II- Effect of fertigation with nitrogen and potassium on vegetative growth, yield and leaf mineral content of "Washington" navel orange trees grown in sandy soils [electronic resource].

Includes references.

The present investigation was carried out during 2000 and 2001 seasons, in order to study the effect of fertigation with nitrogen and potassium on fruit quality and storabilrty of "Washington" Navel orange trees grown in sandy soils. The main results can be summarized in the following points: 1- Increasing drip irrigation and potassium fertilization rates caused a significant increase in fruit weight, TSS, reducing and total sugars percentages, while increasing nitrogen fertilization rate caused a significant decrease in these characteristics. 2- Increasing drip irrigation and nitrogen fertilization rates caused a significant decrease in fruit ground colour. On the contrary, increasing potassium fertilization rate caused a significant increase in this parameter, in both seasons. 3- Increasing drip irrigation and nitrogen fertilization rates caused a significant increase in creased fruit percentage. On the other hand, drip irrigation, nitrogen and potassium fertilization rates had no effect on fruit peel thickness, in both seasons. 4- The percentage of juice acidity decreased with increasing drip irrigation and nitrogen fertilization rates, whereas increasing potassium fertilization rate significanHy increased this characteristic, in both seasons.

Summary in Arabic.

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