Influence of cutting frequency and fertilizer-N application on tiller production and herbage yield distribution over time in a guinea grass (Panicum maximum) sown pasture

An experiment was carried out to evaluate the effects of cutting frequency and nitrogen rates on guinea grass (Panicum maximum) tiller production and herbage yield distribution over time. Plants were grown in the Department of Crop Science Research and Teaching Farm, University of Nigeria, Nsukka. A 4 × 4 factorial experiment replicated three times was set in a randomized complete block design. Treatments comprised four levels of nitrogen fertilizer at 0, 150, 300 and 450 kg ha-1 and four harvesting frequencies of three-, six-, nine- and 12-weekly intervals. Tiller number per square meter of ground significantly (P < 0.05) decreased with increasing interval of cuts, but significantly (P < 0.05) increased with incremental application of fertilizer N in all the years. The three-weeks interval of cuts significantly produced the highest tiller number when combined with the highest N rate of 450 kg N ha-1 in 2003 compared with six- , nine- or 12-week intervals of cut. Grass tiller number significantly (P < 0.05) increased with frequent cutting of intervals earlier in the 2001 season (June to August) than later (September to November) when compared with the infrequent cutting intervals. In most periods of the years, dry matter yields of grass herbage and crop fractions were significantly increased with increase in interval between cuts and with incremental application of nitrogen. However, grass dry matter yields were significantly reduced with longer intervals, relative to the shorter intervals late in the 2001, 2002 and 2003 seasons.Key words: Nitrogen fertilizer, crop fractions, interval between cuts, seasons