From time to time growers will here someone talk about soil structure. It is easy to use the word and it is sometimes used with some understanding of what it means, but most of the time growers and scientists do not know much about soil structure, other than know it is their problem. Good soil structure can be called soft soil, while poor or better yet, the absence of structure is hard soil. Good soil structure comes from good soil chemistry where clay particles are pushed apart by ionic charges. Soil structure is usually but not exclusively limited to clay soils.
Clay soils demand good structure, otherwise, they are impossible to manage.
The best soils of Bordeaux are clay with good structure. These soils have excellent water and nutrient holding capacity and because of good structure they also have excellent internal drainage which allows good absorption of the water and nutrients. The presence of sodium in a soil or water can kill soil structure and serious problems from water saturation from poor drainage results. The most important part of vineyard site evaluation is the determination of soil and irrigation water sodium. When the soil structure is destroyed, heavy applications of calcium sulfate, gypsum, will be needed with heavy leaching of clean sodium free water.