Low Organic Carbon Research Articles

Organic carbon burial and their implication on sea surface primary productivity in the middle Okinawa Trough over the past 200 ka

The long-term burial of organic carbon in marginal seas plays a critical role in Earth’s carbon cycle and climate change. However, the mechanism of organic carbon (OC) burial in the Okinawa Trough (OT) during glacial-interglacial timescales remains unclear. In this study, we analyzed the foraminiferal carbon isotopes, total organic carbon (TOC), and δ13C-TOC over the past 200 ka in core Z1 collected in the central OT. We aimed to reveal the history of OC burial in the middle Okinawa Trough during the past 200 ka, and we combined our findings with relevant paleoenvironmental indices to reveal underlying mechanisms. We found reduced surface primary productivity during MIS 6, which may indicate changes in the pathways of the Kuroshio Current (KC). Furthermore, we observed decoupling between high TOC flux and low OC burial during glacial periods. We proposed that the dilution effect caused by the high sedimentation rate and poor OC preservation during the glacial period resulted in the low TOC content. Ventilation of the North Pacific Intermediate Water (NPIW) regulated the redox conditions of the intermediate water in the Okinawa Trough. Additionally, the intensified Kuroshio Current during interglacial phases led to water column stratification, creating reducing conditions in the bottom water and facilitating improved OC preservation. Subsequently, the enhanced water column oxygenation resulting from the oxygen carried by the intensified glacial NPIW weakened the burial of OC. This study sheds new light on our understanding of the carbon cycle in marginal seas on a glacial-interglacial timescale.

Influence of Date Palm-Based Biochar and Compost on Water Retention Properties of Soils with Different Sand Contents

Generally, soils of arid and semi-arid regions have low water retention properties due to high sand and low organic carbon contents. This study aimed at quantifying the effect of date palm-based organic amendments (OAs) on the water retention properties of two soils (sandy loam and silty loam), as well as the influence of sand supplementation (0.5–2 mm) on the magnitude of the effect of OAs. Different grain size distributions were obtained by adding sand to natural soils. For this purpose, sand was added to the two soils (1/3 and 2/3) and different soil-OA combinations were tested at a dose of 3% by mass: compost alone, biochar alone and a mixture of biochar and compost (50:50 in mass), in addition to unamended control soils. Soil water contents were measured at nine matric potentials ranging from the saturation to the permanent wilting point. Biochar was more efficient than compost at improving soil water retention. The effect of organic amendments on water retention increased with sand content. In most cases, soil water content values were significantly higher for biochar-amended soils than for unamended or compost-amended soils. The weakness of the effect of compost addition (if alone) was probably due to its properties and notably its high mineral content and electrical conductivity. Soil sand supplementation led to higher differences between the OA-amended soils and unamended soils. Changes in available water capacity reached +26% and +80% in a sandy loamy soil enriched with 2/3 sand and amended with compost and with biochar, respectively, compared to the unamended soil. These results show that sand content (and more generally, soil texture) influences the effect of OA application. Thus, the application of biochar from date palm residues in soil seems to be an effective solution to improve the water retention properties of coarse textured soils and contribute to optimizing the use of water resources in irrigated areas.

Biochar Addition to a Mediterranean Agroecosystem: Short-Term Divergent Priming Effects

The goal of this study was to evaluate biochar’s resistance to microbial decomposition and its impact on native soil organic matter (SOM) decomposition. Conducted in a vineyard with a sandy loam Mediterranean soil with neutral pH and low organic carbon content, the experiment involved the application of 6.5 g biochar kg−1 derived from pine (PB) and corn cob (ZB). The monitoring period spanned two years, with soil samples collected at short- and medium-term timepoints (2 and 26 months post-application) and incubated in the lab for an additional 250 days. Soil respiration, the CO2-C isotopic signature, and dissolved organic carbon (DOChw) were assessed to identify potential priming effects (PE) and evaluate their persistence over two years. In the short term, biochar-induced priming effects were feedstock and pyrolysis temperature dependent, exhibiting negative priming in high-temperature wood biochar and positive priming in low-temperature grass biochar. The mechanism behind short-term positive priming was attributed to the higher labile organic carbon (OC) content in ZB compared to PB. In the medium term, initial strong priming effects shifted to slightly negative priming effects in both biochars, indicating the depletion of labile carbon fractions and the emergence of physical protection processes that mitigated priming.

