Soil biogeochemistry

Agricultural plastic mulch films are widely used in specialty crop production systems because of their agronomic benefits. Biodegradable plastic mulches (BDMs) offer an environmentally sustainable alternative to conventional polyethylene (PE) mulch. Unlike PE films, which need to be removed after use, BDMs are tilled into soil where they are expected to biodegrade. However, there remains considerable uncertainty about longterm impacts of BDM incorporation on soil ecosystems. BDMs potentially influence soil microbial communities in two ways: first, as a surface barrier prior to soil incorporation, indirectly affecting soil microclimate and atmosphere (similar to PE films) and second, after soil incorporation, as a direct input of physical fragments, which add carbon, microorganisms, additives, and adherent chemicals. This review summarizes the current literature on impacts of plastic mulches on soil biological and biogeochemical processes, with a special emphasis on BDMs. The combined findings indicated that when used as a surface barrier, plastic mulches altered soil microbial community composition and functioning via microclimate modification, though the nature of these alterations varied between studies. In addition, BDM incorporation into soil can result in enhanced microbial activity and enrichment of fungal taxa. This suggests that despite the fact that total carbon input from BDMs is minuscule, a stimulatory effect on microbial activity may ultimately affect soil organic matter dynamics. To address the current knowledge gaps, long term studies and a better understanding of impacts of BDMs on nutrient biogeochemistry are needed. These are critical to evaluating BDMs as they relate to soil health and agroecosystem sustainability.

A preliminary pot trial was conducted in a greenhouse to determine the effects of rubber effluent on some soil chemical properties as well as early growth and nutrient uptake by maize plant. The levels of rubber effluent used were 0, 50, 100, 150, 200, 250 ml per 2 kg soil. The trial was arranged in a completely randomized design and replicated three times. Results showed that the soil pH, organic carbon, N, P, K, Mg, Ca Na, ECEC, Fe, Mn and Zn were significantly higher (P<0.05) in rubber effluent treated soils than the control, while the control was significantly higher in exchangeable acidity. Except Zn, the N, P, K, Mg, Ca, Na, Fe, Mn content and their uptake by the plant were significantly higher (P<0.05) in rubber effluent treated plant than the control. The plant height, leaf area and number of leaves were also significantly higher in effluent treated plants than the control. The N, P, K, Mg, Ca, Na content and their uptake and the growth parameters however declined at 200 ml treatment while in Fe, Mn and Zn content and their uptake, there was no definite pattern of increase with increasing effluent levels. Conclusively, rubber effluent contained vital plant nutrients which may be favorable to soil fertility improvement and maize growth at the application rates.

Soil organic carbon (SOC) plays a crucial role in mangrove blue carbon formation, yet the differences in microbemediated underlying SOC sequestration between introduced and native mangroves remain unclear. Here, we compared the SOC pool, including recalcitrant organic carbon (ROC) and labile carbon pools, as well as three residual carbon sources (amino sugars, lignin phenols, and lipids) in sediments between mangroves of introduced Sonneratia apetala and native Kandelia obovata, and further connected them with microbial life strategies and C metabolism capability. The results showed that SOC accumulation in S. apetala (SA) sediment was about 30%-50% of that in K. obovata (KO) sediment. ROC was the dominant form of SOC in long-term sequestration (76%-83%), while lignin phenols, amino sugars, and lipids were important sources of ROC. In S. apetala sediments, the ROC content was positively correlated with amino sugars, resulting from the more r-strategist microbes that can rapidly convert plant-derived carbon into microbial biomass, which is subsequently transformed into microbial necromass. In contrast, in K. obovata sediments, ROC content showed a stronger positive correlation with the concentrations of lignin phenols and lipids. More K-strategist fungi in the topsoil of K. obovata increased enzyme activities, while more K-strategist bacteria in the subsoil enhanced carbon utilization capacity, thereby increasing lignin phenols and lipids from plant residues in both soil layers. Meanwhile, higher Ca 2þ concentrations in K. obovata sediments protected three residual carbons from further microbe decomposition. This study provides valuable insights into the molecular mechanisms of SOC sequestration mediated by microbial life strategies in mangrove ecosystems.

