EFFECT OF VARIOUS POTASSIUM AND NITROGEN RATES AND SPLITTING METHODS ON POTATO UNDER SANDY SOIL AND ARID ENVIRONMENTAL CONDITIONS

Abstract

Potatoes require high amounts of potassium (K) and nitrogen (N) fertilizers for optimum growth, production and tuber quality. Farmers and farming industries under the arid conditions and sandy soils of Saudi Arabia are applying K and N fertilizers to potatoes without attention to plant requirements. Therefore, five levels of potassium fertilizer were studied on agronomic performance, tuber quality and total yield of potatoes grown on a sandy soil in the arid environment of Central Saudi Arabia. Also, the effect of four levels of nitrogen fertilizer with different splitting methods on vegetative and tuber yields of potato were studied. The field experiments were carried out during 2002 and 2003 autumn seasons at the Experimental Farm of College of Agric. &Vet. Med., Al-Qassim University. Results reveled that increasing potassium sulfate rates resulted in a significant increase (p>0.05) in plant height, leaf area, chlorophyll concentration, specific gravity, K concentration and carbohydrate content. Marketable tuber yield was also significantly improved with increasing K rates. Also, the application of 300 kg Nha-1 split in three equal doses gave the highest percentage of soil coverage and marketable tuber yield. Under the conditions of this experiment, it is concluded that K and N is needed by potatoes for economic yield. The recommended rate for Al-Qassim and similar regions is 450 kg ha-1 potassium sulfate and 300 kg Nha-1 split in three equal doses which resulted in the highest potatoes yield.