Abstracts |
Grapevine N fertilization may affect and be affected by arbuscular mycorrhizal
(AM) fungal colonization and change berry composition. We studied the effects of different N
fertilizers on AM fungal grapevine root colonization and sporulation, and on grapevine growth,
nutrition, and berry composition, by conducting a 3.5-year pot study supplying grapevine plants
with either urea, calcium nitrate, ammonium sulfate, or ammonium nitrate. We measured the
percentage of AM fungal root colonization, AM fungal sporulation, grapevine shoot dry weight and
number of leaves, nutrient composition (macro- and micronutrients), and grapevine berry soluble
solids (total sugars or degrees Brix) and total acidity. Urea suppressed AM fungal root
colonization and sporulation. Mycorrhizal grapevine plants had higher shoot dry weight and number
of leaves than non-mycorrhizal and with a higher growth response with calcium nitrate as the N
source. For the macronutrients P and K, and for the micronutrient B, leaf concentration was
higher in mycorrhizal plants. Non-mycorrhizal plants had higher concentration of microelements
Zn, Mn, Fe, and Cu than mycorrhizal. There were no differences in soluble solids (degrees Brix)
in grapevine berries among mycorrhizal and non-mycorrhizal plants. However, non-mycorrhizal
grapevine berries had higher acid content with ammonium nitrate, although they did not have
better N nutrition and vegetative growth. |