Seasonal sequestration capacity of chernozem under different agrotechnological impacts in agrocenosis
Laen...
Kuupäev
2024
Kättesaadav alates
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Estonian University of Life Sciences
Abstrakt
The soil's sequestration capacity is primarily determined by the fine-dispersed fraction
of the soil and strongly influences the properties and fertility level of the soil. To assess the
sequestration capacity of C-CO2 humus in soil formation and fertility of typical chornozem (black
soil), to identify the causes, rates, existing limits of the sequestration capacity decrease, it is
important to study the seasonal dynamics of qualitative and quantitative indicators of humus state
in time depending on the method of tillage and fertilization in agrocenoses of short rotation crop
rotations in the central part of the Forest-Steppe region of Ukraine. During the research, a
stationary field experiment was conducted to study the influence of methods of soil cultivation
and fertilizer application on the sequestering capacity of chornozem. Laboratory studies were
conducted to determine the content of humus and to calculate the seasonal reserves of absorbed
carbon and phosphorus and to model the absorption capacity of chernozem. When processing
with chisel plows and applying fertilizers, the increase in the C-CO2 reserve during the April-July
period was +21 t ha-1 (0–0.2 m) and +36 t ha-1
a (0–0.3 m). Under moldboard plowing, the growth
tended to increase by 1.52 times (0–0.2 m) and 1.25 times (0–0.3 m), but occurred at a lower
quantitative level, and in the period July-September, the change in the humus C-CO2 stock was
insignificant, indicating the predominance of C-CO2 sequestration processes in the summerautumn period with chisel plowing. With chisel plowing, the reserve of labile organic substances
(LOS) in April exceeded the stock for plowing in the thickness of 0–0.3 m by 4.34–7.67 times
(without fertilizers), 1.5–2.76 times (with fertilizers); in July - by 4.59–8.90 times (without
fertilizers) and 1.32–3.16 times (with fertilizers); in September - by 4.52–4.04 times (without
fertilizers) and by 1.11–1.93 times (with fertilizers), and the C-CO2 stock of the LOS compared
to fallow land under chisel plowing without fertilizers in April, July, and September was
1.59–1.78 times, 2.31–3.29 times, and 1.4–1.78 times higher, and under fertilization - by 1.99–2.0,
1.86–4.50, and 1.7–2.6 times, respectively, depending on the seasons. Under fallow land
maintenance, the seasonal dynamics of the C-CO2 stock of the LOS is subject to the seasonal
dynamics of Porg(LOS). A direct strong correlation was found at the level of R = +0.89 ± 0.02;
R2 = 79. In the period April-July, the decrease of Porg(LOS) stock in the thickness of 0–0.2 m was
found to be 1.15 times, and in the thickness of 0–0.3 m - 1.1 times. From summer to autumn, the
stock of Porg(LOS) was restored, and the stock in the thickness of 0–0.3 m increased by 1.10 times.
Conclusions. Trends in C-CO2 stocks of humus and LOS indicate that in the series plowingchiseling-fallow land, the cyclicality index under chisel plowing was closer to the value of the
seasonal cyclicality of fallow land than the seasonal cyclicality under plowing, which indicates
the restoration of the CI. Trends in C-CO2 stocks of humus and LOS indicate that in the series
plowing-chiseling-fallow, the index of cyclicality under chisel plowing was closer to the value of
the seasonal cyclicality of fallow land than the seasonal cyclicality of plowing, which indicates
the restoration of the ISC. However, the timing of changes in the Porg(LOS) stock indicates that in
the series plowing-chiseling-fallow, chisel plowing is directed to fallow land by its seasonal
cyclicality. The general regularity of seasonal cyclicality for all parameters of humus condition
lies in the fact that a decrease in the values of ISC, as in fallow land or under moldboardless tillage,
indicates the ordering of ISC, and an increase in the index of cyclicality to destruction, as under
plowing.
Kirjeldus
Received: March 29th, 2024 ; Accepted: May 1st, 2024 ; Published: May 6th, 2024 ; Correspondence: jyri.olt@emu.ee
Märksõnad
organic carbon and phosphorus stocks, plowing, chisel plowing, trends in stock changes, light-hydrolyzable organic matter, articles