Soil Carbon Dynamics

While several studies have examined soil fertility management systems under key food and cash crops in the Sub-Saharan Africa (SSA) region, there is a knowledge gap on soil fertility management under African Leafy Vegetables (ALV) smallholder farming practices particularly in Kenya. The objective of this study was to evaluate the influence of agronomic management and socioeconomic factors on soil chemical fertility in the major ALV production zones in Kenya. Farm surveys were used to gather socioeconomic data, while soil sampling was undertaken in all fields to collect soil chemical data. The findings indicated that Kisii County was characterized by higher proportions of wealthy and more educated farmers, with higher frequencies of input applications relative to Kakamega County. The soil pH was highest in Kenyenya, followed by Gucha, Butere, Mumias, and Khwisero. Gucha and Kenyenya had significantly the highest record of soil carbon concentrations of 3.2 and 3.1 %, respectively compared to other sites, such as Butere (2.0 %) and Khwisero (1.8 %), which had similar soil carbon concentrations, with Khwisero having the least (1.5 %) soil C. The highest mean Zn concentration was recorded in Gucha (6.5 mg kg-1), followed by Kenyenya (6.4), Mumias (4.3), Butere (3.1) and Khwisero (3.0). The study showed that soil fertility under ALV farms in western Kenya was influenced by socioeconomic factors and agronomic management factors. In general, the soil fertility status in Kisii County was better, compared to Kakamega County. Soil carbon was significantly influenced by site, soil texture, plot distance, fertilizer sources, and organic and inorganic fertilizer application frequencies. Gucha and Kenyenya Sub-Counties had higher SOC levels, averaging at 1.2 and 1.1 % higher, visa -vis Butere Sub-County, while Mumias and Khwisero Sub-Counties had lower average SOC levels in contrast to Butere Sub-County. Site differences can differentiate soil nutrient distribution due to inherent differences in soil characteristics and indirect effects arising from localized soil management practices.

This paper presents the development process of a robust and ROS-based Drive-By-Wire system designed for an autonomous electric vehicle from scratch over an open source chassis. A revision of the vehicle characteristics and the different modules of our navigation architecture is carried out to put in context our Drive-by-Wire system. The system is composed of a Steer-By-Wire module and a Throttle-By-Wire module that allow driving the vehicle by using some commands of lineal speed and curvature, which are sent through a local network from the control unit of the vehicle. Additionally, a Manual/Automatic switching system has been implemented, which allows the driver to activate the autonomous driving and safely taking control of the vehicle at any time. Finally, some validation tests were performed for our Drive-By-Wire system, as a part of our whole autonomous navigation architecture, showing the good working of our proposal. The results prove that the Drive-By-Wire system has the beh...

Land use change can affect terrestrial C stocks, resulting in increased CO 2 flux from soil to the atmosphere. In Africa, conversion of natural ecosystems to agricultural lands is the most common land use change. This study investigated the effects of six land use types occurring in Mt. Kilimanjaro ecosystems i.e. (1) lower montane forest (2) grassland and (3) savannah (natural ecosystems) (4) Chagga homegardens (semi-natural ecosystem) and ( ) maize fields and (6) coffee plantation (agroecosystems) on microbial biomass carbon (MBC) and dynamics of 14 C labelled glucose added into soil. Decomposition of 14 C labelled glucose and its incorporation into microbial biomass in surface soils (0e10 and 10e20 cm) were determined. MBC decreased significantly with increased intensity of land use. Mineralization of the 14 C labelled glucose occurred in two phases with contrasting rates: 0e10 days (6e18% of 14 C d À1 ) and 15 e65 days (<0.1% of 14 C d À1 ). Land use intensification in agroecosystems led to an average increase of glucose decomposition of 14%. The decay rates of the labile C pool in intensively used agricultural lands were up to three times higher compared to natural ecosystems. The incorporation of 14 C glucose into microorganisms ranged between 1 and 7% of 14 C input in all soils, and was highest in savannah. Agricultural intensification decreased C content in soil through increased mineralization of organic substances and negatively impacted the upper soil layer more compared to the lower one. Based on these results we conclude that semi-natural ecosystems (e.g. Chagga homegardens) are more sustainable in Mt. Kilimanjaro ecosystems compared to intensive agroecosystems.

Afforestation of gramineous-woody savannah with cocoa agroforestry systems (cAFS) is a common farmer practice in Cameroon considered as sustainable. Nevertheless, the effects of afforestation of savannah with cAFS on soil organic carbon (SOC) turnover and content, and the factors controlling SOC accumulation and stabilization are unknown. SOC content at 0-10 cm soil layer, and SOC distribution in soil particle size fractions (0-20 μm fraction considered as mineral-associated organic carbon, MAOC; 50-2000 μm considered as particulate organic carbon, POC; and 20-50 μm), were compared in different systems settled on degraded savannah (orthic * Corresponding author at: World Agroforestry (ICRAF), Yaoundé, Cameroon.

1,3-Dichloropropene (1,3-D) is a likely alternative soil fumigant for methyl bromide. The objective was to determine root-knot nematode, Meloidogyne incognita, survival in microplots after exposure to 1,3-D for various periods of time in soil that have previously been amended with compost. The treatments were 1,3-D applied broadcast at 112 liters/ha and untreated controls in both compost-amended and unamended soil. Soil samples were collected from each microplot at 6, 24, 48, 72, and 96 hours after fumigation at three depths (0-15, 15-30, and 30-45 cm). One week after fumigation, six tomato seedlings were transplanted into each microplot and root galling was recorded 6 weeks later. Plants grown in fumigated compost-amended soil had more galls than plants from fumigated unamended soil at P </= 0.1. Gall indices from roots in fumigated soil amended with compost were not different from nonfumigated controls. Based on soil bioassays, the number of galls decreased with increasing time after fumigation in both compost-amended and unamended soil at 0-to-15 and 15-to-30 cm depths, but not at 30 to 45 cm deep. Higher soil water content due to the elevated levels of organic matter in the soil at these depths may have interfered with 1,3-D movement, thus reducing its efficacy.

