Termite prevalence and crop lodging under conservation agriculture in sub-humid Zimbabwe.

Provision of permanent soil cover using crop residues in conservation agriculture (CA) is constrained by livestock grazing and termite consumption in smallholder farming systems of sub Saharan Africa. This study evaluated the effects of surface applied maize ( Zea mays L.) crop residues on termite prevalence, crop damage due to termite attack and maize yield over two seasons, 2008/9 and 2009/10. Treatments with residue application rates of 0, 2, 4 and 6 t ha −1 under CA and a conventional mouldboard ploughing (CMP) control were laid out in a randomized complete block design with four replicates on three farm sites in Kadoma, Zimbabwe. Maize residues increased (P < 0.05) termite numbers compared to CMP treatment. Crop lodging at harvest increased (P < 0.05) from 30 to 34% in CMP to 42–48% in CA systems. However, no significant difference was found in crop lodging with increasing residue rates within CA treatments. Significantly higher crop yields were observed under CA (P < 0.05) ranging from 2900 - 3348 kg ha −1 in 2008/9 season compared to CMP with 2117 kg ha −1 . Nevertheless, increasing residue cover in CA did not necessarily increase maize crop yield. Thus, increasing crop residue application rates under CA increased termite prevalence while crop lodging was influenced more by soil tillage system than by crop residue application rates. [ABSTRACT FROM AUTHOR]