ABSTRACT
Survey of soil nutritive deficiencies using potexperirnents. XXIII. Response to sorne fertilizer formuIations, Arauco Province

Gotardo Schenkel S.1, Pedro Baherle V.2, Horacio Floody A.3 y Mauricio Gajardo M.3
 

Three fertilizer treatments were added to 73 soil samples collected in the Arauco Province, in a pot experiment with LoIium perenne x L. multiflorum. The treatments were: ammonium nitrate (N), triple superphosphate + am monium nitrate (NP), and potassium sulfate + ammonium nitrate + triple superphosphate (NPKS). Results confirm that P is the main nutritive soil deficiency in the region. In many cases, but not always, this deficiency coincides with low leveis of S and K. At farm level, it may occur that the response to N fertilization will be limited by the availability of K or S, and not by that of P, when the soil is poorer in one of those nutrients than in the Iast. The response of ryegrass to NP and NPKS fertilization is independent from the intensity of the P deficiency, when the added amount is suflicient to completely overcome this deficiency. In sorne cases, the limited response to NP is due mainy to a Iow leve! of K, S or microelements in the sol!. In sorne solls of Arauco, the deficiency of microelements and/or Mg wilI keep the response to NPKS fertilization below the optimum level.

Keywords:
1 Ing. Quí,,Casilla 244, Osorno, Chile.
2 lng. Agr., M.S., Estación Experimental La Platina (INIA), Casilla 5427, Correo 3,Santiago, Chile.
3 Lab. Quí. y Ayudante de Lab., respectivamente, Estación Experimental Remehue (INIA),Casilla 1110, Osorno, Chile.