An experiment was conducted from August to December 2004 under greenhouse conditions to evaluate the effects of aging residues of different plant species [coverage sorghum (Sorghum bicolor x S. sudanensis 'Cober Exp'), forage millet (Pennisetum americanum 'BN2'), finger millet (Eleusine coracana) and St. Lucia Grass (Brachiaria brizantha)], on the control of Ipomoea grandifolia using the pre-emergence herbicides diclosulam and imazaquin. Crop residues were subjected to chemical analyses. The efficiency of diclosulam was not affected by any of the residues. On the other hand, in association with residues of any of the species, but especially with St. Lucia Grass, this herbicide showed increased weed control efficiency. The control potential of imazaquin was influenced by forage millet and St Lucia Grass residues 90 days after laying residues on the soil. This behavior may be due to cellulose and lignin increase in both forage millet and St. Lucia Grass.
chemical constitution; decomposition; Ipomoea grandifolia; straw; no-tillage; residual herbicides
