Simultaneous effects of deficit irrigation and preferential flow on E. coli retention in soil

Microbial pollution is one of the most important type of water resources pollution as associated with the health of animal and human. In this study, E. coli retention under deficit irrigation conditions and presence of preferential flow was investigated using column study Soil. The irrigation levels were T120, T100, T80, and T60% of field capacity and the number of irrigations were five. The one preferential flow was artificially created in the middle of the soil columns. Cells were injected from top of the soil surface. The number of bacteria after irrigation in different layers was monitored. The results showed that by reducing the irrigation level from 120 to 60%, bacteria transport decreased within the soil profile. The highest accumulation of bacteria was observed on the soil surface. In the T60 treatment, about 90% of the retention was at a depth of 10 cm.Therefore, deficit irrigation, could limit bacteria movement within the soil profile so that may result in less surface water contamination. Preferential flow, caused greater retention of bacteria in the vicinity of matrix as compared to the control columns. The bacterial retention in the vicinity preferred flow state at a depth of 10 cm of soil surface layer was about 45% and 28.5% higher than the treatment similar to them in the non-preferential flow state