ABSTRACT


Gotardo Schenkel S.1, Pedro Baherle V.2, Tatiana Floody A.3 y Mauricio Gajardo M.4
 
Potted experiments were carried-out using 50 different soil samples from the Osorno province, Chile. Indicator plant was rye-grass (Lolium perenne X lolium multiflorum). The fertilization treatments were: (a) N as ammonium nitrate; (b) NP as ammonium nitrate and triple superphosphate, and (c) NPKS as ammonium nitrate, triple superphosphate and potassium sulfate. These experiments confirm the importance of the deficiencies of phosphorus, potassium and sulfur, previously diagnosed by the technique of the lacking element. A review of the information that has been obtained in with field experiment, in that zone is inclueded. In general, the results of these experiments support the validity of the deficiencies identified with pot trials which includes principally the P, K, S and Mg, but not calcium. Conclusions from both groups of experiments -in pots and field- agree in not giving importance to calcium deficiency unless the soil is a "ñadi".
According to the results of this work, previous crops and physiographic conditionsinffuence the nutritive deficiencies of the soils. The "ñadi" soils behave completelydifferent. In every case it is possible to predict the ranking of response to the applicationof the different fertflizers, when it is compared to the corresponding fertilitydiagram. Such a response is conelated to the hierarchy of nutritive deficiencies.A virtual agreement can be observed between the values that define the fertilitylines of the treatment without potassium and that of production with the treatmentNP. Soils that are deficient in potassium will not respond adequately to the NPfertilization, if a supply of the defident element is not provided.The coeficients that characterized the production lines N, NP and NPKS of the50 samples (mean) are: 27.9; 67.5 and 93.8 for A and -0.02421; -0.01779 and-0.00192 for m, respectively.
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1Ing. Químico, Proyecto Fertilidad de Suelo, Estación Experimental Carillanca, Instituto de Investigaciones Agropecuarias (INIA), Casilla 58-4, Temuco, Chile.
2Ing. Agr., Proyecto de Suelo, Estación Experimental Carillanca, INIA.
3Laboratorista Químico. Proyecto Fertilidad de Suelo, Estación Experimental Carillanca, INIA. 4Ayudante de Laboratorio e invernadero, Proyecto Fertilidad de Suelo, Estación Experimental Carillanca, INIA.