Evaulation Of Interaction Between Different Amount And Deep Of Phosphrous Fertlizer Placement On Quality And Quantity Of Sugar Beet Yield.

There has been many studies on optimum amount of fertilizer for sugar beet production , however there was not any studies found on fertilizer placement in Iran . This study was conducted in research station of Kamal-Abad Karaj in March . Amount of 180 kg/h nitrogen fertilizer was broadcast applied at the time of soil preparation and after seedling establishment. Multi-germ sugar beet seed was sown in a split layout experimental design in two different deeps of fertilizer applications and three amount of phosphorous applications during three years, starting in 1987 . After data analysis , treatment means were compared . Growing condition was more favourable in term of root yield and sugar beet yield during 1987 compared to 1988 and 1989. During 1988 and 1989 fertilizer application in 22 cm deep favoured yield increase, but during more favourable year (1978) 12 cm rendered higher yields. This was attributed to known easier fertilizer uptake from closer distance and rapid establishment of the seedlings. Under less favourable growing conditions (1988-89) higher amount of phosphorous fertilization was needed for high yields and low fertilizer efficiencies in term of white sugar yield (20 and 32 kg P2O5 for production of 1000 kg sugar, respectively ). In contrast, under more favourable growing conditions, 90 kg/h P2O5 in shallower fertilizer application deep produced the highest sugar yield and high fertilization efficiency (13 kg P2O5 for production of 1000 kg sugar ). Higher amount of fertilizer caused increases in K/Na ration in sugar beet extracts . Since Na concentration was very low in soil test, high K/Na ratio related to the increased K uptake. It is well-known that optimum phosphorous nutrition, provides higher root densities and higher amount of soil profile was occupied by the roots. Negative relationship between K/Na and K/sugar-content and white sugar yield was the indicators of interference of these ions on sugar crystallization. It was concluded that phosphorous efficiency was depended on year-growing conditions. It seems that under more favourable conditions, less precipitation of phosphorous and rendered more economic uses of the fertilizer .