Expression of glucose (GLUT) and glycerol (GLP) transporters in symbiotic and bleached Cassiopea xamachana (Bigelow, 1892) jellyfish

Cassiopea xamachana is a tropical medusa that lives in symbiosis with dinoflagellate algae, serving as a model organism for symbiotic studies. The symbiosis is necessary for this medusa to complete its life cycle. The symbiotic partners maintain a metabolic exchange of organic molecules that constitute an important source of energy for the animal host, with free organic molecules, like glucose and glycerol, being the primary source. This molecular exchange can be facilitated by cellular internal membrane transport proteins, such as Glucose membrane transporters (GLUTs) and Glycerol transport-like aquaglyceroporins (GLP-like), probably located at the symbiosomal interface. The present study was conducted in October 2021, evaluating the expression of transporter coding genes GLUT3, GLUT8, and GLP9 (two genes) by qPCR under conditions of symbiosis and after the loss of symbionts. Symbiotic medusae donated from Xcaret Park, Mexico (20° 34′ 24.59″ N; -87° 07′ 5.40″ W) were sampled and compared to medusae with an experimental decrease of algal symbionts. In agreement with glucose being an important mobile molecule, our results showed higher transcription levels for glucose transporters GLUT3 and GLUT8 in control compared to bleached medusae. By contrast, bleached medusae showed a higher expression of aquaglyceroporin transporters GLP9-1 and GLP9-2, probably associated with glycerol production after lipid catabolism, to compensate for lower organic carbon levels due to the loss of symbionts. Our results highlight the importance of free carbon molecules transported from symbiont to host and agree with glucose being an energy fuel for this symbiotic association.

Synergistic bioconversion of organic waste by black soldier fly (Hermetia illucens) larvae and thermophilic cellulose-degrading bacteria.

This study examines the optimum conversion of Wuzhishan pig manure by Black Soldier Fly Larvae (BSFL) at various phases of development, as well as the impact of gut microbiota on conversion efficiency. In terms of conversion efficiency, BSFL outperformed the growing pig stage (GP) group, with significantly higher survival rates (96.75%), fresh weight (0.23 g), and larval conversion rate (19.96%) compared to the other groups. Notably, the GP group showed significant dry matter reductions (43.27%) and improved feed conversion rates (2.17). Nutritional composition varied, with the GP group having a lower organic carbon content. High throughput 16S rRNA sequencing revealed unique profiles, with the GP group exhibiting an excess of Lactobacillus and Clostridium. Promising cellulose-degrading bacteria in pig manure and BSFL intestines, including Bacillus cereus and Bacillus subtilis, showed superior cellulose degradation capabilities. The synergy of these thermophilic bacteria with BSFL greatly increased conversion efficiency. The BSFL1-10 group demonstrated high growth and conversion efficiency under specific conditions, with remarkable larval moisture content (71.11%), residual moisture content (63.20%), and waste reduction rate (42.28%). This study sheds light on the optimal stages for BSFL conversion of pig manure, gut microbiota dynamics, promising thermophilic cellulose-degrading bacteria, and the significant enhancement of efficiency through synergistic interactions. These findings hold great potential for sustainable waste management and efficient biomass conversion, contributing to environmental preservation and resource recovery.

Optimizing the QuEChERS method for efficient monitoring of fipronil, thiobencarb, and cartap residues in paddy soils with varying properties.

