Abstract:

According to the soil nutritional requirements of cassava which was from International Center of Tropical Agriculture (CIAT), the results of Secondary-micro nutrient fertilizer trial where had been continuous cropping 15 yeas cassava in Danzhou City, Hainan Province, P.R China showed that Mg fertilizer increased 14.3% fresh root yield and 10.6% starch yield compared to without fertilizer (CK) when the soil exchangeable Mg (12.2 mg/kg) was very low nutrition; but Ca, Zn and Cu fertilizer could not increased fresh root yield and starch yield compared to CK when the soil exchangeable Ca (130.6 mg/kg), available Zn (0.74 mg/kg) and Cu (0.11 mg/kg) were low nutrition. According to the soil survey, the soil exchangeable Mg were very low nutrition in many traditional cassava production area in Guangxi Province and Hainan Province, so it need seriously pay attention to apply Mg fertilizer; moreover, the soil exchangeable Ca, available Zn, Mn, Cu and B were very low or low nutrition on some cassava area in Guangxi Province or Hainan Province, it also needed to pay attention to apply above secondary-micro fertilizer.