which gathers the straw
in a bale showed
that 87% of the total rice straw was burned
and the remaining had limited uses (Ngo, 2005).
Open field burning of rice straw
has become the key factor hampering sustainable management in
intensive rice systems in Southeast Asia. Aside from causing pollution
and reducing the opportunities for value adding, burning
brings losses in nutrients such as 80% of nitrogen, 25% of phosphorus,
21% of potassium, and soil organic matter. This also kills
beneficial soil insects and microorganisms (Mandal et al., 2004).
In addition, rice straw burned in the field increases the emission
of greenhouse gases (GHGs), such as methane (CH4), at a rate of
1.2–2.2 g per kg dry straw (Kadam et al., 2000; Yevich and Logan,
2003).