IN Tanzania, agriculture fits in many descriptions. It is a strenuous economic activity of peasants that produces food for themselves, their dependants and the urban lot.
Agriculture is an activity that employs 80 per cent of Tanzania’s economically active population living in rural areas. Agriculture is an activity that contributes close to 29 per cent to the gross domestic product (GDP), according to official figures.
No wonder agriculture is on the lips of politicians and technocrats in the corridors of power. The importance of agriculture has attracted talented brains. Snags notwithstanding, they are working towards solving problems peasants face. Tanzania’s agriculture is peasant agriculture.
Peasants use hand tools to produce food and cash crops. When rain fails them, agricultural production is crippled, there and then. Hence, agriculture, a back-breaking activity, is shunned by young people who migrate to towns in search of office jobs or an opportunity to do petty business.
Yes, Tanzania’s agriculture faces many woes. It is rain-fed. It thrives when skies are generous. Irrigation is minimal. Available statistics shows that of the 29.4 million ha total land area suitable for irrigation development in Tanzania; only about 460,000 ha are supplied by improved irrigation infrastructure.
When irrigation takes place it does not yield best results due to lack of modern technical know-how and other non-water barriers such as lack of finance/capital and poor access to inputs. So, intervention in irrigation- sub-sector is more than welcome.
And a pertinent intervention has come from a team of researchers whose findings shows that a new innovative soil and water monitoring tools have a great potential to boost the livelihoods of smallholder communities in Tanzania by reducing the time it takes to irrigate crops effectively.
The research findings, published online in a special open access issue of International Journal of Water Resources Development on 30th June, 2020 show that farmers have seen up to a 65 per cent reduction in the amount of time they use to irrigate, allowing for a greater focus on other agricultural tasks such as improving farm management leading to increased food security and improved farmer livelihoods.
The results were recently published by Dr. Makarius Mdemu of Ardhi University in a paper titled: “The role of soil water monitoring tools and agricultural innovation platforms in improving food security and income of farmers in smallholder irrigation schemes in Tanzania.”
Dr Mdemu is leading the research activities in Tanzania under a project funded by the Australian Centre for International Agricultural Research (ACIAR) which has introduced these technologies to farmers in smallholder irrigation schemes.
‘Using the soil moisture and nutrient monitoring tools, farmers have gained a better understanding of the soil moisture and fertiliser dynamics and how these variables are affected by irrigation timing,’ said Dr. Mdemu.
‘With the saved time, farmers are improving farm management through more weeding and farming of other previously uncultivated plots, hence raising their farm yields.
’ The project introduced farmers to the soil water and nutrient monitoring tools consisting of chameleon soil water sensors and wetting front detectors, helping demonstrate to farmers how over-irrigating their crops was negatively impacting the soil and crop productivity.
‘Farmers learnt that over-irrigation leads to the leaching of nutrients below the root zone, where they become inaccessible for the plants. In response, farmers reduced their irrigation frequency and duration, thereby significantly increasing their yields,’ said Dr Mdemu.
The paper was published based on results of the study from Kiwere and Magozi, two among the irrigation schemes under the project in Iringa district.
The tools Wetting front detectors (WFDs), Chameleon soil moisture sensors and readers developed by scientists from the Commonwealth Scientific and Industrial Research Organization (CSIRO) and manufactured in South Africa were used in the project.
When buried in the soil, WFDs are capable of enabling farmers to know the depth to which water has infiltrated into the soil during and after irrigation or rainfall and the farmer is able to determine the levels of salinity and nitrate in the soil from the solution extracted from the WFD using nitrate strips and salinity meters.
On the other hand, the Chameleon soil moisture sensor uses three sensors that measure soil tension, the force a plant needs to use to extract moisture from the soil and therefore it does not need to be calibrated for different soil types.
A portable handheld reader connects to the sensor array and displays the soil moisture as coloured lights (blue for wet, green for moist, red for dry), providing a picture of soil moisture at different depths throughout the root zone.
Thus, the Chameleon lets farmers decide whether to irrigate depending on the coloured lights and the condition of the crop. Detailed description of the tools including their technical aspects can be found at the Virtual Irrigation Academy website (https:via.farm/).
The research team also introduced agricultural innovation platforms (AIPs) in the two schemes to help foster engagement between stakeholders such as farmers, government officials, suppliers and marketers.
In this context, the AIPs were used to address challenges in the irrigation schemes and associated value chains in Magozi irrigation scheme.
According to the findings, the AIP approach helped introduce farmers to higher-value crops, better seeds, new markets and improved farming practices. As a result, farmers participating in the AIPs expanded their operations and now grow a more diverse range of crops such as, soybean, green maize, tomato, onion, and other vegetables.
The AIPs have also encouraged farmers to start using livestock manure on their farms after learning that the organic fertiliser option improves the soil condition and stays in the soil profile much longer than chemical fertilisers.
According to Dr Mdemu, the findings highlighted in this study could help to improve irrigation and innovation on smallholder farms across Tanzania.
On scaling up and out the results to the rest of Tanzania, Dr. Mdemu says they hope to cooperate with the relevant government agencies, districts and various development organisations that support the development of smallholder irrigation projects to enable the innovation reach majority of farmers.
“Such innovations are needed and as experts we are ready to build capacity to benefit more farmers,” he noted. For this to happen he suggests considering allocating a fraction of total budgets for improvement of existing schemes or development of new irrigation schemes by the Government, development partners and development organisations.
Their research demonstrates that investment in the simple soil moisture monitoring is less than 5 per cent of typical investments in irrigation infrastructure.
The introduction of technical and institutional mechanisms to increase water productivity and profitability will enable farmers to pay for water and inputs and self-organize to engage in collective action such as irrigation scheme maintenance.
This research is part of the ACIAR funded “Transforming Smallholder Irrigation into productive and self-sustaining systems in Southern Africa (TISA)” project led by the Commonwealth Scientific and Industrial Research Organisation, University of South Australia, Ardhi University in Tanzania, International Crops Research Institute for Semi- Arid Tropics in Zimbabwe, the National Institute for Irrigation in Mozambique and Food, Agriculture and Natural Resources Policy Analysis Network (FANRPAN) in South Africa.
The first phase of the project started in 2013 to June 2017 while the second phase that started in July 2017 is scheduled to run until June 2021. Emmanuel Rubagumya writes about science, technology and innovation. Email: innovationstz@ gmail.com