The document discusses long-term trials being conducted in Eastern, Western and Southern Africa to evaluate the effects of different organic matter amendments and mineral fertilizers on maize, sorghum and millet yields over multiple seasons. The trials are taking place in Kenya, Zimbabwe and Ghana and include treatments of organic residues like Tithonia, Calliandra, Crotalaria and Leucaena as well as manure, compost and mineral fertilizers applied to maize, sorghum and millet-based cropping systems.

2. SOM TRIALS: Maize-based system Treatments: Tithonia, Calliandra, Crotolaria, Leucaena, maize stover, sawdust, Manure; (1.2, 4 t C/ha, +/-N); Blanket PK; control (+/N at 120 kg/ha)

3. Other Maize-based systems cont:

4. Kabete treatments

5. Maize-based system cont:

6. Millet-based system

7. Sorghum-based systems Saria I-continuous sorghum; sorghum-cotton; sorghum-cowpeas Saria II-sorghum: compost, straw, manure, anaerobic compost, control; all treatments +/N

8. Grain yield (over 12 seasons): Embu, Kenya CI CII CIII CIV

9. Grain yield (over 5 seasons): Domboshawa, Zimbabwe CI CII CIII CIV

10. Grain yield (over 10 seasons): Kwadoso, Ghana CI CII CIII CIV

11. THANK YOU