The agronomy and mineral nutrition of sweet potato (Ipomoea batatas) in the highlands of Papua New Guinea

The object of the paper is to discuss the agronomy and mineral nutrition of sweet potato in the highlands of Papua New Guinea. It is clear that sweet potato is the most important root crop in the highlands. It is cultivated using a wide range of practices and a large number of cultivars. Results from past research indicate that response to inorganic fertilizers by sweet potato is inconsistent. However, consistent significant response to phosphorus (P) and potassium (K) was observed on volcanic ash soils (VAS). The traditional use of compost mounding in sweet potato was found superior to inorganic fertilizer in supplying a wide range and balance of nutrients which significantly increase tuber yields. It is suggested that there is a need to re-examine the effect of inorganic fertilizers on sweet potato to produce meaningful results. It is also suggested that scientific research should focus on P and K nutrition due to their importance to root crops and limitation on VAS which are widely used to grow sweet potato in the highlands.