Influence of Nitrogen and Harvesting Time on Yield and Quality of Forage Pearl Millet and Rhodes Grass in Kiambu County, Kenya

Abstract

Pearl millet (Pennisetum glaucum) and Rhode grass (Chloris gayana) are among the fodder crops of great eye-catching in Kenya. They have multiple cutting nature and high tillering ability. They do not contain poisonous acid and do well when managed properly. Nitrogen is an obligatory nutrient for plants to growth including fodder crops. Inadequate nitrogen leads to poor growth and grasses develop fewer tillers, hence leading to low biomass yield, which impacts on livestock production negatively. This research was carried out to examine the outcome of different nitrogen rates and harvesting periods on the growth, yield and quality of forage pearl millet and Rhode grass. The nitrogen rates were 0 (control), 50 and 100 kg N ha-1, while harvesting times were 30, 44 and 58 days after germination. The pearl millet cultivar was ICMV-22, Boma for Rhodes grass. The experiment was set up in a split-plot design using an RCBD arrangement with three replications. Data collected included the height of plants, tiller number, stem thickness, fresh foliage yield, herbage weight, the content of ash, and organic matter. All the growth parameters and quality data were subjected to analysis of variance using the software. Means separated using Least Square Difference at a five per cent level of probability. The results indicated that the differences were important (p<0.05) on plant heights, number of tillers, stem thickness, foliage weight, yield, dry matter percentage, ash content and organic matter when nitrogen fertilizer was supplied compared to the control. The rate of 100 kg N ha-1 was superior while control recorded the lowest values in all parameters. Biomass dry weight significantly (p<0.05) increased with nitrogen application. The maximum biomass dry weight was observed in 100 kg N ha-1 having a dry weight of 74.63g and 58.49g per plant in pearl millet and Rhodes grass respectively. The effect of nitrogen on dry matter percentage was pronounced more in pearl millet (33.53, 36.47) as compared to Rhodes grass (30.34, 34.01) in short and long rains respectively. Harvesting at 58 days after germination recorded a high forage yield (25.74t/ha, 41.32t/ha) in pearl millet, (18.86t/ha, 26.4t/ha) in Rhodes grass during short and long rains respectively. The effect of interaction between fodder species and nitrogen rates on quality parameters was significant in both seasons. Dry matter and organic matter consistently increased up to the final harvest, while ash content decreased with delaying harvest. Based on these results, the rate of 100 kg N ha-1 was recorded to produce more superior growth parameters for both pearl millet and Rhode grass, implying that additional nitrogen would further increase growth. It can be concluded from the results that in order get a higher yield of pearl millet and Rhodes grass they can be fertilized at the rate of 100 kg N ha-1 and harvested 58 days after germination.