Abstract 389

Gomez-S,-J; Laredo-C,-MA

Instituto Colombiano Agropecuario, Bogota, Colombia.

Revista-Instituto-Colombiano-Agropecuario. 1983, 18: 2, 95-104; 27 ref.

In 1979 at Villavicencio Andropogon gayanus cv. Carimagua 1 was sown at 8 kg/ha with 359 kg dolomitic limestone, 67 kg triple superphosphate, and 67 kg KCl/ha, giving 12-14 plants/m2. Plots were grazed with 2 animal units/ha in the wet season and 1 animal unit/ha in the dry season. N and mineral concn. were measured in samples taken monthly from June 1981 to June 1982. CP concn. was 6.8% of DM in the wet season and 5.3% in the dry season. Mean values for minerals were: 0.47% Ca; 0.045% Na; 0.13%P; 0.17% Mg; 1.4% K; 178 p.p.m. Fe; 336 p.p.m. Mn; 3.88 p.p.m. Cu; and 15.4 p.p.m. Zn. Differences between seasons were not significant for mineral concn. S concn. was 0.1% in the wet season and 0.08% in the dry season. The Fe, Mn and K concn. were sufficient for animal requirements. CP, Mg, Cu, Zn and S concn. were low, and supplementary minerals would be required for cattle.