Anaerobic soil disinfestation (ASD) has been demonstrated as an effective alternative to pre-plant chemical soil fumigation (CSF) commonly used to control soilborne pathogens. However, the ASD effects on spatial and temporal changes in soil microbial communities remain poorly understood in production systems with low soilborne disease pressure. The objective of this study was to assess the influence of ASD treatments on soil microbial community composition at different soil depths during the spring tomato production season in Florida. Soil treatments included ASD using 6.9 m3 ha−1 of molasses with 11 Mg ha−1 of composted poultry litter (CPL) (ASD0.5), ASD with 13.9 m3 ha−1 of molasses and 22 Mg ha−1 CPL (ASD1.0), and chemical soil fumigation (CSF) using a mixture of 1,3-dichloropropene and chloropicrin. Soil microbial community composition was measured at soil depths of 0–15 and 15–30 cm using phospholipid fatty acid (PLFA) analysis at 0, 36, 76, and 99 days after transplanting (DAT...

Soil salinity and sodicity are serious issues worldwide; amelioration through plantation forestry is a low-cost and effective technique to overcome these abiotic stresses. Increase in soil organic carbon (SOC), soil carbon stock, microbial biomass carbon (MB-C) and permanganate oxidizable carbon (POXC) were considered as indicators for soil amelioration. The objective of the study was to determine the changes in different soil depths (0-15, 15-30, 30-45, 45-60, 60-75, 75-90 and 90-105 cm) and tree canopy cover (mid-canopy, canopy edge and canopy gap) in a 6-year old Eucalyptus tereticornis plantation on sodic soils. SOC, MB-C, POXC and soil carbon stock were significantly influenced by soil depth and tree canopy cover. MB-C under mid canopy and canopy edge was statistically similar, whereas, canopy gap had maximum MB-C. POXC was highest under canopy edge followed by canopy gap and lowest in mid canopy. SOC as well as C stock was recorded highest under canopy edge which was significantly higher to mid canopy and canopy gap. The results indicated that Eucalyptus based plantation forestry has significant impact on soil carbon sequestration and reclamation of sodic soils, which ultimately enhanced the productivity of the land use system.

The aim of this study was to analyze soil carbon stock, carbon storage in soil aggregates and clay mineralogy in Eucalyptus tereticornis, Prosopis juliflora and Dendrocalamus hamiltonii (located at Seonthi Reserved Forest, Kurukshetra, 29°59&#39;N and 76°59&#39;E; Altitude is 247 m above msl) in north-western India. The climate of the study area is tropical monsoonal and semiarid. The soil pH varied from 7.44 to 8.11. The organic carbon stock upto 0-60cm soil depth varied from 16.677 to 2.983 Mg C ha ; inorganic carbon was 1.344 to 4.360 1 Mg C ha . The microaggregates (250µm-53µm) and sand and silt associated fractions (&lt;53 µm) formed a large 1 fraction of soil aggregates and protected most of soil organic carbon. The total carbon content was higher in microaggregates (250µm-53µm) as compared to silt and clay associated soil fractions (&lt;53µm). Montmorillonite, chlorite, illite, chasmosite, kaolinite and vermiculite were found to be the main clay minerals in soils of the three...

In modern soil science, the main trend is the affirmation of substantive (substantive-genetic or profile-genetic) principles, according to which soils are diagnosed based on their morphological and analytical indicators.
Professor O. Nabokikh, during the lifetime of V. Dokuchaev, criticized the factor-genetic classification and diagnostic models developed by Dokuchaev and Sibirtsev. He was the first to propose the substantive-genetic approach based on his concept of "guiding soil features." The foundation of Nabokikh's soil formation model was a more complex sequence: "combination of soil-forming agents → type of water regime (dominant factor) → main soil-forming processes → soil features."
A comparative analysis of organic matter content in chernozems has been conducted based on the "detailed soil feature maps," which were first created by O. Nabokikh in 1914–1916.

The  geographic  genetic  features  of  the  humus status of automorphic soil of the North-Western Black Sea region are shown. Parameters dehumification of chernozems are established. The transformation of soil properties (agrophysical and physicochemical, including  buffer  and  soda  resistance),  which  are  related to the features of the content of organic matter, has been studied.

O Cerrado Brasileiro, com sua ampla extensão e heterogeneidade de ecossistemas, abriga uma enorme biodiversidade. Mas as áreas originalmente recobertas com vegetação de Cerrado vêm sendo desmatadas e substituídas por sistemas agropecuários, causando impactos como erosão e alterações no teor e natureza do carbono orgânico do solo. Diante disso, este trabalho objetivou avaliar o teor e a origem do carbono orgânico do solo na Bacia do Ribeirão Bom Jardim (Triângulo Mineiro/MG), após conversão da vegetação de Cerrado em áreas de pastagens manejada e degradada, visando apresentar o potencial de degradação do solo em relação à atividade, ao manejo e ao tempo de uso do mesmo. Os resultados das análises de carbono total (%C) e carbono isotópico (δ 13 C) revelaram um gradativo empobrecimento no teor de carbono nas áreas sob pastagem. Além disso, houve uma substituição do C da MOS de espécies C 3 do Cerrado em C de gramíneas C 4 quando comparadas com o solo de remanescente de Cerrado arbóreo. Palavras-chave: Cerrado brasileiro. Pastagem manejada. Pastagem degradada. Carbono orgânico do Solo.

