Grass covering

The first objective of grass covering is the control of erosion via soil cover. It is set up to stabilize and prepare the soil while waiting for the planting of tree species in areas with soil very sensitive to erosion (low geotechnical cohesion).
SMSE uses this technique to act quickly on the erosion of sensitive areas where direct tree planting is difficult and without any guarantee of results. Thanks to the fast installation of the herbaceous cover (compared to the trees) and its almost total coverage of the grass surfaces, erosion can quickly be contained and thus greatly increase the effectiveness of the revegetation following the grass cover of a patch.
Indeed, a herbaceous cover combining leguminous and grasses will facilitate and promote the implantation of tree species thereafter. Legumes, thanks to their symbiosis with a soil bacterium, will partially restore the fertility of the soil by enriching it with nitrogen, an essential element for the vegetative growth of plants. The fasciculated root system of grasses will allow it to structure and protect the soil. Their presence will limit erosion, the leaching of nutrients present in the soil and finally increase the porosity of the soil and thus allow the development of the microorganisms responsible for fertility.

Soil preparation

Depending on the morphology of the area, land remodeling techniques are used upstream of the grass work to ensure the stability and security of the terrain. Once assured that the area no longer requires the intervention of heavy construction machinery, a last passage of shovel is realized to aerate the ground using the bucket over a depth of about 50cm. This aeration will allow better root growth and installation of the herbaceous canopy.

Aération du sol avant enherbement (2017)

Sowing

The grass is planted during the rainy season. The SMSE is based on its experience for several years now to achieve its mix of grasses and legumes. Thus it mainly uses the following association:

 

                               - 1/3 grasses (Brachiaria Decumbens)

                               - 2/3 legumes (Stylosanthes Campo Grande)

 

The seeding was carried out until 2018 using a manual spreader, with the increase of the surfaces to be treated, the SMSE invested in a rotary spreader carried by the agricultural tractor.

 

The seeding density remains at 10 kg/ha, but the seeding process is greatly accelerated.

The plots were originally fertilized by manual application using a N17 P17 K17 fertilizer at a dose of 400 kg/ha.

 

With the progress of the entire project and the emergence of new objectives to reduce the use of chemical and imported inputs, the chemical fertilizer N17 P17 K17 was gradually replaced by hen manure from agricultural cooperatives in Guyana. The droppings are applied with a dose of 1 t/ha.

 

In addition, the acquisition of the rotary spreader for herbaceous seeding is also used for the fertilization of the plots by allowing the spreading of hen manure faster on the plots.

 

Fertilization will ensure a better start and cover of the vegetation as quickly as possible, which will quickly stem erosion on the grass surfaces, stabilizing the land to allow the reforestation phase to start under optimal conditions.

 

In order to promote contact between the seeds and the soil, and thus increase the germination and survival rate of the seeds, a small harrow passed over the plot to bury the seeds and fertilizer under about 1-2 cm of soil.

During handling, the passages are kept to a minimum to avoid too much settlement of the parcel.

 

 

Semis manuel graines herbacées

Ependage d'engrais à la main

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Enfouissement des graines d'herbacées

Overview

Today, SMSE has planted more than 20 hectares of grass on the Saint-Elie site. These initial tests and results make it possible to improve and optimize the techniques used. In particular, by identifying the most effective associations of herbaceous species depending on the type of soil, as well as soil preparation techniques that are most conducive to grass.