This study aims to optimize the QuEChERS methodology for extracting three pesticides (fipronil, thiobencarb, and cartap) from two paddy soils with distinct characteristics. Various modifications were explored to enhance extraction efficiency, employing acetonitrile (MeCN) or ethyl acetate (EtOAc) for extraction and primary-secondary amine (PSA) and graphitized carbon black (GCB) for the clean-up. Assessment criteria included accuracy, precision, linearity, detection limits, uncertainty, and matrix effects. Results revealed that the clayey soil with lower organic carbon (OC) content (1.26%) and 100% moisture yielded the highest pesticide recoveries (113.72%, 115.73%, and 116.41% for FIP, THIO, and CART, respectively). In contrast, the silty clayey soil with higher OC content (2.91%) and 20% water content exhibited poor recoveries (< 60%). FIP and CART demonstrated better recoveries with MeCN, while THIO performed better with EtOAc under specific moisture conditions. Clean-up sorbents significantly reduced FIP and CART recoveries, with THIO recoveries less affected. Acidifying with HCl substantially improved CART recovery. EtOAc introduced a moderate to strong matrix effect for FIP and THIO, while MeCN in soils with 100% moisture resulted in a strong matrix effect for CART. The study highlighted the substantial impact of extraction conditions, pesticide properties, and soil conditions on the outcomes of the QuEChERS method. A comprehensive understanding of these interplays was deemed crucial for accurately quantifying pesticide residues in agricultural soils.

Region‐specific drivers cause low organic carbon stocks and sequestration rates in the saltmarsh soils of southern Scandinavia

AbstractSaltmarshes are known for their ability to act as effective sinks of organic carbon (OC) and their protection and restoration could potentially slow down the pace of global warming. However, regional estimates of saltmarsh OC storage are often missing, including for the Nordic region. To address this knowledge gap, we assessed OC storage and accumulation rates in 17 saltmarshes distributed along the Danish coasts and investigated the main drivers of soil OC storage. Danish saltmarshes store a median of 10 kg OC m−2 (interquartile range, IQR: 13.5–7.6) in the top meter and sequester 31.5 g OC m−2 yr−1 (IQR: 41.6–15.7). In a global context, these values are comparatively low. Soils with abundant clay (&gt; 20%), older and stable saltmarshes in mesohaline settings, and with low proportion of algal organic material showed higher OC densities, stocks, and accumulation rates. Grazing led to significantly higher OC stocks than neighboring ungrazed locations, likely due to trampling modifying soil abiotic conditions (higher erosion‐resistance and higher clay content) that slow carbon decay. Scaling up, Danish saltmarsh soils, comprising about 1% of the country's area, have the potential to yearly capture up to 0.1% of Denmark's annual consumption‐based CO2 emissions. Our research expands the baseline data needed to advance blue carbon research and management in the Nordic region while highlighting the need for a more comprehensive approach to saltmarsh management that considers the full range of services of these ecosystems and does not only focus on climate benefits.

Interactions of peroxy radicals from monoterpene and isoprene oxidation simulated in the radical volatility basis set.

Isoprene affects new particle formation rates in environments and experiments also containing monoterpenes. For the most part, isoprene reduces particle formation rates, but the reason is debated. It is proposed that due to its fast reaction with OH, isoprene may compete with larger monoterpenes for oxidants. However, by forming a large amount of peroxy-radicals (RO2), isoprene may also interfere with the formation of the nucleating species compared to a purely monoterpene system. We explore the RO2 cross reactions between monoterpene and isoprene oxidation products using the radical Volatility Basis Set (radical-VBS), a simplified reaction mechanism, comparing with observations from the CLOUD experiment at CERN. We find that isoprene interferes with covalently bound C20 dimers formed in the pure monoterpene system and consequently reduces the yields of the lowest volatility (Ultra Low Volatility Organic Carbon, ULVOC) VBS products. This in turn reduces nucleation rates, while having less of an effect on subsequent growth rates.

A Soil Analysis Approach to Assessing Potential Loss of Productive Lands Under Agricultural Land Conversion

