Research Findings: e-ifc No. 15, March 2008

Research work from Argentina: Seasonal variation pattern of nutrients in blueberry plants grown in the northern Buenos Aires province

Pescie, M.A., Lacarra, H. and Lopez, C.G.

Experimental blueberry plantation in North Argentina. Photo by H. Magen, 2000.

Blueberry is a species for which nutrient requirements have not been evaluated because it is native to sandy areas, where nutrient levels are low and supplied at a pH between 4 and 5. In Argentina, where blueberries are a relatively new crop, there is no information about its nutrient requirements. This study determined the seasonal variation of macronutrients (N, P, K, Ca, Mg, and Na) in two major varieties of southern highbush blueberry varieties (O'Neal and Misty). Mature leaves were collected in fruiting branches from the four cardinal points of healthy uniform 7-year-old plants, every 15-30 days (depending on the phenological phase of the crop), from the emergence of the first leaves to the end of the summer. Leaves were dried at 65°C. Nitrogen was determined by Micro-Kjeldahl and P by spectrophotometry. Other nutrients were determined by atomic absorption spectrophotometry. Both, N and P concentrations tended to diminish progressively until the end of the studied period, stabilizing after the end of harvest (December). Potassium increased slightly after harvest, remaining stable until the end of the study. Sodium and Mg contents remained stable throughout the entire growing season, while Ca increased until harvest, then decreased, and increased again at the end of the growing season. The period of highest stability of nutrients was January.