Adjusting Polish law to EU standards, many studies were started in the 1990s on the harmfulness of presumably contaminating elements (PCE) to the environment and the quality of plants intended produced for food purposes. For this reason, in 1987, a unique microplate experiment was established on natural soils artificially contaminated with copper, zinc, lead and cadmium oxides (up to the pollution level of class I, II and III). The soils were diversified in terms of pH (through liming), organic matter content (through the addition of brown coal) and the grain size composition of the humus level (Ap) (strong clay sand and light silt clay). After 14 years from the introduction of different rates of metals into the top layer (0–30 cm) of the two soils studied, relatively large movement of heavy metals in the soil profile occurred. The amount of leached metals depended mainly on the rate of a given element. The more contaminated was the soil was, the heavier the metals that leached to lower genetic levels of soil. Contaminated soils always had a higher concentration of individual metals in Et than in Bt level. The content of the tested metals in the Et layer was determined in HCl (1 mol·dm⁻³) and compared to the humus level. Only at the soil depth below 50 cm (Bt), the content of the studied metals’ forms was much lower than in the surface levels. The calculated mobility coefficients of the tested metals determined in 1 M HCl indicate a larger movement of the tested metals in lighter soils than in medium soils. The highest displacement coefficients were obtained for cadmium, while the lowest were for lead. An increase in mobility was obtained alongside an increase in soil contamination with the heavy metals studied. By analyzing the mobility coefficients (heavy metal increase in the Bt and Et layers), they can be ranked in the following decreasing sequence: on light soils: Cd > Cu > Zn > Pb and on medium soils: Cd > Zn > Pb > Cu.

This study was based on a three-factor experiment carried out since 1980 on a loamy sand (Albic Luvisol) in which arable crops were grown in two 4-years rotations: RotA (grain maize, winter wheat, spring barley and silage maize) and RotB [grain maize, winter wheat plus mustard green manure (GM), spring barley and grass–clover ley (GCL)]. The soil in RotB with an increased input of OM (GM and 1-year GCL) accumulated significantly larger amounts of soil organic carbon and soil microbial biomass C, had higher activities of dehydrogenase and acid phosphatase enzymes and gave significantly higher winter wheat grain yields compared to the soil in RotA. However, in the absence of liming, the soil in RotB, contrary to that in RotA, became more acidic, had reduced activity of alkaline phosphatase and lower contents of Ca and Mg, and contained a diminished proportion of the >0.5 mm macroaggregates fraction. These soil deteriorative effects of crop rotations delivering larger amounts of OM have not been reported so far. In both rotations FYM applied once per 4-year rotation at 40 Mg ha⁻¹ improved all the tested soil properties and had mitigating effects on the negative changes found in the soil of RotB.

The key to soil organic matter management is understanding the transformation processes of fresh organic matter to permanent humus that control soil organic carbon dynamics. This paper presents the results of the effect of long-term soil fertilization with increasing doses of (manure) FYM and ammonium nitrate on the composition of humus compounds not limed of loamy sand. The study showed that both crop rotation and manure fertilization significantly affected organic matter fractions and humus humification index. The soil in crop rotation B (with enriching effect) accumulated significantly larger amounts of soil organic carbon in 0–30 cm layer despite a lower soil pH, but had lower soil organic quality compared to the soil in crop rotation A (with depleting effect). In both rotations, FYM was applied once per 4-year rotation at a dose of 40 t·ha⁻¹ which improved the soil organic carbon content. Depleting crop rotation (A) showed no increase in soil accumulation of humins fractions (H), while the “enriching” crop rotation (B) had such a tendency. Mineral nitrogen fertilization significantly affected the composition of the humic acids fraction. The soil in crop rotation B was characterized by a significantly higher content of fulvic acid (FA) and lower of humins (H) carbon fraction. The large input of organic matter into the soil under lower content pH conditions may hinder its transformation into permanent humus. Changes in the humification index were the consequence of changes in the carbon content of humic and fulvic acids, under the influence of plant selection in crop rotation and manure fertilization. According to the criterion of this parameter, soil in crop rotation A and soil fertilized with manure had lower loss of the more labile FA fraction (lower value of humification index—1.48).

The quantity and quality of soil organic matter (SOM) depending on many edaphic and environmental factors may change in response to agriculture-related practices. The SOM humification process can be supported by the application of mineral fertilizers, but in the production vineyards, such information is lacking. NPK fertilizer alters the soil quality, and therefore, the aim of this study was to: (1) assess the extent and dynamics of different NPK (control—no fertilization; 1st NPK; and 3rd NPK levels) rates to the soil with grass sward cover in a productive vineyard on changes in SOM, humic substances (HS), and soil structure, and (2) identify relationships between SOM, HS, and soil structure. Results showed that the share of humic acids in soil organic carbon decreased only in NPK1 compared to control and NPK3 treatments. The color quotient of humic substance values in NPK1 and NPK3 increased by 4 and 5%, respectively, compared to control. Over a period of 14 years, the content of soil organic carbon increased by 0.71, 0.69, and 0.53 g kg⁻¹ year⁻¹ in the control, NPK1, and NPK3, respectively. The content of HS increased linearly with slight differences due to NPK application. The vulnerability of the soil structure decreased due to fertilization—more at the higher NPK level. The rate of formed soil crust was decreasing in the following order: control > NPK1 > NPK3. In the control treatment, the relations between SOM, HS, and soil structure were most abundant and with the greatest significance, while with the increasing level of NPK, these relations lost their significance.

» Articles | Agricultural Journals

» Articles | Agricultural Journals