Influence of Acacia senegal agroforestry system on growth and yield of sorghum, sesame, roselle and gum in north Kordofan State, Sudan

Abstract

We examined the effects of intercropping with Acacia senegal (L.) Willd on growth and yield of sorghum (Sorghum bicolor L.), sesame (Sesamum indicum L.) and roselle (Hibiscus sabdariffa). Field experiments were conducted in El-Obeid Research farm (13°10′ N; 30°12′ E), North Kordofan State, Sudan, during 2002–2003 in an 11-year-old A. senegal plantation. The experimental design was randomized complete block design (RCBD) with four replications. Data were recorded for plant height (cm), fresh weight (kg·ha−1), dry weight (kg·ha−1), crop yield (kg·ha−1), and gum yield (kg·ha−1). We used Land Equivalent Ratios (LER) and simple financial analyses of gross surpluses to evaluate the productivity and profitability of the different treatments. The results indicated that A. senegal trees had a beneficial effect on crop performance and yield as well as gum yield. Significant differences (p < 0.05) were obtained for plant height, fresh weight, dry weight and crop yield. Therefore, yield of sorghum, sesame and roselle under intercropping system were 13.7%, 23.8% and 20.9% higher than that obtained in the sole cropping system respectively. The highest yield increase was observed with sesame (23.8%). Gum yield (g/tree/picking) was significantly (p < 0.05) increased for sorghum, sesame and roslle under intercropping system. The highest yield of (298 g/tree/picking) was obtained when roselle was intercropped with A. senegal, while the least gum yield of (239 gδtree−1) was recorded in pure A. senegal plot. All the treatments gave land equivalent ratio (LER) of more than one-indicating the superiority of growing the field crops in intercropping over the sole cropping systems. The highest LER of 3.8 was obtained for sesame intercropped with A. senegal (Hashab), followed by 3.7, when sorghum was intercropped with A. senegal and 3.3 when roselle intercropped with A. senegal. All the treatments gave positive net revenues, the highest being for intercropped sorghum (558 SDG·ha−1) (SDG=Sudanese gienh). The intercropping of roselle gave the second net revenue (518 SDG·ha−1), while the sole sorghum gave the lowest net revenue (501 SDG·ha−1).