Vertical vegetable gardening for urban areas

Abstract

ABSTRACT Vertical vegetable gardening for urban areas By Thobile Londiwe Shongwe Supervisor: Dr. D Marais Department: Plant and Soil Sciences Degree: Master of Science (Agric) Agronomy The proportion of the world’s poor living in cities is growing, not only because the poor urbanize faster than the non-poor, but also because many existing and new urban residents are forced into poverty by conditions in the cities. Food insecurity is one of several pressing development issues raised by these demographic and economic shifts. Most poor urban dwellers are failing to meet their daily nutrient intake requirements leading to hidden hunger and obesity as a result of eating high calorie but low nutrient content type of food every day. South Africa is known for its national food security, but according to the latest statistics food inadequacy is still a problem at household level as not all households have adequate access to food. At household level, one in five households in South Africa experience food insecurity. Food insecurity is thus a chronic threat for a large proportion of South Africa's population. Urban farming which is the production of food (plants and animals) within a town or city, for the benefit of the people residing in that town is an umbrella for a variety of farming systems with varied intentions. Some people do farming solely for household consumption, or commercial farming, or for processing. Goods produced are mostly perishables with high turnover crops such as vegetables, spices, and dairy products. The most important trait of urban Agriculture is not the iv location but the fact that it is an integral part of the urban economy, it uses the city’s resources to produce food to feed the city’s people and it affects the urban food security status. It is argued that urban agriculture has the potential to alleviate poverty by subsidizing food expenditure, generating income through the sale of products and working on urban farms, and influencing prices by supplying lower-cost products to the market. Furthermore, urban agriculture is argued to provide far-reaching social benefits. When one thinks of Agriculture and specifically vegetable production, the issue of limited horizontal space is often why urban dwellers cannot produce their own vegetables. Vertical farming is currently a hot topic worldwide, but these systems are highly technical, energy consuming and knowledge demanding in terms of their operation and maintenance. For an urban dweller who is already poor, these vertical hydroponic systems are not an option. It was thus the aim of this project to develop an affordable vertical hydroponic system through implementation of growth media based hydroponic systems. Vertical gardening has been a common practice for ages. Vertical farming is the practice of artificially stacking vegetables and micro-herbs on top of one another. With the technology and methods that comes with vertical farming, this system has the potential to reduce the harm that traditional open field agriculture does, it also has the potential to replace industrial agriculture. Vertical farming is one of the highly recommended farming systems for landless or nearly landless people because it can be practised even on a small patch of homestead land, and it yields higher per square meter of land. Unfortunately, the use of this system seems not to be popular amongst small scale farmers because of the installation and maintenance costs involved. Therefor there is a need to devise a strategy for producing a variety of vegetables by making use of locally available material, to construct affordable vertical hydroponic structures. To attain this objective, a field study was conducted over two growing seasons to test a few highly nutritious vegetable crops in terms of their adaptability to a mixed vertical hydroponic system and a laboratory analysis was done to identify the vegetables nutritional quality in terms of iron (Fe) and zinc (Zn). v The field study was conducted at Innovation Africa at UP (IA@UP) formally known as the Hatfield Experimental farm of University of Pretoria. This trial comprised of vertical wood structures with two cardinal orientations (E -W). Two different growth media (compost and soil) were tested for suitability by growing three different vegetables: beetroot (Crimson globe), garden pea (Sugar snap) and Swiss chard (Fordhook giant). Half of these vegetables were treated with 1 ml of foliar Trelmix (micronutrient rich liquid fertilizer) spray once a week with the other half serving as control plants. The plants were irrigated using a pressure compensated drip system. Parameters evaluated were plant height, leaf area, number of leaves, size of edible roots, number of pods, fresh and dry masses, and yield. Growth media and plant tissue were tested for nutrient quality especially Fe and Zn at the Soil Science laboratory on the Hatfield campus of the University of Pretoria. Growth media was tested before planting and after trial termination. For plant tissue analysis, the whole plant excluding the roots was grinded, digested and tested for the content of iron and zinc. Growth media and season had a significant effect on the yield and yield parameters of all three vegetables. Compost grown plants produced better yields compared to soil. Cardinal orientation and foliar micronutrient increased the yields of the vegetables, but the effect was insignificant. Foliar micronutrient application increased the macro and micronutrient contents of beetroot, garden pea, and Swiss chard in this study, but the differences were not significantly higher than that of the control plants. The plant tissue content of Fe, Zn and K increased while plant P decreased as a result of foliar micronutrient treatment. The study’s findings indicate that compost is the suitable growth media for crop production and Trelmix can be used as a biofortification fertilizer to increase the content of Fe and Zn. In addition, all three crops can be produced with success in this type of vertical production system. This vertical production system could easily be adapted by resource poor households and even small scale producers in urban areas where horizontal space is limited. Keywords: Micronutrient, vertical farming, foliar treatment