Soil Microbial and Enzymatic Properties in Luvisols as Affected by Different Types of Agricultural Land-Use Systems and Soil Depth

Abstract

Determination of the microbial and enzymatic properties in soil is primarily concentrated on the surface layers of the soil profiles; however, it is well known that the transformation of soil organic matter also occurs in the deeper horizons of the soil profile. The aim of this study was to assess any changes in specific sets of enzyme activities and their associated physicochemical properties as affected by two different agricultural land-use systems and soil depth. Changes in the studied properties were determined across four Luvisol profiles in two agricultural land uses (arable land and vineyards). The enzyme activities associated with the transformation of C, N and P were analyzed. Additionally, the activity of some oxidoreductases and the fluorescein diacetate hydrolysis (FDAH) rate were also determined. Moreover, the content of the various forms of soil carbon, nitrogen, phosphorus (including microbial biomass C, N and P) and some other properties (pH, clay and silt content) were assessed. Agricultural land use significantly affected the microbial biomass content and as well as the studied enzyme activities. Most of the studied enzymes exhibited a higher activity in the grapevine (GV) profiles, which was followed by the winter wheat (WW) profiles; however, the largest variability occurred for the urease activity. There was no clear differentiation between the two studied land uses for the activity of nitrate reductase, dehydrogenases, acid phosphatase, or endo- and exo-cellulase. Irrespective of the plant being cultivated, the soil variables decreased significantly with increasing soil depth, wherein the greatest changes were observed between the surface and sub-surface soil horizons (I–II). The activity of some enzymes (e.g., the urease activity in WW profiles) decreased gradually across the soil profiles, while others were located almost solely within the surface layers (e.g., the nitrate reductase activity in the GV profiles as well as invertase in the WW profiles). The α-glucosidase activity did not exhibit any statistically significant changes along the analyzed profiles. The activity of phenol oxidase and peroxidase also revealed different trends along the studied profiles compared to the other enzymes and did not decrease gradually with depth. The microbial biomass of the C, N and P content was generally the highest in the upper horizons and gradually decreased with depth, wherein the largest decrease was observed between the surface and sub-surface horizon. The studied enzyme activities were more dependent on the soil carbon content compared to the other soil properties. And thus, in the C-rich horizons (C > 4 g kg) for the surface and subsurface layers the enzyme activities were highly correlated with TOC, DOC and MBC content as compared to the deeper, C-low horizons (C < 4 g kg). By examining how the microbial and enzymatic properties change across the soil profiles, it is possible to gain valuable insight into the long-term biogeochemical processes that are involved in soil fertility and in the health of agricultural ecosystems.

Soil Enzyme Response and Calorific Value of Zea mays Used for the Phytoremediation of Soils Contaminated with Diesel Oil

“…Higher soil pH is responsible for breaking ionic and hydrogen bonds in the active center of dehydrogenases, an enzyme that indicates the intensity of respiratory metabolism in soil microorganisms [27,36,119]. According to Nannipieri et al [120], Mierzwa-Hersztek et al [121], and Piotrowska-Długosz et al [122], dehydrogenases are enzymes considered as indicators of soil biochemical and microbiological activity. They catalyze the removal of hydrogen atoms from organic compounds, thereby accelerating the oxidation of organic matter.…”

Spatial Distribution of Soil Macroelements, Their Uptake by Plants, and Green Pea Yield under Strip-Till Technology

“…The laser diffraction method was used to determine the soil grain size using a particle size analyzer (Malvern Instruments, Worcestershire, UK) [21]. The organic carbon content was determined using a CN elemental analyzer (Variomax CN, ELEMENTAR, Germany), following the method described by Piotrowska-Długosz et al [22]. During the experiment, after sowing, and during the harvest of peas, soil samples were collected in three replications of each treatment, according to the procedure described in the Polish standard [23], and then subjected to chemical analysis, including determining the content of forms of phosphorus, potassium, and magnesium available to plants, as well as the content of mineral nitrogen.…”