Determination of best concentration of mixture of lime and lime and chlorine on the qualitative and quantitative losses of sugar beet silos.

Post harvest losses of sugar beet increases of with an increase in microbial activity. It is believed that losses can be reduced by using lime. Therefore investigation was conducted during years 2004 to 2005 to study the effect of lime and mixture of lime and chlorine on quality of farm stored sugar beet in KAMAL ABAD research station in KARAJ. Experiments were conducted in a 1000 square meter land and commercial variety SHIRIN using with split plot test with two factors (A×B) and three replications, namely (factor A) as lime (0,3,4 and 5% concentration) and mixture of lime and chlorine ((0,5) , (3,5) , (4,5) and (5,5) percent concentration) in all totally 24 samples. Subplots (factor B) included storage duration (30 and 60 days). Randomized sampling including 58 samples each containing 30 roots were collected and after weighting and washing pulp was prepared with 10 samples as control and remaining 48 samples in two silos with each contain 24 samples and dimension each silo (2L×1.5W×1.8H). During course of study sucrose, invert sugar, sodium, potassium, excess nitrogen, modulus of elasticity and mold contamination percentage was routinely measured and means were compared using DUNKEN multiple test. Results showed that mean temperature for 30 days in year 2004 was 4.7±1.7ºC and for 60 days it was 4.0±2.1ºC. This indicates that the mean temperature in year 2005 for first 30 days was 0.7ºC less and 30 remaining days was 0.5ºC less than the year 2004. Daily sucrose loss due to respiration in the year 2004 was 176.6 grams/ton and for year 2005 was 131.6 grams/ton. Mean RH (relative humidity) in 2005 for first 30 days was 77% and for other 30 days was 79% which shows and increase of 3 and 4% compared to the year 2004. Average weight loss in year in year 2004 was 23.8% which shows 7.1% increase compared to the year 2005. Average percent mold contamination was equal to 7.6% in 2004 and 6.9% in 2005. Average modulus of elasticity for year 2004 was 643.6 and for year 2005 was 753.4 N/Cm2. Results showed an increase in storage time increases the sugar loss as results of reduction weight, percentage sugar, excess nitrogen and modulus of elasticity and as increase percent mold activity and invert sugar. It is worth mentioning that storage did not affect sodium and potassium content. Washing reduced daily sucrose losses at the rate of 95 grams/ton as compared to unwashed beet. Also spraying lime had better effect on control mold as compared spraying with lime and chlorine. Also result showed that level 3% lime with 4.97% mold and 154.48 grams/ton/day sucrose loss was best level among all levels. Finally considering that the level 3% lime resulted in only 112 grams/ton/day sucrose losses as compared to unwashed sugar beet, it can be concluded that using 3% lime is best treatment for control of storage molds of on farm sugar beet silos.