Dataset on elemental composition of soils and plants under long-term application of mineral and organic fertilizers on gray forest soils in Vladimir region, Russia

Long-term application of organic and mineral fertilizers can lead to changes in the elemental composition of agroecosystem components. Both the levels of nutrients and potentially toxic elements can change, as can the potential for these elements to be available to plants through changes in soil properties. Soil and plant samples of two species (pea Pisum sativum L. and oat Avena sativa L.) were collected from plots of a long-term field experiment on the application of mineral and organic fertilizers and their combinations to gray forest soils in the Vladimir region, Russia. Soil samples from the 0-20 and 20-40 cm layers were subjected to acid digestion to determine total element content. Mobile forms of elements were extracted from topsoil samples using acetate-ammonium buffer (pH 4.8). Sample preparation of pea and oat plant organs (stems, leaves, pods/ears) included sample digestion in a microwave sample digestion system ETHOS EASY (Milestone, Italy). The elemental composition of the samples was determined by inductively coupled plasma optical emission spectrometry (ICP-OES) using Agilent 5800 ICP-OES (Agilent Technologies, USA). The dataset includes concentration data for 34 elements, including rare earth elements, in these samples collected in 2021. The dataset also contains general agrochemical characteristics of soils of the experimental groups: pH of water and salt suspension, organic carbon content, mobile forms of phosphorus. The data can be valuable to researchers developing fertilizer application systems and modeling changes in the elemental composition of agroecosystems.


a b s t r a c t
Long-term application of organic and mineral fertilizers can lead to changes in the elemental composition of agroecosystem components.Both the levels of nutrients and potentially toxic elements can change, as can the potential for these elements to be available to plants through changes in soil properties.Soil and plant samples of two species (pea Pisum sativum L. and oat Avena sativa L.) were collected from plots of a long-term field experiment on the application of mineral and organic fertilizers and their combinations to gray forest soils in the Vladimir region, Russia.Soil samples from the 0-20 and 20-40 cm layers were subjected to acid digestion to determine total element content.Mobile forms of elements were extracted from topsoil samples using acetate-ammonium buffer (pH 4.8).Sam ple preparation of pea and oat plant organs (stems, leaves, pods/ears) included sample digestion in a microwave sample digestion system ETHOS EASY (Milestone, Italy).The elemental composition of the samples was determined by inductively coupled plasma optical emission spectrometry (ICP-OES) using Agilent 5800 ICP-OES (Agilent Technologies, USA).The dataset includes concentration data for 34 elements, including rare earth elements, in these samples collected in 2021.The dataset also contains general agrochemical characteristics of soils of the experimental groups: pH of water and salt suspension, organic carbon content, mobile forms of phosphorus.The data can be valuable to researchers developing fertilizer application systems and modeling changes in the elemental composition of agroecosystems.
© 2024 The Author(s

Value of the Data
• The dataset is of interest to soil scientists, agronomists and agroecologists as it provides information on the concentrations of a wide range of elements in soils and associated plants from a unique long-term field experiment in the European part of Russia on soils widely used in agriculture.• The dataset can be useful to researchers involved in developing different fertilizer application systems and modeling the effects of such systems on soil fertility and crop yields.• The data can be used to develop and justify fertilizer application rates.
• The special value of the dataset lies in the data on the concentration of rare earth elements in soils and plants.Such data are still limited and additional information is needed for different areas, soil types and plant species.

Data Description
The dataset [1] contains data on the elemental composition of agrocenosis componentssoils and plants (pea Pisum sativum L. and oat Avena sativa L.) -samples of which were collected from plots of a long-term field experiment on gray forest heavy loamy soil in July 2021.Samples for data acquisition were collected near the city of Suzdal, Vladimir region, Russia ( Fig. 1 ).According to WRB classification (World Reference Base for Soil Resources) soil of the experi- mental field -Luvic Retic Greyzemic Phaeozem (Loamic, Aric) [2] .Long-term field experiment on plots from which samples were taken is included in the geographic network of experiments with fertilizers (Geonet) in Russia under the title "Effect of fertilizer systems in crop rotation on crop productivity, fertility of gray forest soil and its ecological state" [3] .The experiment was set up in 1991 and is still being maintained at the present time [4] .Samples were taken at the beginning of the fourth rotation of the crop rotation, which includes the following crops: annual grasses (pea-oat mixture); winter wheat; oats with grass sowing; first year grasses; second year grasses; winter wheat; barley.Data were obtained for each of the 9 experimental groups of the long-term field experiment, including applications of both mineral and organic fertilizers, as well as their combinations ( Table 1 ).Table 1 summarizes the designations used for the experimental groups in the dataset and their characteristics.Phosphorus-potassium fertilizers were applied under the main cultivation, nitrogen fertilizers were applied in the pre-sowing crop for annual grasses and spring cereals, in the top dressing of winter crops and perennial grasses.Cattle manure was applied to winter wheat after a pea-oat mixture.
In the form of a table, a single file contains concentration data for 34 elements obtained using the inductively coupled plasma optical emission spectrometry (ICP-OES).Dataset is available in the repository ( https://data.mendeley.com/datasets/3cygrjjtf3/10).The dataset presents concentrations of the following elements: Na, P, Ca, K, Mg, Fe, Al, Li, Cr, Mn, Co, Ni, Cu, Zn, Sr, Cd, Ba, Pb and rare earth elements.Rare earth elements represent a separate group in the dataset and include La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y. Data reporting units are mg/kg, or mg/g.Data on the total content of elements in soil (0-20 and 20-40 cm layer), content of mobile forms of elements in soil (0-20 cm layer), content of elements in separate organs (leaves, stems, fruits) of two plant species -pea and oat, and data on the content in above-ground organs of plants as a whole, obtained taking into account the mass fraction of each organ in the plant, on separate sheets of Excel file are presented.The dataset also includes a number of physico-chemical characteristics of soils: pH of water and saline suspension, organic carbon content, content of mobile forms of phosphorus.For each experimental group, three mixed samples were analyzed; accordingly, the dataset presents data for each repetition (sample).The table file contains 11 sheets ( Table 2 ).