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.

Complete removal of carbonates from calcareous soil samples is critical for accurate measurement of the quantity and isotopic signature (d 13 C) of soil organic carbon (SOC). Carbonates confound SOC and d 13 C measurements because they have d 13 C values ranging from (10 to '2, whereas those of soil organic carbon range from (27 to (13, depending on the source of plant residues. Commonly used methods for removing carbonates involve treatment with acid followed by repeated water washings; however, these methods are time consuming, labour-intensive and lead to losses of acid-and water-soluble organic carbon. Fumigation of soil samples with HCl was evaluated as an alternative method, and the time required for complete carbonate removal was determined in this study. Moistened soil samples, taken from 0-to 10-cm and 30-to 50-cm depths, were exposed to HCl vapours for periods of 0, 6, 12, 24, 48, 72, and 96 h, followed by measurements of total C and d 13 C using coupled elemental analyzer-isotope ratio mass spectrometry. The minimum time required to remove all carbonates was ca. 30 h and 56 h for surface and subsurface soils containing 0.80 and 1.94% inorganic C, respectively. Therefore, the fumigation period required is dependent on the total carbonate content of the sample and the nature of the carbonate (pedogenic vs lithogenic). In our study, the rate of removal of inorganic carbon was 0.08Á0.10 mg h (1 for soil samples sizes with 2.4 to 5.8 mg of carbonate-C, a rate similar to previous studies on acid fumigation. A ''correction factor'' was used to account for a change in sample mass due to fumigation and is necessary for accurate determination of SOC concentration using our proposed methodology.

Farmers heavily rely on inorganic sources of fertilizers to replenish their farmlands, which in turn increase production and management cost further with subsidies removal. The cost and environmental implications of these inorganic fertilizers on farmlands calls for innovative technologies for alternate options to sustain soil fertility. The goal for this study therefore was to ascertain the best alternative means of sustaining yields of three improved CSIR-Crops Research Institute of Ghana maize varieties if not increase it and the economic implications using effluents from an aquaponics-based food production system. To achieve this, an on-station study was conducted using effluents from aquaponics-based food production system. The treatments were laid in a 3×3 factorial experiment in a randomized complete block design of maize varieties (Obatanpa, Omankwa and Aburohemaa) and effluents (absolute control, 2L/hill pond water and a combination of half rates of pond water and composted poultry manure recommended). Overall grain yield, cob number, plant height, chlorophyll content varied significantly (P≤ 0.05) due to the application of the treatments. Grain yield of 4 t/ha, 3 t/ha and 2 t/ha was realized for Obantanpa maize variety under pond water and composted poultry manure combination, pond water only and control respectively as compared to the potential yield of 4.6t/ha for the Obatanpa variety. Economic analysis proved that application of freely available effluents in an aquaponics-based food production system did not only increase maize yields to about 50% over the control but also reduced total production costs; thereby leading to improved farmer income and food security.