Land provides physical space and is usually required for various sectoral developments needed to meet the needs of increasing population. Land is a finite natural resource; thus, conflict arises over land use and development. The strategic location of the municipality of Pura in Tarlac province, Philippines within the urban beltway of Central Luzon and the recent opening of the Tarlac–Pangasinan–La Union Expressway provide Pura excellent opportunities for urban and industrial development. However, the precursor to this is agricultural land conversion (ALC), which can change or reduce in the area of productive lands. This paper assessed the degree of productivity of the agricultural lands in the study area that are predisposed to ALC using FAO’s land suitability framework and the revised Storie index for soil productivity. Soil survey and composite soil sampling at 20 cm depth in the selected 34 sampling points were done to analyze the relevant soil physical and chemical properties. Five soil mapping units (SMU) were grouped based on the soil surface texture. The results show that the SMUs are only marginally suitable (S3f) for producing rice and other crops due to their current low soil organic carbon content. However, these SMUs can be highly suitable (S1) for crop production with appropriate soil management. Using the Storie index, the entire tract of land of Pura has an index rating of 58 percent, which corresponds to a grade 3 soil suitable for planting a number of crops with expected good results. The results of the land suitability evaluation and soil productivity assessment further show that the land in the municipality of Pura is productive, and thus can benefit both agricultural production and ALC. As such, whichever spatial strategy or policy direction for ALC that the municipal government chooses to adopt, the municipality of Pura will lose productive land.

Enhancing Organic Carbon Content in Tropical Soils: Strategies for Sustainable Agriculture and Climate Change Mitigation

Background: Tropical soils are characterized by low soil organic carbon (SOC) contents, which can negatively impact soil fertility, water retention, overall agricultural productivity, and food security. Objective: This paper aimed to review and synthesize the current body of literature on the restoration of SOC in tropical soils. Methods: A total of about 152 related articles were downloaded from electronic journal databases using search keywords, such as organic carbon (OC), conservation tillage, intercropping, biochar, and tropical soil. We discussed conservation tillage practices, such as reducing soil disturbance and respiration from the soils, as a means to promote soil OC sequestration. We also highlighted the importance of crop residue retention, which not only increases organic matter inputs and soil nutrients but also promotes soil water retention and reduces soil erosion. Results: Cover crops and crop rotation are identified as effective practices to cover bare ground during planting seasons, reduce erosion, and prevent nutrient losses through leaching and runoff. Additionally, we review the role of fertilizer application, manure and compost application, intercropping, agroforestry, and biochar as strategies to enhance OC content in tropical soils. We highlight the benefits of incorporating organic amendments, such as manure and compost, to improve soil structure and water-holding capacity. Furthermore, we discuss the potential of biochar, a carbon-rich material produced from biomass pyrolysis, as a strategy to sequester OC in tropical soils. Conclusion: Overall, this review provides insights into various strategies that can be implemented to increase the OC content of tropical soils, which can have multiple benefits for soil health, agricultural productivity, and climate change mitigation. Further research and implementation of these practices can contribute to mitigating climate change, conserving soil resources, and promoting sustainable agriculture in tropical regions.

MINERAL NITROGEN DYNAMICS OVER TIME INFLUENCED BY PEANUT-WASTE BIOCHAR APPLICATION IN ALKALINE SOIL

Soil fertility in arid to semi-arid regions is constrained by extreme temperature fluctuations. Soils of such regions typically have low fertility levels, nitrogen (N) availability (due to ammonia volatilization and denitrification), and soil organic carbon (SOC) content. An incubation experiment was conducted to assess how a peanut-waste biochar (PB), produced at 300°C, influences the mineral N and chemical properties of an alkaline soil. The treatments included five PB rates (control, 5, 10, 15, and 20g PB kg−1 soil) and two fertilizer rates [no fertilization without additions of N and phosphorus (P) and fertilization with addition of 120kg N ha−1 and 90kg P ha−1]. The soil was incubated for various durations (0, 14, 28, 42, and 56days). There were significant temporal shifts in the mineral form of N in the incubated soil. Following 56days of incubation under fertilization, the treatment with 20g kg−1 PB revealed soil nitrate-N and ammonium-N levels of 15.8mg kg‒1 and 21.1mg kg‒1, respectively. With no fertilization, 20g kg−1 PB increased mineral N by 2.3-fold over the treatment without PB. This increase was 2.6-fold with fertilization. After 56days of incubation, in the presence of 20g kg−1 PB, there was a 19% increase in cation exchange capacity under fertilization and a 21% increase under no fertilization, compared to the respective treatments without PB. Immediately after the PB application, SOC was significantly increased, corresponding to PB rates. However, substantial increases were observed only in treatments with 15 and 20g PB kg−1 soil. In conclusion, the addition of 15 and 20g PB kg−1 to alkaline soil significantly increased N availability in soil, demonstrating the importance of biochar for N management in agricultural soils.

