Soil Salinity
Salinity affects production in crops, pastures and trees by interfering with nitrogen uptake, reducing growth and stopping plant reproduction. Some ions (particularly chloride) are toxic to plants and as the concentration of these ions increases, the plant is poisoned and dies.
"I live at the Coast and the only water available is saline from wells. I have two questions: What food crops will grow with saline water and does it affect them?"
Farmer
The PH of a soil and indeed irrigation water has a significant effect on the productivity of a given Crop grown in this environment. Soil Salinity affects the availability of Nutrients from the soil solution and thus the uptake by plants. Micro Nutrients such as Zinc, Iron , Copper and Boron as well as critical elements like Nitrogen and Phosphorous become relatively unavailable for plant uptake, which consequently compromises Yields.
Other negative effects of Salinity on plant production include inhibition of water absorption by plant roots due to the increased Osmotic pressure in the soil water and poor soil physical properties like Aeration, structure and drainage.
Saline soils occur due to the accumulation of Sodium salts in the root zone, including Chlorides, Sulphate, bicarbonate and sometimes Nitrate sodium salts. The presence of these salts leave the typical white coloured crust on the soil surface. These Saline soils occur generally in Arid and semi- Arid areas, as well as areas with generally poorly drained soils.
Reclamation and Management
To crop in such Saline soils as in Coastal Kenya, farmers need to embrace practices that will improve the soil drainage and increase the soil buffering capacity. These includes the use of Manure or other Organic matter and where possible till soils in Rows and flood to leach out the soluble salts from the crop root zone. Acidic fertilizers such as Ammonium Sulphate and Elemental Sulphur can also be used to manage the high soil PH.
Tolerant Crops
Crops that that are tolerant or moderately tolerant to Salinity should be encouraged for production in these areas. These include Barley, Wheat, Rice, Sorghum and maize to a lesser extent. Most Vegetable crops like tomatoes and Beans are sensitive to salinity and may not do well.
For Crop-Specific Fertilizer recommendations, please consult your Yara Agronomist near you or the Yara- Accredited stockists and Distributors in your area.
By: Vitalis Wafula
East Africa Regional Agronomist
Yara
