TILLAGE EFFECTS ON GRAIN-SORGHUM (SORGHUM-BICOLOR (L) MOENCH) DEVELOPMENT AND PLANT WATER STATUS IN BURKINA-FASO

The major problem for rainfed agriculture in the Sudan-Sahelian zone i n Africa is the insufficient and uneven distribution of rainfall. Henc e efficient utilization of rain water is necessary. Tillage practices play a significant role in soil water conservation. A field experiment was conducted on a dystic fluvisol soil having rhodic properties (fro m ferrasols) at the Experimental Station of Saria in Burkina Faso (Wes t Africa) to monitor agronomic parameters as well as canopy temperatur e, leaf water potential and the efficiency of intercepted solar radiat ion within the 400-700 nm range (photosynthetically active radiation, PAR) of grain sorghum sown under different tillage treatments. These w ere hand hoeing (H) (as practiced by traditional farmers), ploughing ( P) and tied ridging (TR). Compared with the traditional form of hand-h oeing, ploughing and tied ridging increased soil water content dramati cally and crop performance was improved. Grain yield was greatest with ploughing (2.4 Mg ha(-1)) and lowest with hoeing (1.8 Mg ha(-1)). Bec ause of waterlogging, yield on tied ridging was decreased.Radiothermom etry and leaf water potential measurements at solar noon were found to be useful indicators of the plant water status. However thermometry i s very sensitive to cloudy conditions. The TR treatment had the highes t percentage of energy intercepted in PAR while H had the lowest.