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The aim of the study was to compare variable rate (VRA) and uniform (UNI) application of mineral nitrogen fertilizers in winter wheat and to evaluate the effect on the achieved yields, nitrogen balance and nitrogen use efficiency (NUE). For these purposes, a field experiment with an area of 16.98 ha of winter wheat was established in 2022 at farm Agra Risuty s.r.o. (Czech Republic, EU). Variable nitrogen topdressing was realized twice during the vegetation period based on yield potential (YP) maps. The evaluation of crop yield maps showed high spatial variability of achieved yield levels within the observed field and their coincidence with the zones of YP. In the case of the UNI variant, the same N rate over all zones led to significant over-fertilization in lessproductive zones in the range of 50 - 70 kg N per ha. This was also reflected by the lower value of NUE for zones with a lower value of YP. The results of the experiment thus point to the importance of the identification of YP zones and the reduction of nitrogen doses in the areas with lower yield productivity to ensure equal nitrogen balance and high NUE. [ABSTRACT FROM AUTHOR]

The presented paper deals with the targeted application of pre-emergent herbicides. The field experiment was established in 2022 and 2023; two plots sized 26 ha and 30 ha were selected and the accuracy of the application was tested. There were local outbreaks of weeds on selected plots of land, which had to be eliminated before sowing the main crop - soybeans. Both plots were monitored using an unmanned aerial vehicle (UAV) - Mavic 3M with the multispectral camera. After the end of the monitoring, spectral analysis of images taken by UAV was made using the Pix4D software and vegetation indexes were calculated. The weed outbreaks were identified based on multispectral maps using the MagicTooll algorithm. The final application map was prepared in the QGIS program - two zones with and without herbicide application were defined. The application was carried out by the JD 4150i machine (9 sections per 30 m), the regulatory map was transferred to the machine terminal (4600) via the MyJD link. Subsequently, the entire application process was monitored and analysed using the MyJD programme. The accuracy of the application was analysed by comparing the prescription map and the actual dose applied. The accuracy of application was found to be significantly greater than 90%. [ABSTRACT FROM AUTHOR]

In 2021, a field experiment was conducted with white mustard (Sinapis alba L.) the seed of which is an interesting raw material in agriculture, industry and food production. Stands of tested plants were established without tillage into a freezing catch crop from the Fabaceae family within regenerative agriculture. The stand of clovers was used as a tool of bio-drilling to work the soil and as a source of nitrogen required by the subsequent crop, and the frozen biomass was applied as mulch onto the soil surface. The aim of the experiment was to find out whether the different inter-row distance (RD1 - 0.136 m and RD2 - 0.375 m) affects some yield characteristics: seed yield, 1000-seed weight, contents of oil, glucosinolate, oleic acid, linoleic acid, linolenic and erucic acids in seeds. The crop of interest was sown on 29 April 2021 and the seed was harvested on 9 August 2021. Average of values from the two experimental variants with the different inter-row distance was 2.27 t/ha (seed yield), 6.91 g (1000-seed weight) and 26.9 % (oil content); in these parameters, no statistically significant difference was found similarly as in the contents of glucosinolate, oleic acid, linoleic acid, linolenic and erucic acids. Based on experimental results with the different inter-row distance (RD1 - 0.136 m and RD2 - 0.375 m) it was found out that inter-row distance had no demonstrable influence on the studied parameters in this experiment. Therefore, it can be stated that the gained knowledge paves the way for modern technologies in the cultivation of white mustard seed when principles of regenerative agriculture are complied with. [ABSTRACT FROM AUTHOR]

