title: Evaluation of human urine as a source of nutrients for selected vegetables and maize under tunnel house conditions in the Eastern Cape, South Africa.
abstract: The introduction of ecological sanitation (ECOSAN) toilets in South Africa has created opportunities for safer sanitation and recycling of human excreta, as fertilizers, in rural and peri-urban areas. A study was carried out to evaluate the fertilizer value of human urine (0 to 400 kg N ha(-1)) for maize and tomato, compared to urea, in a tunnel house. Dry matter yield of both maize and tomato, harvested at 9 and 10 weeks after planting, respectively, increased with increasing N rate (both as urine or urea) up to 200 kg N ha(-1). Urea reduced soil electrical conductivity (EC) whereas urine increased it. Leaf tissue Na, in both crops, also increased with urine application. A follow-up study was carried out with two crops with contrasting sensitivity to salinity and using a wider range of N application (0 to 800 kg N ha(-1)). The results indicated increased root and leaf dry-matter yield of beetroot (tolerant to salinity) with increased urine rates up to the highest rate of 800 kg N ha(-1), whereas the leaf and root dry-matter yield of carrot, which is sensitive to salinity, peaked at the low urine application rate of 50 kg N ha(-1). Soil EC increased with urine application up to 4.64 and 13.35 mS cm(-1), under beetroot and carrot, respectively. Generally the results showed that human urine compared well with urea as a source of N for crops but optimum rates depend on the sensitivity of the crops to soil salinity, which should be monitored where human urine is regularly used for fertilizing crops.
authors.affiliation: Department of Agronomy, Faculty of Science and Agriculture, University of Fort Hare, Alice, South Africa. pmnkeni@ufh.ac.za
authors.forename: Pearson N S
authors.initials: PN
authors.lastname: Mnkeni
authors.forename: Funso R
authors.initials: FR
authors.lastname: Kutu
authors.forename: Pardon
authors.initials: P
authors.lastname: Muchaonyerwa
authors.forename: Lorimer M
authors.initials: LM
authors.lastname: Austin
mesh_terms: D018533:Biomass; D004553:Electric Conductivity; D005308:Fertilizers; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000032:analysis; D018517:Plant Roots / Q000254:growth & development; D018520:Plant Shoots / Q000254:growth & development; D012964:Sodium / Q000652:urine; D013019:South Africa; D014556:Urine; D014675:Vegetables; D003313:Zea mays
chemical_list: D005308:Fertilizers; D012964:Sodium; D009584:Nitrogen