RT Journal Article
SR Electronic
T1 Effects of Long-Term Nitrogen, Phosphorus, and Potassium Fertilization on Chenin blanc Vines. I. Nutrient Demand and Vine Performance
JF American Journal of Enology and Viticulture
JO Am J Enol Vitic.
FD American Society for Enology and Viticulture
SP 85
OP 90
DO 10.5344/ajev.1989.40.2.85
VO 40
IS 2
A1 W. J. Conradie
A1 D. Saayman
YR 1989
UL http://www.ajevonline.org/content/40/2/85.abstract
AB The effects of nitrogen (N), phosphorus (P), and potassium (K) fertilization were investigated in a field trial with Vitis vinifera L. var. Chenin blanc over a period of 11 years. Three levels of N (16, 56, and 96 kg N/ha/yr), P (0, 9, and 18 kg P/ha/yr), and K (0, 45, and 90 kg K/ha/yr) were tested in a 3 x 3 x 3 factorial layout on a gravelly sandy loam soil containing 1.1% organic material, 12.7 mg P/kg, and 38 mg K/kg. Nitrogen fertilization increased yield and shoot growth slightly but reduced the pH of the topsoil. It was concluded that the N-supplying capacity of the soil was nearly sufficient to satisfy the N demand of the vines, which had an average yield of 13t/ha, and that an additional fertilization of only 40 kg N/ha was justified in this case. Phosphorus fertilization increased P levels in both topsoil and subsoil and also had a positive effect on yield and shoot growth. Evidence of a P/K antagonism was encountered. Apparently, little P fixation occurred, and it was found that less than 9 kg P/ha/yr was needed on this P-deficient soil to ensure optimum yield and growth. Potassium fertilization increased K levels in the soil as well as yield and shoot mass. A fertilization level of less than 45 kg K/ha/yr was needed on this soil with its marginal initial K content and a soil norm of 50 mg/kg seemed appropriate for K.