The field activities in the cross-border area encompass soil and plant material sampling for the purposes of the realisation of the AGRI-CONTO-CLEEN IPA CBC project. We have been conducting the sampling activities continuously, aiming to determine the average availability of macroelements and microelements and potentially toxic heavy metals and pesticide residue contents in the soil. Other significant soil properties we have been determining are pH, humus, phosphorus and potassium supply in the soil and texture. Further, in order to monitor crop nutrition and potentially toxic heavy metal contents, as well as pesticide residues in the plant material, during the vegetative stage we carry out the sampling of crops and vegetables, as well as organic fertilizers.
The AGRI-CONTO-CLEEN fieldwork teams will, over the two years of the project duration, systematically sample the soil and plants at selected farms. However, all agricultural producers are invited to join the project idea and its realisation by sampling and analysing their agricultural areas. To do so, you just need to contact us and make arrangements on the sampling method (described in detail in the “Soil and Plant Sampling for Agrochemical and Pedological Analyses” handbook available on this website).
The value of the chemical and physical soil analyses that we conduct in the laboratory primarily depends on the proper taking of soil samples which will appropriately represent the status in agricultural areas. Accordingly, the fertilizing recommendation directly rests on the results of the agrochemical soil analysis, where the knowledge of the spatial and temporal variability of the nutritional status in the soil enables the fertilization to be better attuned to the needs of the plants being produced. Therefore, proper soil sampling is also important from the aspect of soil fertility control, as well as for optimal fertilization decision-making.
With the spatial distribution of samples on the selected farms in the cross-border region, we have secured information on soil variability, while the sampling timetable follows the dynamics of nutrient availability and soil properties. Prior to taking the samples for analysis, we evaluate the uniformity of a production area. If the production areas in question are smaller, one average soil sample is sufficient as representative of a 1-2 ha surface area, whereas one average sample for every 3-5 ha (sometimes even up to 10 ha) is taken from larger areas. We make sure to conduct the sampling when the soil is at an optimal humidity level, with the most suitable sampling period being after harvest until soil fertilization and preparation for the sowing of the next crops. However, soil samples can be taken throughout the year, including the vegetative period. In connection with this, during the vegetative period we carry out the sampling for specific purposes, such as determining the supply of mineral nitrogen in the soil. The procedure of soil sampling includes preparation, sampling by a probe or spade, sample labelling, sample packaging and delivery to the laboratory. The weight of the average sample consisting of 20-25 well mixed individual samples is usually 0.5-1 kg. The spatial distribution for taking individual samples is most commonly diagonal across the production area.
The chemical analysis of the plants sampled during the vegetative stage indicates their nutritional status, i.e. the supply of plants with individual elements in a given phenological phase when the sampling is done. The results of an analysis of a whole plant or a specific leaf point to the current concentration of the elements in the plant, and the adopted quantity of elements reflects the preceding availability of nutrients in the soil and the specific properties of the plant species or cultivar.
In this process, we differentiate between the sampling of small cereal crops, row crops and industrial plants during the vegetative stage and the sampling of field crops during harvest. A separate category is the sampling of vegetables, which are divided into root, leaf and fruit vegetables. In the initial stages of field crop vegetation period, we sample the entire plant, while in the latter stages we sample specific plant organs that indicate the nutritional status of the plant, e.g. the leaf below the wheat ear, the leaf below the maize ear, the top triple soybean leaf, the last developed leaf in vegetables etc. The laboratory analysis of plants sampled in harvest is a significant tool for determining the impact of the plant nutritional status on the obtained yield and quality. Using the nutrient concentration and weight of the analysed plant part, it is possible to calculate the quantity of nutrients taken out from the soil with the realised yield.
The sampling for the purpose of yield determination is carried out by mechanical or manual harvesting from a given area or by picking a given number of rows of plants of specific length, while in determining yield components diagonally across the area we select the required number of average plants, typically 10 or 20 average plants.