Soil Organic Carbon (SOC)

Assessment of soil quality is an invaluable tool in determining the sustainability and environ- mental impact of agricultural ecosystems. The study was conducted to assess the quality of the soils under arable cultivation, locally irri- gated and non-irrigated, forestry plantations of teak (Tectona grandis Lin.) and gmelina (Gme- lina arborea Roxb.), and cashew (Anacardium occidentale Lin.) plantation agro ecosystems using soil organic carbon (SOC), soil total ni- trogen (STN) and soil microbial biomass C (SMBC) and N (SMBN) at Minna in the southern Guinea savanna of Nigeria. Soil samples were collected from soil depths of 0-5 cm and 5-10 cm in all the agro ecosystems and analyzed for physical, chemical and biological properties. All the agro ecosystems had similar loamy soil texture at both depths. The soils have high fer- tility status in terms of available phosphorus and exchangeable calcium, magnesium and po- tassium. The irrigated arable land had signifi- cantly (P < 0.05) higher SOC and STN in both soil depths than all the other soils due to greater C inputs into the soil and fertilizer application. The cashew plantation soil had the lowest SMBC value of 483 mg kg -1 while teak soil had the highest value of 766 mg kg -1 which was sig- nificantly (P < 0.05) different from that of the other soils at the surface layer. At both soil depths, in all the soils, the SMBC/SMBN ratios were >6.6 suggesting fungal domination in all the agroecosystems. The forestry plantation soils had higher SMBC and SMBN as a per- centage of SOC and STN respectively than the cultivated arable land soils. Burning for clearing vegetation and poor stocking of forestry planta- tions may impair the quality of the soil. The

Soil organic carbon (SOC) plays an important role as a pool of terrestrial carbon (C) and can be con- trolled by proper agronomic practices. Therefore, arable soils play a crucial role in C cycling and can be considered as a major reservoir and an important sink for sequestering the atmospheric CO 2 (Smith 2004). Patterns of reduced SOC were observed regardless of climate, soil type, or original vegetation. Numerous studies show a decline in SOC content with tillage, insufficient fertilization, and removal and burning of crop residue (Paustian et al. 1997). According to ‘Thematic Strategy for Soil Protection’, an estimated 45% of European soils have a low SOC content, which poses a threat to all soil functions. Zdruli et al. (2004) estimated that in Southern Europe, 74% of soils contained < 2% organic C in the topsoil (0–30 cm).

Soil Organic Carbon (SOC) is a measure of the total amount of organic carbon (C) in soil, independently of its origin or decomposition. Interest in SOC is common among soil scientists and related practitioners because of the importance al, chemical and biological soil ecological functions and because SOC is a universal indicator of soil quality. Consequently, as variations in SOC levels can have serious implications on many environmental processes such as nhouse gas fluxes, the need to estimate SOC changes has become central to global environmental policies. At the international level, all the various Conventions arising from the 1992 United Nations Conference on Environment and Development in Rio (Climate Change, Biodiversity and to Combat Desertification) have the issue of SOC levels at their core. The Kyoto Protocol (UNFCCC, 1998) in particular, allows the use of biospheric carbon sinks and sources originating from human-induced untries’ commitments of greenhouse gas emissions reduction. These activities, listed in Article 3.3 (afforestation, reforestation and deforestation since 1990) and Article 3.4 (forest management, cropland management, grazing of the Kyoto Protocol, are Use Change and

Urban trees sequester carbon into biomass and provide many ecosystem service benefits aboveground leading to worldwide tree planting schemes. Since soils hold ,75% of ecosystem organic carbon, understanding the effect of urban trees on soil organic carbon (SOC) and soil properties that underpin belowground ecosystem services is vital. We use an observational study to investigate effects of three important tree genera and mixed-species woodlands on soil properties (to 1 m depth) compared to adjacent urban grasslands. Aboveground biomass and belowground ecosystem service provision by urban trees are found not to be directly coupled. Indeed, SOC enhancement relative to urban grasslands is genus-specific being highest under Fraxinus excelsior and Acer spp., but similar to grasslands under Quercus robur and mixed woodland. Tree cover type does not influence soil bulk density or C:N ratio, properties which indicate the ability of soils to provide regulating ecosystem services such as nutrient cycling and flood mitigation. The trends observed in this study suggest that genus selection is important to maximise long-term SOC storage under urban trees, but emerging threats from genus-specific pathogens must also be considered.

