Increasing nitrate removal at low temperatures by incorporating organic matter into paddy fields
Article first published online: 1 MAR 2010
© 2010 Japanese Society of Soil Science and Plant Nutrition
Soil Science & Plant Nutrition
Volume 56, Issue 1, pages 163–167, February 2010
How to Cite
TAKAHASHI, T., INAGAKI, H., FUKUSHIMA, T., OISHI, T. and MATSUNO, K. (2010), Increasing nitrate removal at low temperatures by incorporating organic matter into paddy fields. Soil Science & Plant Nutrition, 56: 163–167. doi: 10.1111/j.1747-0765.2009.00435.x
- Issue published online: 1 MAR 2010
- Article first published online: 1 MAR 2010
- Received 3 March 2009. Accepted for publication 3 December 2009.
- nitrate removal;
- organic matter;
- paddy soil;
- water quality
Denitrification of paddy fields is a key process for improving water quality in fields where nitrate concentrations are high. The objective of the present study was to understand the effects of incorporating organic carbon (C) into soil on the denitrification rate of paddy fields in winter. On 11 December 2007, separate paddy field plots were prepared by incorporating 5 Mg ha−1 of rice straw (RS), 11 Mg ha−1 of rice straw compost (RSC) or a control. A field with a high concentration of nitrate in the water (averaging 18 mg N L−1) was irrigated until 29 March. During the experiment, the daily average soil temperature at a depth of 0.05 m ranged between 3 and 15°C. The nitrate concentration in the surface water in the RS plot, where the residence time was 2 days, decreased more than the concentration in the control or RSC plots. The total estimated nitrate removal from each plot in relation to the other plots was RS > RSC = control. Measurements of the soil from each plot on 29 February 2008 showed that incorporation of RS significantly increased the denitrification potential, even at low temperatures (5–10°C). Furthermore, the RS plot contained more dissolved organic C than the control or RSC plots. This result indicates that supplying RS effectively increases denitrification under low-temperature conditions.