O Cerrado Brasileiro, com sua ampla extensão e heterogeneidade de ecossistemas, abriga uma enorme biodiversidade. Mas as áreas originalmente recobertas com vegetação de Cerrado vêm sendo desmatadas e substituídas por sistemas agropecuários, causando impactos como erosão e alterações no teor e natureza do carbono orgânico do solo. Diante disso, este trabalho objetivou avaliar o teor e a origem do carbono orgânico do solo na Bacia do Ribeirão Bom Jardim (Triângulo Mineiro/MG), após conversão da vegetação de Cerrado em áreas de pastagens manejada e degradada, visando apresentar o potencial de degradação do solo em relação à atividade, ao manejo e ao tempo de uso do mesmo. Os resultados das análises de carbono total (%C) e carbono isotópico (δ 13 C) revelaram um gradativo empobrecimento no teor de carbono nas áreas sob pastagem. Além disso, houve uma substituição do C da MOS de espécies C 3 do Cerrado em C de gramíneas C 4 quando comparadas com o solo de remanescente de Cerrado arbóreo. Palavras-chave: Cerrado brasileiro. Pastagem manejada. Pastagem degradada. Carbono orgânico do Solo.

A field experiment was conducted to evaluate the effects of bio and chemical fertilizers on yield and production factors of valerian (Valeriana officinalis L.) at the Homad-Absard Agricultural Complex in Damavand city, Tehran Province, Iran, through a factorial experiment based on a randomized complete blocks design with 3 replications during 2017 to 2020. Experimental factors consist Nitroxin and Phosphate Barvar2 biofertilizers each with 2 levels of inoculation and control, and also the urea (46% N) chemical fertilizer in 5 levels (0, 30, 60, 90 and 150 kg/ha). Measured parameters were root diameter (mm), root length (cm), leaf width (cm) and leaf length (cm) root dry weight (kg/ha), shoot dry weight (kg/ha), valernic acid content (%) and valernic acid yield (g/ha). Results showed that the biofertilizers had significant effect (p≤ 0.01) on the all quantity and quality parameters studied. Unlike the urea chemical fertilizer at all levels which had a negative effect on the yield and amount of valernic acid (%), biofertilizers increased it. Maximum and minimum amount of valernic acid (%) were measured in control (0.465%) and 150 kg/ha urea (0.215%) respectively. The highest and lowest root dry weight were obtained in interaction of Nitroxin+Phosphate barvar2 + 150 kg urea (665 kg/ha) and control (221 kg/ha) respectively. Results of this experiment showed that biofertilizers with positive effects on experimental parameters are able to replace the chemical fertilizers.

con la Sociedad" enfatiza el necesario reconocimiento mutuo entre los ecólogos y el resto de la sociedad. La sociedad evoluciona más rápidamente que nunca, en un contexto de crisis global con profundas raíces ecológicas, económicas y sociales. Aunque las raíces ecológicas son muy importantes y evidentes para los ecólogos, nuestro mensaje llega con dificultad a la sociedad. Una parte importante del problema es, quizás, que hay mucho desconocimiento en el público general sobre la Ecología y los ecólogos. Por otro lado, no es fácil para los ecólogos encontrar los canales adecuados de comunicación. En este sentido, la AEET realiza un esfuerzo creciente para divulgar el conocimiento ecológico y sensibilizar sobre los problemas ambientales, tanto locales como globales. Esperamos que este Congreso suponga un impulso más para seguir moviéndonos en esta dirección, presentar los últimos avances en la ciencia de la Ecología y propiciar una oportunidad para compartir algunas de estas investigaciones con la sociedad.

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High latitude terrestrial ecosystems are key components in the global carbon (C) cycle. The Northern Circumpolar Soil Carbon Database (NCSCD) was developed to quantify stocks of soil organic carbon (SOC) in the northern circumpolar permafrost region (18.7 × 10 6 km 2). The NCSCD is a digital Geographical Information systems (GIS)

Limited water resources and climate change in arid and semi-arid regions have negative impacts on food and water security. Management of irrigation and compost may be used to tackle this issue. Crop models are the powerful tools that could predict grain yield (GY) and water productivity (WP) under a broad range of irrigation, compost and temperature interactions. In addition, modeling irrigation management requires the selection of the most suitable evapotranspiration (ET) approach to achieve robust simulations. To achieve this goal, two crop models in Decision Support System for Agrotechnology Transfer (DSSAT) (i.e. CERES-Wheat and N-Wheat), were calibrated and evaluated using a field dataset of three growing seasons in a high-temperate region in Egypt (Luxor). Then, the models were applied to explore GY and WP across a wide range of irrigation (11 options) and compost (8 rates) interactions using two ET routines such as Priestley-Taylor (PT) and FAO 56 Penman-Monteith (PM). The models were also used to predict (GY) and (WP) within the same range of irrigation and compost interactions at higher temperatures (i.e. +1,2,3 and 4) compared to the baseline outputs (1981-2010). Simulation results showed that, deficit irrigation up to 80% and 85% from soil available water achieved the highest values of GY (7.5 t ha-1) and WP (18.4 kg ha-1 mm-1) respectively, provided that using higher rate of compost (12 t ha-1). Rising temperature up to 4 • C decreased GY and WP by 17.2% and 7.4% respectively relative to the baseline without any benefits from compost. Compost technology does not help offset the negative impacts of temperature, but increased yield reduction and greenhouse gas emissions (GHG). Higher compost rates may be used to mitigate the effect of deficit irrigation on wheat yield and water productivity, but not compatible with mitigation of climate change in arid and semi-arid regions.

