Knapsack Shield for Herbicide Weed Control in Field Crops

Over dependence on inefficient tools such as hoes for critical field operations limits crop production in developing countries.

Bonsu, P. O.; Boateng, M. A.

2013

English

Over dependence on inefficient tools such as hoes for critical field operations limits crop production in developing countries. One such operation is weed control. A knapsack shield that suits the spray pattern of a drift reduction off centre nozzle (AirMix. ®. Nozzle) was developed and tested for herbicide weed control in cassava. The shield was developed locally using a thin aluminum sheet and it was tested at two locations in the forest and forest savanna transition ecological zones in Ghana. Paraquat was applied through the shield at a rate of 3l /ha to control mainly Euphorbia (Euphorbia heterophylla). The treatments were: i) spraying half row width with each pass with paraquat through the shield, ii) spraying entire row width with each pass with paraquat through the shield, iii) timely hand hoeing and iv) delayed hand hoeing. Weed control with the shield was effective and it resulted in similar cassava yields as timely hand hoeing. Economic analysis showed that the highest cost was incurred in the timely hand hoeing plots whilst the least cost was incurred in the delayed hand hoeing plots. Timely hand hoeing gave higher net benefit than shielded weed control but the reverse was true for marginal rate of return.