Mineral balance and absorption from soil of Pennisetum sp at different stages

Abstract

Forage availability, in quantity and quality, is essential for livestock development. In this context, the aim of this study was to characterize the macro and micro elements of Maralfalfa grass (Pennisetum sp) in function of different harvest frequencies under subsurface drip irrigation. The results showed that mineral concentration in plants depends on: (i) the retention in soil and/or elapsed time for nutrient to be available after a manure application. In this sense, due to the large Pretention capacity of Andosols, soil P and Mg mineralization were very slow, in spite of root activity and its influence in the soil balance (ii) the age of the plant: all element concentrations decreased as the plant grew old, except Na. The concentration values between leaf and sheath showed significant differences for all elements except for P and Cu. Thus Ca, Mg, B, Fe and Mn contents were significantly higher in leaf than in sheath while K, Na and Zn were lower in leaf. B contents were also higher in leaves. The ratio K/ (Ca+Mg) for all ages of the plant was higher than 2.2, increasing the possibility of induced hypocalcaemia