Agronomical and Quality Performance of Rhodes Grass (Chloirs gayanaKunth) Cultivars Under Different Nitrogen Levels and Production Systems in the Sudan

Abstract

Researchexperiment and field survey were conducted during 2016 – 2018 to study the effect of variety and nitrogen fertilization on the agronomic and quality performance of Rhodes grass and to investigate the husbandry practices of Rhodes grass in the major production systems in the Sudan.The experiment was conducted in Shambat (2016-2017) in the demonstration farm of the College of Agricultural Studies, Sudan University of Science and Technology. Two Rhodess grass varieties (Fine Cut and Reclaimer) and three nitrogen levels (60kg N /ha, 120kg N /ha and 0.0kg N /ha (Control) were studied across seven cuts. The treatments were replicated four times in split plot experiment with fertilizer doses assigned to the main plots and the varieties to the sub-plots. The data collected included agronomic (forage yield and related traits) and quality traits (NDF, ADF, CP). The field survey (2017-2018) was conducted in 15 projects covering Khartoum, River Nile and Northern States. The questionnaire was designed to comprehend the major features of Rhodes grass production as compared to Alfalfa under two production systems based on Pivot and surface (Border) irrigation method The questionnaire data were subjected to descriptive and regression analysis.Differences between varieties and their interaction with cuts were not significant for forage yield. Differences between fertilizer doses for dry yield and their interaction with cuts were highly significant. The nitrogen dose 120kgN/ha significantly increased forage yield and plant height over 60kgN/ha and the control with yield increment of 118%. The dose 60kgN/ha failed to show significant increase in yield over the control. The highest forage yield was obtained in the first cut after establishment then started to decease. The nitrogen dose 120kgN/ha maintained comparatively high forage yield throughout the subsequent cuts. Differences between varieties were not significant for Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF) and Crude protein (CP). Nitrogen dose and cutting age have significant effect on NDF and ADF. Crude protein was significantly affected by cutting age but not nitrogen dose. The interaction effect of nitrogen dose and cutting age was significant for NDF and ADF. The dose 60kgN/ha gave desirable ADF percentage compared to 120kgN/ha whereas the opposite is true for NDF. Cutting age at 182 and 268 days resulted in desirable ADF percentage compared to 75 day whereas the opposite is true for NDF. Crude protein was the best at cutting age of 75 day compared to 182 day. The field survey study provided data on dry yield, plant height, fertilization, seed rate, sowing method, days to zero (seed) cut, number of cuts per year, cutting interval and farm size. The results pointed to the possibility of further increasing the yield in farmer’s field as it was lower than that obtained at the experimental level. Reduction in yield due to poor permeable soils (Sundos Scheme) was lower for Rhodes grass (32.1%) than Alfalfa (63.6%).The survey study reported different dosage used in the farmer’s fields for Nitrogen (Urea), Diammonium phosphate (DAP), Triple Super Phosphate (TSP), Potassium sulfate (K2SO4), Ammonium sulfate (NH4)2SO4), Micro elements and humic acid. Unlike Alfalfa, Rhodes grass yield responded positively to nitrogen (Urea) whereas it’s response to phosphorous was lesser than that of Alfalfa. Rhodes grass yield showed little or no response to fertilization with micro-elements. The yield of Rhodes grass showed negative response to seed rate, no response to number of cuts/year and number of days taken to zero cut whereas that of Alfalfa responded negatively to number of cuts/year and positively to days to zero cut. Unlike Alfalfa, Rhodes grass yield responded positively to plant height. Lack of significant differences between Rhodes grass varieties in forage yield was due to the narrow genetic base of the diploid group. More attention should be given to Tetraploid varieties (Callide, Samford) to enhance productivity of the dairy farms. Nitrogen application has significant positive impact on productivity of Rhodes grass. Future research should focus on optimizing management of nitrogen dose across cuts, fine-tuning of seed rate and investigating strengths and weaknesses of Rhodes grass production under surface (Border) irrigation system especially in soils of low permeability.