Abstract

The use of farmyard manure to improve soil productivity is a key element in mixed crop/livestock farming systems. Browse/maize silage mixtures (20% browse DM basis) of Calliandra, Gliricidia, and Leucaena and maize silage alone and their corresponding cattle faecal manure were applied to the soil to determine their effect on soil productivity. Hopi Red Dye Amaranthus (Amaranthus cruentus) was used as the test crop. Its dry matter (DM) yield, and crude protein and fiber content were determined. The browse/maize silages had higher total N and narrower C:N ratio than that of maize silage alone. Calliandra/maize silage mixture had higher levels of ADFN and lignin. Cattle faecal manure derived from the browse/maize silages had higher total N and ADFN content and narrower C:N ratios compared to the faecal manure from maize silage alone. Application of the browse/maize silages and the corresponding cattle faecal manures raised C, N and C:N of the soil compared to the control soil. The treated soils maintained higher levels of C and N up to the third crop but the C:N ratios were similar with the control soil. Amaranthus DM yield was highest with faecal manure treatments. Treatments with silages had no DM yield advantage over the control soil. Addition of faecal manure from maize silage alone gave highest DM yield followed by feacal manure from Gliricidia/maize and Leucaena/maize silages. Faecal manure from Calliandra/maize silage gave lower yields in spite of having similar levels of N. Much of its N was fiber bound, thus limiting availability of the N for plant growth.

Key words: Calliandra, Gliricidia, Leucaena, Amaranthus, browse.