Fertilization (N-P-K) of the range of the Mediterranean subhumid zone of Chile

Julia Avendaño R.1, Hernán Acuña P.2 y Carlos Ovalle M.2

In nine sites in the provinces from Talca to Ñuble, the rangos primary productivity response to fertilization was studied, during the year of the fertilization (1978) and in the next two. In each site, a factorial experiment, in a randomized block design with two replications, cs stablished; the levels were 0 and 80,0 and 100 (43.64) and 0 and 50 (41.5) kg/ha of N, phosphoricandhidrid (P) and potassium oxide (K), respectively. Three of the five locations to the north of the Maule river, responded significantly to N and P, in the first year. The range with N fertilization yielded 2,028 kg of DM/ha versus 1,569 the non fertilized one. On the second year, only one location responded to P, and two to N. The N fertilízed plot yieldcd 41% more than the check. To the south of the Maule river, significant responses to the three elements were observed, but these were dependant on one or the two other elernents, in the first year. In the next two years, residual responses were observed in sorne of the locations, being significant the first and second order interactions. It was concluded that the dryland rango of the Mediterranean sub-hurnid zone responded mainly to N and P fertilizers; N is more irnportant to the north of the Maule river, and both to the south of it. Response to K was localized and dependant on the other two elements

1 Subestación Experimental Cauquenes (INIA), Casilla 165, Cauquenes, Chile.
2 Estación Experimental Quilamapu (INIA), Casilla 426, Chillán, Chile.