizer need to be reduced and nitrogen balance needs to be controlled.