The Effect of Tillage on Organic Carbon Stabilization in Microaggregates in Different Climatic Zones of European Russia

Abstract

Tillage may affect the microstructural organization of soil, including the distribution of microaggregates with different mechanical strengths. We quantified the impact of tillage treatment on the amount and distribution of free organic matter, microaggregates (unstable and stable under low intensity sonification) and their components, in the upper horizons of zonal soils of the Center of the Russian Plain. Under plowing, the carbon content decreases, both in unstable and stable microaggregates. The loss of carbon in unstable microaggregates was~24%, whereas in stable microaggregates, it was~37%, relative to native soils. The carbon content of organic (LF oc ) and organo-clay (Clay rd ) fractions in unstable microaggregates (C LF oc /C Clay rd ) was almost identical in the upper horizons of native soils: the ratio of these components is for Albeluvisols (1.1), Phaeozem (0.8) and Chernozems (1.0). Under plowing, these decrease to: Albeluvisols and Chernozems (0.6) and Phaeozem (0.5). The shares of carbon accumulated within the unstable and stable microaggregates (C unstable /C stable ) are constant under equilibrium conditions and show a tendency to decrease from north to south on the order of: Albeluvisols and Phaeozem (2.2) > Chernozems (1.0). Under plowing, they increase to: Albeluvisols (3.0) and Phaeozem (3.2) > Chernozems (1.5).

Localization of C Cycle Enzymes in Arable and Forest Phaeozems within Levels of Soil Microstructure

“…Samples (four for each soil) from two A horizons of Phaeozems were collected in August 2021: Greyic Phaeozems (Albic) under a temperate mixed forest (>70 years; dominant species were Querqus Robur and Tilia Cordata ) from the V.V. Dokuchaev Soil Science Institute Ivanovsky Field Station (Russia, Tula region, 54°78′25.67″ N, 38°03′52.99″ E; additional information about the aggregate composition and mechanical properties, [ 35 ]; microbial community, [ 36 ]); and soil from the nearby arable field—four-field crop rotation by conventional tillage practice (54°45′56.1″ N, 38°01′28.9″ E) (SOM fractions, for both arable and forest soils, [ 37 ]). Since we took soil samples in August, at the end of the growing season, the harvest had already been taken and the field had not yet been ploughed.…”

The Role of Organic and Mineralogical Interaction Products in the Structure Forming and Humus Forming of the Basic Types of Soils in the Center of Russian Plain

“…Установлено, что с утяжелением гранулометрического состава увеличивается масса неустойчивых (крупных) микроагрегатов. Доля этой группы микроагрегатов в среднесуглинистых почвах (дерново-подзолистые почвы) более чем в 2 раза выше по сравнению с легкосуглинистыми и в 1.3 раза выше в глинистых (черноземах) по сравнению со среднесуглинистыми (Artemyeva, Kogut, 2016). Это подтверждается наличием тесной корреляционной связи между количеством неустойчивых микроагрегатов и содержанием легкодиспергируемого ила (R 2 = 0.98, при P < 0.01 (рис.…”