Experimental Design, Materials and Methods
Soil samples were collected from 0-20 and 20-40 cm layers.One mixed sample was formed from three individual samples.Three such mixed samples were taken from each experimental plot.Plant samples were also collected in triplicate for each experimental group.The area of one plot is 100 m 2 .
Soil samples were dried at room temperature to air-dry condition, ground in a porcelain mortar and sieved through a sieve with 1 mm hole diameter according to the Russian State standard [5] and then stored in plastic bags.Plant samples were dried at room temperature in a ventilated unlit room.Plant samples were divided into individual organs -leaves, stems, pods or ears, and the mass of each part was recorded.The samples were then pulverized and stored in plastic bags until analysis.
Water (H 2 O) and salt (1 M KCl) pH of soil samples were determined potentiometrically (Sartorius PB-11, Sartorius AG, Finland) at a suspension with solution to soil sample ratio of 1:2.5 [6] .Soil organic carbon content was determined by wet dichromate oxidation according to the modified Tyurin's method with photometric ending using a UNICO-1201 spectrophotometer (UNICO, USA) [7] .The content of exchangeable phosphorus was determined photometrically according to the Kirsanov method [8] .
Dry soil and plant samples were subjected to sample preparation prior to elemental analysis by ICP-OES method.To determine the total content of elements in soil samples, complete acid digestion of samples was carried out with a mixture of nitric, perchloric and hydrofluoric acids.A soil sample (0.2 g) is placed in a Teflon beaker (50 mL volume), moistened with a few drops of distilled water, 2 mL of 37 % H 2 O 2 and 2 mL of water are added.The beakers are placed on a stove and boiled until evaporated.Then 1 mL of 65% HNO 3 , 1 mL of 65% HClO 4 and 6 mL of 45% HF are added to the Teflon beakers.The beakers are placed on a stove, covered with a Teflon lid, brought to a boil and heated for 30 min.Then the lids are removed and evaporated until the appearance of intense white vapors, remove the cups from the stove, cooled, washed the walls with a small amount of distilled water and further evaporated to wet salts.Then 4 mL of 37% HCl and 0.4 mL of 0.1 M H 3 BO 3 are added to each beaker, placed on the tile and evaporated to 1-2 mL.The solutions are transferred to 10 mL plastic tubes and brought to the mark with distilled water.
The mobile forms of elements were extracted with NH 4 Ac (acetate-ammonium buffer) pH 4.8 at a soil to solution ratio of 1:10 (5 g soil, 50 mL solution) [9] .The tubes were shaken on a rotator for one hour, then centrifuged and filtered through a blue ribbon paper filter [10] .
All obtained solutions (after acid digestion of soil, extraction of mobile forms of elements, acid digestion of plant samples) were analyzed by ICP-OES.We used an ICP-OES 5800 spectrometer (Agilent Technologies, USA) with easy-fit 1.8 mm torch one piece for 50 0 0 Series VDV/SVDV ICP-OES with a 1.8 mm ID injector with extended outer tube with slot for radial viewing (Agilent Technologies, USA), a double-pass glass cyclonic spray chamber (Agilent Technologies), an OneNeb nebulizer (Agilent Technologies, USA), and a Trident Internal Standard Kit (Glass Expansion).Samples were introduced manually.A peristaltic pump used the white/white poly-vinyl chloride pump tube for feeding and the blue/blue one for drain.V solution (100 mg/L) internal standard was added online (white/white poly-vinyl chloride pump tube) to increase the accuracy of measurements.Conditions of ICP-OES measurements are presented in Table 3 .Three replicates of signal accumulation were made for each sample.Results were collected and processed by ICP Expert software 7.5.3(Agilent Technologies).All lines were measured simultaneously.Linear functions were used for the calibration.The position and baseline correction were made for all the peaks of uncommon elements using the tools of the spectrometer software.
Deionized water (18.2M × cm from a Simplicity system, Millipore, France) was used for the preparation of all the solutions and washing.A rare earth standard solution CCS-1-125ML (Inorganic Ventures) was used for calibration in the range of 10-10 0 0 μg/L.The standard solution of the other metals was multi-element ICP-standard-solution IV (Carl Roth GmbH + Co. KG,

Table 1
Description of the experimental groups of the long-term field experiment used for sampling to obtain the dataset.the beginning of the first rotation of the crop rotation.Background for experimental groups with fertilizer application, which were also limed PK Phosphorus and potassium fertilizers were applied to the soil in one dose per rotation:

Table 2
Contents of the dataset table.