The distribution of organic carbon, its forms and macroelements in agricultural soils

Abstract

The objective of the present study was to estimate the distribution of soil organic carbon (SOC) and its forms (protected and labile organic carbon) and total nitrogen (N tot), plant available phosphorus (P 2 O 5) and pottassium (K 2 O) within 0-30 cm layer of a ploughed horizon in agricultural soils as influenced by tillage and fertilisation. Research was carried out in two regions of Lithuania: in Central (sites I and II) and Northern (site III) parts of Middle Lithuanian Lowland. Tillage systems, including conventional tillage (CT) and no-tillage (NT), straw management methods and mineral fertilisation were investigated on a loam and sandy loam top layer of glacial morain Eutric Endocalcaric Endostagnic Cambisol in site I. Five fertilisation treatments were tested in a grassland with a sandy loam top layer of glacial morain Endocalcaric Albic Brunic Endogleyic Arenosol in site II: without fertilisation and fertilisation with separated liquid and separated solid digestates at rates of 85 and 170 kg ha-1 N. The field experiment on a glaciolacustrine Eutric Endocalcaric Amphistagnic Endogleyic Cambisol with clay loam in site III involved the following tillage systems: conventional tillage (CT), ploughless tillage (PT), ploughless tillage with lime sludge incorporation (PT + LS) and no-tillage with a cover crop for winter mulch (NT + WM). Long-term NT caused pronounced stratification of N tot , available K 2 O and SOC within the arable layer of Eutric Endocalcaric Endostagnic Cambisol. The highest accumulation of SOC and chemically protected-humified carbon in the grassland on an Endocalcaric Albic Brunic Endogleyic Arenosol was determined at the highest digestate rate of 170 kg ha-1 N. High SOC accumulation potential was shown by PT + LS in a Eutric Endocalcaric Amphistagnic Endogleyic Cambisol. This significantly increased the share of humified carbon fraction bound with calcium in 0-10 and 10-20 cm soil layers. Reduction of tillage intensity by applying PT and NT + WM increased the concentration of labile organic carbon in the soil, especially in the upper 0-10 cm layer. The lime sludge application reduced the amount of labile organic carbon by its incorporation with calcium in this amendment, while increasing the stability of carbon compounds. In Eutric Endocalcaric Endostagnic Cambisol, the mean results of 0-30 cm layer revealed that the share of F4 carbon fraction, resistant to degradation, in the SOC was significantly higher under NT than under CT.

Solid and Liquid Phases of Anaerobic Digestate for Sustainable Use of Agricultural Soil

“…Our data show that the significantly higher SOC concentration in the investigated soil layer (0-30 cm) occurred in the treatment fertilized with 170 N rate of both digestates, and only a tendency of increasing SOC concentration was evident under other rates of fertilization (Table 6, Figure 3). It should be noted that the study year and soil layer also influenced the SOC content [50]. In previous studies, LD and SD had different effects on non-fertile soil [4,11].…”

Effect of plant edges strips on the conservation soil properties in modern farming field

“…High soil aggregation is a significant soil quality parameter since it increases porosity, and therefore increases infiltration and water-holding capacity, and reduces erosion and runoff [ 24 ]. It is also known that soil aggregates stability increases with soil organic matter content and that soil management practices such as reduced tillage, crop residues and organic fertilizers can improve soil quality [ 25 ]. SOC, N total and P total had a positive effect on the formation of water-stable aggregates in different tillage [ 7 ].…”

“…The data of Lithuanian colleagues showed that C transformation in the soil and chemical composition of the soil reflect this transformation, depending on soil management applied and the inherent properties of the soil itself. SOC has been increasingly considered as a key indicator of soil quality [ 25 ]. Literature sources claim that different types of clover–grass swards promoted SOC immobilization in microbial biomass and, at the same time, stabilized the sward ecosystem in the topsoil layer (soil respiration in 0–10 and 10–20 cm layers were lower) more effectively than the lucerne–grass sward [ 29 ].…”

Application of Smart Agricultural Practices in Wheat Crop to Increase Yield and Mitigate Emission of Greenhouse Gases for Sustainable Ecofriendly Environment

“…In respective aspects, about 100 mL of the sample was placed in a conical flask along with 5 mL of chromous mixture (consisting of 0.2 M potassium dichromate within (1:1) dil. H 2 SO 4 ) following standard protocols [18][19][20]. A thermostat was used to facilitate the lowering of temperature.…”