Imagine walking across a cashew plantation and spotting these half-moon-shaped bunds filled with water at the base of every tree planted. What are these, and how are these structures contributing to an estimated 32% increased yield in cashews? What we just described are crescent-shaped bunds. The crescent bund is one of the most effective in situ soil and water moisture conservation methods. In-situ moisture conservation practices improve soil structure and porosity, increase infiltration and hydraulic conductivity, and consequently increase the soil water storage that helps the crops to withstand moisture stress. Then there are the modified crescent bunds which include several other treatments in addition to digging the bund like coconut husk burial and leaf litter (the coconut husks are buried in an open basin for a longer time to absorb the air - moisture or rain water). The modified crescent bund is a simple yet effective soil and water conservation structure used in cashew plantations. It consists of a crescent-shaped earthen barrier measuring 6 metres in length, 1 metre in width, and 0.5 metres in height, with a curve radius of 2 metres. Positioned upstream from the cashew terrace, this bund serves multiple purposes. It efficiently retains water and captures leaf litter, which in turn helps conserve soil moisture and control erosion. This design optimises water management and soil protection in cashew cultivation, promoting healthier and more productive trees. Cashews and Odisha Cashew (Anacardium occidentale L) has been a primary source of livelihood for Indigenous communities (Scheduled Tribes and others), and the Soura tribe form the majority in this BfTW project area, primarily involved in cashew production. The state has approximately 183,000 hectares under cashew cultivation, representing about 6% of India's total cultivation area, with an annual production potential of 93,000 metric tons (DCCB, 2017). The annual rainfall ranges between 1200 to 1400 mm in parts of Odisha. Despite the adequate rainfall earlier, there was a significant issue with water scarcity due to the absence of water harvesting structures. The economy of these project villages heavily relies on cashew cultivation for livelihoods. Farmers typically receive prices ranging from Rs 90 to Rs 120 per kilogram, varying according to the market conditions, without sorting the cashews by size. On average, farmers produce 6-8 quintals of cashew per acre. Despite the significant local demand in India and the lucrative export market, which reached US$ 452 million in 2021-22, farmers from these communities are increasingly concerned about the impacts of climate change on cashew cultivation. Why do cashew plantations need crescent bunds? In India, cashew trees experience significant moisture stress from January to May, a critical period during their harvesting season. This stress adversely affects flowering and fruit development. High temperatures (above 34.4°C) and low relative humidity (below 20%) can cause flowers to dry out, reducing yields. Additionally, unseasonal rainfall and heavy dew increase the risk of pests and diseases during flowering and fruiting stages, which is detrimental to the kernel quality and often results in blackened nuts. “Earlier, there was no irrigation facility for these plantations; agriculture relied solely on rain. Insufficient monsoons severely affected cashew production,” explains WOTR field staff in Odisha. Installing irrigation infrastructure on hilly slopes is challenging and costly, making in situ water and soil conservation measures highly effective. Research shows that in situ soil and water conservation techniques are superior for capturing pre-monsoon and post-monsoon rainfall, making it available to cashew plants during critical periods. These methods significantly enhance the growth of cashew plants and yield (coconut husk burial yielded 6.60 tonnes per hectare and modified crescent bunds yielded 6.45 tonnes per hectare compared to a control yield of 4.88 tonnes per hectare), indicating a yield increase of 32–35%. The net profit from well-managed cashew gardens over the first seven years ranged from US $4,332 to $4,335 per hectare, compared to $3,097 per hectare in the control group. (Rejani, R., et.al., (2010)) Modified crescent bunds and coconut husk burial treatments reduced annual runoff (20% and 22% of rainfall compared to 37% in control) and soil loss (47% and 49% less than control), while increasing mean soil moisture content (15.6% and 15.8% dry basis compared to 11.6% in control). These practices also improved nutrient content in both soil and leaves. The harvested rainwater has raised groundwater levels in nearby wells and ponds, demonstrating that even steep barren lands can be effectively utilized for cashew cultivation with proper soil and water conservation measures like modified crescent bunds or coconut husk burial in staggered trenches across slopes. (Rejani, R., et.al., (2010) WOTR has mobilised communities in its project areas and 1860 crescent bunds have been created, with an additional 140 in progress, positively impacting 40 hectares of cropped land across 11 villages in the Gunupur block of Rayagada district, Odisha. This initiative benefits approximately 2,000 trees, particularly cashews, and supports around 85 households. How did the crescent bunds come about in the Rayagada district of Odisha? Several structures in Ganjam district, Odisha, constructed earlier to conserve water and soil for various plant species lack maintenance and therefore became ineffective. “The Indian Council of Agricultural Research (ICAR) cashew pamphlet published in 2020 and the W-CReS study published in 2024 suggested that these measures were essential for moisture retention and could lead to a 25% increment in average income for cashew farmers. Convinced by the research, the village development committees along with Wasundhara Sevaks and Sevikas, began mobilising the community. A meeting was held to discuss future actions, propose ideas, explain designs of crescent bunds, and offer employment opportunities to local villagers for this work. Initially, some villagers expressed concerns that the structures might harm the roots of the cashew trees due to inadequate spacing between them. However, after thorough explanations that the digging would be done after keeping a 2m distance between the trees and the pit, the villagers agreed to take action and constructed the crescent bunds in September. The bunds were built quickly in a month. The analysis from the study by the W-CReS team of WOTR in the project area in 2024 of month-wise water requirements for cashew plantations in the Rayagada district revealed significant variations in water demand based on the age of the trees and plantation spacing. Younger trees (up to 4 years) and those between 4-10 years have significantly lower water requirements. Older trees (above 10 years) have the highest water needs, particularly during the peak growth stages from January to May, with demand reaching up to approximately 105 litres/day/tree in wider-spaced plantations (7m x 7m). This study helped to design plans regarding the digging of pits and how to space them. Broader positive effects of the Crescent Bunds The modified crescent bunds will create the potential to harvest 6000 cubic metres of water/ 6 million litres for every filling event. The average number of fillings is estimated to be 3-5 times each year, thus making a harvesting potential of 30,000 cubic metres (30 Million litres). The harvested water would be available as soil moisture to the cashew trees and rainfed crops being grown on the foothills. Most of this water will also be recharged to the underground aquifers to increase the groundwater table in the check dams and dug wells for irrigation. This will employ the local people and thus generate an income for them too. Since September 18, 2024, when the work was commenced, it was possible to generate employment for multiple labourers who worked on the 1,860 pits dug. During 2025, in some pits, it is seen water filling up to an elevation of 100 cm, while for others, it is 200 cm according to rainfall. It is also planned to redesign the bund to increase the storage capacity and water harvesting potential. The field staff inform that it will take two harvests for the beneficiaries to notice an increase in the cashew yields with this method, but the effect will be long-term then. The project has achieved the impossible feat of providing water and irrigation in an area where it was close to impossible to do so. How? Through the collective effort of the community striving to build resilience. Read the blog here: WOTR website