Pulse keeps the pulse beating: Why pulses are important

Every year on 10 February, the world celebrates the day of pulses. The theme this year is "Pulses for a Sustainable Future". This day is dedicated to raising awareness and promoting the consumption of pulses.

But, what are pulses?

Pulses are edible dried seeds of legumes. They are harvested as dry grains as opposed to vegetable crops, which are picked while green. According to The United Nations Food and Agriculture Organization (FAO), pulse crops fall into 11 different types: chickpeas, dry beans, broad beans (fava beans), lentils, dry peas, cow peas, pigeon peas, bambara beans, vetches, lupins, and a group called pulse nes, which includes several smaller categories.

Common bean (Phaseolus vulgaris) is among the most popular and consumed pulses in Africa supporting over 200 million people. It is the most important, widely grown and consumed grain legume in Eastern, Central and Southern Africa, where about 8 million hectares of land is used to grow beans every year. Per capita bean consumption in Eastern Africa is the highest in the world - in western Kenya, Rwanda and Burundi people eat their body weight in beans every year (around 50 - 60 kg).

The Alliance of Bioversity International and CIAT is considered the home of beans as it is home to more than 37,000 accessions of beans in the Future Seeds genebank in Colombia. These materials are useful in supporting research for bean improvement globally.

In Africa, bean research is advanced through the Pan-Africa Bean Research Alliance (PABRA) and has resulted in the release of more than 550 new bean varieties across 31 countries in the past 25 years.

Why are pulses important?

Pulses have sustained human civilization for thousands of years as an essential part of the diet, keeping people healthy. Pulses are an inexpensive source of complex carbohydrates, micronutrients, protein, and vitamin B, which are vital parts of a healthy diet. Low in fat and rich in fibre, pulses are excellent for managing cholesterol, digestive health and regulating energy levels.

Through a process of biofortification, bean researchers at PABRA have developed bean varieties with high levels of iron and zinc. In Kenya, researchers at Kenya Agriculture and Livestock Research Organization (KALRO) developed and released three bean varieties high in iron and zinc. The bean varieties include Nyota, Angaza and Faida which are now widely commercialized by KALRO Seed Unit, East Africa Seed, Dryland seed, Bubayi Seeds, Agripack among other licensed private sector seed companies.

Producing and eating beans rich in iron and zinc is a cheap way to address the problem of anaemia and stunting that is widespread across the continent among children under five, expectant mothers and adolescents.

Studies have shown that fibre and complex carbohydrates in pulses form a health address for anaemia and stunting widespread across the continent among healthy diets for people with diabetes and heart conditions. Pulse keeps the pulse beating

Pulses have a longer shelf life. After harvesting, they can be stored for a long time without deteriorating; this means less wastage and enhanced household food security throughout the year. They can easily be sold and converted to cash to meet urgent household needs.

Pulses as a climate-smart food

Food production is a major contributor to climate change and other forms of land degradation. However, different foods have differing impacts on the environment. Pulses contribute to sustainable food systems in several ways. Pulses are a major component of the cropping systems where they are grown either in rotation, inter-cropping or sequence. Pulses can be planted with other crops such as maize, cassava, banana, coffee, and avocado. Cropping systems integrating pulses are more diverse and resilient to climate change.

Pulses fix their own nitrogen from the atmosphere, thus reducing the need for the application of nitrogen fertilizers. For example, research has shown that common beans have potential to fix 39-52% nitrogen. The litterfall leaves nitrogen-rich residues in the soil after harvesting which enriches the soil for the benefit of the subsequent crop.

Studies have shown that production of plant-based foods tends to have lower greenhouse gas emissions and use less land and water than producing animal-based foods. As such, growing pulses such as beans contributes to sustainable food production systems in a changing environment.

Pulses play a significant role in ensuring access to food in dry environments where food security is often a challenge. This is so because several legumes are drought-tolerant and have short maturity periods. Early maturing, higher yielding and hardier varieties can provide farmers with bumper harvests up to three times a year, guaranteeing productivity and household food security throughout the year. For example, KALRO through the PABRA developed a drought-tolerant variety, Nyota bean, that has proved a game changer under drought conditions. This variety is early maturing (takes 70-75-day to grow), compared to other varieties that take 90-120 days. The fast growth and early maturity characteristic enable the variety to use the little available rainfall more efficiently and to escape drought The variety is suitable for semi-arid areas such as Machakos, Makueni, Tharaka Nithi, Narok, Elgeyo Marakwet and Baringo. It is also suitable for areas experiencing erratic rainfall patterns. Combined with its quick cooking, low flatulence, and being high in essential micronutrients, including zinc and iron, Nyota is proving to be a pulse of choice for farmers in Kenya.

Pulses and income

Pulses are a major tradeable food crop from household local level to international markets earning millions income. For example, bean sales in Africa exceed US$500 million annually and have an export value of about US$110 million. At household level, a farmer with one acre harvesting 720kg (8 bags) of beans per acre and selling each bag at Ksh. 8,000 can earn a net income of over Ksh. 39,000 (US$ 320) over a period of three months. Farmers have used beans to pay school fees. The growth of specialized niche bean markets along with rapidly expanding urban populations, and healthy diets, have contributed to the rapid growth in the pulse trade.

Value addition of pulses

Beyond eating dried beans, they can be transformed into innovative products served at home and high-end hotels and restaurants. Traditionally, beans are eaten as boiled Githeri, a mixture of maize and beans. Today, beans are being processed into products such as bean flour, precooked beans, bean snacks and bean noodles. The precooked bean takes less than 15 minutes to serve as opposed to 2 hours to cook when preparing boiled beans. This is an innovation that is climate smart; saving energy and trees. A fast-cooking product such as this ensures that households can have a nutritious bean meal at highest level of convenience. For plant-based diets, the bean flour is used to blend with other flours such as maize, wheat, sorghum, and orange flesh sweet potato to produce nutritious composite gluten-free flours for porridge or baking. Enterprises run by women and youth are emerging around bean value addition, creating jobs and earning incomes for thousands of actors along the commodity value chain.

(Dr Boaz Waswa is Soil Fertility Specialist at the Alliance of Bioversity International and CIAT)