Graham Brodie

By Graham Brodie

Part of the book: Advances in Induction and Microwave Heating of Mineral and Organic Materials

By Graham Brodie

Part of the book: The Development and Application of Microwave Heating

By Muhammad Jamal Khan and Graham Ian Brodie

Herbicides resistance has challenged sustainable rice productivity. Consequently, interest in chemical-free weed management has increased to overcome this constraint. This chapter has demonstrated the effect of pre-sowing microwave soil heating as a new alternative to chemicals for confirmed herbicide resistant weeds of the Australian rice production system. Microwave can superheat weed plants, creating micro-steam explosions in the plant structures to kill weeds. This requires the least amount of energy to achieve weed control and can be likened to a ‘knock down’ herbicide treatment. Considerably, more microwave energy can be applied to the soil to achieve weed seed bank deactivation; however, there is growing evidence that this strategy also changes the soil biota and nutrient profile in favour of substantial increases in crop yield, when crops are planted into this microwave-treated soil. An energy application of approximately 400–500 J cm−2 gave approximately 70–80% reduction in weed establishment in three field trials conducted at two agro-ecological zones of the Australia. In addition, there was a 10 times higher nitrogen use efficiency, and a 37% higher water use efficiency was achieved through this aspect of the microwave technology. There is also evidence that the soil treatment strategy provides persistent effects, beyond a single season; therefore, the rice production is better than when using conventional weed control methods.

Part of the book: Rice Crop

By Graham Brodie

Electromagnetic fields are complex phenomena, which transport energy and information across space. Information can be imposed onto electromagnetic waves by human ingenuity, through various forms of modulation; however, this chapter will focus on the acquisition of information as electromagnetic waves are generated by materials or pass through materials. The chapter will also consider how energy is transferred to materials by electromagnetic fields.

Part of the book: Electromagnetic Fields and Waves

By Graham Brodie, Muhammad Jamal Khan and Dorin Gupta

Crop yield gaps can be partially overcome by soil sanitation strategies such as fumigation; however, there are fewer suitable fumigants available in the marketplace and growing concerns about chemical impacts in the environment and human food chain. Therefore, thermal soil sanitation has been considered for some time and microwave soil treatment has some important advantages over other thermal soil sanitation techniques, such as steam treatment. It is also apparent that microwave soil sanitation does not sterilize the soil, but favors beneficial species of soil biota making more nutrients available for better plant growth. From these perspectives, microwave soil treatment may become an important pre-sowing soil sanitation technology for high value cropping systems, allowing agricultural systems to better bridge the crop yield gap.

Part of the book: Sustainable Crop Production

By Mohammed Humayun Kabir, Graham Brodie, Dorin Gupta and Alexis Pang

Arsenic (As) contamination in soil and accumulation in food crops has raised much concern worldwide due to its phytotoxicity and possible human health risk. This study was conducted to determine whether microwave (MW) soil treatment could alleviate As phytotoxicity and reduce wheat grain As concentration or not. Experimental soils were spiked to five levels of As concentration (As-0, As-20, As-40, As-60, and As-80 mg kg–1) prior to applying three levels of MW treatment (MW-0, MW-3, and MW-6 minute). Significantly higher plant growth and grain yield and lower grain As concentration was recorded in MW treatments compared with the control treatment. For instance, significantly higher grain yield (28.95 g pot–1) and lower grain As concentration (572.03 μg kg–1) were recorded in MW-6 treatment compared with MW-0 (22.03 g pot–1 and 710.45 μg kg–1, respectively) at the same soil As concentration. Hence, MW soil treatment has the potential to alleviate As phytotoxicity and to reduce the grain As concentration. Ultimately, MW soil treatment will reduce As bioaccumulation in the human body even if wheat is grown in As contaminated soil. Nevertheless, further validation experiments are needed to explore the effectiveness of MW treatment in field conditions.

Part of the book: Wheat