Changes in Relationships between Humic Substances and Soil Structure following Different Mineral Fertilization of Vitis vinifera L. in Slovakia

Abstract

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 (HSs), and soil structure, and (2) identify relationships between SOM, HSs, 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 HSs 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, HSs, and soil structure were most abundant and with the greatest significance, while with the increasing level of NPK, these relations lost their significance.

Assessing the Impact of Soil Humic Substances, Textural Fractions on the Sorption of Heavy Metals (Cd, Pb)

“…Changes in TOC content can provide insights into alterations in land use, management practices, and environmental conditions, making it a valuable parameter for evaluating soil health and productivity [53,54]. The main elements of soil organic matter are HSs, which include FAs and HAs [55]. They are essential in soil structure, nutrient retention, and the complexation of toxic elements.…”

“…The relationship between these textural fractions is fundamental for understanding soil's physical and chemical characteristics and its potential impact on plant growth and environmental quality. The texture and structure of the soil were impacted by the quantity and size of the particles (loam, clay, and sand) [55]. Sand particles are the largest, followed by silt, and then clay, which has the smallest particle size.…”

Effect of Long-Term Different Land Uses on Improving Stable Humic Compounds in Arenosol

“…A similar composition of HS was found in the UAL soil, although, unlike in the GRfert, the aboveground biomass of the plant was not removed from the field, and after the end of vegetation, it remained mineralised on the soil surface. However, the application of mineral fertilisers increases [51] the biomass of grasses by 2-3 times in GRfert, which leads to the formation of a larger root mass and a higher amount of post-harvest residues in this land use. Therefore, the mineralisation processes of plant residues in both land types had a similar effect on the relative amount of HS fractions: they formed similar amounts of HA, FA, and HD.…”

Vermicompost Application on Shallot (Allium cepa, L.)

“…Soil organic matter from vermicompost will eventually improve soil structure, allowing a better proportion of soil air and moisture. Humic acid from organic matter decomposition will act as a bridging agent among clays to form soil aggregates; hence, the improvement of soil structure (Kobierski et al, 2018;Zhou et al, 2019;Simansky et al, 2022). Vermicompost also provides three important phytohormones (Indole 3-acetic acid, Gibberellic acid, and Kinetin) for plant growth (Ravendran et al, 2016).…”