The positive effect of nitrogen fertilization in agriculture inevitably increases residual nitrogen losses. Water pollution led to legal restrictions of some farm practices within the framework of ...the Nitrates Directive of the EU. Nevertheless, even several decades later, the situation has not improved significantly. We present a possible science-based explanation of such a state and provide it to farmers and government as a support for environmental management settings. This study aimed to compare an established approach to implementing the Nitrates Directive, specifically the climate-based zoning of nitrogen fertilization restrictions using data from the mid-20th century. We evaluated this approach by juxtaposing the initial climate data with more recent data spanning from 1991 to 2020. Subsequently, we examined this zoning framework from the perspective of the non-vegetative period, characterized by temperatures below 5 °C, which is widely acknowledged as a critical threshold for nitrogen intake by plants. We found out that i) the employed climate-born zoning does not correspond to recent climate data; ii) nonvegetation period is longer than nitrogen fertilization restrictions. Therefore, despite a noteworthy 22 day reduction in the nonvegetation period from 1961/1962 to 2019/2020, we cast doubt on the notion that the period limiting nitrogen fertilizer application should also be shortened, while admitting that there are other abiotic and biotic factors affecting nitrogen behaviour within the ecosystem.
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•Nitrogen management in the Czechia affects water quality of 11 states.•Continuous unsatisfactory water quality calls for Nitrates Directive scrutiny.•We bring climatologically based contribution to the discussion on nitrogen management.•Vegetation period in Central Europe has prolonged about 20 days over last 6 decades.•Nitrogen application bans and nonvegetation period differ about tens of days.
Most agronomy practices such as fertilization, irrigation, and soil treatment involve plant root interactions. However, the role of plant roots is rarely assessed during agricultural experiments due ...to the lack of suitable methods. Plant varieties with a larger root system use soil water and nutrients in dry environments more effectively than varieties with a smaller root system. Such large root varieties can be developed by breeding. Therefore, we evaluated the effects of selection for large or small root systems in 12 barley populations developed via the mutual crossing of four parents in the F₃ generation as a response to selection in the preceding F₂ generation. Root system size was analyzed by measuring electrical capacitance. Results show that our selection method was effective because the progeny of plants with larger root systems also had larger root systems. Conversely, the progeny of plants with smaller root systems also had smaller root systems. The average differences were +40 and −43 % in the parental segregating generation and +4 and −2 % in the progeny. The root system size impacted the grain yield, which showed a twofold greater response to selection. Indeed, plants with a root system increase of 3.9 % exhibited a yield increase of 8.1 %. Some varieties transmitted larger root systems to their progeny, and some transmitted smaller root systems. Thus, we show that the method used enabled the comparison of root system size in the same crop, in the same soil, and at the same time, which is particularly suitable for selecting root system size in practical breeding. We do not know any other suitable method for the repeated evaluation of intact plants and harvesting of seeds from the selected plants. Root system size has not yet been reported by other authors as a selection criterion in practical breeding, with the exception of root crops such as sugar beet and carrots.
The water erosion represents one of the most dangerous degradation processes on agricultural land. Its estimation is thus necessary for setting rules and defining appropriate strategies for soil ...protection. An estimation of a long-term average annual soil loss by water erosion is frequently based on the Universal Soil Loss Equation (USLE) defined as a product of six factors, where rainfall erosivity factor (R factor) is a leading one. R factor is a multi-annual average index that measures rainfall kinetic energy and intensity describing the effect of erosive efficient rains (EER) on sheet and rill erosion. EER were defined by total higher than 12.7 mm and intensity higher than 6.4 mm in 15 minutes. As those ERR criteria are being used differently by various studies, we decided to compare R factor derived by two variants of ERR criteria: i) EER must fulfil both minimal total and minimal intensity (VAR_AND); ERR must fulfil either minimal total or minimal intensity (VAR_OR). Based on 1-minute precipitation totals database of Czech hydrometeorological institute for 111 stations for 1991–2021 we conclude that mean of Ra VAR_AND across altitude is about 30% lower than Ra VAR_OR while there is high statistical significant correlation between those two variants. In addition, annual values of R factor derived by both variants show a statistically significant increase in a long run which calls for updating the R-factor values to reflect increasing climate change impacts.
In the Czech Republic, the Universal Soil Loss Equation provides the basis for defining the soil protection strategy. Field rainfall simulators were used to define the actual cover-management factor ...values of the most extensively seeded crops in the Czech Republic. The second purpose was to assess rainfall-runoff ratio for different crops and management to contribute to the debate of water retention effectiveness during approaching climate change. The methodology focused on multi-seasonal measurements to cover the most important phenological phases. The rainfall intensity was 60 mm·h−1 for 30 min and a plot size of 16 m2. More than 380 rainfall simulation experiments provided data. Soil conservation techniques proved to have a significant effect on runoff reduction. Conventionally seeded maize can reduce the runoff ratio to around 50%. However, cover crops combined with reduced tillage or direct seeding can reduce the runoff ratio to 10–20% for ‘dry’ conditions and to 12–40% for ‘saturated’ conditions. Conventionally seeded maize on average loses 4.3 Mg·ha−1 per 30 min experiment. However, reduced tillage and direct seeding reduce soil loss to 0.6 and 0.16 Mg·ha−1, respectively. A comparison with the original USDA values for maize showed that it is desirable to redefine the crop cover factor.
