Urban Vegetable Farming Research Articles

Urban Vegetable Crop Production and Production Efficiency

The problem of food availability and access has become more acute in urban areas as growth has concentrated in metropolitan areas. Uneven distribution of income, prevalence of poverty, diminishing farmlands, inefficient distribution systems, and rising expectations have contributed to increasingly critical problems of food supply and distribution. Urban agriculture in developing economies has evolved in response to changing demand and supplies. The study was carried out in southwestern Nigeria, to determine the production efficiencies and causes of inefficiencies in urban production on a low lying, seasonally flooded, plain that has enough retained moisture to support dry season cropping of short duration crops. This is termed fadama agriculture. A sample survey of 242 urban vegetable farmers was conducted between and March 2006. Data on yield, planting combinations, and farm size were analyzed using descriptive and inferential statistics. The stochastic frontier model of technical efficiency was used in estimating the production efficiencies of farms, and the sources of technical inefficiency. Mean farm size was 0.54 ha; the mean age of producers was 42.6 years while the mean technical efficiency was 74.36%. The major sources of technical efficiencies were found to be in the employment of labor, and in the use of land and seed or cultivar resources. Telfaria occidentaleHook, Amaranthus hybridusL. and Zea maysL. combinations were found to be the common crops mix on fadama farms. Fadama agriculture can be used to alleviate food shortages among urban dwellers in countries with developing economies.

Reducing microbial contamination on wastewater-irrigated lettuce by cessation of irrigation before harvesting.

To assess the effectiveness of cessation of irrigation before harvesting in reducing microbial contamination of lettuce irrigated with wastewater in urban vegetable farming in Ghana. Assessment was done under actual field conditions with urban vegetable farmers in Ghana. Trials were arranged in completely randomized block design and done both in the dry and wet seasons. Seven hundred and twenty-six lettuce samples and 36 water samples were analysed for thermotolerant coliforms and helminth eggs. On average, 0.65 log units for indicator thermotolerant coliforms and 0.4 helminth eggs per 100 g of lettuce were removed on each non-irrigated day from lettuce in the dry season. This corresponded to a daily loss of 1.4 tonnes/ha of fresh weight of lettuce. As an input for exposure analysis to make risk estimates, the decay coefficient, k, for thermotolerant coliforms was 0.66/day for the wet season and 1.49/day for the dry season. In combination with other measures for improving water quality, the measure can significantly reduce faecal contamination of lettuce during the dry season. However, it is not suitable for the wet season due to unfavourable conditions for pathogen die-off and re-contamination by splashes from contaminated soils. The results provide a good basis for risk assessments and for devising more appropriate measures for risk reduction, especially in sub-Saharan Africa.

Effect of low-cost irrigation methods on microbial contamination of lettuce irrigated with untreated wastewater.

To assess the effectiveness of simple irrigation methods such as drip irrigation kits, furrow irrigation and use of watering cans in reducing contamination of lettuce irrigated with polluted water in urban farming in Ghana. Trials on drip kits, furrow irrigation and watering cans were conducted with urban vegetable farmers. Trials were arranged in a completely randomised block design with each plot having all three irrigation methods tested. This was conducted in both dry and wet seasons. Three hundred and ninety-six lettuce, 72 soil, 15 poultry manure and 32 water samples were analysed for thermotolerant coliforms and helminth eggs. Lettuce irrigated with drip kits had the lowest levels of contamination, with, on average, 4 log units per 100 g, fewer thermotolerant coliforms than that irrigated with watering cans. However, drip kits often got clogged, required lower crop densities and restricted other routine farm activities. Watering cans were the most popular method. Using watering cans with caps on outlets from a height <0.5 m reduced thermotolerant coliforms by 2.5 log units and helminthes by 2.3 eggs per 100 g of lettuce compared with using watering cans without caps from a height >1 m. Simple, cheap and easily adoptable irrigation methods have great potential to reduce crop contamination in low-income areas. When used in combination with other on-farm and post-harvest risk reduction measures, these will help to comprehensively reduce public health risks from using polluted water in vegetable farming.