Abstract

In order to investigate the productivity and forage quality of Clitoria ternatea under arid lands with poor soils, a field experiment was conducted to examine the effects of different fertilizers on forage productivity, quality, leaf area index (LAI) and stomatal conductance (g_s). Three types of fertilizers were applied; NPK (18-18-5+1.5 MgO), Urea (46) and Phosphate (DAP 18-46) at the rate of 90 tons/ha in three doses, in addition to the control. Dry and fresh yields (Tons/ha), were determine over five harvests. Leaves minerals (P, K, Mg, Na Ca), protein, fiber and ash contents were analyzed. LAI was measured by plant canopy analyzer and g_s was measured by leaf porometer. The results showed significant effects of fertilizers applied on yield, quality, LAI and g_s. Addition of fertilizers significantly increase dry and fresh forage yield, protein, LAI, minerals uptake, decreased fiber and ash compared to the control. NPK obtained the highest value in most of the parameters studied. There was strong relationship between LAI with forage productivity and quality. LAI also increased with an increase in plant growth. The results concluded that LAI can be a good estimate of plant productivity at different growth stages. Addition of NPK fertilizer improved forage productivity and quality over the control and other fertilizers.

Key words: LAI, stomatal conductance, forage productivity, forage quality, minerals.