Soil organic matter can be analyzed on the basis of the different fractions. Changes in the levels of organic matter , caused by land use, can be better understood by alterations in the different fractions. Therefore in order to discover tendency of soil fertility sustainability it is significant to research on stable and labile form fractions of soil organic carbon by advanced methodology and modern technique. Our research work aimedto evaluate the effect of mineral and organic fertilizers on the labile and stable organic carbon of the chestnut soil in Mongolia. The soils samples used in this study we collected from variants of mineral ( N60P40K40), organic (biohumus 1t / hec.) Fertilizer and their combination of the Long-term fertilizers experiments of Plant and Agriculture Institute Changes in soil organic C by land use for agricultural purposes occurred mainly in the fraction of particulate organic matter (>20 µm ). The clay and silt fractions were quatified with a Mastersizer S after distruction organic substances and carbonates using H 2 O 2 and HCI and the sand fraction

Fate of soil organic carbon and polycyclic aromatic hydrocarbons in a vineyard soil treated with biochar.. Rombolàa, Will Meredithb, Colin E.[r]

The assumption is that hedge-banks store a considerable, hitherto unknown quantity of SOC which must be considered when calculating the carbon footprint of an agricultural holding. This paper aims to do a quantitative evaluation of SOC on an agricultural holding based on the agricultural experimental farm operated by the Institute of Organic Farming (OEL) in Trenthorst, Schleswig-Holstein. The aim is to evaluate the role of the above mentioned mar- ginal areas within the overall carbon footprint of a holding. This will form the basis of pre- liminary estimates of SOC in hedge-banks.

chemicals, energy crisis and environmental protection, it is becoming more important to rely on local abundant agricultural bio resources than on chemical fertilizer. Understanding the effects of organic farming on the soil quality parameters, such as microbial activity and soil nutrient content, is of central importance to concepts of sustainability. Investigation were done on the quantity, type and application of organic amendments on temporal dynamics of paddy soil organic carbon (SOC), soil total nitrogen (STN) and soil microbial biomass (SMB). The study was conducted in a paddy wetlands of Padayatti in Erumayur panchayat, Palakkad, Kerala as part of the “Agro-Biodiversity Enhancement Programme” by Kerala State Biodiversity Board, to promote organic farming in the state. The data collected on the soil chemical and microbial parameters from selected organic farming stations (St. 1-3) in comparison to chemical fertilizer applied conventional stations (St. 4) from July 2009 to October 2010 formed the basis of this paper. In the present study it was observed that soil in Padayetti under organic cultivation was able to maintain marginally increased concentration of total soil organic carbon (SOC), soil organic matter (SOM), total nitrogen (TN) and soil microbial biomass as compared to the conventional fertilizer systems. Even though considerable variation could be observed in the organic and conventional fields in the context of soil chemical and biological parameters, however they were not very much pronounced. The average soil organic carbon value ranged from 0.379 to 1.26% whereas soil total nitrogen was in the range of 0.739 to 0.85%. Study stations with organic amendments showed enriched microbial biomass and nutrient availability than fertilizer applied fields. The heterotrophic microbial count showed an average highest value of 20x 10 6 cfu/g soils in organic station, whereas was 90x10 4 cfu/g soils in fertilizer applied station. Therefore this study recommends long term application of organic inputs for restoring the native soil properties and health.

