ABSTRACT.


Gotardo Schenkel S.1, Pedro Baherle V.2, Tatiana Floody A.3 y Mauricio Gajardo M.4
 

The behaviour of three fertilizer combinations (N, NP and NPKS) on potted trials with Lolium perenne X Lolium multiflorum was studied. Theresults given by these treatments on seventy two soil samples, collected in the province of Valdivia, is interpreted by a fertility diagram.
A low increase in fertility is observed with the NP application, and the response was lower with N alone, in comparison with the soil potential. The variation in the degree of response to the N fertilization is larger for the different locations than the one for the different dephts of soil sampling. This tendency is less outstanding for the NP combination. The NP production line coincides well with the potassium fertility lineo Potassium deficiency is severe in this soils and, in general, coincides with that of phosphorus.
The NPKS combination increases drastically the fertility of these soils, until micronutrients become limitant. The production NPKS line and the fertility of the samples line with no micronutrients are almost coincident for the topsoil samples. With deeper samples, the yield indexes fol' the NPKS combination are higher. Two micronutrients are supposedly defficient. Only one of them is provided by the triple superphosphate or the potassium sulphate, and the deficiency in the deeper samples is corrected.

Keywords:
1Ing. Químico, Proyecto Fertilidad de Suelo, Estación Experimental Carillanca, Instituto de Investigaciones Agropecuarias (INIA), Casilla 58-D, Temuco, Chile.
2Ing. Agr., Proyecto Fertilidad de Suelo, Estación Experimental Carillanca, INIA.
3Laboratorista Químico, Proyecto Fertilidad de Suelo, Estación Experimental Carillanca, INIA.
4Ayudante de Laboratorio e Invernadero, Proyecto de Fertilidad de Suelo, Estación Experimental Carillanca, INIA.