**3.1 Water availability**

Zimbabwe is a dry country with limited wetlands2 . Water can be accessed from direct river abstractions or through storage works. The country also boasts groundwater reserves which have been grouped into 10 hydro-geological units which yield approximately 1.8 x 106 megalitres from registered and monitored uses [5]. Additional water can be obtained through recycling which mostly takes place in urban centres where, potentially, wastewater can be treated to sufficient standards for discharge into public river systems.

Agriculture uses most of Zimbabwe's water that is 81 per cent for irrigation, fish farming and livestock watering. The urban and industrial sectors uses 15 per cent of available water, while mining accounts for 2 per cent of the water [9]. According to the National Climate Policy (NCP) [10], key challenges in water availability for agriculture under the changing climatic scenarios are rooted in three major issues


The three major issues point to the need for effective harvesting and management of water resources in order to sustain agriculture in the presence of variable

<sup>2</sup> Zimbabwe's long-term average annual surface run-off is estimated to be 23.7 x 10 megalitres. The distribution of average runoff varies from 21 mm per year in the Gwayi catchment to 126 millimetres per year in the Mazowe and parts of the Save catchment [5].

*Climate Change Risks in Horticultural Value Chains: A Case Study from Zimbabwe DOI: http://dx.doi.org/10.5772/intechopen.97211*

**Figure 7.** *Precipitation predictions for Zimbabwe under RCP 8.5. Source: Unganai [6].*

rainfall and extreme temperatures. Nonetheless, Zimbabwe has the most dams in the Southern African Development Community (SADC) region after South Africa. The country has almost 40 medium-to-large dams and lakes including Lake Kariba as well as about 10,200 small dams. In 2001, about 152,000 hectares of land were under formal irrigation with a total of a further 600,000 hectares of land nationwide that can be made available for irrigation development [2].

### **3.2 Sectoral and development impacts**

Zimbabwe is particularly vulnerable to climate change due to its heavy dependence on rainfed agriculture and climate sensitive resources such as hydro-electric power, wildlife tourism and other ecosystem goods and services. Zimbabwe has an agriculture-based economy with the sector contributing about 15 per cent each year to the GDP [11]. As a result of this linkage, climate is a major driving factor for most of Zimbabwe's socio-economic activities such that Zimbabwe's Gross Domestic Product (GDP) is tightly linked to rainfall patterns [9]. Robertson [12] further illustrated this point showing that in the years when Zimbabwe experienced droughts economic growth levels also declined (see **Figure 8**<sup>3</sup> ).

Livelihoods of the poor, particularly women4 who are highly dependent on climate sensitive sectors like agriculture, are likely to be impacted by climate change in various ways. Climate change impacts are also expected to disproportionately affect the young, elderly, sick, and otherwise marginalised populations who may not have the necessary livelihood capital assets —natural, financial, physical, human and social—to allow for adaptation or recovery when climate disasters strike.

<sup>3</sup> All years with red columns were drought years while those with orange columns were years of the fast track land reform programme. Blue years are considered normal years.

<sup>4</sup> Rural women had gender related duties that saw them increase their level of effort due to the negative effects of climate such as drought and extreme temperatures [13, 14].

#### **Figure 8.**

*Relationship between GDP and drought in Zimbabwe. Source: [12].*

#### **3.3 Climate risks and horticulture value chains**

Zimbabwe's agricultural sector is divided into four major sub-sectors namely; large scale commercial farms, small scale commercial farms, communal and resettlement areas. The agrarian structure has changed with the recent land reform in Zimbabwe with 99 per cent of the farmers now being smallholder farmers (SHF). Of these 81 per cent are communal farmers, 18.7 per cent resettled farmers and 0.1 per cent large scale farmers [11].

Zimbabwe has a diverse horticultural subsector, producing vegetables —for export and domestic sales—, fruits —for export and domestic markets— and flowers —primarily for export—. The major horticultural exports from Zimbabwe are destined mostly to European and other African markets. At its peak in the late 1990s, horticulture was the second largest agricultural foreign exchange earner after tobacco, recording export figures in 1999 of up to US\$144 million. Its trade balance however declined significantly over the years, influenced by the dollarization and the previously mentioned land holding changes. This negative trend reversed recently with exports recording significant growth in 2018 —more than \$112 million against \$50.9 million in 2017— [15]. The sector is also a significant earner of foreign currency thereby improving the country's terms-of-trade in addition to numerous downstream benefits in the packaging, processing, input suppliers and transport industries. According to the ITC [16], there is potential for the horticulture sector in Zimbabwe to contribute significantly to growth due to the following important factors:


The UKTP [15] together with Shone [17] noted a number of constraints inhibiting the growth of the sector that may be summarised as follows:

*Climate Change Risks in Horticultural Value Chains: A Case Study from Zimbabwe DOI: http://dx.doi.org/10.5772/intechopen.97211*


#### **3.4 Major risks and possible mitigation**

Regarding inputs in the horticulture sector, production works best under dripirrigation hence drought tolerant seed varieties may not be necessarily applicable in this case. However, seed varieties that are resistant to frost and heatwaves are crucial given the expected cooler winters and higher temperatures in future. Crops may also be prone to pests which will likely increase in the incidence of longer hotter summers. In this regard, the use of tissue culture and the development of varieties that are resistant to temperature extremes is essential for mitigating seed related climate risk. Tissue culture will assist the expansion of horticulture production and build resistance to water shortages, specific pests and temperature extremes.