Assessment of the nutritional status of crop stand and other plant biophysical parameters can be a suitable source of information for the application of nitrogen fertilizers in precision agriculture, especially in conditions of high spatial heterogeneity of farm fields. Determination of the application rate of nitrogen fertilizers can be performed based on the plant diagnosis and estimation of plant biophysical parameters, such as nitrogen content, total amount of aboveground biomass and nitrogen uptake (Nupt), or on the basis of non-invasive sensing methods via measurement of spectral reflectance of plants. The aim of this study was to verify and compare the methods of proximal and remote sensing for the evaluation of crop parameters of cereals. Input data were obtained from farm field trials with winter wheat in 2020 at Rasovice (Czech Republic) with a total area of 40 ha. To estimate the total amount of aboveground biomass, the nitrogen content in the plants and the nitrogen uptake, a plant sampling was performed with 21 samples in the stem elongation vegetation phase (BBCH 32-35). Spectral properties were obtained from the from satellite imagery of Sentinel-2 as the set of broadband vegetation indices (EVI, NDMI, NDVI, NDRE, REIP, etc.) and proximal crop sensor system AgLeader OptRx (vegetation index NDRE only). Spatial data were processed and analyzed using tools of geographic information systems and then statistically evaluated relationships between variables by using correlation analysis. The high level of correlation coefficients was reached between Nupt and biomass, which shows a significant influence of the amount of aboveground biomass on the nitrogen utilization. High values of the correlation coefficient were also achieved between Nupt and vegetation indices Sentinel-2 (r = 0.679 - 0.888 for all calculated indices), the highest value was reached for the EVI index. Also high level of correlation was achieved between Nupt and NDRE index from the proximal sensing system (r = 0.830). In this case both sensing platforms performed results in, which can be used for whole field mapping of crop status and serves as the input information for variable rate application of nitrogen fertilizers. [ABSTRACT FROM AUTHOR]

The presented paper deals with the issue of assessing the condition of winter wheat (Triticum aestivum L.) stand during its development in the spring period. The field experiment was established in 2020; two plots sized 25 ha and 16 ha were selected with a model plant of winter wheat. In the spring period (BBCH 35 and BBCH 51), both plots were monitored using an unmanned aerial vehicle (UAV) and Sentinel 2 satellites. After the end of the monitoring, spectral analysis of pictures taken was made and a basic NDVI vegetation index was calculated. Subsequently, spectral maps with this vegetation indexes were prepared. In the initial stage of model plant growth (BBCH 35), Unmanned aerial vehicles exhibited a greater sensitivity of measured data and was able to detect local damage to the stands. Differences in the measured data between UAV and Sentinel 2 were decreasing with the increasing amount of Triticum aestivum L. biomass, and in the advanced stage of vegetation (BBCH 51), a moderately strong positive correlation (R > 0.65) was found between the data measured by UAV and Sentinel 2. The measured values showed that satellite images were less accurate in detecting the occurrence of plant biomass at the beginning of growth. On the other hand, they can be more effective than UAV with the increasing plant biomass as satellite technologies can cover a considerably large area of earth surface during a single flight. [ABSTRACT FROM AUTHOR]

The main aim of this work was to evaluate the effect of flat (UNI) and variable application (VRA) of mineral nitrogen fertilizers (NF) on the yield of winter wheat grain using yield maps. VRA NF technologies represent a wide range of procedures and processes that are a part of precision farming. The technologies are used to optimize the applied NF dose in order to fertilize high-yield crops with regard to their nutritional needs and the condition of the land where they are located. VRA NF on winter wheat fields were made based on application maps that were prepared in a SatAgro system. All application maps were prepared based on spectral analysis of satellite images (Sentinel 2, SPOT) taken maximum 5 days before the scheduled application. The selected application maps contained at least one 60 m long control strip where the UNI application of NF was implemented. VRA NF was used for production and qualitative fertilization of winter wheat. The yield principle was used for both applications, i.e. the highest doses of NF were applied to those parts of the land where the vegetation was the most abundant and vice versa. The hypothesis was that weak parts of the crop are not able to withdraw the same amount of N as the stronger ones. The variability in the NF dose between zones was 30%. The field experiment was established in Spearhead Czech Ltd., where selected VRA technologies were used for approximately 5,000 ha in 2018. The main parameters for the assessment of VRA NF effect were grain yield (GY) and grain quality (gluten and Ncompounds content). GY was detected using yield maps which are based on harvester data and calibrated according to total yield weight. In all years of the experiment, a significant positive effect (LSD, at level of significance P < 0.05) of VRA NF on grain yield was found. The difference in yield when comparing UNI and VRA technology has always been minimum 6% in favor of VRA. Grain quality was at a similar level in both variants, no negative effect of VRA technology on gluten and N-compounds content was found. [ABSTRACT FROM AUTHOR]

