The outcomes of previous studies have resulted in differing recommendations on the rate and timing of fertilizer N applications for forage maize. In order to gain an improved understanding of the role of N fertilizer, a field experiment was carried out to investigate the effects of time and rate of N application on total and plant-fraction yield, nutritive value and efficiency of nutrient utilization in early- and late-sown forage maize. Treatments included two sowing dates (early, late), two rates of N (0, 135kg/ha) applied pre-sowing (N1) and three rates of N (0, 79, 158kg/ha) applied post-sowing (N2) at the six-leaf stage (V6). Application of N at N1 (N0 vs. N135) increased dry-matter (DM) stover yield by 11% and total yield by 7%. Application of fertilizer N at N2 (N0 vs. N158) increased grain yield by 44% and total yield by 34%. Application of N2 also increased irrigation and total water-use efficiency (WUE) from 30 to 40 and 46 to 61 kg DM/mlwater respectively. Late sowing increased DM yield by 6%, but decreased WUE compared with early sowing. The results indicate that application of N at both N1 and N2 is essential to maximize total DM yield from forage maize, but application at V6 is recommended when N input is reduced.
Journal articles from the Grassland Society of Southern Africa (GSSA) African Journal of Range and Forage Science as well as related articles and reports from throughout the southern African region.