Weed management practices and benefits in CA systems

Abstract

Since the birth of agriculture, the control of undesired vegetation has been managed through one form or other of mechanical soil movement (tillage). In CA systems, the minimization or even absence of soil disturbance demands alternative ways to keep weed populations within acceptable limits. This chapter elaborates on the different approaches that are used to manage weed populations in agricultural production systems, including physical, chemical, biological and agricultural management practices. At present, physical weed control methods under CA are, in most cases, reserved to farmers that embrace CA principles but cannot use herbicides (e.g. organic farmers) or where herbicides are not available for a specific crop or are not able to control specific weeds, or simply not affordable. Research on mechanical weed control, by burying, cutting or pulling weeds, has been focussing, in recent years, on the mechanized intra-row weeding in order to obviate the need of hand-weeding, both in permanent and annual crops, complemented with reduced tillage techniques for inter-row. This research trend is further enhanced by the development of image analysis and artificial intelligence applied to robots. The use of plastic sheets (polyethylene) as soil cover, is growing but not without concerns on soil and environmental pollution. Thermal methods, such as direct flaming or soil solarization, have limited use due to equipment/energy costs, adequacy and climatic or other environmental constraints.