Possibilities of Killing Weeds by Microwave Power

Weeds are the main problems for organic and traditional cropping system. According to the researches, it was found that weeds decrease the yield by 21-61% especially in cotton and corn production. Herbicides use for controlling weeds destroys the environment and increases the cost. Recently microwave applications are considered for controlling weed plants due to the growing concerns about herbicide resistance and chemical residues in the environment. Recent studies proved that microwave can kill the weeds effectively. In this study, the possibilities of using microwave energy to kill the weeds between the rows were investigated in corn and cotton production at laboratory conditions. Four weed varieties cocklebur (Xanthium strumarium), Johnson Grass (Sorghum halepense (L.)), Black Nightshade (Solanum nigrum), Bermuda Grass (Cynodon dactylon) were selected since they are the most common weeds found at corn and cotton production. In the experiment, weeds with three different development stages: weeds with four leaves, eight leaves and weeds at seeding stage were exposed to minimum 0.8 kW and maximum 5.6 kW microwave power with four different forward speeds were 0.05 –0.1 – 0.3 - 1 m s-1. According to the results; all four types of weeds were be able to be killed by microwave applications. The required microwave power to kill the weeds increased with increasing forward speed. It was found that forward speed of 1 m s-1 was not effective to kill the weeds with maximum power of 5.6 kW. All four weeds required more power for killing when they are at late growing stages. Generally, cocklebur and Black Nightshade required less power comparing Johnson Grass and Bermuda Grass. Bermuda Grass was the only weed which required maximum 5.6 kW microwave power level at all forward speeds at laboratory conditions.