Impact of Irrigation Scheduling and Nitrogen Management Through Drip Irrigation System on Nutrient Content and Uptake of Rabi Maize (Zea mays L.)

The state of the soil's nutrients can be significantly impacted by improper irrigation and nitrogen application, which may accelerate nutrient losses and cause soil erosion and ground water pollution. A field experiment was conducted during consecutive two rabi seasons of the years 2021 and 2022 at Regional Research Station, Anand Agricultural University, Anand, Gujarat, India to study the “Impact of irrigation scheduling and nitrogen management through drip irrigation system on nutrient content and uptake of rabi maize (Zea mays L.)”. The soil of the experimental field was loamy sand in texture, with low organic carbon and available nitrogen, medium available phosphorus and high potassium with soil pH 8.21. The experiment was carried out in split plot design with four levels of irrigation scheduling based on Alternate Day Pan Evaporation Fraction (ADPEF) were considered in main plot viz., I1 : Irrigation scheduling at 0.8 ADPEF, I2 : Irrigation scheduling at 1.0 ADPEF, I3 : Irrigation scheduling at 1.2 ADPEF and I4 : Control (Flood irrigation) and three nitrogen management treatments viz. N1 : 100% RDN through inorganic fertilizer, N2 : 75% RDN through inorganic fertilizer + Bio NPK consortium, N3 : 50% RDN through inorganic fertilizer + Bio NPK consortium + 5 t/ha FYM were assigned in sub plots, comprised of 12 treatment combinations. Result of the experiment showed that irrigation scheduling at 1.2 ADPEF (I3) recorded significantly higher N content in grain and stover and it was remained at par with irrigation scheduling at 1.0 ADPEF (I2) during 2021, 2022 and pooled analysis. P and K content in grain and stover was found non-significant due to various irrigation scheduling treatments during individual years and on pooled basis. Irrigation scheduling at 1.2 ADPEF (I3) recorded significantly higher N, P uptake by grain and stover and K uptake by grain during 2021, 2022 and on pooled basis. K uptake by stover found significantly higher under irrigation scheduling at 1.2 ADPEF (I3) during 2021-22 and pooled basis. While K, uptake by stover found non-significant. Nitrogen management with 100% RDN through inorganic fertilizer recorded significantly the highest N content in grain and stover and pooled analysis. While, P and K content grain and stover found non- and pooled analysis. Application of 100% RDN through inorganic fertilizer found significantly higher N, P and K uptake by grain and stover and pooled basis. Interaction effect of irrigation scheduling and nitrogen management treatments was found significantly higher N uptake by grain and K uptake by stover (pooled basis) under irrigation scheduling at 1.2 ADPEF with 100% RDN through inorganic fertilizer (I3N1).

Soil carbon-nutrient cycling, energetics, and carbon footprint in calcareous soils with adoption of long-term conservation tillage practices and cropping systems diversification

Calcareous soils, comprising vast areas in northern and eastern parts of India, are characterized by low soil organic carbon (SOC) with high free CaCO3 that results in low nutrient bioavailability with poor soil structure. Improvement of this soil can be achieved with conservation tillage with residue retention coupled with diversification of cropping system including legumes, and oilseeds in the system. Concerning all these, a long-term experiment was carried out in the calcareous soils having low organic carbon and high free CaCO3 (∼33 %) with varied tillage practices, viz. permanent bed with residue (PB), zero tillage with residue (ZT), and conventional tillage without residue (CT); and cropping systems viz. maize-wheat-greengram (MWGg), rice-maize (RM), and maize-mustard-greengram (MMuGg) during 2015–2021. From this study, it was observed that PB and ZT resulted in ∼25–30 % increment in SOC compared to the initial SOC, while CT showed a 4 % decrease in the SOC. Conservation tillage practices also resulted in better soil aggregation and favourable bulk density of the soil. Furthermore, PB and ZT practice exhibited 10–13 %; 15–18 %; 11–15 %; 40–60 %, 20–36 %, and 23–45 % increments in the soil available N, P, K, soil microbial biomass carbon, dehydrogenase activity, and urease activity, respectively over those under CT. Crop diversification with the inclusion of legume and oilseed crops (MMuGg, and MWGg) over cereal-dominated RM systems resulted in better soil health. Maize equivalent yield and energy use efficiency (%) were also found to be the maximum under PB, and ZT, in combination with the MMuGg system. ZT and PB also reduced the carbon footprint by 465 and 822 %, respectively over CT by elevating SOC sequestration. Hence, conservation tillage practices with residue retention coupled with diversification in maize-based cropping systems with mustard and greengram can improve soil health, system productivity, and energetics, and reduce the carbon footprint in calcareous soils.

