The effects of sowing date on the growth and nutritive value of Lablab purpureus

In two similar experiments, Lablab purpureus was sown at different dates in July and August to evaluate the effects of sowing date on the yield and nu tritive value of the plant and shed leaves. On each occasion, an interim ha rvest was performed on half of the plants sown at each date and the regrowt h recorded. The interim harvest reduced the total yield, and in particular that of shed leaves. In one of the two experiments, late sowing resulted in a considerable reduction in yield, increased crude protein and reduced mod ified acid-detergent fibre concentrations. Ash concentrations were higher i n plants sown later and their shed leaves. Sodium concentrations were inade quate for ruminants and, like phosphorus concentrations, tended to decrease with later sowing. However, both calcium and magnesium concentrations incr eased with later sowing and were sufficient for ruminant production. Potass ium concentrations were high and were little affected by sowing date. It is concluded that both an interim harvest and late sowing are disadvantageous when lablab is grown for ruminant livestock, the former because of yield r eduction and the latter because of yield reduction, increases in ash concen tration and reductions in sodium and phosphorus concentrations.