Quantitative study on nitrification in flooded rice soil

Watanabe, Iwao; Padre, Benjamin C.; Santiago, S.

doi:10.1080/00380768.1981.10431292

Cited by 17 publications

(2 citation statements)

References 7 publications

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“…Nitrification rates were faster at the beginning of incubation than toward the end and ranged from 96 to <11 ng N g-~ soil h z (Table 3). Previous isotope dilution estimates of nitrification rates in unfertilized paddy soils ranged from between 4 and 10 ng N g-~ soil h -1 [18,26] to between 10 and 30 ng N g-~ soil h -~ [37]. Much faster rates have been measured in N-fertilized soil.…”

Section: Inhibition Of Nitrite Oxidation Nitrite Accumulated After 1mentioning

confidence: 99%

Estimation of nitrification rates in flooded soils

et al. 1995

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Three techniques for estimating nitrification rates in flooded soils were evaluated in short-term incubation experiments using three soils. The techniques were based on inhibition of either ammonium or nitrite oxidation and (13)N isotope dilution. Of four inhibitors of ammonium oxidation evaluated, one (allylthiourea) was ineffective and two (2-ethynylpyridine or phenyl acetylene dissolved in ethanol) promoted immobilization of ammonium. Emulsified 2-ethynylpyridine and acetylene were equally effective inhibitors of ammonium oxidation and had little or no effect on gross rates of N mineralization and immobilization. Four inhibitors of nitrite oxidation were evaluated, but this approach was compromised by the nonspecificity of three of the compounds-potassium cyanide, 2-ethylamino-4-isopropylamino-6-methylthio-s-triazine (ametryne) and 3-(3,4-dichlorophenyl)-1-methylurea (DMU)-and by the partial effectiveness of another (potassium chlorate). Two methods based on isotope dilution gave similar estimates of nitrification rates. These rates were similar to those estimated by inhibition of ammonium oxidation in one soil but were lower in the other two soils. In the latter two soils, nitrification of labeled ammonium derived from dissimilatory nitrate reduction resulted in underestimation of nitrification rates by isotope dilution.

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Section: Inhibition Of Nitrite Oxidation Nitrite Accumulated After 1mentioning

confidence: 99%

Estimation of nitrification rates in flooded soils

et al. 1995

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“…While some previous studies have observed a relationship between soil pH and denitrification rate, others did not ( Drury et al, ; Xu and Cai , ; Sun et al, ; Yu et al, ). Some previous studies also suggested that the denitrification rate in flooded soils could be regulated by nitrification rate, i.e ., the production of

{NO}_{3}^{-}

, rather than the activity of denitrification enzymes ( Watanabe et al, ; Harrison et al, ; Zhou et al, ). Thus, N losses through coupled nitrification–denitrification are also likely to be controlled by the rate of nitrification ( Rao et al, ; Chen et al, , 1998b; Zhou et al, ).…”

Section: Introductionmentioning

confidence: 99%

Nitrification is the key process determining N use efficiency in paddy soils

Wang

Zhao

Zhang

et al. 2017

J. Plant Nutr. Soil Sci.

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Nitrogen (N) fertilizer use efficiency (NUE) in flooded paddy fields is relatively low. Many N fertilizer management options have been proposed to enhance NUE and minimize environmental damage. However, few investigations are focusing on the role of the characteristics of soil N transformations in regulating NUE and N losses in paddy fields. In this study, we test the role of soil N transformations on NUE and N losses under rice growth conditions in two paddy soils collected from Jiangxi (JX) and Sichuan (SC) in China. The N recoveries of applied 15N either as nitrate or ammonium in plant and soil, and N losses estimated by 15N balance were investigated in rice pot experiments using a 15N tracing technique. The results showed that gross nitrification rates in soil collected from JX were much lower than those in soils collected from SC either at 60% water holding capacity (WHC) or rice growth (flooding) conditions, which could be due to the difference in soil pH. The NH4 + ‐N concentration in soil solution was maintained at a relatively high level for a long time period after N fertilizer application in the JX soil (41 d) compared to the SC soil (26 d), caused by different nitrification rates owing to different soil pH. The 15N uptake by rice in the JX soil (29–78%) was always significantly higher than that in the SC soil (22–54%), while N losses from the plant–soil system in the JX soil (17–21%) were always significantly lower than those from the SC soil (20–34%) at the same rice growth stage in the labeled 15N ammonium treatment. However, there were no significant differences in 15N uptake by rice and N losses in applied 15 NO3 - treatment between the two studied soils. These results indicate that nitrification, not denitrification, was the key process determining NUE and N losses in paddy soils. The results of the N application gradient experiment also indicated that higher amounts of N fertilizer should be applied for the same amount of N uptake, however, this caused higher N losses, in soils characterized by high nitrification rate (e.g., the alkaline soil). Results highlighted that soil N transformations in particular nitrification rate provided a very good guideline for an optimized N management.

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