Influence of Cutting Date and Nitrogen Fertilizer Levels on Growth, Forage Yield, and Quality of Sudan Grass in a Semiarid Environment

Abstract

Sudan grass is less sensitive to water shortage and produces large amounts of biomass. For these reasons, it is a promising summer forage crop for arid and semiarid regions where natural pastures are rare and water scarcity limits summer forage production. The aim of the present work was to investigate the influence of cutting date (early and late, for three cuts) and three nitrogen (N) fertilizer levels (35, 70, and 105 kg N/ha/cut) on Sudan grass (Sorghum sudanense (Piper) Stapf.). The study was carried out in the experimental farm of Faculty of Agriculture, Zagazig University, Egypt, during 2016 and 2017 summer seasons using a split-plot design. The results obtained revealed significant differences between the two cutting dates on growth, forage yield, and quality of Sudan grass. The late cutting date (56 days after sowing DAS and 42 days after the 1st cut) gave the highest values for almost all the growth characters, dry forage yield in addition to total dry yield (TDY) in both seasons. The highest number of shoots/plant (1.911), leaf area/plant (2841.6 cm2), and dry forage weight (g)/plant (76.65 g) were obtained by late cutting (56 DAS) with the application of 105 kg N/ha/cut. The lowest values of these characters were recorded with 35 kg N/ha/cut. Quality parameters were significantly affected by N levels during both seasons, while cutting date significantly affected the protein yield (kg/ha). The interaction result apparently indicated that the highest dry forage yield of Sudan grass (16.26 ton/ha) was achievable at the 1st cut with the application of the highest N level (105 kg N/ha/cut).