Effect of Growth Stage on the Macro Mineral Concentrations of Forbs and Grasses in a Semi-arid Region of Sudan

Sudan is a large country with an area of 1.88 million Km2, and has the second largest animal population in Africa consisting of 52.08 million sheep, 43.44 million goats, 41.76 million cattle and 4.62 million camels (MARF, 2013). The majority of animal wealth is concentrated in western Sudan (40%), followed by central Sudan (23%) (MARF, 2011). Minerals are divided into two groups, macro-minerals, those that are required at 0.1% or more in the diet, and micro-minerals, are those that are required at very small amounts measured in part per million (ppm). Changes in mineral concentrations with maturity often reflect increases in the proportion of stem to leaf with stems showing lower mineral concentrations than young leaves. The objective of this research was to assess the status of the macro mineral elements, Na, K, P, Ca and Mg in the dominant native species during the flowering and seed set stages of plant growth. This experiment was conducted at El Obeid Research Station Farm at Bannu area, Sheikan Locality, North Kordofan State, Sudan, over 2012/2013 seasons. The data indicated a higher content of macro minerals in forbs compared with grasses. Flowering stage showed higher concentrations of macro minerals compared with the seed set stage. It was concluded that the rangelands of North Kordofan State, containing a mixture of grasses and forbs, are good sources of macro minerals. It was considered that macro elements content in forbs and grasses in the study area is adequate for sheep, especially during the stage before plants set their seeds.