Based on the initial and final percentages of the SOC content, the parameter of carbon sequestration percentage (CSP) was calculated for each treatment according to equa- tion. The results for uncultivated and cropland soil are presented in Figs 4 and 5, respectively. The order of the CSP values for both soils was nearly similar. In general, the application of 1% FYM mixed with the soil surface layer of 0-7 cm (M1SUR) showed the highest value of CSP, whereas the least CSP values were obtained for the application of 3% straw residue homogeneously mixed with the 0-20 cm soil layer (S3MIX). This means that, at higher rates of organic matter added to the soils, lower values of CSP were obtained and vice versa. This could be partly attributed to the fact that microbial activity in the soil was stimulated in the presence of available organic matter, and may be result of the priming effect (Gajda, 2010; Kuzyakov, 2010). Consequently, at Fig. 2. Comparison between the soil organic carbon content affected by the different methods of organic matter application.Results of the 4-month pot experiment where SUR – mixed with the soil surface layer of 0-7 cm, MIX – homogeneously mixed with the 0-20 cm soil layer, S1 – 1% wheat straw residue, S3 – 3% wheat straw residue, M1 – 1% FYM, M3 – 3% FYM. Other explanations as in Fig. 1.

16’ E) to study the effect of Nitrogen fertilizer (inorganic) and organic manures combination on the major chemical properties of the soils. The treatments consisted of four levels of nitrogen fertilizers (0, 45, 60 and 90 kg/ha N) combined with three different sources of organic manures (cow dung, municipal waste and poultry droppings) applied at three different rates of each organic manure (0.0, 2.5, and 5.0 tons/ha). The experiment therefore contained twenty-eight (28) treatments laid out in factorial design and replicated three times in a randomized fashion. Soil texture (particle size analysis), soil pH, electrical conductivity (EC), effective cation exchange capacity (ECEC), percentage base saturation (PBS), soil organic carbon (SOC), total N, C:N ratio, available P (Bray-1), and exchangeable K were determined before the experiment. Also some few chemical properties of the three organic manures used were analyzed. The result showed that soil of the study area was sand-loam in texture, slightly acidic (pH = 6.20), low in ECEC, organic carbon, and total N, wide C/N ratio and free from salinity (EC = 0.01 dS/m). The major soil chemical properties affected by the combined application of nitrogen fertilizer and different organic manures include soil pH, ECEC, soil organic carbon, total nitrogen and C/N ratio. There was significant decrease in soil pH as nitrogen fertilizer was applied in combination with poultry droppings in 2008, 2009 and in the combined analysis. The pH value was lowest at 90 kg N/ha in combination with 5.0 tons/ha of poultry droppings in 2008 (5.52), 2009 5.52) and in the combined analysis. Nitrogen fertilizer applied at 90 kg N/ha in combination with cow dung at 5.0 tons/ha had significantly highest amount of ECEC in 2009 and in the combined. On the other hand application of nitrogen fertilizer at 90 kg/ha in combination with municipal wastes at 5.0 tons/ha showed

Measuring the carbon content. Soil samples were taken at different depths in each of the three plots. Randomly located soil cores were taken in 20-cm increments from a depth of 20–260 cm (samples from 0–20 cm were taken every 5 cm) using a cy- lindrical steel corer (diameter 8 cm, length 20 cm), with three replicates for each standard tree per plot. The nine soil samples from each plot were combined, and soil bulk density was determined using the cutting ring method. After removing lit- ter and rocks, the bulked samples were air-dried, ground, and passed through a 2-mm mesh sieve, and then stored at room temperature until analy- sis. Soil organic carbon (SOC) and plant organic carbon (POC) of plant samples (trunks, branches, leaves, and roots), understory vegetation, litter, and dry soil samples were measured by dry combus- tion using a CHNS-O elemental analyzer (Fisons Instruments, Beverly, USA) (Dube et al. 2012). Inorganic carbon is primarily CaCO 3 ; CaCO 3 was estimated as a proportion of soil carbon according to Conant et al. (2003).

