Sustainable agriculture: Green manure for tea fields

As part of our efforts in working towards sustainable organic farming we will be sowing legumes to also be used as green manure for our tea fields.

"Legume" is the term commonly used plants from the Fabaceae family and are known to be rich in protein and fibre. Aside from the dietary benefits it brings to our diets, planting legumes also has numerous benefits for the soil.

The legumes that we will be using on our tea fields is called “Hairy Vetch”. Hairy vetch or vicia villosa, is a common choice due to its innately high nitrogen fixation rate and allelopathic tendencies. In other words, the hairy vetch can effectively convert nitrogen found in the air to a form that is beneficial for the surrounding plants, making residues in the soil nitrogen-rich.

The second reason hairy vetch is suitable for tea fields is due to the legume’s ability to naturally produce cyanamide. Based on the chart on the right, the cyanamide is subsequently converted into dicyanamide. Dicyanamide has the ability to suppress nitrifying bacteria, which decomposes ammonia nitrogen into nitrate nitrogen. Unlike most vegetables, tea trees absorb nitrogen more readily when it is in an ionised form (NH4).

Last but not least, hairy vetch is said to aid in suppressing the germination of other weeds.

Hopefully through this project we will be able to produce our own green manure, improve the quality of our tea, work alongside nature, and reduce our carbon footprint through cutting out any unnecessary steps.