Wednesday, February 24, 2010

How salinity builds up over the irrigation season


Salinity builds up in the plant root zone during the irrigation season. This occurs in the rootzone of grapevines (above) and also Olives, Almonds, Strawberries, indeed any irrigated crop.

Above: Water and salts come into the vineyard with your irrigation water. Water is taken into the vine, pushed up the trunk and respired out of the leaves. Salts build up in the soil. Without rainfall leaching it has no where to go. The vine works hard to exclude taking up salt (certain vine rootstocks are very efficient at doing this) but unfortunately once the salt levels in the rootzone build it takes it up into the plant.

If heavy winter rain doesn’t fall, leaching and drainage will not occur and soil salinity may quickly increase to unsustainable levels. More symptoms of salt would be expected to be seen and a reduction in the quality and yield of the fruit is expected.

Recent research has shown that if you need to apply irrigation to leach the salts that have built up in your soil this is best applied during winter when the soil is full. Any extra water from irrigation is pushed down into the soil.

In the aftermath of this season dealing with the salinity that has built up in the soil is a major issue. If good winter rains do not flush the salt through the soil, irrigators may have to flush the soil with a winter irrigation.

Consider a soil test, and seek specialized advice.

No comments: