Cover crops play a crucial role in sustaining soil health and benefitting farmers, offering an eco-friendly alternative to synthetic fertilisers.
Sar Veng, a technical adviser at the Cambodian Conservation Agriculture Research for Development Centre (CARDEC), highlights the positive impact of cover crops on Battambang province’s 2,069ha land area. Over 1,550 households adopting cover crop cultivation say they have experienced increased yields, promoting sustainable soil management.
Lim Sokhom, a farmer from Reaksmey Sangha village in Battambang, shifted from chemical fertilisers to cover crops, enriching his soil and contributing to climate change mitigation.
His 10ha plot follows a crop rotation pattern, incorporating red corn, beans, slender leaf rattlebox (Crotalaria ochroleuca) and sunn hemp (Crotalaria juncea) to enhance organic fertility.
In previous years, he used three to four bags of chemical fertiliser per hectare, costing 200,000 riel ($50) per bag.
However, in 2021, CARDEC officers educated area farmers about conservation agriculture, promoting cover crops that not only enrich the soil with nutrients but also absorb higher carbon levels, showcasing a sustainable approach for farmers.
“I gave it a go; chemical nutrients are pricey and lead to soil hardness and erosion. Yet, when I shifted to planting cover crops, I noticed the soil recovering fertility. These crops enrich the soil with nutrients, serving as excellent natural fertiliser,” Sokhom shares.
Sustainable soil focus
Veng shares that conservation agriculture, in play since 2009, centres on cultivating cover crops to cut down ploughing and encourage sustainable soil management.
CARDEC’s focus is on a cultivation system that prioritises practices enabling carbon incorporation into the soil through cover crops. These crops absorb CO2 from the atmosphere, helping combat climate change by reducing greenhouse gas emissions and promoting carbon storage in the soil.
“So, using cover crops or crop purification captures carbon in the soil – whether taken from the atmosphere or stored through conservation agriculture practices. This not only removes CO2 from the atmosphere but also transforms it into a beneficial substance for the soil,” he explains.
Regarding CARDEC’s activities, Veng mentions their active involvement in Banan, Ratanak Mondol, Sangke, Samlot and Kors Kralor districts, along with initiatives in Sala Krao district in neighbouring Pailin province.
He recalls that initially, farmers in the Ratanak Mondol district showed little interest in conservation agriculture or cover crop cultivation, as the soil at that time remained fertile for rice. However, a shift occurred in 2018 and gained momentum by 2023, covering over 2,000ha.
The growth is credited to the backing of the Cambodia Climate Change Alliance (CCCA), a collaborative effort between the government and development partners.
This alliance is dedicated to addressing climate change and consistently strives to enhance information and knowledge about climate change.
Sem Savuth, a CCCA climate change officer, highlights the distinctive nature of the cover crop initiative. It focuses on enhancing farmers’ capacity, promoting agricultural production and fostering cohesive farming communities. This conservation agriculture project introduces a new technique where farmers opt for cover crops instead of artificial fertilisers.
“In highland areas, climate change poses a significant threat, especially through soil erosion. Once erosion occurs, the land becomes unfit for agriculture. Hardened soil doesn’t support crop growth, so the key agricultural technique is turning this soil into fecund and thriving ground. Introducing organic fertiliser also encourages the presence of beneficial insects in the soil,” he explains.
He mentions that farmers have participated in the project for over a decade. They experimented by cultivating tall cover crops in challenging soils, aiming to understand how much greenhouse gases get absorbed from the atmosphere into the soil. The adoption of cover crops, as opposed to traditional methods, increases agricultural yields and uplifts the overall livelihood of farmers.
“We aim to spread the word across Cambodia, encouraging more farmers to think about cultivating crops without ploughing. Opting instead for cover crops is a great alternative. Ploughing releases carbon from the soil, and carbon, being a greenhouse gas, is released into the atmosphere,” he says.