The impact of climate change on the soil microbiome potentially alters the biogeochemical cycle of terrestrial ecosystems. In semi-arid environments, water availability is a major constraint on biogeochemical cycles due to the combination of high summer temperatures and low rainfall. Here, we explored how ten years of irrigation of a water-limited pine forest in the central European Alps altered the soil microbiome and associated ecosystem functioning. A decade of irrigation stimulated tree growth, resulting in higher crown cover, larger yearly increments of tree biomass, increased litter fall, and greater root biomass. Greater amounts of plant-derived inputs associated with increased primary production in the irrigated forest stands stimulated soil microbial activity coupled to pronounced shifts in the microbiome from largely oligotrophic to more copiotrophic lifestyles. Microbial groups benefitting from increased resource availabilities (litter, rhizodeposits) thrived under irriga...

Numerous geographic data on peatland exist but definitions vary, and the correspondent classes are often neither harmonized nor interoperable. This hinders the efforts to employ the available national datasets on peatlands and wetlands for policy monitoring and reporting. The existing meta-languages, such as ISO-Land Cover Meta Language (LCML) and EAGLE, offer the possibility to “deconstruct” the relevant nomenclatures in an object-oriented manner, allowing the comparability and interoperable use of related information. The complex nature of peatlands calls for a dedicated and structured vocabulary of keywords and terms, comprising the biotic substrate and the soil. In the SEPLA project, a semantic meta-model has been developed, combining the hierarchical ontology of the LCML with the matrix structure of the EAGLE model. The necessary elements were provided to describe peatland bio-physical characteristics, while representing the definitions in a concise and user-friendly manner (semantic passports). The proposed semantic meta-model is innovative as it enables the documentation of the spatial distribution of peatland characteristics, considering also their temporal dimension, their intrinsic relation with land use, and the soil. It has been successfully implemented for the translation of the national peatland nomenclature into common land categories relevant for reporting under LULUCF regulation, as part of the EU Climate Law.

Biofertilizers are eco friendly and are now most, necessary to support developing organic agriculture and sustainable agriculture. They can provide to the small and marginal farmers an ecofriendly viable weapon to attain the ultimate goal of increasing crop productivity. Cyanobacteria also called blue green algae which are useful to mankind in various ways and constitute a vast potential resource in varied application such as food, feed, fuel, fertilizer, medicine, industrial products and in combating pollution. Coir pith, a light lignocellulosic material which is spongy, highly hygroscopic and extremely compressive having high lignin content, accumulated in tons creating environmental problems. Hence, recycling the waste by using cyanobacteria in order to get pollution free environment and useful products from coir pith will be an economical and purposeful one. The purpose of this study was to evaluate the effect of different amount of coir pith based cyanobacterial biofertilizers named cyanopith individually on the morphological and biochemical characteristics as well as yield of Aloe barbadensis Miller (Aloe vera). The pot experiment was conducted at the Model Organic Farm of Bharathidasan University located in Tamilnadu, India. Different treatments of cyanopith (Solid form) fertilizer viz., cyanopith 25g, 50g, 75g, 100g, 125g and 150 g/pot, and the plants without any treatment were considered as control. It was observed that the plant appeared maximum height, number of leaves and leaf weight, leaf breadth, number of offsets and significant improvement in gel and latex yield, as well as Chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, free amino acids and sugar contents were found to be improved with 100g cyanopith over control. Hence, it revealed that 100g of cyanopith fertilizer was the optimum concentration for maximum improvement of the plant characteristics and yield of A. barbadensis Miller.

Cyanobacteria also called blue green algae which are useful to mankind in various ways and constitute a vast potential resource in varied application such as food, feed, fuel, fertilizer, medicine, industrial products and in combating pollution. Coir pith, a light lignocellulosic material which is spongy, highly hygroscopic and extremely compressive having high lignin content, accumulated in tons creating environmental problems. Hence, recycling the waste by using cyanobacteria in order to get pollution free environment and useful products from coir pith will be an economical and purposeful one. The intention of this study was to evaluate the effect of different concentrations of coir pith based cyanobacterial biofertilizers named cyanospray individually on the morphological and biochemical characteristics as well as yield of Aloe barbadensis Miller (Aloe vera). The pot experiment was conducted at the Model Organic Farm of Bharathidasan University located in Tamilnadu, India. Different treatments of cyanospray (Liquid form) fertilizers viz., cyanospray 0.1%, 0.2%, 0.3%, 0.4%, 0.5% and 0.6% were treated with the plants and without any treatment was considered as control. It was observed that the plant appeared maximum height, number of leaves and leaf weight, leaf breadth, number of offsets and significant improvement in gel and latex yield, as well as Chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, free amino acids and sugar contents were found to be improved with 0.4% cyanospray over control. Hence, it revealed that cyanospray fertilizer alone at 0.4% concentration was the optimum concentration for maximum improvement of the plant characteristics and yield of A. barbadensis Miller.

