Comparative efficiency of foliar and soil potassium application on sugar beet productivity and quality.

摘要

In this study the efficiency of soil and foliar potassium fertilizer was examined under North Delta conditions to develop potassium management recommendations that maximize yield and quality of sugar beet to increase net profit and stop land degradation and decrease pollution of water and environment caused by soil fertilization. Studies were conducted at Belqas, Dakhlia, Governorate, Egypt during two successive winter seasons 2008/2009 and 2009/2010 to evaluate the effects of soil and foliar potassium application during different growth stages on sugar beet (cv. Raspoly) productivity and quality. The experiment includes 6 potassium fertilizer treatments, applied either as soil (114 Kg K₂O/ha) or foliar (3% K₂O) applied as (full dose or split into two doses) during root formation or at sugar storing stages in addition to the control treatment (without K₂O). All potassium treatments significantly increased yield characters i.e. root, top, sugar yield and recoverable sugar yield (RSY) as well as root weight and dimensions compared with the untreated one (control). However, K₃ (soil application of 114 kg K₂O/ha) in two doses (1/2 at root formation+1/2 at sugar storing) surpass all the other treatments. Potassium application significantly increased sucrose %, purity, quality index and recoverable sugar %, while it decreased all impurities contents i.e. K, Na and alpha -amino nitrogen as well as sucrose loss to molass values in sugar beet juice extraction. Moreover, soil potassium application was more efficient than foliar one. Application of potassium fertilizer during root formation stage produced the highest root yield, while applying it at sugar formation stage produced the highest sugar % and consequently the highest values of (RSY). Furthermore, splitting potassium fertilizer dose maximizes sugar beet yield and quality. The best strategy would be to split 114 kg K₂O/ha into two doses applied to the soil (at root formation and at sugar storing). This treatment recorded the highest potassium use efficiency (KUE) values.