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Nutrient Recycling Using Human Urine: Potential for Low Input Farming



Author(s)

Onesimus Semalulu, Margaret Azuba, Patrick Makhosi, Fred Semyalo and Shuaib Lwasa

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DOI:10.17265/2161-6264/2012.08B.006

Recycling human urine for farming was assessed in a peri-urban Kyanja parish, Kampala district, and in a rural Migyera parish, Nakasongola district, to demonstrate its potential and develop local use guidelines. Test crops were maize, Nakati (Solanum aethiopicum), kale, spinach, cabbage, tomatoes, egg plants. Urine-water mixtures (0, 10%, 20%, 30% urine) were applied weekly or bi-weekly. At Kyanja, 30% urine weekly gave the highest maize yields. Within 2 months, 10% urine weekly increased Nakati yield from 5,444 to 24,667 kg ha^-1. 20% Urine weekly increased kale yield (7,556 to 16,111 kg ha^-1) and spinach (4,222 to 19,022 kg ha^-1). At Migyera, 10% urine weekly increased cabbage yield (4,975 to 16,113 kg ha^-1) but 30% urine weekly decreased cabbage head-weight by 36%. Weekly applied urine produced heavier cabbage heads than bi-weekly (548 g vs. 427 g, P < 0.05). Leaf N was higher for weekly than bi-weekly applied urine (3.3% vs. 3.0%), implying more protein in the former than the latter. From this study, the following guidelines are proposed: Kyanja area, maize: apply 30% urine weekly for 8-weeks; Nakati: apply 10% urine weekly for 8-weeks; Kale and spinach: apply 20% urine weekly; For Migyera area, cabbage and spinach: apply 10% urine weekly. Apply urine 15 cm around each plant starting 2-weeks after transplanting. So kale and spinach prolong urine application for continued harvesting.

Human urine, ecological sanitation, closing the loop, organic fertilizers, urban agriculture.