Broom grass cultivation to prevent soil erosion in sloping area [Lao People's Democratic Republic]

Good Practices

Broom grass cultivation to prevent soil erosion in sloping area [Lao People's Democratic Republic]

Definition of the Technology:

The technique involves the planting of broom grass in order to prevent landslide in mountainous and stream areas which are adjacent to agricultural land. This is because broom grass has an extensive root system which can help to bind the soil. Additionally, farmers can generate an income from broom grass.

Description:

Climate change has impacted agricultural practices and the livelihoods in rural mountain areas. Due to the occurrence of more volatile climate conditions including more frequent and intense rainfall in July and August, it has affected soil erosion on steep slopes. Therefore, broom grass was introduced to help stabilize soil composition and to prevent erosion and landslide.
In 2011 farmers at Chorlaving village, Ta-oy district started the technology by taking the broom grass rhizomes from the natural forest and replanting these on their own land which had been impacted by soil erosion. Their main objective was to prevent landslides that could impact their crops. At the same time it is also easier to manage and harvest broom grass on their land, which will be sold to merchants coming to the village. Most importantly, broom grass - a native species - has an extensive root system into a depth of 1 – 2 meters that helps to bind the soil. Furthermore it is highly adaptive to local climatic and environmental conditions and is seldom affected by diseases or becomes a food source for animals (as its leaves are hairy and rough). For the collection of broom grass rhizomes simple equipment is needed. This includes blades, knifes and baskets. The rhizomes should be selected along steep slopes in mountainous areas. Then the stems are removed from the parent plants, whole young plant is removed including the root and culms of about 30 cm. The broom grass plantation of this case study area has a length of 300 meters and a width of 80 – 120 meters on a sloping terrain with a gradient between 11-15%. The seedlings can be grown from healthy rhizomes collected in local forest areas, with approximately 6,000 seedlings per hectare. They are usually planted in April and May when the soil is still warm and stimulates the growth. To start off with, the farmers need to collect broom grass rhizomes from forest areas for one or two days. Afterwards they should be maintained for few days in a well shaded area, watered and covered by plastic bags. Land preparation firstly involves bush clearance. After, the farmers create rows by digging 20 x 20 cm holes at a distance of approx. 2 meters from one hole to the next. Planting may commence at the bottom of the field with the farmer placing 4 – 5 rhizomes in each freshly dug hole as he moves upward the row following the contour of the land. Yangbong trees, but also other plants can be intercropped in every two rows of broom grass. The grass helps to retain soil moisture which promotes e.g. the Yangbong trees’ growth. Once a year the broom grass area needs weeding and thinning. After harvest of the grass the cuttings and fragments can be used for mulching the soil surface around the broom grass stems and the trees. This not only retains soil moisture, but by the decaying process it enriches the soil by nutrients (natural compost).Typically, broom grass can be harvested 2 – 3 years after it has been planted. During the rainy season (June to October), the roots and the new shoots of broom grass grow quickly. The strengths of a broom grass plantation are that firstly it prevents soil erosion and secondly its different elements (e.g. flowers) which provide a higher household income. Model farmer’s broom grass plantation is 1.5 ha and may generate an income of around 2,000,000 Kip/ton/year. Currently, broom grass can be used for handicrafts, household products such as brooms and can also be sold to neighboring countries. There are currently many households engaged in planting broom grass for commercial purposes on their own land. This reduces conflicts among the village people araising when it had to be collecte in natural areas.
Weaknesses: The root system of broom grass grows quickly which may result in the competition for nutrients and space with the other crops. Therefore appropriate management may be required by cutting and removing excessive rhizomes and culms. Furthermore, the roots can expand so extensively (difficult to remove when they grow up) that it would exceed the farmer’s capacity to control them in order to get enough space for inter-crops. And planting broom grass on sloping terrain may cause difficulties to maintain and harvest the crop.