Relationship between soil final infiltration rate and the physical / chemical characteristics, case study: Ghezlagh Research farm- Tehran University

Water infiltration rate is one of the most important parameters of soils and it is a function of the physical and chemical soil characteristics. Also، the infiltration rate is a basic input data in irrigation and drainage projects. Wrong estimation of the infiltration values can lead to wasting the national investments. Although، the infiltration phenomenon has been focused by many researchers، recently، but it is necessary to investigate the importance of the best fitting equations between the infiltration rate and the physical or chemical soil characteristics. The current research، which is based on a case study، aims to determine the relationship between final infiltration rate and the physical or chemical soil characteristics and the emphasis has been to work out the accuracy criteria of the calculation by comparing different correlation coefficients. The main recorded physical parameters were; soil texture، porosity، color and the specific gravity of the soils. Also، some chemical factors such as; pH، EC، Na، Ca+Mg and the amount of organic materials were measured and recorded. Kostiakov- Lewis method was used to measure the infiltration rates in three repetitions. General basic statistical methods were used to analyze data and find the relationships between the final infiltration rate data and either physical or chemical characteristics of the soils. The regression functions، correlation coefficients and the best fitting equations were calculated. According to the results، the biggest rate of the correlation coefficient (r) belongs to the power regression، which shows the relationship between the final infiltration rate and the EC of the soils. However، there was not recorded very strong correlation coefficient in the results. The importance of the best fitting equations has been demonstrated.