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Responses of pea (Pisum sativum L.) to the rising atmospheric concentration of carbon-dioxide
185-188Views:425The atmospheric concentration of carbon dioxide increases from decade to decade in increasing pace. In 1957, atmospheric carbon dioxide levels were around 315 ppm, while in 2012 it amounted to 394.49 ppm concentration. In parallel, the global temperature is rising,which is projected to average 1.5–4.5 °C. The carbon dioxide concentration is a key factor – in interaction with the light – affects the plant's photosynthesis. Among the various factors significant interactions prevail: environmental factors affect - the growth and the development of plants, leaf area size and composition, the function of the photosynthetic apparatus, the duration of growing season.
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The effect of rising concentration of atmospheric carbone dioxide on crop production
81-84Views:242In the atmosphere, the amount of carbon dioxide and other greenhouse gases are rising in gradually increasing pace since the Industrial Revolution. The rising concentration of atmospheric carbon dioxide (CO2) contributes to global warming, and the changes affect to both the precipitation and the evaporation quantity. Moreover, the concentration of carbon dioxide directly affects the productivity and physiology of plants. The effect of temperature changes on plants is still controversial, although studies have been widely conducted. The C4-type plants react better in this respect than the C3-type plants. However, the C3-type plants respond more richer for the increase of atmospheric carbon dioxide and climate change.
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Examinations of the carbon dioxide emission of the soil in the case of different tillage methods in a field experiment
209-212Views:554Today's global challenge is the increasing concentration of carbon dioxide (CO2) and other greenhouse gases in the air. The level of CO2 emissions may be significantly affected by the agriculture and, more specifically, the applied tillage method, even though to a lesser extent than industrial production. On a global scale, the CO2 emission of an agricultural area is insignificant in comparison to that of a large-scale plant in an area of the same size, but areas under cultivation, including arable land, have a large global area. In this paper, we investigated the relationship between applied soil tillage methods and carbon dioxide emissions in the case of different fertiliser treatments. In our experiment we examined four types of tillage with five different fertiliser effects. Comparing fertiliser treatments and tillage methods, it was found that their interaction significantly affected carbon dioxide emissions, the lowest value was obtained in the case of the 210 l ha-1 Nitrosol+N-LOCK – tillage radish treatment. Strip and tillage radish methods have relatively homogeneous, low value. -
Daily soil carbon dioxide flux under different tillage conditions
141-144Views:477Over the last few years, warming of the atmospheric layer near Earth's surface is increasingly experienced and researchers have also established that concentration of numerous greenhouse gases have risen over the past two centuries value. Change is basically a legitimate process - considering atmospheric concentration as well - but the change experienced during the past centuries could not have become this critical without the contribution of human activity. Due to the nature of the greenhouse effect, the result of a very fragile, complex process is experienced currently on Earth, which can be significantly unbalanced even by a slight change. Carbon dioxide emitted from the soil is involved in the global cycle and has an impact on the greenhouse effect. The rise in soil respiration may result in the further intensification of warming. In the scope of the present study, it was examined how carbon dioxide emissions of the soil evolve over a day. The results have been established based on the comparison of the effects of different parts of the day, tillage methods and irrigation.
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The effect of different herbicide on the number and activity of living microorganisms in soil
76-82Views:247Sustainable plant growth, considering the difficulties of weed elimination, cannot be effective without the application of herbicides. However, these chemicals have enormous ecological implications, including effects on the microbiological communities of soils. It is advisable to use herbicides that have minimal secondary effects on the environment and soil-living microorganisms. In contrast, herbicides with prolonged growth stimulating or inhibiting effects are not suitable, because both types have strong influences on the number and activity of bacteria, thus causing changes in the ecological equilibrium.
Preceding small plot experiments, laboratory tests were carried out to study the effect of herbicides used in maize cultures on the number of bacteria and growth of microscopic fungi.
Substances that were observed to have stronger influences were applied in small plot experiments set up in the experimental garden of the Department of Plant Protection of the University of Debrecen. We studied the effects of four herbicides (Acenit A88EC, Frontier 900 EC, Merlin SC and Wing EC) on the microbiological properties of the soil. These herbicides were used in different concentrations in maize culture, and we investigated the effects in different soil layers.
In the laboratory experiments, we determined the total number of bacteria and microscopic fungi and examined the growth of Aspergillus niger, Trichoderma sp. and Fusarium oxysporum on peptone-glucose agar containing herbicides.
During the small plot experiments, soil samples were collected 3 times a year from 2-20 cm depth. The total numbers of bacteria and microscopic fungi were determined by plate dilution method, while the method of most probable number (Pochon method) was used to determine the numbers of nitrifying bacteria and cellulose decomposing bacteria. To evaluate the microbiological activity of the soil samples we measured carbon-dioxide release (after 10 days incubation), nitrate production (after 14 days incubation) and the concentration of C and N in the biomass.
We can summarize our results as follows:
• In laboratory experiments, herbicides caused a decrease in the number of bacteria and inhibited the growth of microscopic fungi.
• Frontier 900 EC and Acenit A 880 EC had the strongest inhibiting effect on microorganisms.
• In small plot experiments, herbicide treatment decreased the total number of bacteria and microscopic fungi.
• Herbicides caused a significant increase in the number of nitrifying and cellulose decomposing bacteria.
• Different herbicides containing the same active compound had similar influences on soil microoorganisms.
• A significant increase was observed in the physiological processes of tolerant microorganisms surviving the effects of herbicides