Effect of different potassium fertilizer sources on growth and fruiting of balady mandarin trees

Abstract EN

This investigation was carried out at the experimental orchard, Faculty of Agriculture, Assiut University, Egypt, to study the effect of slow release (feldspar), organic (vinasse) fertilizer and biofertilizer (yeast & potassiumage) on growth, nutritional status and fruiting of Balady mandarin trees during 2011, 2012 and 2013 seasons.

Potassium sulphate and potassium thiosulpahte were added at two equal batches on mid of April and July.

Yeast, potassiumage and feldspar were applied once on March.

Vinasse adding as soil dressing on mid of March and July, whereas, vinasse spraying was applied three times on mid of March, June and August.

The obtained results were summarize as follow: Using vinasse or feldspar alone or combined with yeast or potassiumage as source of potassium significantly increased the growth and leaf traits compared to fertilize by potassium sulphate (check treatment).

Using vinasse spraying or feldspar plus yeast gave the highest growth traits values, whereas potassium thiosulphate spraying 36% and untreated trees recorded the least one.

The maximum C/N ratio of shoots were recorded in shoots of trees that fertilized by feldspar with yeast followed by vinasse and feldspar with potassiumage in descending order.

The maximum yield/tree were recorded on the trees treated with feldspar plus yeast followed by vinasse spraying.

Contrarly, spraying potassium thiosulphate 36% and potassium sulphate (check treatment) gave the minimum fruit retention, number of fruit and yield/tree values.

It is evident from the foregoing results that using feldspar alone or plus biofertilizer as well as vinasse improved the growth, nutritional status and fruiting of mandarin trees.

In addition, they are beneficial in the organic farming production.

Such method reduces the cost of production as well as environmental pollution problems (chemical fertilizer and industrial wastes).