We took a total of 252 soil samples (4 types of samples from 21 sites with 3 replications). Th e sample type was: (i) disturbed soil sample for chemical analyses prepared by a standard process to air-dried and sieved soil sample of fi ne particles (< 2 mm) (ISO 11464). SOC (soil organic carbon) was determined as C ox (total oxidized carbon in ISO/FDIS 14235), SOM (soil organic matter) was expressed by 1.724 C ox (assumption that SOM con- tains 58% of organically bound carbon in Nelson, Sommers 1982), fractionation of humic substances (HS) as a ratio of HA:FA (according to the method described in Richter, Hlušek 1999), pH KCl by po- tentiometry (according to ISO 10390), cation ex- change capacity (CEC) and exchangeable cations measured by AAS-Varian240 (according to ISO 13536); (ii) undisturbed soil samples (Kopecký cyl- inders – volume 100 cm 3 , according to ISO 11508)

include bulk density, pore structure, water availability and soil organic carbon [45]. Thus, changes in bacter- ial communities are likely to occur. This has been reported by multiple studies [46–50]. Especially CT disturbs bacterial habitats and dilutes nutrient pools by mixing topsoil with subsoil. In our study, soil or- ganic carbon (SOC), dissolved organic carbon (DOC) and microbial biomass carbon (Cmic) had higher values in the tillage horizon under RT compared to CT. This corresponds to the data found in the litera- ture [23, 51–53]. The increase of Cmic suggests that the absolute number of bacteria capable of synthe- sizing EPS and LPS should be higher under RT. Thus, we assumed that the higher DOC concentra- tions promotes bacteria which are able to produce EPS and LPS, and that the stable aggregate fraction (SAF) of the soil is higher under RT. Surprisingly, at our sampling site, SAF was comparable between the two tillage systems and increased significantly only below the tillage horizon. However, this might be caused by soil physical properties. Specifically, the clay content (45%) was very high at our site. Meta-analysis performed by Cooper et al. [7] sug- gests that the differences between tillage systems could be more pronounced in soils with a lower clay content (< 40%). Building good soil structure is more challenging in light, sandy soils, as they lack the fine particles necessary to form stable soil aggregates [54]. Conversely, soil biology has a strong influence on SAF. This includes the activity of bacteria, fungi, earthworms and plants. On one hand, the effect of plants and earthworms is rather indirect and in- cludes for example cast formation by earthworms or increasing microbial activity by the release of organic substances to the soil via the rhizosphere of plants [15, 16]. On the other hand, bacteria and fungi dir- ectly promote aggregate formation by the excretion of gluing agents such as EPS, LPS and fungal glyco- proteins, or by physical binding of soil particles by fungal mycelium [15]. Similar to the general increase of Cmic in the topsoil under RT, Kuntz et al. [55] also observed higher fungal abundances in that soil layer.

Soil organic matter (SOM) is important for maintaining soil structural stability (SSS). The influence of soil organic carbon (SOC) and different organic matter components on various SSS measures were quantified. We used a silt loam soil with a wide range of SOC (0.0080-0.0427 kg kg-1 minerals) sampled in spring 2015 from the Highfield Ley- Arable Long-Term Experiment at Rothamsted Research. Four treatments were sampled: Bare fallow, continuous arable rotation, ley-arable rotation, and grass. Soils were tested for clay dispersibility (DispClay), clay-SOM

A positive impact of salvage-logging practice on soil organic carbon (OC) was observed in this study, with values remaining higher in logged areas compared to unlogged areas almost a year after logging. Fernández et al. [12] also found limited perturbation of logging op- erations on the soil organic layer and the upper centime- ters of mineral soil. Also, according to Beghin et al. [5], salvage-logged, non-planted areas exhibit a dense herb layer that, in time, might compensate for organic matter losses. Parallel to the increase in organic carbon, an in- crease in dissolved organic-carbon (DOC) levels in logged areas was also recorded in this study. This in- crease was time-limited (lasted only until 1.5 years after logging), and then decreased to lower values than those found in the unlogged, naturally regenerated areas. Johnson and Curtis [34] explained the higher soil C lev- els in logged plots by the incorporation of slash into the mineral soil, especially in coniferous forests, which, when harvested, produce more soil C and N than hard- wood. However, in this study, there was less impact of logging on total soluble nitrogen (TSN) levels, which increased in logged compared to unlogged areas only 3 months after logging, and then decreased to non-signify- cant levels. Decreases in DOC and TSN levels in the salvaged-logged areas in this study could be a result of plant establishment in the exposed, unshaded areas of logged plots, which quickly utilize available N and C, on the one hand, and increase organic matter on the other.

