Buganga, a pretty village surrounded by lush green hills dotted with banana trees, is a picture of rural tranquility; it contrasts starkly with the dusty streets and bustle of Goma, a city in the east of the Democratic Republic of the Congo (DRC).

Josephine Mwamini has just helped her husband to harvest haricot beans, which lie in a heap drying in the sun. Sitting on a plastic chair in the shade of a tree outside her home, she speaks of her satisfaction with the harvests of the past two years after new techniques boosted yields on the small plot where her family grows beans, peanuts and maize.

"I'm very happy, the new methods have helped a lot, we have more to eat and we sell what is left over," she says.

It's the same story for the 2,000 farmers organised into groups of 30 in farmer field schools as part of a project involving World Vision. Learning about improved techniques has enabled them to increase yields: where once they harvested two bags of cassava, now they get 15. They plan to form business associations designed to improve farmer access to markets.

Through these associations – essentially collectives – farmers pool resources to build storage facilities, strengthening their bargaining power when buying seeds and equipment from suppliers. At the other end, the farmers' groups get better prices by cutting out the middleman and selling directly to markets in the nearby town of Minova and even further afield in Goma, a couple of hours' drive on a bumpy road that twists and turns around Lake Kivu.

The project places much emphasis on empowering women. Its elements include the use of radio programmes to discuss issues such as violence against women, the introduction of labour-saving devices – machines to slice cassava, for example – and training women to become community leaders.

The techniques adopted through farmers' field schools are strikingly simple. A similar approach has been successfully applied elsewhere, benefiting smallholder farmers from Kenya to Uganda, and from Ethiopia to South Sudan.

Planting in a straight line, instead of scattering the seeds randomly, is key. The plants, whether cassava or cabbage, should also be spaced appropriately so the roots have sufficient room. In Buganga, the new cassava plants, with their broad leaves and pink-reddish stems, are spaced 25-30cm apart.

It is striking that such simple techniques can be so effective. The villagers in this area of North Kivu province are fortunate in that the volcanic soil here is highly fertile. In dry areas of Kenya, other simple methods such as drip irrigation, where water is released drop by drop directly on to the roots of the plant, are also of tremendous help.

Given that the adoption of these methods can go a considerable way towards alleviating hunger – a major objective of the If campaign launched last week by more than 100 NGOs – one wonders why they are not used even more widely.

In the past two years, increased yields of groundnuts, cassava, beans, maize and other crops have been the good news for the villagers of Buganga. But life is anything but simple in DRC, a land ravaged by recurrent outbreaks of fighting between indisciplined, underequipped and underpaid government troops and a proliferation of militias, where the state is so weak that people are left largely to their own devices.

In the latest flare-up of violence in the area in December, army troops retreating before the M23 rebels – whom the UN says are backed by neighbouring Rwanda – forced the villagers to carry their supplies and pick cassava leaves, tomatoes and cabbage for them to eat. In short, they stole the villagers' food. The fighting has subsided, but fears linger as a weak government in Kinshasa holds talks aimed at striking a durable peace deal with the rebels.

In the longer term, the area of North Kivu has been hit by a disease known as "banana wilt", which is killing banana trees not just in the eastern Congo but in Rwanda. The effects are clear to see in Buganga, where the tree trunks have rotted.

In this part of DRC, the picture for food security is mixed: farmers are seeing encouraging results as they adopt simple methods recommended by NGOs, but renewed conflict is causing disruption and disease is killing off a vital crop.

• This article was amended on 30 January 2013 to correct references to South Kivu, which should have been to North Kivu