ChileanJAR

Previous estimates of phosphate fertilization for peas (PIsum satlvum L.) grown in Southern Chile of about 66 kg P/ha appeared insufficient for new high-yielding cultivars with improved management, which are allowing yields of 50-70 qqm/ha of grain in experiments. Cvs. Solara (afila) and Progreta (reduced foliage) were planted at five levels of applied phosphate (0, 17.5, 35, 70 and 140 kg/ha of P) on two Andisols (Regional Research Center Carillanca, Cautln rainfed central valley, and Hualprn, rainfed coast) of the IX Region of Chile. Yield increased with applied phosphate up to a level of about 120 kg P/ha and stabilized thereafter. Both cultivars exhibited a similar quadratic response, irrespective of location. Pods per plant was the only yield component to be affected (increased by phosphate). Though associated to high experimental error, tlat pods percentage significantly increased through phosphorus application. At the stage of 6-7 nodes, the plants with the highest phosphate dose accumulated 150% (Carillanca) and 213% (Hualprn) more dry matterthan the check with no phosphate. At later stages of development this difference was increasingly higher. These results confirm that peas grown on Andisols of Southern Chile have phosphate requirements substantially higher than those estimated before the introduction of high-yielding cultivars and improved management, particularly in relation to plant population and weed control.