Alkaline soil

Alkaline soils are widely distributed in the drier areas of the world. A great deal of foodstuff is produced on soils where salts may be a problem. In regions of low rainfall, salts accumulate where drainage is poor. The tolerance of various plants to soluble salts in soils differs greatly. Among the less tolerant agricultural crops are beans, peas, clover, vetch, oats and peaches. The presence of high concentrations of salts limits the intake of water by plant roots. Yields are reduced approximately in proportion to the osmotic pressure of the nutrient solution. Concentrations of more than 0.2% of salts in a soil will harm crop yields. Alkaline salts are toxic at even lower concentrations. Many irrigation projects have failed because the soil has become alkaline through lack of proper drainage facilities or failure to use enough water to move excess salts down and out of the soil. Others have failed because of the high concentration of sodium in the irrigation water.

1. Soil salinization
2. Soil infertility

1. Calcareous soils

1. Unused land
2. Undeveloped irrigation system
3. Environmental plant diseases
4. Deficiency diseases in plants

1. Unsustainable short-term improvements in agricultural productivity

1. Treating shallow alkaline topsoil

1. Shallowness