Effect of Harvesting Dates and Potassium Fertilization Levels on Vegetative Growth, Tuber Yield and Quality of Jerusalem Artichoke

The effects of three harvesting dates; 120 150 and 180 days after planting (DAP) and four potassium fertilizer levels; 0, 48, 72 and 96 Kg K2O fed -1 , on vegetative growth characteristics, tuber yield potential and quality of Jerusalem artichoke (cv. Balady) were studied. Two field experiments were conducted during the two successive summer seasons of 2001 and 2002 at the Experimental station Farm, at Abeis, Faculty of Agriculture, Alexandria University. The results revealed that delaying harvesting date up to 180 days after planting was accompanied with significant increases in plant height, leaf's dry matter content (%), number of main stems and canopy fresh mass per plant. Moreover, yield potential; i.e. tuber yield / plant, total tuber yield / m 2 and average tuber weight; were positively and significantly increased by the late harvest (180 DAP). It was also noticed that the late harvesting date lowered the leaf's N content, but raised the leaf's K content. However, leaf's P content was not significantly affected by harvesting dates. The harvested tubers at 180 days age were characterized with high contents of total soluble solids, total carbohydrates, inulin, protein and K; indicating that the late was the harvest J.Agric.&Env.Sci.Alex.Univ.,Egypt Vol.4 (2)2005 38 date the higher was the nutritional quality of Jerusalem