The 2012 ASHS Annual Conference

The objective of this study was to find out increase of starch with nitrogen control for reducing freezing injury by soil injection of ethyl alcohol as a carbon source.  The tested variety was 'Kawanakajima Hakuto' which was one-year-old tree. Twentyfold diluted solution 1µ¤ of ethyl alcohol(95%) per a tree was injected into rooting zone at August 7, 2011. Fertilizer was applied with the recommended application of fertilizer based on soil testing and 25% added amount that of fertilizer N. Nitrate content of soil and leaf severly got lower than non-treatment no later than 5 days after injecting ethyl alcohol. Lower nitrate contents of soil and leaf lasted for 20 days with the recommended application of fertilizer based on soil testing and for 15 days with the 25% added amount that of fertilizer N. Similarly, foliar nitrogen content was lower soil injection of ethyl alcohol than non-treatment for 10 to 30 days after injecting of ethyl alcohol regardless of nitrogen fertilization level. On the contrary, foliar starch content was higher soil injection of ethyl alcohol than non-treatment for 10 to 30 days after injecting of ethyl alcohol. The average freezing injury level of flower bud was 11.0% with the soil injection of ethyl alcohol, but that was 26.0% in case of non-treatment, where the minimum air temperature of early February was below –23 °C for 2 days.  In conclusion, it was possible that the soil injection of ethyl alcohol reduced freezing injury according to increasing starch as a result of reducing nitrogen.