Researcher Diaries: adoption of cover crops in mango and longan orchards in Cambodia

As part of my field assignment, I participated in the first phase of the Pinoy Tannin project, where the team carried out a screening for suitable local sources of tannins in the Philippines.  

Tannin is a natural substance present, to different extents, in various plants and biomasses. Traditionally it is used for leather tanning and can be used as an industrial, natural substitute for chemical wood adhesives. 

Together with the Pinoy Tannin project team, we selected potential tannin sources among biomasses that were usually left to decay in the fields or used as firewood. 

The bark of 21 tree species widely planted in the Philippines and the husks, shells, spikelets and roots of diverse coconut varieties were collected, and extracted with hot water at the local laboratory. 

This screening represents a unique and important contribution to the international scientific literature on tannin extraction, reporting a wide comparison among potential tannin sources commonly growing in Southeast Asia. It includes the analysis of never-before-investigated tree species. 

Overall, the results show that suitable tannin sources have been successfully identified in the Philippines. An analysis of the production capacity and costs to identify the market potential of the local tannins has also been carried out.  

The project involved BFH-AHB and BFH-HAFL teams in cooperation with Philippine institutions – the Forest Products Research and Development Institute (DOST FPRDI), the Philippine Coconut Authority (PCA), and Visayas State University College of Agriculture and Food Science (VSUCAFS) – in the context of the Swiss Programme for Research on Global Issues for Development (r4d). 

Benefits of cover crops

After Rosa and I arrive in Bourn Chour village, we search for the first farmer’s house. We ask some villagers for directions and finally find it. We carry out a one-hour interview and afterwards ask the farmer to show us his longan orchard. Like many other farmers in the area, he had to cut down all of his mango trees because of their low demand and continuously falling market prices. The farmer explains to us that he started growing cover crops because he had weed problems; since then, he has stopped using herbicides and is very satisfied. We give him one of the “Kramas” to thank him for his time and take a picture with him. In exchange, he gives us a bag full of longan.  

We ride to the next farmer. This time we interview a conventional farmer who does not grow cover crops. He has never heard about cover crops and their use and is interested to know more. We explain the benefits of cover crops and he seems open to the idea because he has problems with weeds and soil erosion. Before we leave, the farmer sees our bag of longan and insists on giving us some more from his farm.  

After our lunch break, we meet our third farmer who used to grow cover crops but stopped because they died out. She told us that she will grow them again during the rainy season. Like the first two farmers, she does not let us leave without taking some longan.  

Around 15:00, Rosa and I ride back to Battambang town with two full bags of longan and a lot of interesting information.
 

Researcher Diaries

The Researcher Diaries series provides photo snapshots and testimonials from researchers and students participating in BFH-HAFL and partner projects in the field all over the world.