The effect of intercropping Lablab purpureus L. with sorghum on yield and chemical composition of fodder

In two years the growth and composition of mixtures of sorghum with Lablab purpureus as strips, paired rows and alternate rows were compared with thos e of sorghum and lablab monocrops. In the first year, when sowing did not o ccur until 7 August, the sorghum yields were low in the monocrop and even l ess in the mixed crops. Lablab yield was also reduced in mixtures compared with the monocrop, but total forage yield was greater for the mixed crops c ompared with sorghum alone. Of the mixed cropping systems, a reduction in t he yield of lablab plants and in the phosphorus and potassium content of sh ed lablab leaves in paired rows suggested that there was more competition f or nutrients between lablab plants grown in this treatment. In the second y ear, earlier sowing increased sorghum growth at the expense: of lablab yiel d in the mixed cropping systems, with the result that total forage yield wa s not increased when sorghum was intercropped with lablab. However, the cru de protein content of sorghum stems and leaf yield were increased in mixed crops, particularly in paired and alternate rows rather than strips, demons trating that close configuration of the legume and cereal are necessary for the cereal to obtain most benefit from nitrogen fixed by the legume. It is concluded that, when conditions are favourable for rapid sorghum and labla b growth, the sorghum will benefit more when it is grown in paired rows wit h lablab rather than in strips. However, the close spacing normally adopted for paired rows may encourage competition between lablab plants and increa se the requirements for phosphorus and potassium fertilizer.