Effects of on farm storages cover types on the quality and quantity in sugar beet.

Cover types of on_farm storages are playing important role to reduce the freezing damage and respiration of beet roots in the pile. This experiment was conducted in 2006 and 2007 in the Karaj region in order to evaluate the effects of cover types of storage on the mass loss and sugar losses. The experimental design was split plot in CRBD with three replications. The main plots consisted of: a1= a layer of straw with 10-15 cm depth, a2= a layer of sugar beet top with 10-15 cm depth, a3 = propylene cover with 0.55 mm diameter and a4= without cover as a check. The sub plots consisted of two storage duration's b1- 30 days and b2- 60 days. The size of pile was 2 meters width 1.5 meters high and 3 meters length in the N-S direction. Air temperature inside and outside the pile was recorded daily using a max-min thermometer. Weight and technical quality of beet samples were determined before and after storage. The results showed that mean air temperature under all cover treatments were greater than uncover pile as a check treatment. Mean pile temperatures during sixty days of storage were 0.1 and 1 degree of centigrade in 2006 and 2007 respectively. The main effect of cover types were significant for water content in 2006 and for water content, weight loss, sugar loss and molasses sugar in 2007. In 2007, due to warmer conditions more traits were affected by pile covers compare to uncover treatment. Dry matter for uncover and sugar beet top treatments were 25.45 and 24.71% that they were significantly more than propylene 24.56% and straw 24.42% treatments. In comparing between covers, because both propylene and straw covers water content had significantly more than from sugar beet top and then they were better. Mean sugar loss in the first 30 and 60 days were 497 and 445 g/t/d that it may be related to greater respiration rate of sugar beet in 30 days storage. In conclusion, under conditions of this experiment covering sugar beet with both propylene and straw covers under on-form storage had more water content and may consider as pile cover.