Ecology, Environment and Conservation Paper

ASSESSING SOIL MOISTURE DEFICIT INDEX (SMDI) IN DROUGHT MONITORING (CASE STUDY: LISHTAR DISTRICT, KOHKILUYEH AND BOYER-AHMAD PROVINCE, IRAN)

Fatemeh Taffakor and Seyed Amir Shamsnia

Abstract

Soil moisture is one of the most important factors impacted by drought and can directly cause product reduction. One of the most important drought indices that consider soil moisture an input parameter is Soil Moisture Deficit Index. To evaluate agricultural drought based on soil moisture in a statistical period, models can be used that are based on the connection between water and soil. One of the models that can determine soil moisture in different levels of soil in the temporal period is the Aqua Crop model. In the current study, measured meteorology data was used from 1994 until 2010 in the statistical period, namely: Daily precipitation information, maximum and minimum temperature, relative humidity, and average wind speed and sunshine hours. Then by using two models of ETO and Aqua Crop the amount of soil moisture in levels of 5, 15, and 25 to95 centimeters was estimated. Then based on the amounts and changes in soil moisture, lack of soil moisture percentage and SMDI were calculated to monitor drought in Dogonbadan, which is the nearest station to irrigation network of Lishtar. Based on the results of the indices between 1995 and 1996, drought didn’t occur and in between 2003 and 2009 to 2010 drought occurred. Also, analyses of the process of changes in drought indices show that it was possible to forecast the increase in drought severity in the area. In other words, the amount of rainfall in the area is decreasing and the danger of drought is increasing. This issue must be considered in this area which is one of the agricultural focuses.