engleski

Climate changes and weeds

Climate change is one of the main factors that affecting the entire agroecosystem. This takes place in different ways and leads to shift in productivity and stability of agricultural production systems. One of the indirect ways in which climate change is affecting crop production is weeds occurrence. Weeds represent very important factor in crop production due to the strong influence from an economic and environmental point. Weed communities on arable land are widespread and highly variable component of the vegetation in Pannonian basin. Climate changes affect the composition of the weed flora directly through environmental conditions (changed temperature and precipitation, increasing CO2 concentration in the atmosphere, frequency and intensity of extreme weather events) and indirectly through changes in land use and management practices which are the result of adaptation to climate change. Compared to crops, weeds have a greater genetic diversity and the ability of adapting to new conditions. With changing of a basic resource such light, water, CO2 and plant nutrients in the environment, it is expected that weeds will be better in growth and reproduction response related to crops. Increasing temperatures can contribute to the expand of weeds from the warmer areas and thus affect the competitive balance between crops and weeds species, intensifyng weed pressures. Changes in rainfall and water availability can have an influence on biological properties of weeds (germination, plant size and seed production). Moreover, a decrease in annual precipitation could lead to distribution of weeds from the dryer regions. Consequences of increasing CO2 affects weeds and weed/crop competition in different ways depending on the mode of energy capture (photosynthesis). C3 weeds may grow more rapidly under higher carbon dioxide levels and become more competitive. Extreme weather events like droughts, floods, heatwaves, storms and fires can cause native vegetation stress and lead to colonisation of bare areas with invasive weeds. All above may cause great changes in weed distributions and competitive ability. Weeds in agroecosytem are well adapted to the environmental conditions resulting from the various farming practices. In addition, they are closely related with the cropping system. Since the land use management is affected with climate change this has indirectly influence on weeds as well. Adopting cropping systems and management measures to new climate conditions (different crops, crop rotations, sowing dates, conservation tillage methods) has an indirect influence on the weed occurrence. The need to research climate change effects on weed populations will increase in the future since the weed management is a significant ecological, financial, logistical and research challenge.

climate change ; effects ; weeds

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