Impact of Mixing Biogas Liquid Manure with Soil on Water Infiltration under Flood Irrigation System

Biogas liquid manure is byproduct from biogas production projects. It is free from insects, flies, mosquitoes. Since the biogas projects are currently deployed in Egypt and the trend towards increased use, so the mixing such manure with soil can affect the water infiltration into the soil. The study assessed the contributions of biogas liquid manure on water infiltration of a sandy clay loam soil when using three water qualities. The biogas liquid manure was applied at rates of 0, 2, 4 and 6 lit/m2.The double-ring infiltrometer was used to get infiltration data. An electronic device was utilized to note the time the water begins to infiltrate. The results showed that the rate of biogas liquid manure and water quality had a significant effect on cumulative infiltration. The range of cumulative infiltration after 180 min was varied from 128 mm to 490 mm. The cumulative infiltration significantly decreases with the increasing of biogas liquid manure rate at any of water quality. The constants of the Kostiakov infiltration equation were influenced by biogas liquid manure and water quality. The highest constant () of 14.6832 was observed for application rate of 0 lit/m2 biogas liquid manure to the soil and the lowest constant () of 7.5895 was observed for application rate of 6 lit/m2.The highest constant () of 0.7217 was observed for application rate of 0 lit/m2 of biogas liquid manure to the soil and the lowest constant () of 0.4728 was observed for application rate of 6 lit/m2 biogas liquid manure to the soil. A multiple linear regression was employed to estimate final cumulative infiltration after 180 min based on the rate of biogas liquid manure and sodium adsorption ratio of used water with coefficient of determination of 0.9183. Moreover, a regression model was developed to estimate the cumulative infiltration at any time up to 180 min based on biogas liquid manure application rate and sodium adsorption ratio of water.