Long-Term Effects of Sugarcane Cultivation on the Physicochemical Quality Indices of Saline and Sodic Soils: A Case Study of South Khuzestan

Sugarcane cultivation has a long history in Iran, particularly in Khuzestan province. However, the sugarcane expansion has always been challenging due to environmental impacts and high water demand in this area. Changing soil quality (SQ) is one of the environmental impacts caused by the sugarcane expansion which can be considered when making decisions. Therefore, this research was carried out to assess the long-term effects of sugarcane cultivation on the SQ. For this purpose, soil samples were taken from the sugarcane fields (SC) of Mirza Koochak Khan Site and surrounding lands with different land use such as wheat-rice rotation (WR) and desert pasture (DP) from 0 to 30 cm depth. After air-drying and sieving (2-mm), soil samples were analyzed for several key physicochemical properties. Two sets of data were generated, including the total dataset (TDS) and the minimum dataset (MDS). Finally, the changes in SQ were investigated using soil quality indices (SQIs) such as IQI and NQI. The results depicted that both selected indicators were able to quantify the SQ changes between different land uses. Moreover, there was a positive and strong correlation (R2 = 0.80-0.92) between the SQI obtained from both the TDS and MDS, indicating that if the TDS is not available, the MDS can be used to assess and monitor changes in SQ. Regardless of the type of dataset and the type of index, the SQ of SC is significantly higher than that of the others. According to the IQITDS and NQITDS indices, the functional capacity of the soil in the SC was 68% and 52%, respectively, which is between 44% and 58% higher than that of the DP. The functional capacity of the soil in the WR and DP were 61% and 44%, respectively. Soil compaction and water infiltration rates are the important issues that need to be addressed to improve soil productivity of SC.