engleski

Effects of climate change on crop production

In modern agriculture, abiotic stresses are probably the biggest constraints factor of food production. Agriculture is affected by climate changes, but it also contributes to approximately 25% of the greenhouse gases emissions. The effects of climate change on crop production will depend on the current climate and soil conditions, the direction of change and the availability of natural resources. Plants respond to climate change with morphological and/or physiological adaptations. Tolerance of plants to extreme conditions of the external environment is supported by very complex biochemical - physiological mechanisms that regulate probably several hundred genes through the appropriate enzyme-controlled reactions. The important determinants of plant distribution depend on the temperature effects–average, minimum or maximum, rainfall and some other factors (such as soil type). The Earth is facing global warming and we can expect an increasing damage in plant production from high temperatures. The estimates of yield reduction with increasing temperature range up to 17% for every 1°C. The reduced ability of plants to disclosure of excess heat is the most common cause of heat stress and significantly affects the function of biological membranes, denaturation of proteins with increased cellular respiration. The enhanced resistance of plants to high temperatures can be achieved by using adenine, kinetin, vitamin B and Zn - complexes which affect the metabolism of nucleic acids, amino acids and proteins. The increase in global average temperatures would further result in drastic shifts in the annual precipitation with a 20% reduction per year, and about 20% loss in soil moisture. Higher atmospheric CO2 levels tend to reduce transpiration, lowering thereby the latent heat loss and causing higher leaf temperatures. The effect of the lack of water is usually observed reduced growth which is associated with a decrease rate of photosynthesis and metabolic disorders of nitrogen and carbon. The reaction of plants to drought conditions is complex, because the drought stress is usually associated with the problems of reception and transport of nutrients, which is reflected in the overall metabolism. The excess water and/or floods cause physiological disorders and damage plant roots, as incompletely oxidized metabolic products accumulate to toxic levels, and the root of these conditions can provide the plant with sufficient nutrients. The stress caused by an excess of water results in an increase in the concentration of abscisic acid (ABA) and ethylene in the waterlogged roots with slowed or retarded plant growth. Understanding how plants will respond to the rapid change in CO2 concentration, the temperature and precipitation variations with developing knowledge about their ability to adapt, is an essential initial step in understanding the full impact that the multiple interacting factors of global change will have on agroecosystems.

effects ; climate change ; crop production

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