Determination of the optimum sowing window not only can improve maize yield significantly but also can fit maize in the existing cropping pattern. To get the advantages of sowing maize at the optimum time, a study was designed and carried out at the research field of Bangladesh Agricultural Research Institute, Rangpur, Bangladesh during 2015–2017. Another aim of the study was to forecast the yield of maize for the northern and western regions of Bangladesh using the CERES-Maize model. The study considered 5 November, 20 November, 5 December, 20 December, and 5 January as sowing dates for maize to identify the optimum sowing window. Three hybrid maize varieties, viz., BARI Hybrid Maize-9 (BHM-9), NK-40, and Pioneer30V92 were used. The study was laid out in a split-plot design, assigning the sowing dates in the main plot and the varieties in the sub-plot. To forecast the yield, the daily weather data of 2017 were subjected to run the model along with thirty years (1986–2015) of weathe...

Public land managers are on the front lines of vegetation management and decision making as essential players in urban sustainability efforts. Green infrastructure, including lawns, has the potential to relieve climate changerelated strains on municipal budgets while enhancing the quality of life. The most common urban vegetation that managers make decisions about is turfgrass, which dominates urban areas across North America and Europe. Recent appeals for changes in the ubiquitous lawn, promoting a transition from high input (e.g., fertilizer, water) to low input, more sustainable forms of urban vegetation have arisen. Despite the broad critique of the lawn, perspectives from public land managers on issues of transitioning to low input turfgrasses in urban areas remain mostly unknown. We conducted focus groups with land managers across the northern United States, specifically in Oregon, Indiana, and New Jersey to understand factors they consider opportunities and barriers in transitioning to low input cool-season turfgrasses, using the example of fine fescue varieties. Overall, managers articulated significant opportunities for a transition to low input turf. Across all groups, managers noted labor and time savings, as well as anticipated future climate and other challenges (e.g., watering restrictions, declining water quality), which could aid in the adoption of low input turfgrasses now and in the near future. Mangers also articulated significant current barriers such as previously negative experience with earlier varieties of fine fescues and their confusion around the naming of current varieties to overcome before widespread adoption could take place. More work needs to be done to demonstrate the benefits of low input turfgrasses, get managers hands-on experience with improved varieties, as well as work on simplifying and organizing the publicly used names of fine fescues.

This study aimed to better understand the stabilisation of rice rhizodeposition in paddy soil under the interactive effects of different N fertilization and water regimes. We continuously labelled rice ('Zhongzao 39') with 13 CO2 under a combination of different water regimes (alternating flooding-drying vs. continuous flooding) and N addition (250 mg N kg-1 urea vs. no addition, then followed 13 C incorporation into plant parts as well as soil fractions. N addition increased rice shoot biomass, rhizodeposition, and formation of 13 C (new plant-derived C) in the rhizosphere soils under both water regimes. By day 22, the interaction of alternating flooding-drying and N fertilisation significantly increased shoot and root 13 C allocations by 17% and 22% respectively, over the continuous flooding condition. The interaction effect also increased 13 C allocation to the rhizosphere soil by 46%. Alone, alternating water management increased 13 C deposition by 43%. In contrast, N addition increased 13 C deposition in rhizosphere soil macroaggregates under both water regimes, but did not increase macroaggregation itself. N treatment also increased 13 C deposition and percentage in microaggregates, as well as in the silt and clay-size fractions of the rhizosphere soil, a pattern that was higher under the alternating condition. Overall, our data indicated that combined N application and a flooding-drying treatment stabilised rhizodeposited C in soil more effectively than other tested conditions. Thus, they are desirable practices for improving rice cropping, capable of reducing cost, increasing water use efficiency, and raising C sequestration.

Soil microbiome plays a significant role in soil’s ecosystem for soils to be physically and biologically healthy. Soil health is fundamental for plant growth and crops productivity. In the introduction part, the roles and dynamics of the microbial community in soils, primarily in the cycle of soil organic carbon and CO2 release and absorption, are deliberated. Next, the impact of crop management practices and climate change on the soil carbon balance are described, as well as other issues related to soil degradation, such as unbalanced nutrient recycling and mineral weathering. In response to these issues, various approaches to soil regeneration have been developed in order to foster an efficient and active soil microbiome, thereby balancing the CO2 cycle and carbon sequestration in the soil ecosystem.

Since the process of gas dynamics in agricultural soils is mainly studied during plant growth, only few studies have focussed on these dynamics in frozen soils covered with snow. Nevertheless, gas dynamics during the cold season is important to quantify the yearly mass balance of gas emitted to the atmosphere. Spatio-temporal concentrations of CO 2 and N 2 O have been measured from the prefreezing to the thawing period in a pasture soil during two cold seasons along with soil temperature and other soil properties. The spatial dynamics of these gases differed from each other and depended on the spatial and temporal variability of soil temperature as long as the soil surface temperature was above 0°C. Two main occurrences of gas release occurred during thawing, one related to trapped gases, similar for both gases, and the other to reactivation of microorganisms, different between both gases. Once the soil was frozen, both gas concentrations increased throughout the frozen period, even during very cold conditions, indicated a gases production faster Page 1 of 40 https://mc.manuscriptcentral.com/cjss-pubs Canadian Journal of Soil Science than the loss. Under frozen condition, their spatial variability was independent of soil temperature during which their correlation was up to 90%. Three periods related to gas dynamics were observed during both cold seasons: freezing with spatio-temporal trends different between both gases, completely frozen with similar trends, partial to complete thawing with trends different between both gases.

