ABSTRACT


Elías Letelier Almeyda1
 
In the period 1947-52 several fertilizer field-trials on potatoes were carried on, most of them at Centinela Experiment Station. Centinela has highly organic soil and a rainfall of about 1.500 milimeters.Rate of fertilization.- important increases of yields are produced up to a rate of 100, 200, 300 (Kg. per hectare of N, P2O5, K2O). Over these rates increments are rather small and erratic.Comparison between several phosphates.-According to their effect on the yield the tested phosphates can be ranked as follows:1. Melón, Pelícano, Superphosphate, Red Guano.2. Bone flour.3. Fosforite, (rock phosphate) Phosphal.Melón, Pelícano and Phosphal are fused phosphates. All the phosphates tested gave measurable increases in yield.Comparison between organic and mineral fertilizers.- Using the same amounts of nutrients, organic fertilizers always had a better effect than mineral fertilizers.
Key words:
1Ingenieros Agronómos de la Sección Suelos y Sección Fitotecnia, respectivamente, del Departamento de Investigaciones Agrícolas.