Resumen

DIAZ, Yris; ESPINOZA, Freddy  y  GIL, José L. Phosphorus fertilization effect in the soil-plant-animal relationship in acid soils of Cojedes state, Venezuela.. Zootecnia Trop. [online]. 2004, vol.22, n.4, pp.317-331. ISSN 0798-7269.

With the purpose of evaluating the effect of two phosphorus sources on pasture yield and beef production, it was carried out an experiment in the central savannas of Cojedes state, Venezuela. Treatments were randomly distributed as, T1: Control (no P), T2: 300 kg/ha of partially acidulated rock phosphate (PARP), and T3: 500 kg/ha of rock phosphate (RP). The variables were: dry matter pasture yield, crude protein, crude fiber content, calcium content, P content in grass, soil, blood and feces, and beef production by area. No significant differences were found among treatments (P>0.05) for any of the variables; however, it was observed an increase in y matter yield when pasture received P (2.4 and 2.6 t/ha/cut for PARP and RP, respectively), compared to control (2.3 t/ha/cut). Also, animal production by area was higher with PARP treatment (206.4 kg/ha). It was not observed a response to P fertilization, possibly due to the lack of some other macro and micro nutrients, mainly nitrogen. Phosphorus applications improved the balance of this element in the system, which would indicate the need of periodical P fertilization to avoid pasture degradation.

Palabras clave : Phosphorus cycling; rock phosphate; soil-plant-animal system; tropical acid soils.