Intercropping in a temperate environment for irrigated fodder production

Fodder crops such as maize and oats are very productive under irrigation in a temperature environment; however, their protein content is too low for rapidly growing or lactating animals. Intercropping with legumes could help overcome this protein limitation.Dry matter (DM) production, protein content and total protein yield were measured in a range of intercropping combinations. For summer fodder production, maize (Zea mays L.) was intercropped with lablab bean (Lablab purpureus L.) or soybean [Glycine max (L.) Merr.]. For winter production, oat (Avena sativa) was intercropped with field pea (Pisum sativum).Alternative-row maize-plus-soybean was the most promising intercrop combination. Averaged over two years, the intercrop yield was 14.1 t¹/ha compared with a sole maize yield of 17.5 t/ha, while protein contents were 93 and 71 g/kg. In one of the two years protein production per unit area of the intercrop was significantly greater than that of sole maize.Intercropping with lablab bean planted in the same rows as maize increased protein content by approximately 10 g/kg. Reducing the maize population to one third of normal (2.4 vs 7.2 plants/m²) decreased maize yield and increased lablab bean production in one year but had no effect in the next year. Intercropping with soybeans in the same row as maize was less effective than with lablab bean.The oat-with-pea intercrops were similar to maize-with-lablab bean in raising the protein content about 10 g/kg. None of the planting patterns used reduced the dominance of the oats to a level where the peas contributed more than 10% of the total DM.