Nutrient Balances and Economic Performance in Urban and Peri-Urban Vegetable Production Systems of Three West African Cities

Abstract

Urban and peri-urban (UPA) cultivation supplies fresh vegetables and employment for the increasing number of urban inhabitants. It is characterized by the use of large nutrient inputs to increase productivity and often associated with negative environmental risks. For these reasons, this study quantified nutrient (nitrogen, N; phosphorus, P; and potassium, K) flows and economic performance of UPA gardening of the three West African cities of Kano, Nigeria; Bobo Dioulasso, Burkina Faso; Sikasso, Mali, during a 2-year period using the Monitoring for Quality Improvement (MonQI) toolbox considering inflows and outflows sources. Average annual N, P and K balances were positive for all gardens in the three cities with N balances of 279, 1127 and 74 kg N ha −1 in Kano, Bobo Dioulasso and Sikasso, respectively, except for annual K deficits of 222 and 187 kg K ha −1 in Kano and Sikasso, respectively. Nitrogen use efficiencies were 63%, 51% and 87% in Kano, Bobo Dioulasso and Sikasso, respectively, with poor P use efficiencies due to excess application in all three cities. However, a high K efficiency was observed in Bobo Dioulasso (87%) while applications of K were lower than required in Kano and Sikasso with efficiencies of 121% and 110%, indicating possible K mining. The average annual gross margins from gardening indicated a statistically higher (p < 0.05) return of US$3.83 m −2 in Bobo Dioulasso than returns obtained in Kano (US$0.92 m −2 ) and Sikasso (US$1.37 m −2 ). Although an economically vibrant activity, intensive UPA vegetable production needs to be reviewed for strategic planning towards improving N and P use efficiencies in order to maintain its productivity as well as safeguard the environment. Appropriate K fertilization is necessary to avoid long term K depletion in Kano and Sikasso UPA gardening.

The economic performance of urban gardening in three European cities – examples from Ljubljana, Milan and London

“…Costs are also lower in comparison to gardeners in Guelph, Canada who spend 121 EUR (9.6 EUR/m 2 ) in an average garden of 12.55 m 2 (CoDyre et al, 2015) and higher in comparisons to commercial urban gardens in African cities, such as Kano, Nigeria (673 m 2 ) with 236 EUR (0.35 EUR/m 2 ), and Sikasso, Mali (2112 m 2 ) with 287 EUR (0.11 EUR/ m 2 ) (Abdulkadir et al, 2015). Integrating all findings we can state that the economies of size, where average cost per unit of production decreases as the production area increases, is applicable also to urban gardening of small size.…”

“…Results indicate the unprofitable nature of urban gardening in European cities, where only the occasional urban gardeners sell their surpluses, in comparison with African cities where it is a widespread activity. (Abdulkadir et al, 2015;Glavan, 2015). It is to mention that in Europe, urban gardening is generally defined as non-profit activity (due to the history/emergence, regulations, etc.…”

Nutrient Balance of Farming Systems in Tigray, Northern Ethiopia

“…Denisse Opazo-Salazar and Gabriel Corral-Núnez current addresses are unknown Nutrient balances (sum of inputs flows minus sum of output flows) are commonly used as indicators of soil fertility trends (Bindraban et al 2000;Abdulkadir et al 2015;Van beek et al 2017). During the last 30 years, many studies have documented soil degradation through nutrient depletion in Ethiopia (Getahun 1978;Elias et al 1998;Corbeels et al 2000;Amede et al 2001;Haileslassie et al 2005;Abegaz et al 2007;Lema et al 2019;Okolo et al 2020).…”