Exploring cost-effective maize integrated weed management approaches under intensive farming systems
Several production constraints have led to low yields (< 2.5 t ha-1) in maize (Zea mays L.) inUganda, among which are weeds. This study investigated the most cost-effective integrated weedmanagement (IWM) approach in maize in eastern Uganda. An experiment was conducted atIkulwe station, Mayuge in 2011 and 2012 using nine integrated weed management (IWM)approaches. Results showed yields (P < 0.001) in decreasing order of three hand-hoe weedings(3hh), two hand-hoe weedings (2hh), pre-emergence application of atrazine, followed by onehand-hoe weeding (pre-Atz+1hh) and post-emergence application of atrazine, followed by onehand hoe weeding (post-Atz+1hh) (5.9 - 6.4 t ha-1) and lastly, where no weeding was conducted (2.7t ha-1). Returns on investment (ROI) were highest under pre-Atz+1hh and 2hh (180%), followedby post Atz+1hh (167%). The no weeding treatment registered the lowest value (67%). In 2012 and2013, the IWM approaches with highest ROI (> 160%) were established on-farm in Bugiri, Kamuliand Iganga districts with one hand-hoe weeding (1hh) as the control. The pre-Atz+1hh producedthe highest grain yield (4.5 t ha-1; P < 0.01) and ROI (105%); while 1hh gave the lowest grain yield(3.4 t ha-1) and the lowest ROI (60%). Therefore, pre-emergence application of atrazine (2 l ha-1),followed by one hand-hoe weeding (28 days after planting) is the most cost-effective IWM optionin maize.
Key words: Atrazine, returns on investment, Zea mays