Comparison of woody vegetation in cotton fields in Mali

The overall objective of WP4 of the SustainSahel project is to design locally adoptable integrated crop-shrub/tree-livestock systems (CSL) that can improve soil quality and productivity, food security and the resilience of farming systems to climate change.

Training of technicians in the use of GPS and measurements of total tree/shrub height, height of the first basal branch, trunk diameter and average crown diameter on a farm in the village of Zoumana-Diassa in December 2021. Author: Yaya Traoré

Vitellaria paradoxa agroforestry in the village of Zoumana-Diassa in March 2021. Basal branches are cut to facilitate ploughing and tractor work and also to limit the effect of the trees' shade on the crops. Author: Sidi Sanogo

Project location and methodology

In order to assess the floristic composition and density of woody vegetation in the fields and to better understand the role of trees in the agrosystem, a floristic inventory was carried out in the villages of Nagnassoni, Zoumana-Diassa (Photo 2) and Touroumadié, which belong to the same agroecological zone of the Sudanian zone of Sikasso in southern Mali.

In each village, an inventory of woody vegetation was carried out in 100 m x 50 m plots following systematic one-stage sampling. In each plot :

All woody species were measured at a pre-count diameter of 3 cm at breast height (1.30 cm from the ground).
The dendrometric data (Photo 1) being diameter at breast height, total height of the tree, height of the first basal branch, average crown diameter, were collected on each tree and/or shrub.
Natural regeneration consisting of low tree/shrub offshoots and stems smaller than the pre-count diameter were counted by simple counting.

Results

The results obtained showed that :

Vitellaria paradoxa and Parkia biglobosa are the dominant species with 72% and 10% respectively.
These species have on average :
- 41 cm in diameter at 1.30 m from the ground,
- a height of 10.4 m
- an age is estimated at 123 years.
For all 3 sites, 70% of the trees and shrubs are healthy, 28% are affected and 2% are dead.
The density of trees/shrubs varies from 3 to 10 individuals per hectare.

Written by: Dr Sidi Sanogo, Researcher in the Forest Resources Programme at the Institute of Rural Economy (IER) of Mali