Vine roots under study
From the September 2007 edition of Agriculture Today.
Better understanding the relationship between vine root activity and nutrient and carbohydrate availability is the focus of a study being undertaken at the National Wine and Grape Industry Centre (NWIGC).
Root growth is known to occur in two periods during the growing season, between bloom and veraison, and after harvest, but recent work has shown that root growth activity can vary between seasons and pruning systems.
"Carbohydrate transport to the roots is also high when root growth is flushing, indicating a strong linkage between carbohydrate availability and root growth," NSW DPI viticulture researcher, Dr Bruno Holzapfel, said.
"Under limited nutrient availability conditions, further root growth can be initiated, hence requiring further carbohydrate supply.
"The process of nutrient acquisition also requires energy for the nutrient uptake processes."
A preliminary investigation on root dynamics in a Shiraz rootstock trial at the Charles Sturt University Wagga Wagga vineyard is currently being conducted.
To assess root activity throughout the season, polycarbonate tubes that allow a small camera to be inserted have been placed in the soil near vines.
"High quality pictures will be taken at certain depth segments in the root zone during the growing season," said Dr Holzapfel.
"This initial work will be followed by a larger study on the impact of crop load and nitrogen supply on root activity and nutrient uptake conducted in the Riverina grape growing region.
"The role that vine carbohydrate reserves play in root growth in early spring or in vines with high crop loads is relatively limited.
"Similarly, the function of vine nutrient reserves at critical times during the growing season and under stress situations is a major issue in grape production.
"This further comprehension on nutrient acquisition will allow optimising fertiliser application to enhance vine performance and berry composition under stress situations, which is an important factor in determining productivity levels in grapevines.
"The root activity study is supported by the Winegrowing Futures program, a joint initiative of the Grape and Wine Research and Development Corporation and the NWGIC.
Contact Dr Bruno Holzapfel, Wagga Wagga, (02) 6933 4023.
