When the level of total soluble salt in soils exceeds an EC of 4 in the soil solution, plants and fruit are visibly affected. Salinity levels above this result in plant stunting and senescence. Even in the absence of visual stress symptoms, salinity restricts root and above ground plant growth (Figures 4 and 5). Plant height, circumference and leaf area, can all be adversely affected by higher levels of salinity.
Excessive potassium, sodium and magnesium levels also create nutrient imbalances, reducing uptake of other nutrients. At high sodium levels, contents in roots can rise to 1.5% - around three times the normal level - especially when potassium is deficient.
Bananas seem to be more sensitive to sodium than to chlorine. For example, crops will still grow where there is excessive, sucker growth and fruit fill is restricted. AAA type bananas (e.g. Cavendish) are more sensitive than plantains (AAB/ABB types) to both aluminum toxicity and salinity stress. Where possible, growers should irrigate to leach out salts and hence minimize salinity damage.
