Possibilities of Killing Weeds by Microwave Power

Abstract

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.

Keywords

• Microwave power

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