3: Contribution of soil organic carbon in the different depths to total soil carbon in the profile (%) in the natural forest (NF), sesame-sorghum rotation (S-S) and continuous sorghum.[r]

Abstract. While we know that understory vegetation affects the soil microbial biomass and extracellular enzyme activ- ities in subtropical Chinese fir (Cunninghamia lanceolata) forests, we are less certain about the degree of its influence. We determined the degree to which the soil abiotic and bi- otic properties, such as PLFAs and extracellular enzyme ac- tivities, were controlled by understory vegetation. We estab- lished a paired treatment in a subtropical Chinese fir plan- tation, which comprised one plot from which the understory vegetation and litter were removed (None) and another from which the litter was removed but the understory vegetation was left intact (Understory). We evaluated how the under- story vegetation influenced the soil abiotic properties, the bacterial, fungal, and actinobacterial PLFAs, and the activ- ities of five hydrolases and two oxidative enzymes. The dis- solved organic carbon (DOC), particulate organic carbon, soil organic carbon, ammonia nitrogen (NH + 4 –N), and total nitrogen contents and soil moisture were 18 %, 25 %, 12 %, 34 %, 8 %, and 4 % lower in the None treatments than in the Understory treatments, respectively (P < 0.05). Soil bacte- rial, fungal, and total PLFAs, and the potential activities of β - 1,4-glucosidase (βG), β-1,4-N-acetylglucosaminidase, phe- nol oxidase, and peroxidase, were as much as 24 % lower in None treatments than in Understory treatments (P < 0.05). The specific activities of C-acquiring enzymes were as much as 41 % higher (P < 0.05), and the ratio of C- to N-acquiring

Soil organic carbon sequestration rates by tillage and crop rotation. Soil 301[r]

To maintain soil quality in agricultural ecosystems, it is important to restore soil carbon (C) stocks with organic C additions, and the application of the soil C saturation theory can help identify soils with large soil C storage potentials and estimate rates and durations to reach maximal soil C storage. The goal of this study was to test whether soil C saturation can be observed in a wide range of soil types in agricultural ecosystems, and to find soil mineralogical properties that could influence soil C saturation. Seven long- term agricultural field experiments at Gongzhuling, Zhengzhou, Qiyang and Laiyang, China, and at Melfort and Dixon (two experiments at this site), Canada were selected for this study. Soils from these seven experiments have different mineralogy, and represent typical soil types in the northern, middle, and southern regions in China and dominant croplands soils in the central prairies of Canada. Multiple levels of organic C inputs for 10-20 years at each experiment were used to test for soil C saturation behavior in each soil. Surface (0-20 cm) soils were sampled from the seven experiments in 2010 or 2011 were fractionated to obtain bulk soil (<2 mm), particulate organic matter

However, this paper focused on the SOC i.e. OC under natural conditions such as forests and rangeland. The purpose of this article was to review the existing knowledge on analytical techniques and amount of SOC in Tanzania and reflecting other sub-Saharan Africa [20, 29, 33, 57]. In doing so, we reviewed 57 publications related to the study. Priority is given to scientific publications from international peered-reviewed journals from the web of sciences. Despite of the missing of some information, we tried to correct that discrepancy. This work has significant contribution to scientific research. It gives what has done and not yet and thus brings insights to original research. In addition, the study has economic implications as SOC contributes significantly to increased yields for both consumptions and sale. Ecologically, SOC favors the functioning of soil microorganisms especially mycorrhizal fungi which influence the capacity of nutrients uptake from the soils.