Nutritive deficiencies diagnosis in soils under rice monoculture. II. Effect on grain yields and sorne agronomical variables

Carlos Rojas W.1, Ciro Belmar N.2 y Pablo Grau B.2

In arder to detect possible nutritiva deficiencias on representativa soils subjected to rice monocullure allhe rice produetion area of Talca-Ñuble (Chile) yield trials were stablished (Ñiquén and Huencuecho Sur) in the spring 1986 in order to compare grain yield response of different cultivars (treatments) to fertilizer formulas (FF: subtrealments) in a split-plot designo In the mast austral trial (Ñiquén) grain yield components, and sorne grain characteristics were evaluated. According to results the following conclusions were obtained: In both locations, all cultivars were affected in terms of grain yield when phosphorus was absent in the FF employed. A significant grain yield decrease was evident due to polassium absence in most of lhe employed cultivars with exception of the 67108 Une at the lacatian where this available nutrient in the soíl was less than 80 ppm. Grain characteristics were nol affeeted by FF employed, neither the components: panicle lenght, filled grain number by panicle, and weight of 1,000 filled grains. However, these features were significantly linked to rice genotypes employed.

Keywords: grain yield, rice cultivar response, nutrient deficiencies.
1 Estación Experimental La Platina (INIA), Casilla 439, Correo 3. Santiago, Chile.
2 Estación Experimental Quilamapu (INIA), Casilla 426, Chillán, Chile.