Linkages between crop residues, termite prevalence, crop lodging andudsubsequent crop yield under conservation agriculture in Zimbabwe

摘要

Farmers believe that addition of residues to fields in conservationudagriculture (CA) attract termites hence increase lodging,udalthough they are beliefs that termites prefer feeding on dryudmatter and leave the crop. This study carried out in Kadomaudand Chikombedzi, Zimbabwe established links between cropudresidues, termite prevalence, crop lodging and yield. Resultsudfrom Kadoma showed that in 2008/9, 4t/ha of residue hadudsignificantly more termites compared to conventionaludmouldboard plough systems (CMP). In 2009/10, 4 and 6t/haudresidues resulted into a significantly higher termite comparedudto CMP. In both seasons in Chikombedzi, results were similarudwith those of Kadoma. In Chikombedzi in 2009/10, lodging inudCA was significantly higher compared to CMP. In Kadomaud2008/09, yields (2900-3348kg/ha) were significantly higher underudCA compared to CMP (2117kg/ha). Similar results wereudobtained at Chikombedzi. A significant and positive relationshipudwas observed between percentage soil moisture and termiteudnumbers, suggesting that CA attract termites although it alsoudincreases yields. It is therefore necessary to integrate termiteudcontrol measures in maize production under conservationudagriculture systems.udKey words: Humus, nutrient cycling, organic carbon, soil cover,