A Review on Parameters Affecting the Choice of Alternative (Non-Chemical) Weed Control Methods

Abstract

Chemical using as a weed control method is the most preferred method in weed control because they are easily accessible, easily applicable and inexpensive. But, with the new environment-friendly regulations, the importance of non-chemical methods has increased all over the world. In addition, organic farm and non-chemical agricultural methods are gaining importance with increasing social environment and health awareness. Non-chemical methods, called, "alternative methods” have been one of the most popular research subjects in recent years. The physical removal or killing of weeds is usually done by hand or by means designed tools for this task, which varies from country to country. The most known modern non-chemical weed control methods are; electric current, microwave heating, superheated steam, infrared using, pneumatic system, freeze-drying, laser cutting, and fresnel lens systems. The most popular of these methods are; electric current method and microwave heating. In electric current and microwave heating methods, there are no chemical residues in soil and plants after application. It has been shown in the studies that, the microwave weed control method can destroy weeds and seeds when appropriate frequency, sufficient time and required power level are selected. Therefore, in the selection of non-chemical weed control methods, some important parameters of plant and soil should be known. The electrical and dielectric properties of plants and soil such as, electrical resistance (R), impedance (Z), dielectric constant (ε’), loss factor (ε’’), the permittivity (permeability ( and conductivity (σ) should be known especially in microwave and electric current methods. The other parameters like the age, height and density of the plant is an issue to be considered in all control methods. But, the moisture content of soil and plant may not be taken into consideration in hot water and steam applications. For the freeze-drying method, the moisture and water content of the plant and soil must also be taken into account.