Annual nitrogen leaching to subsurface drainage water from a clayey aquic soil cultivated with onions in Hokkaido, Japan

Dissolved N2O, CH4, and CO2emissions from subsurface-drainage in a structured clay soil cultivated with onion in Central Hokkaido, Japan

“…The nitrate concentration in the drainage ranged from 8.5 to 25.5 mg N L -I (Fig. If), which was similar to those recorded in the previous study (Hayashi and Hatano 1999).…”

“…The soil was classified into fine mesic mollic Fluvaquent (Soil Survey Staff 1999). Some physical and chemical properties of the soil horizons were described in the report of Hayashi and Hatano (1999).…”

“…They reported that the direct Np emission from this field increased in mid-summer (around harvest time) when abundant precipitation OCCUlTed, and that the direct N 2 0 emission ranged from 3.5 to 15.6 kg N ha-I in 1995to 2000. Hayashi and Hatano (1999 reported that the annual N leaching through subsurface-drainage from this onion field was 179 kg N ha-I year-I, which corresponded to 58% of applied N, and that 95 kg N ha-I was leached during rain events from harvest to April, and that 21 kg N ha-I was leached in only 11 d during snowmelt.…”

Characteristics of nutrient load in a stream flowing through a livestock farm during spring snowmelt

“…Syversen (2002) showed that 90% of the annual P discharge from agricultural fields in Norway occurred in winter. Also, Hayashi and Hatano (1999) showed that 12 % of the annual N discharge from an onion field in Hokkaido occurred within 11 d of the snowmelt period. In Hokkaido, seasonally concentrated N discharges pose a high risk of eutrophication in coastal ecosystems.…”

Soil water conditions and flow characteristics in the subsoil of a volcanic ash soil: Findings from field monitoring from 1997 to 1999

“…Barbee and Brown (1986) showed that chloride concentrations sampled with a suction cup and a pan sampler were different for soils with macropores. Hayashi and Hatano (1999) also observed differences in the nitrate concentration in the soil solution and in water flowing out from a drain pipe in a clayey aquic soil. Most soils have both macropores and micropores, and the contribution of macropores to the downward flow is influenced not only by the soil structure but also by the intensity and amount of rainwater as well as previous soil water conditions.…”