EFFECT OF DIFFERENT POTASSIUM FERTILIZER RATES AND FOLIAR APPLICATION WITH SOME SOURCES OF POTASSIUM ON GROWTH, YIELD AND QUALITY OF CARROT PLANTS (Daucus carota L.)

Abstract

Two field experiments were carried out at Barramoon experimental farm, Hort. Res., Institute, Dakahlia Governorate, Egypt, during the two winter seasons of 2007/2008 and 2008/2009 to study the effect of different rates of potassium fertilization (0, 25, 50 and 75 kg K2O /fad.) as potassium sulfate in addition to foliar application by water (control), liquid potassium (3 ml/ L), potassium borate citrate (3 ml/ L) and NPK- humate (3 ml/ L) and their interaction on production and quality of carrot cv. “Chantenay Red Core. Potassium foliar applications were made 3 times at 20 days intervals with the same doses during the growing period (20, 40 and 60 days after sowing). The highest potassium fertilization rate (75 kg K2O /fad.) gave the tallest shoot, the highest number of leaves per plant and the highest fresh weight of shoots as well as the highest total yield per fadden in both seasons. Also, the obtained results reported that the root measurements expressed as (root length, root diameter, root weight, TSS and carotenoids content, as well as leaves chemical composition (N, P and K concentrations) were increased with increasing potassium fertilization rate in both seasons. On the other hand, spraying carrot plants with potassium humate at a rate of 3 ml/ L markedly increased vegetative growth, yield, root quality and chemical composition in both seasons. The favorable effects of the potassium on the growth, total yield and root parameters were obtained when carrot plants fertilized with 75 kg K2O /fad. as potassium sulfate plus foliar application of potassium humate (3 ml/ L) followed statistically by 75 kg K2O /fad. with foliar application of potassium borate citrate (3 ml/ L) in both seasons.