Effect of different levels of potassium on vegetative growth and mineral content of "Williams" banana transplants grown in sand culture.

Abstract

This work was carried out for two seasons on young banana plants (Musa sp. "Williams Hybrid") grown in sand culture. The experiment included five levels of potassium (0%, 50%, 100% (S.N.S.), 200% and 400% K) relative to K in the standard nutrient solution (S.N.S.). Removing potassium from the nutrient solution gave the lowest values of vegetative growth than those of other treatments. The oldest leaves lost their green colour from the margin inwards and marginal necroses developed beside a spread of an orange yellow colour on the leaves which curved downwards. Thereafter, the leaf dried up and the petiole broke. On the other hand, all vegetative growth parameters were gradually increased by increasing potassium level in the nutrient solution. The maximum increase was obtained by (200% K) and (400% K) treatments which in most cases gave similar values. Thus; it seems that, 200% K treatment seems to be adequate for the vegetative growth of "Williams" banana plants. Removing potassium from the nutrient solution decreased K content but increased N and P content in leaf blades. However, there was a gradual decreased in nitrogen and phosphorus content by increasing potassium level in the nutrient solution. Depending on the values of interaction between treatments and sampling dates, potassium in the two seasons ranged between 1.15-2.08%, 1.46-2.59%, 1.48-3.00%, 2.07-3.22% and 2.52-3.50% for plants grown under lack, low, optimum, high and very high level (excess) of potassium, respectively.