Correct application of nitrogen fertilizers in crop management on arable land has high importance both from economic and environmental point of view, mainly in the condition of higher spatial variability of farm fields. One of the solutions could be a variable rate application (VRA) of nitrogen fertilizers based on the management zones, which addresses site specific changes in soil properties and crop requirements. The main aim of this study was to analyze the spatial variability of two fields from crop yield maps and to evaluate benefits of VRA for topdressing of winter wheat crop stand by ISARIA sensor system. Experimental work was carried out at two fields (43.9 and 69.8 ha) on farm enterprise Spearhead Czech located in Zdounky (Kromeriz, Czech Republic) in 2016 and 2017. For assessment of spatial heterogeneity of fields, crop yield maps recorded by harvesters were used and analyzed in Geographic Information System (GIS). Variable application of nitrogen fertilizers was realized for second (N2) and third (N3) topdressing nitrogen application in winter wheat by proximal sensing system Fritzmeier ISARIA. This system evaluates nitrogen status of plants by measuring of spectral response in visible and near infrared wavelengths (vegetation indices IBI and IRMI) and immediately changes application rates on spreader. The results of yield maps analysis showed that values of crop yield varied from 5.55 to 11.53 t.ha-1 in 2016 and from 4.86 to 14.30 t.ha-1in 2017. However, coefficient of variability was in both cases under 10 % (8.26 % in 2016, 9.97 % in 2017). Uniform application of nitrogen according to the average crop yields would lead to underdosing of N rates on 6.27 % of area in 2016 (15.04 % in 2017) and overdosing on 11.05 % in 2016 and 14.83 % in 2017. Summary of applied fertilizers by ISARIA system showed that in 2016 only 14.36 % of area was applied by average N rate in second application (N2) and 26.78 % of area in third application (N3). In 2017 the values differ – 74.56 % of area was covered by average N2 dose and 61.78 % of area in N3. It can be concluded that distribution of nitrogen doses by variable application has positive effect on the nitrogen use for specific crop yield level and on the reduction of environmental risks by nitrogen losses. [ABSTRACT FROM AUTHOR]

Assessment of cereal plant status and other biophysical parameters, such as nitrogen uptake, nitrogen content and total amount of aboveground biomass, is important information for decision support of agronomists for correct treatment of crop management practices. Especially in in precision farming, where whole area mapping is required, this information could be provided by remote sensing as an efficient method for the monitoring of crop within field heterogeneity. The aim of this study was to verify the use of unmanned aerial multispectral imaging for estimation of agronomic relevant crop parameters of winter wheat. For this purpose, an field experiment was conducted in 2018 in locality Kojcice (Czech Republic) with two fields (10.2 and 26.2 ha) sown by winter wheat. The aboveground biomass of canopy (dry), nitrogen concentration in plants and nitrogen uptake were estimated by plant sampling realized in two important vegetation stages – stem elongation (BBCH 33) and heading (BBCH 51). Plant samples were taken from 23 (Field Kazy) and 33 samples (Field Vrcha). Simultaneously with plant sampling, an unmanned aerial mission was carried out by Micasense Red Edge multispectral camera, which records images in visible (RGB), red-edge (RE) and near-infrared (NIR) spectrum. Set of nine broadband vegetation indices was calculated: NDVI, GNDVI, EVI2, MSAVI2, NDRE, NRERI, RENDVI, SRI, etc. The results of correlation analysis showed that relationship between nitrogen uptake and vegetation indices differs in both vegetation stages and each field. In stem elongation, the correlation with N uptake was lower (max. r = 0.665, NDRE) in comparison to heading stage (max. r = 0.856, MSAVI2). Also sensitivity of indices to the vegetation indices varied - red-edge indices (NRERI, NDRE) proved positive correlation in stem elongation. In phenology stage BBCH 51 statistically significant positive correlation to the N uptake was reached (r = 0.685 – 0.856) for all computed vegetation indices. As the conclusion could be stated that multispectral imaging is appropriated for identification of nitrogen uptake within the fields by remotely piloted aerial systems. However the relationship between crop parameters and vegetation indices was not consistent in vegetation stages and also in both fields, thus calculation of set of vegetation indices is useful, at least from the red-edge part of electromagnetic spectrum. [ABSTRACT FROM AUTHOR]

