effect of climatic parameters on the increase of sugar content of sugar beet in 2007 in iran, case study: chenaran sugar factory

in order to study the reason for the prominent increase of the average of sugar content in sugar beet produced in iran in 2007 and finding the relation of this increase with climatic parameters, chenaran sugar factory district was chosen. due to precise and reliable statistical data of sugar factory during the campaign and weather data, chenaran sugar factory was chosen for this investigation.  the most important climatic parameters affecting the sugar content of sugar beet (temperature, precipitation, relative humidity, sunshine hours and wind speed) as well as their changes in 2007 in comparison with the previous years were investigated. regression analysis on the final number representing the sugar content of sugar beet produced in the factory during 2001-  2007 as dependent variable and monthly climatic parameters as the independent variables was conducted. furthermore, the effect of climatic parameters on soil tare and sugar content of sugar beet during the campaign was analyzed. the daily data of soil tare and sugar content in darzab district during the campaign of the sugar factory in 2007 were arranged in the form of 10-day averages which were fitted against the 10-day averages of sugar beet soil tare and sugar content and subsequently linear correlation coefficients were calculated.  by using the stepwise method, the most important factors were determined. the results showed that among the climatic parameters, the most significant factor affecting sugar content was the minimum temperature in august.  the decrease of minimum temperature on august is justifiable by considering the plant physiological changes. the number of days with a temperature of -4°c or less (freezing days) and relative humidity, respectively, had the highest correlation with the soil tare and sugar content in 2007.  therefore, the climatic parameters, especially the minimum temperature in august and in case of the severe increase of temperature, proper and well-timed irrigation has significant effect on sugar content.  proper planning of harvesting and delivering the sugar beet during autumn regarding to meteorological forecasting in each zone can play a substantial role in decreasing the soil tare and increasing the sugar content of sugar beet.