Evaluation of land suitability and radiation-thermal production potential of sugar beet by FAO method in the fields of Department of Agriculture of Lorestan, Iran and its comparison with Silakhoor Plain

The study was carried out in the fields of Department of Agriculture, University of Lorestan, Iran (Lat. 32°18´ N., Long. 45°22´ E.). According to the data gathered in the nearest synoptic meteorological station, the studied region is classified under semi-arid cli-mates. Mean maximum and minimum daily temperatures have been recorded in July and January as 29.5 and 5.5°C, respectively. Mean annual precipitation is 509 mm. Four control profiles were selected out of 30 dug profiles. The soils were in two categories of Inceptisols and Entisols. In total, 4 families and 12 soil field units were recognized. The objective of the current study was to compare the qualitative evaluation of land suitability and radiation-thermal production potential of sugar beet in two regions of Khorramabad and Silakhoor Plain, Iran, by FAO method. Results showed that sugar beet production potential was 67950 kg.ha-1 in Khorramabad and the land suitability classes were determined as S2 and S3 by parametric method, whereas land suitability classes were S2, S3 and Ns in Silakhoor Plain. The main soil constraints included CaCO3, relief and detritus in Khorramabad, while they were drainage, relief, soil texture, detritus, soil reaction and exchangeable Na percentage in Silakhoor. Therefore, farmers can improve the productivity by removing the modifiable limitations and improving management. But, the expenses of physical, chemical and mineralogical analysis of soil samples were low in this study. In this method, samples were taken from the selected profiles, thus the cost of chemical, physical and mineralogical tests of soil samples in this method is low.