Abstract
The objective of this study was to investigate the effects of co-situs application of controlled availability fertilizer and the broadcast application of readily available fertilizer on the growth and nutrient uptake of dent corn (Zea mays L.) and weeds. Field experiments were conducted for two years (1996-1997) in Andisol. No treatment of herbicide increased biomass, and the nutrient uptake by weeds decreased the yield and nutrient uptake of dent corn as compared with treatment using herbicides. In co-situs application plots, dent corn had a constantly higher plant length and tended to have a higher yield than that in broadcast application plots. Weed biomass in the co-situs plot was not different than that in the broadcast plot. However row/total (row+inter row) rate of weeds dry weight was about 50% in the co-situs plot and about 20% in the broadcast plot. Nutrient uptake of dent corn in the co-situs plot was higher than that in the broadcast plot. The nutrient absorption of weeds in the co-situs plot was high in-row and lower inter-row as compared with that in the broadcast plot. As explained above, it appears to be possible to maintain corn yield using small amounts of herbicide, if the co-situs application of controlled availability fertilizer is combined with the row application of herbicide.
