Carbon and nitrogen availability in an Alfisol sandy loam soil as influenced by rice straw quality

Abstract

Agricultural residues are primary sources of organic material added to the soil in many cropping systems. Residue quality attributes affect the decomposition rate and release of nutrients from the organic materials. A glasshouse experiment was conducted to study nutrient availability after straws of different quality of selected rice varieties ('Soc Nau', 'IR-67962' and 'IR-30') were incorporated to an Alfisol sandy loam soil. The effects of soil water condition (flooded and non-flooded) and rate of fertilizer application (low and high) on the availability of nutrients in the soil were examined at different sampling times (active tillering, maximum tillering and maturity). Carbon and nitrogen availability was greater in the high quality rice straw of 'Soc Nau' (low C:N ratio, high digestable organic matter and N level) compared to the straw of other cultivars. A higher concentration of total carbon (CT) and total nitrogen (NT) was measured in soils which had been maintained under non-flooded than flooded condition. There were significant differences in the concentration of CT, NT, labile C (CL) and non-labile C (CNL) between sampling times, with a higher concentration at active tillering than at maturity. The concentration of CL increased from its original level at all sampling times; the highest concentration was observed at active tillering.

Source or Periodical Title

Philippine Agricultural Scientist

ISSN

317454

Page

379-386

Document Type

Article

Subject

Decomposition, Labile carbon, Organic material, Plant residues, Rice straw, Total carbon

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