The aim of the study was to analyse the effect of atmospheric cadmium (Cd) pollution of atmospheric origin in maize compared to a control without Cd pollution. The plant parameters investigated were the timing of phenological phases, leaf area index (LAI) and yield, while radiation and water regime parameters were represented by albedo (reflection grade) and evapotranspiration, respectively. In treatments with and without irrigation, Cd caused a significant reduction in LAI, accompanied by lower evapotranspiration. The mean annual albedo in the Cd-polluted treatment only rose to a moderate extent in 2011 (in 2010 there was hardly any change), but changes within the year were more pronounced in certain phases of development. Cd led to greater reflection of radiation by plants during the vegetative phase, so the radiation absorption of the canopy was reduced leading to a lower level of evapotranspiration. In the dry, hot year of 2011 maize plants in the non-irrigated treatments showed a substantial reduction in grain dry matter, but maize yield losses could be reduced by irrigation in areas exposed to Cd pollution.
Authors:Adnan Eser, Hajnalka Kató, Laura Kempf, and Márton Jolánkai
Water availability is one of the major physiological factors influencing plant growth and development. An assessment study has been done at the Szent István University, Gödöllő to evaluate and identify the water footprint of protein yield of field crop species. Twelve field crop species (Sugar beet Beta vulgaris, spring and winter barley Hordeum vulgare, winter wheat Triticum aestivum, maize Zea mays, sunflower Helianthus annuus, peas Pisum sativum, potato Solanum tuberosum, alfalfa Medicago sativa, oilseed rape Brassica napus, rye Secale cereale and oats Avena sativa) were involved in the study. Evapotranspiration patterns of the crops studied have been identified by the regular agroclimatology methodology and physiologically reliable protein ranges within crop yields were evaluated.
The results obtained suggest, that water footprint of cereals proved to be the lowest, however maize values were highly affected by the high variability of protein yield. Oilseed crops had considerably high protein yield with medium water efficiency. Alfalfa, potato and sugar beet water footprints were in accordance with their evapotranspiration patterns.
Protein based water footprint assessment seems to be more applicable in crop species evaluations than that of yield based methodologies.
The effect of spraying maize weekly with a 0.5 M concentration of Cd was studied in Hungary at two water supply levels. Cd reduced the size of the leaf area and the annual water loss. The intensity of evapotranspiration (mm water/unit leaf area) of the polluted crops grew. The higher net radiation of polluted maize resulted in an increase in sensible heat and a warmer canopy. The warmer the canopy, the higher the stress level of the contaminated crops was. While Cd caused a 28% significant decline in plant dry matter production in the rainfed plots, only a declining tendency amounting to a few percent was recorded in the ET treatment.Cd of atmospheric origin was only detected in the leaves; it was not accumulated in the grain. It was concluded from the results that the yield losses in grain maize grown on Cd-polluted areas could be mitigated by irrigation. The production of silage maize, however, is not recommended in regions affected by Cd pollution, especially in areas where irrigation is required, since supplementary water supplies promote the accumulation of Cd in the vegetative organs.
The climatology of soil respiration in Hungary is
presented. Soil respiration is estimated by a Thornthwaite-based biogeochemical
model using soil hydrophysical data and climatological fields of precipitation
and air temperature. Soil respiration fields are analyzed for different soil
textures (sand, sandy loam, loam, clay loam and clay) and time periods (year,
growing season and months). Strong
linear relationships were found between soil respiration and the actual evapotranspiration
for annual and growing season time periods. In winter months soil respiration
is well correlated with air temperature, while in summer months there is a
quite variable relationship with water balance components. The strength of
linear relationship between soil respiration and climatic variables is much
better for coarser than for finer soil texture.