Soils will require nutrient augmentation and the use of chemical fertilisers can have adverse impacts on agro-biodiversity and can result in eutrophication through erosion in the case of flash floods related to climate change. Use of fertilisers is linked to increased GHG emissions particularly in the case of methane and nitricoxide. As such, in is critical to improve availability of fertilisers / build capacity for composting and to promote crop rotation to increase soil nutrients. Crops are also susceptible to attacks by pests and viruses. The increase in extreme temperatures can increase the prevalence of certain pests and viruses or reduce that of insects that attack pests. Thus, it is essential to explore organic / agrobiodiversity solutions for specific pests in order to maintain organic production. It is also useful to identify ideal crops for intercropping and integrated pest management.

Regarding information services in Zimbabwe, extension services may be considered as limited in resources. Nonetheless, there is scope for electronic messages on weather trends. Messaging is however limited by weak communication infrastructure and low forecasting capacity. As such, it is useful to strengthen early warning systems —including Geoinformation Science (GIS) and Earth Observation —on cropping season quality, rangelands conditions, droughts, floods, disease/pest outbreaks and wildlife movement; Strengthen capacity to generate new forms of empirical knowledge, technologies and agricultural support services that meet emerging development challenges arising from increased climate change and variability and Strengthen the capacity of farmers, extension agencies, and private agro-service providers to take advantage of current and emerging indigenous and scientific knowledge on stress tolerant crop types and varieties, including landraces that are adaptable to arising climatic scenarios.

In the Zimbabwean horticulture sector, SHFs are often constrained by the lack of adequate technology for production, harvesting, handling and storage. In some cases hostile temperature fluctuations hinder production or storage processes as better technology may be required to deliver the same quality output in the presence of *inter-alia* heatwaves, frost, hailstorms, droughts and floods. The absence of adequate technology for all SHF may open up opportunities in the public and private sector for sharing agricultural equipment using equipment pooling mechanisms that may see the emergence of pool tractors, trucks, ploughs, etc. This is already happening using the VAYA agricultural sharing tools platform. Such a service could be extended by the public sector. It is also necessary to develop appropriate storage which can handle high temperatures and maintain humidity will build resilience in the horticulture sector.

From and agricultural production perspective, the increased temperatures are likely to increase evapotranspiration and potentially salinity as more groundwater is extracted for irrigation purposes. Also, there is potential increased erosion due to long dry spells. Also, the erratic supplies of water rooted in the recurrent droughts have been the major negative effect of climate change. The commencement of the rainy season is often delayed and there is an overbearing need for water harvesting and irrigation if at all the value chain is to be viable. Drip irrigation is used in most of commercial horticulture production as it is more efficient and ideal. In the absence of water reservoirs, horticulture production would be seriously compromised. Given the above, it would be essential to identify latest technology for minimum tillage production models in order to conserve the soil. Also, the promotion of the regeneration of native species in and around growing areas could be encouraged together with water harvesting.

Horticulture tends to be dominated by monoculture. Monoculture leaves crops more vulnerable to pests and diseases as well as speeds up soil degradation. Monoculture also compromises biodiversity conservation efforts as it limits species diversity. In the presence of negative climate changes —e.g. temperatures that promote the breeding of particular pests— the overall ecosystem loses resilience and the risk of total loss of produce increases. Farmers can maximise productivity by selecting appropriate crops to be utilised for intercropping; this will not only provide shade for the soil but also maintain soil health and provide additional income.

From an energy dimension, it is important to note that Zimbabwe's electrical energy comes from hydro and thermal —coal fired power stations—generation mechanisms. The absence of regular dependable rainfall makes hydro-electricity generation a challenge. This in turn pushes the nation to depend on coal fired thermal power which increases GHG emissions. Furthermore, this negatively affects irrigation and other farm activities that require electrical energy given the energy deficit rooted in drought. Dwindling hydro-power potential and increasing emissions in coal fired power stations opens up new avenues in public and private investment in clean renewable energy. As such it is critical to promote and invest in the production of clean energy.

Harvest management often requires the use of complex energy consuming equipment. Previous sections in have already explained the climate risks that limit the access to hydro-power and ultimately energy. Furthermore, deliberations on access to finance also exposed challenges in accessing complex equipment. Furthermore, processing is undertaken by the large off-takers and climate related risk is entirely shouldered by them. Most of this risk is again related to energy availability and processing activities that also require energy. Water availability is also crucial in the processing phase. As such, the recurrent droughts again present risks to the effectiveness of the processing stage. This phase also generates a lot of waste that is often dumped into the natural environment creating negative externalities that are a great ecological cost to society.

Finally, this study exposed a number of climate risk factors to consider in the various horticulture value chain models. A significant number of the risk factors may be countered using the knowledge possessed by the farmers regarding climate change management. In the absence of such knowledge, farmers may fail to deal with the negative aspects of climate change resulting in higher climate risk.
