[01] Christian Shingiro, School of Agriculture Engineering and Environmental Management, College of Agriculture Animal Science and Veterinary Medicine, University of Rwanda, Nyagatare, Rwanda. [02] Guillaume Nyagatare, School of Agriculture Engineering and Environmental Management, College of Agriculture Animal Science and Veterinary Medicine, University of Rwanda, Nyagatare, Rwanda. [03] Hubert Hirwa, Department of Environmental Economics and Natural Resources Management, Faculty of Environmental Studies, University of Lay Adventists of Kigali (UNILAK), Kigali, Rwanda. [04] Uwingabire Solange, Department of Soil and Geological Sciences, College of Agriculture, University of Agriculture, Morogoro, Tanzania.

The high nitrogen levels in human urine are favorable for plant growth, however excessive use can also cause a buildup of salts in soil. This study has evaluated the effect of human urine at different dilution ratio and human urine combined with tea compost on soil physical and chemical properties. The experimental design consisted of pots where maize were planted in a randomized complete block design within five treatments and three replications: treatment 1/urine at 1:3 ratio (1L of urine in 3L of water), treatment2/urine at 1:5 ratio (1L of urine in 5L of water), treatment 3/urine at 1:3+TC (1L of urine, 1kg of compost and 3L of water), treatment 4/urine at 1:5+TC (1L of urine, 1kg of compost and 5L of water) and treatment 5/a control (tap water). The results showed that the electrical conductivity, sodium adsorption ratio for both soil and leached water significantly increased with decreasing in urine dilution ratio and increased with tea compost application, pH significantly increased with increasing in dilution ratio and tea compost application. Results also showed that they have been a significant increase in soil porosity, soil infiltration rate and aggregate stability with increasing in human urine and tea compost in the soil. The soil moisture characteristics curve showed that there were much available water at low pressure and less available water at high pressure for soils treated with human urine and tea compost compare to control. The analysis concluded that the application of human urine with or without tea compost increased significantly soil salinity to the soil; however soil structure was improved while combined with tea compost. Therefore salinity management measures should be included in urine fertilization programs. For example a well-adapted crop rotation system with salt-tolerant varieties and an adequate drainage system to remove leached salt.

Soil Salinity, EC, Human Urine, Tea Compost, SAR, pH, Dilution Ratio

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