The leaching of mineral nitrogen (Nmin) represents a serious problem of modern agriculture in the European Union and also in the Czech Republic. The reason is the loss of nutrient important for plants from the soil environment and subsequent threat to the quality of soil ecosystem. The main goal of the present work is to show the influence of the mixed cropping system in the sowing process on Nmin leaching of from arable soil. Mixed cropping system represents cultivation of different crops at one field simultaneously, in particular mixture of leguminous and non-leguminous crops. Three replicates of 2 x 10 m plots per treatment were arrayed in a blocked design with the following variants: sole crop of winter wheat (140 kg N/ha) and mixed cropping of winter wheat and winter pea with or without fertilization (0 kg N/ha; 70 kg N/ha; 112 kg N/ha). Measurement of Nmin leaching from arable land was carried out to study the mentioned goal in 2013 and 2014 using ion exchange resins. In both years of the experiment, the results showed the cultivation of mixed culture had effect on decrease in Nmin leaching. However, the effect has not always been significant. The reason is that when mixed crops (legume and non-legume) are cultivated together, it is possible to reduce N inputs into the soil without reducing overall production, because part of the N needs is satisfied through biological fixation of N by legume plant. On the other hand, if the gained N is not used by plants, there is a risk of its loss from soil e.g. by leaching. Nevertheless, the measured values indicated a positive effect of mixed culture cultivation on N utilization and thus the reduction of the environmental risk of Nmin loss from the arable soil. [ABSTRACT FROM AUTHOR]

The paper deals with the monitoring of selected indicators of soil health and quality in order to assess the impact of farm using conventional farming on arable land. The main objective of the work was to find suitable indicators of the state of the soil environment, and to set the monitoring of these indicators to obtain information usable for the agronomics of the monitored enterprises when deciding on interventions on land. Every responsible farmer tries to care best for his land because only good and healthy land is a guarantee of future profitable harvests. This is also the case of the Spearhead International Ltd company, which is active in agricultural primary production in the UK, Poland, the Czech Republic, Slovakia and Romania at almost 80,000 ha. In the Czech Republic, there are: Eurofarms Jihlava, Eurofarms Agro-B, Salix Morava, Agrosumak, Agro-druzstvo Morava, Rolana. In 2016, monitoring of the following indicators was started: the total C and N content in soil, microbial C (Cmic), oxidizable C (Cox) and humus, and the ratio of humin (HA) and fulvic (FA) acid and more. All soil samples are taken annually in the first half of April before any application of fertilizers or other amending substances, taking into account weather. The same sampling sites were used every year. For the period 2016-2017, the measured values of the individual indicators point to a slightly atypical situation in a conventional farm with a lower intensity of a livestock production. The humus content of the soil was slightly above the average of 3.5 % indicating a good organic matter content (SOM). The relatively high amount of SOM indicates a higher Ctot content (> 1.80 %). On the other hand, the HA and FA ratio was about 0.85 and the average C:N 9.1. Therefore, it can be stated that the selected agronomic model (cultivation of inter-crops, leaving post-harvest residues, minimization of soil processing) used on the monitored land has a positive effect on soil SOM content, but cannot significantly affect its quality. This requires the application of high-quality organic fertilizers, which unfortunately are not available to the required extent. Improvements can be brought by new farming principles, for instance Corg in the form of sugar molasses or humic substances, and increased use of higher quality leguminous crops (Leguminosae). [ABSTRACT FROM AUTHOR]

Variable rate application (VRA) of fertilizers represents specific crop management where N is applied on the basis of information about field yield potential, plant health and quality. The main goal of this study was to assess the influence of nitrogen VRA (VRA-N) on grain yield and nitrogen use efficiency in winter wheat production. The VRA has been realized according application maps only for production and qualitative dose of N. Application maps for individual fields were prepared by SatAgro Company on the basis of analysis of satellite images (Sentinel 2, SPOT). The main output of this analysis was the determination of the amount of the plant biomass on the field using vegetation index NDVI. The principle of fertilization was different for production and qualitative dose. During production application of N, the highest doses were applied on the part of the field with the lowest amount of nitrogen and conversely. Above all during qualitative application, the highest dose of N was applied on the best part of the field. The field experiment with the application maps from SatAgro Company was established in Spearhead Czech, in 2016 and VRA technologies have been tested there on more than 4 000 ha each year since 2012. Measurements of grain yield (GY) and nitrogen use efficiency (NUE) were carried out to study the above goal in 2016 and 2017. In both years of the experiment, the results showed that the VRA-N had significant positive effect on GY and NUE by wheat. The average GY from variants with VRA-N was higher by 200 kg/ha in 2016 and by 317 kg/ha in 2017, compared to the variant where conventional technology was used. Above all, the ratio between the amount of N removed from the field with the winter wheat and the amount of applied N, i.e. NUE, was higher by about 6 % in variant where VRA technology was used. The values NUE showed a positive effect of VRA-N on utilization of N indicating the reduction of the environmental risk of N loss from the agro-ecosystem. [ABSTRACT FROM AUTHOR]