The sequestration of organic matter (OM) is linked with soil microaggregates and mineral surfaces. This work aimed to resolve the distribution and arrangement of OM in soils and how they are influenced by fine mineral particle surfaces and microaggregation. Distinct spatial interactions were found to govern the sequestration of OM at the microscale. A successive development of OM patches and a piled-up arrangement were revealed. The effect of soil microaggregates on OM depends on soil texture and aggregate diameters, which are controlled by different failure mechanisms.Die Bindung organischer Substanz (OBS) ist verknüpft mit Bodenmikroaggregaten und mineralischen Oberflächen. Diese Arbeit zielt auf ein besseres Verständnis der Verteilung und der Anordnung von OBS in Böden ab und wie diese von feinen mineralischen Partikeloberflächen und Mikroaggregierung beeinflusst werden. Es wurde festgestellt, dass räumlich ausgeprägte Interaktionen die Bindung von OBS auf der Mikroskala maßgebli...

Rice (Oryza sativa) is usually grown under flooded conditions, leading to anoxic periods in the soil. Rice plants transport oxygen via aerenchyma from the atmosphere to the roots. Driven by O 2 release into the rhizosphere, radial gradients of ferric Fe and co-precipitated organic substances are formed. Our study aimed at elucidating the composition and spatial extension of those gradients. Air-dried soil aggregates from a paddy field were embedded in epoxy resin, cut, and polished to produce cross sections. Reflected-light microscopy was used to identify root channels. With nano-scale secondary ion mass spectrometry (NanoSIMS), we investigated transects from root channels into the soil matrix and detected

Soil particulate organic matter (POM) represents a labile soil organic matter (SOM) fraction and is an important source of nutrients for soil microorganisms and plants. This study assessed C and N stocks in POM and soil mineralassociated fractions for forage mixtures of rhizoma peanut (RP; Arachis glabrata Benth.) and bahiagrass (Paspalum notatum Flüggé) in contrast with their monocultures. Treatments included two bahiagrass entries receiving 90 kg N ha-1 harvest-1 , two RP entries, and the four bahiagrass-RP combinations. Samples were collected from the 0-to 15-cm soil depth in July 2015 and in September 2016, after seven harvests. Soil samples were fractionated into POM and mineral-associated organic matter (MAOM) by dispersion with sodium hexametaphosphate and sieving (53 mm). Samples were analyzed for d 13 C, d 15 N, and total C and N. Groups of bahiagrass, bahiagrass-RP, and RP were contrasted. There were no differences in N stocks among forage treatments. Bahiagrass-RP mixtures had greater soil POM-C stock (5.1 Mg C ha-1) than RP monocultures (4.0 Mg C ha-1). Soil POM C/N ratio was lower for bahiagrass (18.2) and RP monocultures (16.2) than bahiagrass-RP (20.6). Bahiagrass-RP and bahiagrass had similar soil d 13 C and were less depleted than RP (-23‰ vs.-26‰ and-26‰ vs.-28‰, for POM and MAOM, respectively). Soil POM-C stock under forage mixtures was not different from N-fertilized bahiagrass, and it was greater than RP. Hence, mixing RP and bahiagrass can be an option to increase POM-C without the need of N fertilizer.

Devising agricultural management schemes that enhance food security and soil carbon levels is a high priority for many nations. However, the coupling between agricultural productivity, soil carbon stocks and organic matter turnover rates is still unclear. Archived soil samples from four decades of a long-term crop rotation trial were analysed for soil organic matter (SOM) cycling relevant properties: C and N content, bulk composition by NMR spectroscopy, amino sugar content, short term C bioavailability assays, and long-term C turnover rates by modeling the incorporation of the bomb-spike in atmospheric &lt;sup&gt;14&lt;/sup&gt;C into the soil. After &gt; 40 years under consistent management, topsoil carbon stocks ranged from 14 to…

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The Massachusetts Turf and Lawn Grass Council Incorporated is chanered under the laws of the Commonwealth of Massachusetts as a non-profit corporation. The turf council seeks to foster ' 'Better turf through research and education. '' More detailed information on the subjects discussed here can be found in bulletins and circulars or may be had through correspondence with the editor. Permission to reproduce material appearing in the Turf Bulletin must be obtained from the respective publications where the article is reprinted from. If an article is not a reprint, permission is granted to reproduce it, providing full acknowledgement is made of the au th or. The Editor wishes to thank Loretta], Cassel for her research and technical assistance in the construction of this bulletin.

Soil aggregate structure is likely to exert fundamental control on soil biology (e.g., microbial activity and community composition) and soil biogeochemistry including the stabilization and mobilization of soil organic matter (SOM). Aggregate hierarchy concept (Tidall and Oades, 1982) has been verified for most temperate and tropical soil types except for Andisols developed from tephra and volcanic rocks are known for strong aggregate stability and high SOM storage capacity. We recently showed the first evidence of hierarchical structure in Andisol (Asano and Wagai, 2013). After maximum dispersion (achieved only after 5 kJ/mL sonication following sodium saturation), most of macroand micro-aggregates were broken down to much smaller particles (&lt;0.2 and 0.2-2 um) that accounted for dominant proportion of total C, N, and extractable phases of Al, Si, and Fe. These &lt;2um particle-size fractions appeared to act as persistent binding agent, contributing to the high physical stability...

