Growth, yield, fruit quality and nutrient uptake of tissue culture-regenerated 'Barhee' date palms grown in a newly established orchard as affected by NPK fertigation

A field experiment was conducted during 2013 and 2014 seasons to compare fertigation and conventional soil broadcast fertilization on growth, yield, fruit quality and nutrient uptake of tissue culture-regenerated 'Barhee' date palm grown in sandy loam calcareous soil in a newly established orchard. In the conventional treatment (CT), the recommended dose (450 g N, 225 g P and 225 K g/tree) was applied as a soil broadcast in three equal doses. In the fertigation treatments, the NPK fertilizers were injected with irrigation water in 12 equal doses, (T2), (T3) and (T4), represent all NPK amounts of CT, 2/3 CT and 1/3 CT, respectively. The highest fertilization regime either applied as soil broadcast or as fertigation produced the highest total yield per palm compared with other fertigation treatments. However, fruit physical quality parameters were higher at T3 and T4 than other treatments. On the other hand, fruit biochemical quality characteristics showed unspecific trend. Palm growth parameters, chlorophyll a, b, and total chlorophylls concentration as well as chlorophyll a/b ratio were not affected by the fertilization treatments. The CT and the fertigation treatments T2 and T3 increased nitrogen availability without, however, a further increase in leaves, except for T2. At the end of the sixth growing season (third flowering season from transplanting), all the cultivated 'Barhee' palms were rapidly and strongly growing without any losses in all the treatments. However, some flowering abnormalities were observed such as multiple carpels formation, a relatively low fruit set percentage and albinism that were lower in 2014 than 2013 season. In conclusion, fertilization is critical to increase yield of young tissue culture-regenerated palms which might have a relatively high nutrient demand. (C) 2014 Elsevier B.V. All rights reserved.