The current application of local climate zones (LCZs) often ends with (inter)zonal comparation of land surface temperature (LST) or air temperature (AT). LST evaluation employs an enhanced concept of ...LCZs together with cluster analysis for LCZs grouped based on LST. The paper attempts to combine them into a complex approach derived from the case study on a medium-sized Central European city (Hradec Králové, the Czech Republic). In particular, the paper addresses the following. (i) The relation of LST and AT, when the daily course of temperature profile ranging clear off the surface up to 2 m was fitted by a rational 2D function. The obtained equation enables derivation of the AT from LST and vice versa. (ii) The differences in thermal response of LCZs based on LST or AT, where the highest average LST and average maximum LST show LCZs 10, 2, 3 and 8, i.e., with a significant proportion of artificial surfaces. The cluster of LCZs with a significant representation of vegetation, LCZs 9, B, D, A and G, have significantly lower LST. (iii) The contribution of LCZs to understanding of LST/AT relation and whether their specific relation could be expected in particular LCZs, when subsequent interaction assessment of LST and AT revealed statistically their significant correlation in LCZs for certain cases.
Climate change is contributing to an increased risk of flower damage by late spring frosts. Monitoring flower temperature is critical for the timely start of frost protection systems. However, there ...are many weak points that complicate the use of this method. The aims of this study were to: i) find the method of air temperature measurement with the best relationship to the surface temperature of plant tissues and ii) quantify the differences between plant tissues surface temperature and ambient temperature during different weather situations. The surface temperature of plant tissues (budding leaves of grapevine, apricot flower, and unripe pear fruit), air temperature and humidity in the radiation shield, wet bulb temperature and air temperature with an unsheltered thermometer were measured at ten-minute intervals in the spring months. The average temperatures obtained by the individual methods as well as the lowest temperatures were determined from each measurement. Differences between air temperatures and plant surface temperatures, including variation ranges, were also determined. An unsheltered thermometer, in which the energy balance corresponds approximately to that of the evaluated plant surfaces, provided the best relationship with plant tissue temperature. The air temperature measured by the standard method (in a Stevenson screen or in the radiation shield) was almost always higher than the temperature of the plant tissue during periods of negative energy balance. The difference between the minimum temperatures was approximately 0.5 °C. Temperatures more than 1.5 °C higher than the actual temperature of plant tissues were measured in extreme cases.
Wheat is a major source of protein for human food, a critical issue at a time when mankind is growing by 77 million people per year. Wheat was domesticated approximately 10,000 years ago and has been ...systematically bred for about 200 years. However, this breeding selection has been done using only aerial plant parts. Indeed, wheat roots, the hidden half of plant, were not considered in breeding programs due to the lack of an appropriate method. Here, we evaluated roots of 18 wheat populations. The root system size was measured by its electrical capacitance directly in field. The plants in third and fourth generations were evaluated during shooting and heading. Then plants were selected for large and small root system. In dry conditions, progeny of plants with large and small root system had yields of 17.1 and 10.9 g per plant in the third generation and 18.5 and 10.0 g per plant in the fourth generation. Our results show that the progeny of the plants selected for large roots have larger roots than their parents, also in next generation. Similarly, the progeny of small root plants have smaller roots. The selection process showed a greater response for larger root system size. This response can be evolutionarily advantageous and make selection easier than, for example, selection for grain yield. Our unique method enables accurate, repeated evaluation and harvest of selected plants. Selection for higher wheat root system size can be easily used to breed for drought tolerance and higher efficiency of water and fertilizer use.
Forest ecosystems are faced with a variety of threats, including increasingly prolonged droughts and other abiotic stresses such as extreme high temperatures, very strong wind, invasive insect ...outbreaks, and the rapid spread of pathogens. The aim of the study was to define crucial abiotic stressors affecting Central Europe forest ecosystems and, with regard to their possible simultaneous effect, develop a universal method of multi-hazard evaluation. The method was then applied to the particular area of interest represented by part of the Czech Republic with forest land cover (12–19 ° E, 48–51 ° N). Based on National Threat Analysis, the most significant threats of natural origin with a close relationship to forest stability were identified as drought, high temperature, and wind gusts. Using suitable indicators, a level of their risk based on occurrence and consequences was estimated. The resulting combined level of risk, divided into five categories, was then spatially expressed on a grid map. The novelty of our paper lies in: (i) all relevant climatic data were combined and evaluated simultaneously with respect to the different level of risk, (ii) the developed methodological road map enables an application of the method for various conditions, and (iii) multiple hazards were estimated for the case study area.
The rheological characteristics of gluten-free doughs and their effect on the quality of biologically leavened bread were studied in amaranth, chickpea, corn, millet, quinoa and rice flour. The ...rheological characteristics (resistance to extension R, extensibility E, R/E modulus, extension area, stress at the moment of dough rupture) were obtained by uniaxial dough deformation. Specific loaf volume of laboratory prepared gluten-free breads was in significant positive correlation with dough resistance (r = 0.86), dough extensibility (r = 0.98) and peak stress at the moment of dough rupture (r = 0.96). Even if the correlation between R/E modulus and the characteristics of loaf quality were not significant, the breads with the highest specific loaf volume were prepared from flours with R/E closer to the wheat check sample (18 N∙mm-1). The results showed, in general, good baking flours exhibited stronger resistance to extension and greater extensibility, but differences found were not directly related to the results of baking tests.
•Resistance to extension of rice dough closest to wheat dough.•Extensibility of chickpea dough closest to wheat dough.•Ratio number of buckwheat dough similar to wheat dough.•Highest quality bread prepared from buckwheat, chickpea and rice flour.
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