Product simulation programs with DSSAT are based on the principle of predicting the potentials of yield and other phenological parameters of wheat varieties with different fertilizer application doses in different climatic and soil conditions. For this purpose, different wheat varieties (Bayraktar, Tosunbey) were used in order to test the use of the DSSAT simulation model in semi-arid conditions in the Ikizce experimental area of the Haymana District of Ankara Province, Field Crops Central Research Institute, during the 2017-2018 and 2018-2019 periods. The aim of this study is to predict yield in wheat varieties (Bayraktar, Tosunbey) using CERES and CROPGRO sub-models of DSSAT v.4.7.5 simulation model. In the study, the model was run at different nitrogen application doses (0, 6, 12, 18 kg/da) to reveal the yield prediction potential of the wheat cultivars in semi-arid conditions. For the calibration of the model, the grain yield, plant height and Leaf area index (LAI) data obtained...

We identified the most sensitive genotype-specific parameters (GSPs) and their contribution to the uncertainty of the MANIHOT simulation model. We applied a global sensitivity and uncertainty analysis (GSUA) of the GSPs to the simulation outputs for the cassava development, growth, and yield in contrasting environments. We compared enhanced Sampling for Uniformity, a qualitative screening method new to crop simulation modeling, and Sobol, a quantitative, variance-based method. About 80% of the GSPs contributed to most of the variation in maximum leaf area index (LAI), yield, and aboveground biomass at harvest. Relative importance of the GSPs varied between warm and cool temperatures but did not differ between rainfed and no water limitation conditions. Interactions between GSPs explained 20% of the variance in simulated outputs. Overall, the most important GSPs were individual node weight, radiation use efficiency, and maximum individual leaf area. Base temperature for leaf development was more important for cool compared to warm temperatures. Parameter uncertainty had a substantial impact on model predictions in MANIHOT simulations, with the uncertainty 2-5 times larger for warm compared to cool temperatures. Identification of important GSPs provides an objective way to determine the processes of a simulation model that are critical versus those that have little relevance.

Current estimates of carbon (C) storage in peatland systems worldwide indicate tropical peatlands comprise about 15 % of the global peat carbon pool. Such estimates are uncertain due to data gaps regarding organic peat soil thickness and C content. Indonesian peatlands are considered the largest pool of tropical peat carbon (C), accounting for an estimated 65 % of all tropical peat while being the largest source of carbon dioxide emissions from degrading peat worldwide, posing a major concern regarding long-term sources of greenhouse gases to the atmosphere. We combined a set of indirect geophysical methods (ground penetrating radar, GPR, and electrical resistivity imaging, ERI) with direct observations from core samples (including C analysis) to better understand peatland thickness in West Kalimantan (Indonesia) and determine how geophysical imaging may enhance traditional coring methods for estimating C storage in peatland systems. Peatland thicknesses estimated from GPR and ERI and confirmed by coring indicated variation by less than 3 % even for small peat-mineral soil interface gradients (i.e. below 0.02 •). The geophysical data also provide information on peat matrix attributes such as thickness of organomineral horizons between peat and underlying substrate, the presence of wood layers, buttressed trees and soil type. These attributes could further constrain quantification of C content and aid responsible peatland management in Indonesia. BGD 12, 191-229, 2015 C stock estimates and peat soil X. Comas et al.

We conduct a model-data analysis of the marine carbon cycle to understand and quantify the drivers of atmospheric CO 2 concentration during the last glacial-interglacial cycle. We use a carbon cycle box model, "SCP-M", combined with multiple proxy data for the atmosphere and ocean, to test for variations in ocean circulation and Southern Ocean biological export productivity across marine isotope stages spanning 130 000 years ago to the present. The model is constrained by proxy data associated with a range of environmental conditions including sea surface temperature, salinity, ocean volume, sea-ice cover and shallow-water carbonate production. Model parameters for global ocean circulation, Atlantic meridional overturning circulation and Southern Ocean biological export productivity are optimized in each marine isotope stage against proxy data for atmospheric CO 2 , δ 13 C and 14 C and deep-ocean δ 13 C, 14 C and CO 2− 3. Our model-data results suggest that global overturning circulation weakened during Marine Isotope Stage 5d, coincident with a ∼ 25 ppm fall in atmospheric CO 2 from the last interglacial period. There was a transient slowdown in Atlantic meridional overturning circulation during Marine Isotope Stage 5b, followed by a more pronounced slowdown and enhanced Southern Ocean biological export productivity during Marine Isotope Stage 4 (∼ −30 ppm). In this model, the Last Glacial Maximum was characterized by relatively weak global ocean and Atlantic meridional overturning circulation and increased Southern Ocean biological export productivity (∼ −20 ppm during MIS 3 and MIS 2). Ocean circulation and Southern Ocean biological export productivity returned to modern values by the Holocene period. The terrestrial biosphere decreased by 385 Pg C in the lead-up to the Last Glacial Maximum, followed by a period of intense regrowth during the last glacial termination and the Holocene (∼ 600 Pg C). Slowing ocean circulation, a colder ocean and to a lesser extent shallow carbonate dissolution contributed ∼ −70 ppm to atmospheric CO 2 in the ∼ 100 000-year leadup to the Last Glacial Maximum, with a further ∼ −15 ppm contributed during the glacial maximum. Our model results also suggest that an increase in Southern Ocean biological export productivity was one of the ingredients required to achieve the Last Glacial Maximum atmospheric CO 2 level. We find that the incorporation of glacial-interglacial proxy data into a simple quantitative ocean transport model provides useful insights into the timing of past changes in ocean processes, enhancing our understanding of the carbon cycle during the last glacial-interglacial period.

