Integrated nutrient management research on sweet potato at Hobu, Morobe Province

摘要: In order to investigate the effect of organic and inorganic nutrient sources on sweet potato tuber yield, we carried out a series experiments at Hobu, Morobe Province, PNG. first experiment, plots were planted with Piper aduncum , Gliricidia sepium Imperata cylindrica . After one year, these plants slashed was planted. Sweet yield lowest in previous gliricidia, but there no differences between piper imperata. second season, significant difference yields plots. The experiment consisted factorial fertiliser trial four levels nitrogen (0, 50, 100 or 150 kilograms per hectare) two potassium (0 50 hectare). Nitrogen fertilisers increased depressed third seasons. significantly vine all three Potassium had marketable nonmarketable yields. compared provided by poultry litter rates No found litter, highest hectare. response observed. This research indicates that can be either applications, although variation is considerable. after fallow moderate less variable than following inputs. Fallowing seems safest way obtain steady yields; extra inputs through may strongly decreased.