Potassium, the third of three elements in healthy soil nutrition, can greatly increase crop yields. It aids in water absorption and retention, also encourages strong roots, sturdy stems, and healthy, full grown crops that have longer shelf life.
Potassium is in the soil naturally in two forms, one of the forms is able to be absorbed into the plant, while the other is unavailable to the plant. Many agricultural crops depend on abundant supply of potassium so they must rely on fertilizers and soil amendments to add to the potassium that’s in soil. Agricultural products that contain potassium are water soluable, allowing it to be absorbed by crops in through the nutrient rich soil.
Healthy plants use potassium in the cell system that uses water, the stomata. Potassium aids the plant in using water efficiently, preventing many diseases and heat damage. Potassium helps cycle nutrients through leaves, roots, and stems.
Sources of potassium
- Artificial fertilizers e.g. sulphate potash
- Oil palm residues
- Crop residues + organic manure especially cereal and root crops.
- Ash from burning vegetation cover.
- Volcanic soils are rich in potassium.
- Clay soils are also very rich.
Importance of potassium
- It encourages root growth and development of stems reducing lodging.
- It improves plants vigour and resistance against certain diseases therefore quickening maturity.
- It promotes development of good quality well developed seeds and fruits.
- Essential for chlorophyll formation.
- It is necessary for formation of starch and transportation of sugars within a plant.
- It is needed for nitrogen metabolism and protein synthesis so it has a balancing effect on phosphorous and nitrogen up take by plants.
Deficiency symptoms of potassium
- The edges of the leaf get scorched starting from the tips and progressing to the margin and also developed small dots (nottling).
- Curbing of leaves especially the lower ones.
- The stems and branches become weak and fall off the plants.
- Poorly development roots and rubbers.
- Damage of deeds as they germinate if it not well incorporated in the soil.
- Suppresses uptake of magnesium and baron by plants roots.
Sulphur is an essential building block for all life on earth, and it is critical in agriculture. Sulphur is crucial in a number of key processes in the crop:
- Production of oils
- Production of proteins
- Production of chlorophyll
- Uptake of other nutrients – especially nitrogen
Sources of sulphur
- Small amount in rain (which is absorbed directly by the leaves)
- Obtained from artificial fertilizers e.g. ammonium sulphate
- Organic matter e.g. crop residues and animal manure.
- Industrial gases e.g. when coal is burnt, sulphates are released and these can be absorbed directly by the same plants.
- Weathering of rocks.
Importance of sulphur
- Protein formation and plant hormones.
- Activation of enzymes and most metabolic processes.
- It increases oil content in oil crops e.g. soya beans and g.nuts.
- It is involved in formation of some vitamins e.g. & B1
- IT influences nitrogen fixation by legumes.
Ways through which sulphur can be lost.
- Through erosion
- Vocalization (when temperatures are high sulphur escapes as a gas)
- Being fixed by clay soils that are rich in iron and columinium in the subsoil so that it can’t be reached by shallow root crops.
Deficiency symptoms of sulphur
- Thin stems
- Lack of root nodules on legumes
- Retarted root development that will lead to slow growth of the whole plant.
- Chlorisis in leaves especially the older ones and other colours may appear on the leaves.