Smart farms

: 04 November 2022; Hits: 1319

Not just a pest: the value of termites in African agriculture

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By George Munene

Although termites are considered agricultural pests they are crucial in the distribution of natural resources, i.e, water and nutrients in soils within the tropics.

These engineers of tropical ecosystems have a huge impact on the biological, physical, mineralogical, and chemical properties of soils. They play a key role in organic matter decomposition, soil fertility, soil formation, digging tunnels that enable plants better access to water, vegetation growth, and encouraging species diversity.

Soils surrounding termite mounds are in Carbon, basic cations that impact soil pH, clay minerals, and oxides that affect plant development.

They also increase nitrogen in soils by transmitting nitrogen-heavy bacteria in their stomachs in form of saliva and feces into the soil.

According to research done by the University of Sydney, wheat farmers in sub-Saharan Africa saw a 36 per cent increase in their yield by treating their land with termites and ants.

Related News: Used engine oil tames termites

“Termites refertilise Savannah soils by breaking down dead wood to organic matter and bringing up minerals from deeper soil layers to the ground layer-- this is the section in which most agricultural activities take place,” explained Dr. Sebastian Doetterl-- founder of the Congo Biogeochemistry Observatory during a talk held on Thursday on soil landscapes and their development in the 21st Century.

Termites constitute 10 per cent of all animal biomass in the tropics. With over 1,000 species, Africa has the richest diversity of the insect. Some termite species are key pests of trees, and crops such as maize sorghum, and yam causing up to 45 per cent in losses.

“It is unfortunate that tropical ecosystems remain largely underresearched. There has been little study done to distinguish non-pest termite species from their destructive relatives as well as sensitization of farmers on their importance,” Sebastian said.

Intensive and large-scale commercial agriculture has seen the leveling of termite mounds. Spreading and mixing of this mound material leads to a short-term spike in soil fertility but after a few cropping seasons this is depleted and crop yields diminish as termites-- a major source of soil fertilisation-- have been lost.

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: 04 November 2022; Hits: 1385

30% of global arable land made useless due to excessive irrigation

Channel Irrigation of cotton crops WARREN 50

While most agricultural stakeholders are touting irrigation as the best way of bringing more land under cultivation, a report in the National Centre for Biotechnology Information shows that at least a third of global arable land, an equivalent of 10m hectares has been rendered useless due to soil salinity, caused by over-irrigation.

The report further warns that the rapid global climate change, which has seen sea waters sweep the mainland in some countries, is going to worsen the situation, destroying more arable land and threatening global food production. According to the report, saline soils have more than 4ds/m at 25 degrees centigrade and contain high sodium and chlorides.

This revelation might lead the Kenyan government to tread cautiously as it launches various irrigation projects in a bid to reclaim more land for agricultural production. This is in consideration of the fact that 80 per cent of the country’s land is arid or semi-arid and depends on water bodies or aquifers for irrigation.

An example of governmental effort to groom arid land for crop production through irrigation is the 1m acre Galana-Kulalu irrigation scheme on the Kenyan coast.

In spite of conducting a production analysis worth Sh1b, and a contract awarded to Green Arava, an Israeli company, the 500-acre maize farm only managed to produce 10, 90kg, bags of maize per acre against the projected 3600kg per acre. 16 suitable maize varieties were used on the farm, according to Richard Lesiyampe, Acting PS, Water, and Irrigation, but the people involved lacked a definite answer for the low production.

Dr. GM. Mailu of the National Council of Science and Technology thinks that poor quality water was used for irrigation hence affecting the production. He explains that the area being near the Indian Ocean is characterized by salty water, and the quality of water used for irrigation should be keenly analyzed. He explained that most sea and groundwater in Kenya has high contents of sodium and chlorides which when used directly for irrigation cause soil salinity. He listed the spotty growth of crops and the presence of white crusts on the soil surface as key indicators of soil salinity.

In a study, he conducted in collaboration with KALRO, dubbed ‘the impact of groundwater quality on irrigation in Wajir, 64 per cent of 116 boreholes water sampled had high sodium and chloride contents, hence unsuitable for irrigation. Samples from the Lorian swamp also indicated high alkalinity. The research recommended an intensive analysis of the water meant for irrigation in the region.

Even as soil salinity is threatening global food production, innovators are constantly developing technologies to counter it. SGS, a global agricultural integrated service provider with an office in Kenya is for instance reclaiming saline soils through leaching, a process involving pondering fresh water on the soil surface and allowing it to infiltrate. This process is said to have almost 80 per cent success in dealing with soil salinity.

The company has also developed a precise soil tool for testing, and mapping using GIS. The company tailors the GPS-aided tool to the farmer’s operation to test for soil salinity and send the response to the farmer’s smart or android phone. Other salinization control mechanism provided by various companies across the globe to mitigate the loss of arable land includes genetic engineering, scrapping, and flushing.

The NCBI study however recommends extensive studies by global agricultural stakeholders to come up with more effective and practical ways of dealing with soil salinity. It however did not rule out environmental conservation to curb the impacts of climate change which is the primary cause of soil salinity.

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: 03 November 2022; Hits: 1349

Partial Root-Zone Drying irrigation enables potato farmers halve water usage

partial root drying technique

Small-scale potato farmers using furrow irrigation can make use of little water to bring more acreage under cultivation by applying the partial irrigation method.

Partial Root-Zone Drying method, which can save between 30 per cent and 50 per cent of the total water used in an acre, relies on the alternate supply of the commodity to the root system of the crop.

One side of the root system is supplied with water while the other is left dry. On the second round of irrigation, the other roots that were left without water are fed.

David Ramírez of Potato International Centre says the method allows for better development of abscisic acid in the sections of the soil that were ‘skipped’ during the process.

Ramírez, who heads the Crop Ecophysiology department, says the acid is a hormone that induces tuber formation and promotes the closing of leaves’ stomata. Closing of the stomata reduces water loss via transpiration.

One acre of sweet potatoes requires between 1,400 cubic meters and 2,600 cubic meters for a farmer to receive maximum yield for best returns.

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Furrow irrigation is one of the methods that has been used for several years, majorly relying on gravity to push water from one point to the other.

Farmers near rivers and streams find it easy to fetch and pour or channel some water through parallel pathways into crop-growing fields.

However, the expert said more research is ongoing to determine the exact amount of water to be supplied to avoid reducing carbon intake by the plants.

Alternate irrigation has been tried and worked well in Peru, China and Ethiopia.

Once adopted by farmers it would increase harvests, at a time when climate change is reducing the amount of water available for irrigation and domestic use.

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