Yasukazu Hosen

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N2O and NO emissions from an Andisol maize field were studied. The experimental treatments were incorporation of urea into the plough layer at 250 kg N ha–1 by two applications (UI250), band application of urea at a depth of 8 cm at 75 kg N ha–1 plus incorporation of urea into the plough layer at 75 kg N ha–1 (UB150), band application of polyolefin-coated(More)
Because rice is critical for food security in so many of the poorest countries, investments in the rice sector should be designed to alleviate poverty and meet the food demands of still growing—and increasingly urbanized—populations. In all rice environments vital ecosystem services— such as biodiversity, groundwater recharge, and flow regulation—in(More)
This experiment was conducted in maize field plots to study the effects of controlled release and application depth of urea on soil microbial biomass and activities at two depths of surface soil of a Japanese Andisol from June to September, 2001. Three N amendment treatments and a Control were included in this experiment: deep application (8 cm) of(More)
Many factors are concerned in the changing forms of nitrogen compounds in soil, so it is not easy to make precise models to simulate the concentration profiles of soil nitric oxide (NO) and nitrous oxide (N2O) and their emission rates under various soil conditions. We prepared a simple mathematical simulation model based on soil concentration profiles of NO(More)
A modeling study revealed that the depth of nitric oxide (NO) production in soil is crucial for its flux, while that of nitrous oxide (N2O) is not. To verify this result, laboratory experiments with soil columns classified as Andisol (Hydric Hapludand) were conducted, with changing the depth of urea application, at 0–0.1 or 0.1–0.2 m. All the NO(More)
Nitrogen wet deposition was monitored for two years (2001.6-2003.5) at the Changshu Ecological Station in Taihu Lake region. The results showed that the amount of nitrogen wet deposition had a strong seasonal pattern, with higher levels in summer and spring, and low values in autumn and winter. The proportions of NH4(+)-N, NO3(-)-N and DON (dissolved(More)
Methane (CH4) emissions from paddy fields are believed to contribute to the greenhouse effect. Yet, in the literature, only a few reports are available on the effects of soil moisture regime and straw application in the non-rice-growing season separately on CH4 emissions during the rice-growing season. The objective of this study was to investigate CH4(More)
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