Evaluation of a Cryogenic Sprayer Using Liquid Nitrogen and a Ballasted Roller for Weed Control

Abstract

Abstract Current weed-control practices might not be sustainable because of the increased incidence of herbicide-resistant weeds and the limited effectiveness of organic weed-control techniques. A cryogenic weed-control system was developed to improve weed control in row crops without the input of synthetic or organic pesticides. The cryogenic system applies liquid nitrogen to target weeds through a modified sprayer and then crushes the weeds with a ballasted mechanical roller. Greenhouse studies were initially performed to validate the biological impact of directed liquid nitrogen and mechanical pressure on large crabgrass (Digitaria sanguinalis L. Scop). Field studies were performed to evaluate the effects of the liquid nitrogen volume, spray nozzle height, and mechanical roller pressure on pitted morningglory (Ipomoea lacunosa L.) control. This weed was most effectively controlled with 9360 l/ha of liquid nitrogen applied with a nozzle raised 30 cm above the soil surface, followed by 41 kPa of pressure with the mechanical roller. The concept of cryogenic weed control was validated in a field experiment using mostly standard farm equipment. This cryogenic system provides a successful prototype for future designs utilizing liquid nitrogen for weed control.