Variação espaço-temporal da comunidade bentônica do rio Itajaí-Mirim, Itajaí (SC), nos canais original e retificado

The rectified channel was installed in the Itajaí-Mirim river in the mid-1960s to increase the river flow in the urban area of Itajaí, which suffers from flooding and inundation during periods of high precipitation. The present study aimed to evaluate the spatio-temporal variations of the benthic macrofauna of the Itajaí-Mirim river, in the original and rectified channels. The distribution of organisms was evaluated with samples collected at four points, two located in the natural channel and two in the rectified channel, during the four seasons of 2021. At each sampling point, with a van Veen dredge, three samples were collected for macrofauna and one for granulometric characterization. In total, 715 individuals were identified, and distributed in eight taxa. PERMANOVA revealed that the differences observed in the abundance of organisms considering seasonality were not significant, however, they were significant between the channels. The rectified channel exhibited 67% of the total abundance of the analyzed fauna. In this region, the organic matter and CaCO3 exhibited the highest concentrations and the sediment was classified as silt, while in the natural channel, the granulometry varied between fine sand and silt. The oligochaete Tubificida was the most abundant organism, representing 97% of the fauna. Considered tolerant, this organism inhabits freshwater sediments with low oxygen concentration and high organic carbon load. The low richness of the community and the high dominance of Tubificida characterized the evaluated region as a highly altered environment.

Soil organic matter and biogenic-abiogenic interactions in soils of Larsemann Hills and Bunger Hills, East Antarctica

Although Antarctic soils are usually described as weakly developed, recent studies indicated the significant variability in soil forming conditions across the sixth continent as well as considerable diversity of soils. The identification of pedogenetic processes in Antarctica is crucial for understanding not only the current state of its environment, but also for better understanding of soil development on Earth through time. Our study provides a detailed investigation of micromorphological features and molecular composition of organic matter of soil and soil-like bodies of remote areas of East Antarctica - Larsemann Hills and Bunger Hills, which are characterized by harsh environmental conditions. Studied soils showed predominantly coarse structure and low organic carbon content, alkaline to almost neutral pH range. Thin sections of studied soils were characterized by predominance of grains of quartz, feldspars, and other primary minerals with angular shapes indicating relatively weak degree of their alteration. All studied humic substances are characterized by the predominance of aliphatic structures. Moreover, it was observed that studied humic acids contains significant amounts of carbohydrates, polysaccharides, esters and amino acids and hydrophilic fragments predominate. Organo-mineral interactions were mostly connected with development of biofilms in the topsoil horizons with the maximal biological activity among studied soils.

