Nitrogen transformations and loss in flooded soils and sediments

Reddy, K. R.; Patrick, W. H.; Broadbent, F. E.

doi:10.1080/10643388409381709

Cited by 421 publications

(255 citation statements)

References 151 publications

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“…This would be especially true for the alkaline soils due to their high pH and the presence of calcite (Singh and Nye 1986). Indeed, floodwater pH in the pot trials (pH 7.5-10.5) was high enough to support substantial NH 3 volatilization losses (Reddy and Patrick 1984). We observed consistently higher NH 4 + concentrations in the floodwater of C treatments, which confirmed the suppression of volatilization (Chen et al 1998) and underlined the importance of volatilization losses on the alkaline soils.…”

Section: Discussionsupporting

confidence: 72%

Effect of Straw Application on Rice Yields and Nutrient Availability on an Alkaline and a pH-neutral Soil in a Sahelian Irrigation Scheme

Asten

Bodegom

Mulder

et al. 2005

Nutr Cycl Agroecosyst

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Like elsewhere in the Sahel, actual rice yields (3-5 t ha À1 ) are far below yield potential (±8 t ha À1 ) in an irrigation scheme in central southern Mauritania. Earlier studies showed that yields are especially low on alkaline soils due to N and P deficiency. We investigated the potential of rice straw application as a mean to improve yields and fertilizer efficiency on an alkaline soil (pH 8.2) and a pH-neutral soil (pH 6.2). Application of 5 t straw ha À1 increased yields by 1.1 t ha À1 on average, independent of soil type and fertilizer dose. Contrary to our study, similar studies in Asia showed little short-term effects of straw on yield and N uptake. Straw application improved N availability, but not P availability. The improved N availability was attributed to N mineralized from the straw, from increased mineralization of soil organic matter (SOM) with a low C:N ratio (<7.2) and from increased mineral fertilizer N (urea) recovery efficiency. We deduced that improved N fertilizer recovery upon straw application was due to reduced nitrification-denitrification losses. On the alkaline soil, volatilization was important, but that process seemed unaffected by straw application. We hypothesize that the positive effects of straw application at our study site are due to low soil C content (<43 g kg À1 ) and low C:N ratio compared to most lowland rice soils in Asia.

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Section: Discussionsupporting

confidence: 72%

Effect of Straw Application on Rice Yields and Nutrient Availability on an Alkaline and a pH-neutral Soil in a Sahelian Irrigation Scheme

Asten

Bodegom

Mulder

et al. 2005

Nutr Cycl Agroecosyst

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“…Furthermore, from the stepwise regression analyses it can be deduced that, within this mesocosm experiment, there is an overall control of potential DEA by soil nitrate concentrations with respect to the agricultural grassland soils. This is in line with earlier studies (e.g., Reddy and Patrick Jr. 1984;Groffman and Tiedje 1989;Schipper et al 1993). Additional analyses revealed that indeed in both soil types nitrate and/ or carbon addition increased DEA (not shown).…”

Section: Mesocosm Application Considerationssupporting

confidence: 81%

Response of nitrogen dynamics in semi-natural and agricultural grassland soils to experimental variation in tide and salinity

et al. 2007

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In the framework of rehabilitation efforts to enhance the ecological value of closed-off estuaries, we studied the effects of restoring a tidal movement and seawater incursion on soil nitrogen conversion rates and vegetation response of semi-natural and agricultural grasslands in an outdoor mesocosm experiment. Intact soil monoliths including vegetation were collected in June 2004 on two locations on the shores of the Haringvliet lagoon in the southwestern part of the Netherlands, which used to be a well-developed estuary before closure in 1970. For more than 1 year, soil monoliths were continuously subjected to a full-factorial combination of tidal treatment [stagnant/tidal (0.20 m amplitude)] and water type [(freshwater, oligohaline (salinity = 3)]. Soil, soil moisture and water nitrogen concentrations were monitored for a year, as well as vegetation response and nitrogen conversion rates in the soil. As expected, nitrogen mineralization rates were enhanced by the tidal treatment in comparison with the stagnant treatment. Denitrification rates however, were much less affected by tide and were even lower in the tidal treatments after 3 months in the agricultural grassland soils, implying that in general, soils were more oxic in the tidal treatments. Oligohaline treatments had virtually no effect on soil nitrogen conversion rates compared to freshwater treatments. Vegetation performance, however, was lower under saline conditions, especially in the semi-natural grassland. No further significant differences in response to the tidal and oligohaline treatments were found between the two soils although they differed strongly in soil characteristics. We conclude that if the rehabilitation measures in the former Haringvliet estuary are carried out as planned, drastic changes in soil nitrogen processes and vegetation composition will not occur.

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“…However, wetland vegetation transports atmospheric oxygen through the stem, to the root, and into adjacent soil, which may oxidize the reduced microzone around the root surface (Armstrong, 1964;Brix & Schierup, 1990). Two distinct layers are formed around a root surface favoring nitrification-denitrification (Reddy & Patrick, 1984). Trapped sediments provide ammonification sites; nitrification can utilize ammonification product in the aerobic water, surface sediments and root surface; and denitrification occurs in the underlying sediment, releasing dinitrogen or nitrous oxide.…”

Section: External Sources Of Nitrogen In the Littoral Zonementioning

confidence: 99%

Spatio-temporal distribution of nitrogen in the undulating littoral zone of Lake Taihu, China

et al. 2007

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Nitrogen transformations and loss in flooded soils and sediments

Cited by 421 publications

References 151 publications

Effect of Straw Application on Rice Yields and Nutrient Availability on an Alkaline and a pH-neutral Soil in a Sahelian Irrigation Scheme

Effect of Straw Application on Rice Yields and Nutrient Availability on an Alkaline and a pH-neutral Soil in a Sahelian Irrigation Scheme

Response of nitrogen dynamics in semi-natural and agricultural grassland soils to experimental variation in tide and salinity

Spatio-temporal distribution of nitrogen in the undulating littoral zone of Lake Taihu, China

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