In a field study , with rice plants, of flooded rice soils whose organic matter
content was 1.5 % ,incorporation of composted rice straw either alone or in
combination with nitrogen fertilizer affected the availability of some nutrients NH4-N,
P, K ,Fe²+,Mn²+and Zn²+ in addition to N03-N concentration. The obtained data
showed that the integration of composted rice straw plus nitrogen fertilizer increased
the availability of NH4-N, P, K ,Fe²+ and Mn2+ but decreased Zn²+ availability and
N03-N concentration. Data of simple correlation coefficient (r) between the
phosphorus availability and zinc availability was positively. The linear regression
coefficient showed that the prediction equation for zinc availability (y) could be
formuled as follows: Available Zn = - 0.477 + 0.0540 Available P.