Validation Cropping Systems and Input Management in Calcareous Vertisols

Inputs were tested and validated to supply optimum P and Zn content in index leaf of Bt hybrid cotton during squaring to flowering stage, such as seed treatment with NPK consortia to encourage soil biological activities in low organic carbon highly Calcareous Vertisols alongwith 75% RDF. Bentonite sulphur @20 kg ha-1 yr-1 soil application (SA) + RDF; Sagarika seed treatment @ 0.2% alongwith twice foliar sprays @ 0.002% at squaring and flowering + RDF; Nano ZnO 4% Seed treatment twice foliar sprays@0.004% + RDF produced significant agronomic response during 2019, exception was during 2020, the magnitude was 50% less due twice torrential (&gt;60-100mm) and five times medium (25-50mm) rains during July and August months upset the reproductive physiology of cotton, shedded all the fruiting bodies, unable to maintain index leaf NPK, besides heavy pink bollworm attack. All these treatments were applied with 100% RDF @90:45:45 N:P2O5:K2O granular, two splits of basal spot application having 6.5% Sulphur containing, N: P2O5: K2O @ 22.5 kg ha-1 twice on 15, 30 DAS and twice as Urea at 45 and 60 DAS, Bentonite Sulphur @ 20 kg ha-1 +RDF or seed treatment and foliar applications of bio-stimulants Sagarika @ 0.02% and twice foliar applications of the same @ 0.002% and Nano ZnO @ 0.004% twice produced 67-86 ppm Zn in index leaf of the Bt hybrid cotton, similar to that of chelated Zn 0.5%. These inputs produced 161-287 kg lint ha-1 i. e. more than double 38 to 50% due to better nutrient uptake, biomass production, boll number with more than ₹. 15 to 30, 000/- ha-1 profitability and 1.5 to 2.2 C:B ratio, FUE 1.6 to 1.2 and lowest cost of production in both the years. Large scale OFTs in Kalmeshwar Tq, Nagpur district (M.S.) India in highly Calcareous soils, on suitable field and horticulture crops, irrigations and inputs management confirmed the beneficial effect of RDF 150% @120:60:60 N:P2O5:K2O three splits fertilizers mixture of SSP + Urea + 20:20:0:13 soil application and also Bentonite sulphur or with and without two winter irrigations in late September besides seed treatment with PGPRs or Sagarika 0.002% before sowing and twice foliar applications with the same or alongwith chelated micronutrients 0.5% + WSF 17:44:0 and 0:0:50 2.0% + Boron 0.3% alternately with ZnSO4 0.5% or nano ZnO 0.004% alongwith Urea 2% and Boron 0.3% or were help full in doubling the seed cotton yields besides reducing the pre mature leaf reddening by maintaining optimum index leaf nutrient content.

Carbon Storage Potential of Soil in Diverse Terrestrial Ecosystems

Soil is one of the largest carbon reservoirs sequestering more carbon than vegetation and atmosphere. Due to the enormous potential of soil to sequester atmospheric CO2, it becomes a feasible option to alleviate the current and impending effects of changing climate. Soil is a vulnerable resource globally because it is highly susceptible to global environmental problems such as land degradation, biodiversity loss, and climate change. Therefore, protecting and monitoring worldwide soil carbon pools is a complicated challenge. Soil organic carbon (SOC) is a vital factor affecting soil health since it is a major component of SOM and contributes to food production. This review attempts to summarize the information on carbon sequestration, storage, and carbon pools in the major terrestrial ecosystems and underpin soil carbon responses under climate change and mitigation strategies. Topography, pedogenic, and climatic factors mainly affect carbon input and stabilization. Humid conditions and low temperature favor high soil organic carbon content. Whereas warmer and drier regions have low SOC stocks. Tropical peatlands and mangrove ecosystems have the highest SOC stock. The soil of drylands stores 95% of the global Soil Inorganic Carbon (SIC) stock. Grasslands include rangelands, shrublands, pasturelands, and croplands. They hold about 1/5th of the world’s total soil carbon stocks.

Integrated Weed Management in Summer Sesame (sesumun indicum L.)

A field research was evaluated at the Seed Technology, S. D Agricultural University, Sardarkrushinagar-385506, Banaskantha (North Gujarat) in the year between summer 2019 to 2021 to study the effect of weed management practices in summer sesamum. Experimental plot was loamy sand in texture with low organic carbon and available N, medium in available P2O5 and high in available K2O.&#x0D; Treatments were weed free (IC fb HW at 20 and 40 DAS), weedy control, pendimethalin 30 EC 0.750 kg/ha PE application fb IC+HW at 30 DAS, pendimethalin 30 EC1.0 kg/ha PE application fb IC+HW at 30 DAS, oxadiargyl 6 EC 75 g/ha PE fb IC + HW at 30 DAS, oxadiargyl 6 EC 90 g / ha PE fb IC+HW at 30 DAS, quizalofop-ethyl 5 EC 40 g/ha PoE 20 DAS fb IC+ HW at 40 DAS, quizalofop-ethyl 5 EC 50 g/ha PoE at 20 DAS fb IC+ HW at 40 DAS, pendimethalin 30 EC 0.75 kg/ha PE fb quizalofo-pethyl 5 EC 40 g/ha at 30 DAS and pendimethalin 30 EC 1.0 kg/ha PE fb quizalofop-ethyl 5 EC 40 g/ha at 30 DAS.&#x0D; The results revealed that significantly maximum seed yield (0.90 t/ha), stalk yield (2.14 t/ha), number of capsules per plant (73.1) and number of branches per plant (5.2) were obtained under weed free (IC fb HW at 20 and 40 DAS) treatment with maximum net realization (₹52322/ha).&#x0D; Minimum weed density at harvest/m2 and weed dry weight/m2 (67.17/m2 and 32.51g/m2) and maximum weed control efficiency (71.62%) were found under weed free (IC fb HW at 20 and 40 DAS).