Most crop simulation models require the use of Genotype Specific Parameters (GSPs) which provide the Genotype component of G×E×M interactions. Estimation of GSPs is the most difficult aspect of most modelling exercises because it requires expensive and time-consuming field experiments. GSPs could also be estimated using multi-year and multi locational data from breeder evaluation experiments. This research was set up with the following objectives: i) to determine GSPs of 10 newly released maize varieties for the Nigerian Savannas using data from both calibration experiments and by using existing data from breeder varietal evaluation trials; ii) to compare the accuracy of the GSPs generated using experimental and breeder data; and iii) to evaluate CERES-Maize model to simulate grain and tissue nitrogen contents. For experimental evaluation, 8 different experiments were conducted during the rainy and dry seasons of 2016 across the Nigerian Savanna. Breeder evaluation data were also collected for 2 years and 7 locations. The calibrated GSPs were evaluated using data from a 4-year experiment conducted under varying nitrogen rates (0, 60 and 120kg N ha-1). For the model calibration using experimental data, calculated model efficiency (EF) values ranged between 0.88-0.94 and coefficient of determination (d-index) between 0.93-0.98. Calibration of time-series data produced nRMSE below 7% while all prediction deviations were below 10% of the mean. For breeder experiments, EF (0.58-0.88) and d-index (0.56-0.86) ranges were lower. Prediction deviations were below 17% of the means for all measured variables. Model evaluation using both experimental and breeder trials resulted in good agreement (low RMSE, high EF and d-index values) between observed and simulated grain yields, and tissue and grain nitrogen contents. It is concluded that higher calibration accuracy of CERES-Maize model is achieved from detailed experiments. If unavailable, data from breeder experimental trials collected from many locations and planting dates can be used with lower but acceptable accuracy.

All carbon cycle models referenced by the IPCC have a common feature: Increased carbon dioxide in the atmosphere originates from anthropogenic emissions. It is also generally known that the CO2 concentration observations show that about 44-46 % of yearly CO2 emissions seem to have accumulated in the atmosphere; the ocean and biosphere take up the rest. Therefore, this straightforward conclusion that the increased atmospheric CO2 is anthropogenic may seem correct, but there are profound physical problems. An unusual feature is among carbon budget presentations, that they do not calculate the isotopic composition of the atmospheric CO2 nor refer to the observed global d 13 C used as a measure of isotopes 13 C/ 12 C ratio from 1750 to the present time. The analyses of this study show that the current d 13 C value of-8.6 ‰ in the atmosphere conflicts with physical processes and applied recycling flux values meaning that the increased atmospheric CO2 since 1750 cannot be exclusively anthropogenic. This study's atmospheric anthropogenic CO2 amount of 70 GtC is much smaller than the 279 GtC reported by the IPCC for 2019. Also, the removal rate of anthropogenic CO2 from the atmosphere can be approximated to be about 64 years-the same as the radiocarbon 14 C removal rate after the 1964 nuclear tests corresponding to the e-folding time of 11 years. The total CO2 removal rate would be about 220 years meaning an e-folding time of 38 years.

High value crop producers in California rely heavily on soil fumigation to control a wide array of soil borne pests including nematodes, pathogens and weeds. Fumigants with broad biocidal activity can affect soil microbial communities that contribute to nutrient cycling and plant nutrient uptake which can impact soil health. It is often thought that soil microbial communities make a relatively rapid recovery following fumigation. However, recently it has been found that repeated application of fumigants over time can have greater and longer lasting impacts on soil microorganisms than single fumigation events. Therefore, the main objective of this study was to determine the effect of long-term repeated application of fumigants on soil microbial communities and compare them with non-fumigated and organic sites. Soil samples were collected from fields in Watsonville, CA. Chronosequence sites were defined by number of years of annual fumigation (yaf) with methyl bromide (15, 26, 33, 39 yaf) at the time of sampling, and representative non-fumigated sites were also included for comparison. Phospholipid fatty acid (PLFA) analysis was used to analyze the samples. The canonical variate analysis showed that microbial communities in sites with a longer history of fumigation (33 and 39 yaf) were similar to one another; however, they differed significantly from 15 yaf site and further analysis concluded that non-fumigated sites were significantly different than fumigated sites. This study showed that the proportion of arbuscular mycorrhizal fungi (AMF) was lower in all fumigated (15, 33 and 39 yaf) sites as compared to their non-fumigated counterparts, which could be a threat to sustainability since AMF plays a major role in soil health and quality.

High value crop producers in California rely heavily on soil fumigation to control a wide array of soil borne pests including nematodes, pathogens and weeds. Fumigants with broad biocidal activity can affect soil microbial communities that contribute to nutrient cycling and plant nutrient uptake which can impact soil health. It is often thought that soil microbial communities make a relatively rapid recovery following fumigation. However, recently it has been found that repeated application of fumigants over time can have greater and longer lasting impacts on soil microorganisms than single fumigation events. Therefore, the main objective of this study was to determine the effect of long-term repeated application of fumigants on soil microbial communities and compare them with non-fumigated and organic sites. Soil samples were collected from fields in Watsonville, CA. Chronosequence sites were defined by number of years of annual fumigation (yaf) with methyl bromide (15, 26, 33, 39 yaf) at the time of sampling, and representative non-fumigated sites were also included for comparison. Phospholipid fatty acid (PLFA) analysis was used to analyze the samples. The canonical variate analysis showed that microbial communities in sites with a longer history of fumigation (33 and 39 yaf) were similar to one another; however, they differed significantly from 15 yaf site and further analysis concluded that non-fumigated sites were significantly different than fumigated sites. This study showed that the proportion of arbuscular mycorrhizal fungi (AMF) was lower in all fumigated (15, 33 and 39 yaf) sites as compared to their non-fumigated counterparts, which could be a threat to sustainability since AMF plays a major role in soil health and quality.