Combined effect of N fertilizer and 2,4-di-tert-butylphenol (2,4-DTBP) for weed control in okra (Abelmoschus esculeentus L. Moench) fields.

Okra is a popular health food in human diet. To find out the effect of nitrogen fertilizer (urea) and phytotoxic compound, 2,4-di-tert-buthylphenol (2,4-DTBP) herbicidal weed control on the various growth parameters of okra, an experiment was conducted at the glasshouse, University Malaysia Kelantan, Jeli Campus. The treatments consisting 3 application rates of N fertilizer (urea); 50, 100 or l50 kg ha⁻¹and 2,4-DTBP; 1.2, 2.4 or 4.8 kg ai ha⁻¹. 2,4-DTBP exhibited potent herbicidal activity by strongly inhibited the germination and reduced the shoot fresh weight of Eleusine indica by >80% at the concentration of Tr4 (2.4 kg ai ha⁻¹ 2,4-DTBP + 50 kg ha⁻¹ urea) with negligible effect on the growth of okra. These results imply that 2,4-DTBP and urea act synergistically to inhibit E. indica without injured the okra plant, thus confirmed that weed control was influenced by level N environment (urea).