How does biochar influence soil nitrification and nitrification-induced N2O emissions?

Nitrification is a major pathway of N2O production, especially in aerobic soils. The amendment of soils with biochar has been suggested as a promising solution to regulate soil N cycle and reduce N2O emissions. However, there is a lack of comprehensive and quantitative understanding of biochar impacts on soil nitrification and nitrification-induced N2O emissions. In this study, a meta-analysis was conducted using data compiled across 95 peer-reviewed studies. Results showed that biochar in general significantly increased soil nitrification rate by 56 %, with overall no significant effect on nitrification-induced N2O emissions, suggesting that biochar likely restricted the fraction of nitrified N emitted as N2O emissions. The abundance of ammonia-oxidizing bacteria (AOB) was significantly increased by 37 % following biochar addition, but that of ammonia-oxidizing archaea (AOA) did not change significantly, indicating that the impact of biochar on AOB rather than AOA may play an important role in soil nitrification. The impacts of biochar on soil nitrification processes were heterogeneous depending on soil properties. Biochar increased soil nitrification rate and AOB abundance to a larger extent in poorly pH-buffered soils such as those with acidic pH (<5), low organic carbon (<10 g kg−1), or poor texture (rich in either sand or clay), which may be attributed to the liming and structural effects of biochar that regulate soil pH and water-air status. The overall no significant effect of biochar on nitrification-induced N2O emissions was due to a positive effect in acidic soils, a negative effect in alkaline soils, and little effect in neutral soils. This study provides a comprehensive insight into how different factors mediate the response of soil nitrification processes to biochar amendment, which contributes to a new understanding of biochar function in regulating soil N2O emissions, and can assist in designing biochar projects that would benefit soil N cycle while minimizing undesirable side effects.

Agroecosystem modeling of reactive nitrogen emissions from U.S. agricultural soils with carbon amendments

Fertilizer-intensive agriculture is a leading source of reactive nitrogen (Nr) emissions that damage climate, air quality, and human health. Biochar has long been studied as a soil amendment, but its influence on Nr emissions remains insufficiently characterized. More recently, the pyrolysis of light hydrocarbons has been suggested as a source of hydrogen fuel, resulting in a solid zero-valent carbon (ZVC) byproduct whose impact on soil emissions has yet to be tested. We incorporate carbon amendment algorithms into an agroecosystem model to simulate emission changes in the year following the application of biochar or ZVC to the US. fertilized soils. Our simulations predicted that the impacts of biochar amendments on Nr emissions would vary widely (− 17% to + 27% under 5 ton ha−1 applications, − 38% to + 18% under 20 ton ha−1 applications) and depend mostly on how nitrification is affected. Low-dose biochar application (5 ton ha−1) stimulated emissions of all three nitrogen species in 75% of simulated agricultural areas, while high-dose applications (20 ton ha−1) mitigated emissions in 76% of simulated areas. Applying zero-valent carbon at 20 ton ha−1 exhibited similar effects on nitrogen emissions as biochar applications at 5 ton ha−1. Biochar amendments are most likely to mitigate emissions if applied at high rates in acidic soils (pH < 5.84) with low organic carbon (< 55.9 kg C ha−1) and inorganic nitrogen (< 101.5 kg N ha−1) content. Our simulations could inform where the application of carbon amendments would most likely mitigate Nr emissions and their associated adverse impacts.Graphical