Better nutrition for the improvement of sweetpotato and taro yields in the South Pacific. (06)

Authors

  • Siosiua M. Halavatau Ministry of Agriculture and Forestry, P.O. Box 14, Nuku'alofa, Kingdom of Tonga
  • Jane N. O'Sullivan Department of Agriculture, The University of Queensland, Brisbane 4072, Australia
  • Colin J. Asher Department of Agriculture, The University of Queensland, Brisbane 4072, Australia
  • F. Pax C. Blamey Department of Agriculture, The University of Queensland, Brisbane 4072, Australia

Keywords:

Sweetpotato, Taro, Nutrient deficiency, Soil fertility, Nitrogen, Phosphorus, Potassium

Abstract

Poor crop nutrition contributes to the low yields of root crops in the South Pacific region where symptoms of nutritional disorders are frequently observed. This study was therefore undertaken to assess the effect of inorganic fertilizers on sweetpotato [lpomoea batatas (L)] and taro [Colocasia esculenta (L.) Schott] yields. It indicates the importance of the correct diagnosis of the nutritional problems at each site for improved nutrition management and describes procedures used to identify and correct nutritional limitations to growth. Nutrient deficiencies were detected using nutrient omission pot trials and the amounts of fertilizer nutrients required to correct deficiencies were determined in a series of pot and field trials. Placement of P fertilizers and number and timing of N applications were found to increase fertilizer efficiencies. Critical leaf concentrations of N and P were determined. Leaf concentrations sampled during early vegetative growth were found to be good indicators of the effect of N or P deficiency on yield. Economic analysis of fertilizer applications demonstrated a high level of profitability.

Issue

Section

Research Papers