Integrating legumes in rice fields to cope with climate change

Farmers in a rice field creating water ways in the rice garden for the planting of legumes. PHOTO/GEORGE KATONGOLE

What you need to know:

  • In Uganda, intensive cropping has reduced the fertility of the soil. This situation can be improved by on-farm cultivation of legumes for livestock as an integral component of the cropping system.
  • Experts explain that integration of legumes with rice-based cropping systems is an appropriate technology for improving productivity.

As effects of climate change, witnessed through drying water sources and unreliable rainfall continues to be manifested in Uganda, adoption of climate-smart agriculture practices will now be a prerequisite  for continued production. One of the practices for rice farmers is the Rice Legume Integration. 

The practice, which involves planting legumes in gardens where rice has been harvested, allows leguminous crops to tap into the moisture from the soils after rice has been harvested.

It is one the climate smart agriculture practices, that organisations such as Kilimotrust is rolling out in rice growing areas in Uganda and Kenya.  This is being promoted through the Reduce-Reuse-Recycle Rice Initiative for Climate Smart Agriculture (R4iCSA) project, funded by IKEA foundation of the Netherlands. 

Anthony Mugambi, the project team leader, said through the project, they aim to make sure that rice farmers and other value chain actors adopt sustainable rice production practices for continued rice production and increase in yields. 

How does the rice legume integration practice work?
Mugambi said the practice breaks the cycle of continuous rice farming by interrupting it with leguminous crops.

“In this practice, the legume is not planted in the flooded areas, instead the water is flooded or given a water way, leaving the place with no water, so legumes that usually mature within three months can utilise the moisture left in the soil,” Mugambi explains.

Advantages The beauty about the practice, according to Mugambi, is that it breaks the cycle of pests and diseases, at the same time fixing nutrients such as Nitrogen. 

Common pests in rice production, according to the Ministry of Agriculture,  Animal Industry and Fisheries (Maaif), include Stalked-eyed flies, where the larvae bore and feed on plant tissues, destroying the stems. Others include stalk borers that destroys the tissue, resulting in whitish rice plants. 

Termites that eat and cut the stem of rice plants and birds are the invasive pests.
Rice diseases, whose lifecycle can be interrupted by the practice include Rice Blast, said to be most destructive fungal disease in rice. It produces spots or lesions on leaves, nodes, panicles and grains, causing up to 50 per cent damage. 

Rice yellow mottle virus mainly found in lowland or swampy rice field, in a field where the diseases is present, there is yellowish leaves even when the crop is not mature enough.  Brown Spot, common in soils that are poorly drained among others.

Recommended legumes
For those intending to embrace the practice, they should go for early maturing legumes such as green gram, cowpeas, soybeans and pigeon peas, among others. He adds that such crops fix at least 20 per cent of nitrogen based on their studies, have higher protein content, act as cover crops and some can be fodder for animal feeds.

“From our studies leguminous crops can fix up to 20 per cent of nitrogen requirements in a season, that means a farmer can then use only 80kg of fertiliser,” he added.

Besides fixing nitrogen, which is one of the highly consumed nutrients, the practice promotes diversification of farmers incomes and improved nutrition from the legumes said to be having higher levels of protein.
“Some farmers just allow the piece of land to furrow or rest, but we are saying let us not just leave it furrow, but plant leguminous crops as these allow families to get proteins that can supplement the carbohydrates and other food values in rice,” Mugambi adds.

In Uganda, the two-year project is being piloted and promoted in rice growing areas like Doho rice scheme in eastern Uganda and some parts of Kenya, with soils similar to those in Uganda.

Dr Lawrence Owere, the director of Buginyanya Zonal Agriculture Research and Development Institute (BugiZardi), also the implementing partner, said that the project will help increase rice production in the region, if supported with a functioning soil testing laboratory.

According to Owere, although eastern region contributes about 40 per cent of rice consumed in Uganda, the yields keep reducing.  He attributes the decline to over cultivation of rice, without allowing the soils to rest, but also poor or no application of fertilisers. 

In terms of productivity, Owere adds there are rice varieties, which when combined with other technologies can produce up to six tonnes per hectare but on average, Uganda produces two tonnes of rice per hectare, which is low compared to demand for rice.

“We are growing rice season after season, without putting back anything. That is why yield is not increasing. With integration, soil will rest, that means pests and diseases will be reduced, also farmers will grow legumes to supplement incomes from rice and nutritional needs at home,” said Owere. 

He added that for the project to succeed, there is need for an understanding of the missing nutrients in soils in rice growing fields but also for the region under the institute. 

Currently the institute takes care of districts in Busoga, Bukedi, Elgon, and Sebei regions but lack a functional soil testing laboratory or facility. Those who can afford prefer testing their soils from neighbouring Kenya and Makerere University.

Other climate-smart practices
Other smart-climate agriculture practices being promoted by the project include the use of rice husks as soil amendments to enhance fertility in rice growing areas.

Mugambi explained that biochar boosts soil fertility and improves soil quality by raising soil pH, increasing moisture holding capacity, attracting beneficial microorganisms closer to roots of the plants, hence retaining nutrients in the soil for the plant.

It also acts as a carbon sink that draws carbon dioxide from the atmosphere back to the soil, hence reducing a buildup of greenhouse gases that are fuelling most effects of climate change such as increase in higher temperatures.

Rice Legume Integration is a very positive step for rice production because it improves soil fertility because legumes will fix nitrogen, which will benefit the rice. Rice alone is consuming a lot of nitrogen that is why the soil get depleted fast.

Legumes suppress weeds while rice is easily invaded by weeds, therefore any crop planted after legumes, will help the farmer to reduce the costs of weeding. -- Dr Jimmy Lamo, rice breeder& Head of Cereals Programme at the National Crop Resources Research Institute (NaCRRI).


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