The effects of levels of N and K fertilizer on insoluble oxalate content are presented in Table 3. At almost all the
cuttings, the insoluble oxalate content was affected by N and K fertilization and their interaction. 
Application of N at 600 kg/ha produced significantly higher content of insoluble oxalate than at 150 or 300 kg/ha,
which is in agreement with our previous study (Rahman et al., 2008b).
The insoluble oxalate content in plants appeared to decrease with increasing K level, 
and the difference was statistically significant between K levels of 150 and 600 kg/ha. 
There was a significant interaction between N and K fertilizationfor insoluble oxalate content, 
and the greatest increase in insoluble oxalate content with N level at 600 kg/ha 
was found at the low level (150 kg/ha) of K application. Ward. (1979) reported that ingested insoluble oxalate from
plants may pass through the digestive tract without a harmful effect on body metabolism.