DYNAMICS OF AVAILABLE NITROGEN IN PADDY SOILS : I. Changes in Available N during Rice Cultivation and Origin of N
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概要
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A field experiment was conducted to evaluate 1) the pool size of mineralized N, determined by flooded incubation of chloroform-fumigated soil (available N or MinNacf); 2) effects of N changes on the rice pant during cultivation; and 3) N turnover, determined by ^<15>N tracer technique. Three surface soils and one subsoil from Philippine paddy fields, placed in concrete tanks, were treated with ^<15>N labeled ammonium sulfate, flooded, and either planted to rice or kept fallow. The amount of ammonium N formed during incubation of unfumigated soil (MinN) was about 60-70% that of the ammonium N formed during incubation of fumigated soil (MinNacf). At the soil surface (0-1 cm), MinNacf contents increased in both the planted and unplanted plots. This increase was not observed when the penetration of light through the flood water surface of concrete tanks kept in the greenhouse was inhibited by layers of black cloth. Chlorophyll-type compounds and mineralized N after air-drying and re-flooded incubation also accumulated at the soil surface in proportion to the amount of MinNacf. Below the surface soil (1-15 cm deep) MinNacf contents in both planted and unplanted plots decreased gradually, but the differences in contents were slight. The ^<15>N abundance in ammonium-N found in concrete tanks and in MinNacf decreased with time. The ^<15>N applied was quickly incorporated into the MinNacf pool and its atom percent abundance first increased, and then decreased gradually during incubation, particularly in planted soils.
- 社団法人日本土壌肥料学会の論文
著者
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Watanabe Lwao
The International Rice Research Institute
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Inubushi Kazuyuki
The International Rice Research Institute
関連論文
- DIFFERENTIAL PHOSPHORUS REQUIREMENTS OF AZOLLA SPECIES AND STRAINS IN PHOSPHORUS-LIMITED CONTINUOUS CULTURE
- NITROGEN-FIXING (C_2H_2-REDUCING) ACTIVITY AND PLANT GROWTH CHARACTERS OF 16 WETLAND RICE VARIETIES
- PLANT ASSOCIATED N_2 FIXATION (C_2H_2-REDUCTION) BY FIVE RICE VARIETIES, AND RELATIONSHIP WITH PLANT GROWTH CHARACTERS AS AFFECTED BY STRAW INCORPORATION
- DYNAMICS OF AVAILABLE NITROGEN IN PADDY SOILS : II. Mineralized N Of Chloroform-Fumigated Soil as a Nutrient Source for Rice
- MICROBIAL BIOMASS NITROGEN IN ANAEROBIC SOIL AS AFFECTED BY N-IMMOBILIZATION AND N_2-FIXATION
- IMPROVEMENT OF PHOSPHATE FERTILIZER APPLICATION TO Azolla
- DYNAMICS OF AVAILABLE NITROGEN IN PADDY SOILS : I. Changes in Available N during Rice Cultivation and Origin of N
- ^N DILUTION TECHNIQUE OF ASSESSING THE CONTRIBUTION OF NITROGEN FIXATION TO RICE PLANT
- NITROGEN FIXATION ASSOCIATED WITH DEEPWATER RICE
- FATE OF NITROGEN FROM A BLUE-GREEN ALGA IN A FLOODED RICE SOIL
- RESPONSE OF WETLAND RICE TO INOCULATION WITH Azospirillum lipoferum AND Pseudomonas SP
- AVAILABILITY TO RICE PLANTS OF NITROGEN FIXED BY Azolla
- RELATIONSHIP BETWEEN SOIL PHOSPHORUS AVAILABILITY AND Azolla GROWTH