Biomass Surveys

Biomass studies at the RBG During our baseline research for the Community-Based Rangeland Rehabilitation project, biomass surveys were conducted in April and May of 2008, 2009 and 2010.

The surveys obtained information on biomass production in the Garden, used to calculate the site's carrying capacity, determine the effect of grazing on biomass production and develop appropriate grazing management scenarios.

A method known as the "transect technique" was used to estimate biomass productivity.

The data obtained showed that the biomass in many sectors more than doubled in three years.

The doubling of the biomass throughout the site by 2010 was linked to the following factors:

Full site protection: The local herders used to let their sheep graze in the site without permission, especially in some sections where heavy grazing occurred. In 2008, the RBG decided to involve the local community in the project, to help them manage their flocks and ensure their cooperation in protecting the site.
Rainfall: The data show high rainfall in 2009 and especially in 2010, considered the wettest season in 10 years.
Grazing: The data proved that controlled grazing positively affects biomass production as it stimulates plants to re-grow and produce edible leaves, more than the woody parts, especially for shrubs.

The study found that grazing should not exceed a moderate level, in order to ensure regeneration and uniform forage production the following year.

The research also confirmed that the best time for grazing is the fall, since plant response is positive in that period, new re-growth is encouraged, and all the plants have set their seeds in the ground by then.