Climate change is likely to have huge impacts on the problematic weeds and their management. Therefore, continuous research is needed to formulate new management strategies to combat them. However, along with climate change, socio-economic, technological, and geopolitical changes will also take place in the 21st century that will likely affect the environment and agricultural systems (including weed management) and our ability to sustain crop productivity.
A major threat to crop production that growers continually battle with are undesirable plant species, deemed as weeds. On a global scale, weeds caused approximately 34% yield loss in crops. Weeds are opportunist plant species that are well adapted to colonize and, in many cases, dominate an ecosystem by forming an extensive population.
Other than wide ecological amplitudes, a set of unique biological characteristics like competitiveness, aggressiveness, adaptability, and high fecundity enable weeds to survive in a wide range of adverse environmental conditions in crop fields or any other disturbed habitats.
As per Darwinian concept of “struggle for existence”, weeds are the most successful species evolved on Earth. Unlike other crop pests, weeds share a similar trophic level and compete with crops for limited resources like water and nutrients causing huge crop yield reductions. Apart from yield loss in crops weeds are also known to have negative impact on rangelands, forests, and ecosystem dynamics including species diversity. Therefore, effective weed control and management are crucial to sustain crop productivity.
Climate change is a looming crisis in agriculture. Both crop and weed species respond to climate change, but the impacts are still unclear in many cases. Especially, the consequences of interactions between two or more factors (like CO2, temperature, water) for either crop or weed species are very poorly understood. Furthermore, the complexity derived from the multiple interacting factors may produce unexpected dramatic indirect effects on the agroecosystem.
In general, the stimulatory or inhibitory behavior of climate change on crops might also hold true for weeds, but most probably, in many cases, weeds are likely to outcompete crops because of their higher plasticity, superior adaptability, and wider ecological amplitudes compared to crops.
There are reasons to believe that increasing temperatures, CO2 concentrations, and associated problems like erratic rainfall, frequent cyclones, and storms will certainly aggravate the problem of weeds and make them difficult to manage. Until now it has been a big question whether or not CO2 fertilization could compensate for the other negative impacts of climate change on crop–weed interaction.
Apart from weed biology, weed floral composition, distribution, prevalence, invasiveness, proliferation, and dispersal will be affected by climate change and most likely result in the failure of existing weed management practices. Many seminal reviews confirm the need for reassessment and transformation of current weed control technologies particularly herbicidal control in the context of climate change.
Thus, climate change is likely to have huge impacts on the problematic weeds and their management. Therefore, continuous research is needed to formulate new management strategies to combat them. However, along with climate change, socio-economic, technological, and geopolitical changes will also take place in the 21st century that will likely affect the environment and agricultural systems (including weed management) and our ability to sustain crop productivity.
This paper presents a comprehensive review on impact of climate change on weed distribution, growth, biology, and weed management, with indications for formulating new management strategies. The purpose of this review also includes inviting further debate on this issue.
There are strong empirical reasons for expecting climate change to alter weed management. In addition to climate change, edaphic factors and crop management practices including use of new classes of herbicides are likely to influence weed biogeography and their degree of damage to agriculture and integrated weed management practices.
Furthermore, increasing availability and cultivation of genetically modified crops specific for given herbicides is likely to result in persistence of those herbicides and changes in weed community composition further aggravating the weed management problem. Hence, under the changing climate scenario weed management will be a major concern in the future.
Understanding and assessment of the impact of simultaneous change in multiple climate factors and their complex interactions on crops and weeds are therefore necessary to formulate an adaptive weed management approach and build resilience.
However, it is likely that with the tremendous effort from the scientific community new weed management strategies (such as new herbicides, herbicide resistant varieties, new bioagents), to build resilience and reduce vulnerability to climate change, will be evolved, but the huge concern remains about the economic, environmental, and health cost of implementing those strategies.
Read the study:
Anwar MP, Islam AKMM, Yeasmin S, Rashid MH, Juraimi AS, Ahmed S, Shrestha A. (2021) Weeds and their responses to management efforts in a changing climate. Agronomy, 11(10):1921.