Use of animal manure-based soil amendments may offset the detrimental effects of slash-and-burn practice by smallholder farmers. Cattle dung is relatively more abundant but mineralizes slower and hence less effective than poultry droppings which can be made even more effective by co-application with the more readily mineralized compost. This study evaluated the potential of a 50% substitution of the slow-release cattle dung with a mix of equal volumes of poultry droppings and fruit-waste compost (CD:PD&FWC) for restoring the fertility of slash-and-burnt tropical soils on the growth of mung bean as a test crop. Screenhouse soil fertility trials were carried out utilising slash-and-burn managed sandy-loam Ultisols from a Nigerian rainforest, with soil properties showing slight improvement over the unburnt soil. Treatments were CD:PD&FWC (10 t ha -1 ), cattle dung (10 t ha -1 ), NPK-15:15:15 (125 kg ha -1 ), and unamended control. At the termination of crop growth after 10 weeks, CD:PD&FWC showed the highest soil pH (5.86), soil organic matter (33.70 g kg -1 ), total nitrogen (2.00 g kg -1 ), available phosphorus (25.15 mg kg -1 ), and cation exchange indices. Soil content of exchangeable acidity showed a reverse trend with lowest values from CD:PD&FWC (0.36 cmol kg -1 ) and highest from NPK-15:15:15/control (1.10 cmol kg -1 ). Cattle dung gave longer plant roots than CD:PD&FWC, but the two produced higher root dry matter (2.74-3.27 g pot -1 ) than NPK-15:15:15/control (0.70 g pot -1 ). The CD:PD&FWC gave taller 10-week-old plants (30.69 cm), more root nodules (415) and higher shoot dry matter (37.80 g pot -1 ) than cattle dung; NPK-15:15:15/control gave the lowest (14.77 cm, 26-37 and 5.95 g pot -1 , respectively). The CD:PD&FWC and, to lesser extents, cattle dung improved soil fertility and mung bean growth. Organic amendment CD:PD&FWC is, therefore, preferred to sole cattle-dung manure for improving the productivity of slash-and-burnt acid coarse-textured soils of the humid tropics.

Ramnarine, R., Wagner-Riddle, C., Dunfield, K. E. and Voroney, R. P. 2012. Contributions of carbonates to soil CO2 emissions. Can. J. Soil Sci. 92: 599–607. Carbon dioxide (CO2) is released in soil as a by-product of microbial and root respiration, but soil carbonates may also be a source of CO2emissions in calcareous soils. Global estimates of inorganic carbon range from 700 to 900 Pg as carbonates stored in soils, representing a significant potential source of CO2to the atmosphere. While previous studies have focused on the total CO2efflux from the soil, our goal was to identify the various sources and their contribution to total CO2emissions, by measuring the isotopic signature of the CO2emitted from the soil. Calcareous Luvisolic silt loam soil samples were obtained from conventional tillage (CT) and no-tillage (NT) plots in southern Ontario, Canada. Soil samples (root- and residue-free) were laboratory-incubated for 14 d and the isotopic signature of the CO2(δ13CCO2) released wa...

The application of rice huskbiochar enriched with farm yard manure (cattle dung) as ameliorant to soils have shown benefits for production such as maize (Zea mays), shallot (Allium cepa), and peanut (Arachis hypogea), particularly through improving soil properties and crop productivity. However, studies examining the effects of enriched rice husk biochar on farms in upper land area of Karawang District not yet reported. This paper presents the results of research focused on the use of enriched rice husk biochar (enriched cattle dung manure) and rice husk only at the rate of 5ton.ha -1 and 10ton.ha -

Decomposing vertebrates, including humans, result in pronounced changes in surrounding soil biogeochemistry, particularly nitrogen (N) and carbon (C) availability, and alter soil micro-and macrofauna. However, the impacts of subsurface human decomposition, where oxygen becomes limited and microbial biomass is generally lower, are far less understood. The goals of this study were to evaluate the impact of human decomposition in a multi-individual, shallow (~70 cm depth) grave on soil biogeochemistry and soil microbial and nematode communities. Three individuals were interred and allowed to decay for four years. Soils were collected from two depths (0-5 and 30-35 cm) along linear transects radiating from the grave as well as from within and below (85-90 cm depth) the grave during excavation to assess how decomposition affects soil properties. Along radiating surface transects, several extracellular enzymes rates and nematode richness increased with increasing distance from the grave, and likely reflect physical site disruption due to grave excavation and infill. There was no evidence of carcass-sourced C and N lateral migration from the grave, at least at 30-35 cm depth. Within the grave, soils exhibited significant N-enrichment (e.g., ammonium, dissolved organic N), elevated electrical conductivity, and elevated respiration rates with depth. Soil biogeochemistry within the grave, particularly in the middle (30-35 cm) and base (70-75 cm depth), was significantly altered by human decomposition. Mean microbial gene abundances changed with depth in the grave, demonstrating increased microbial presence in response to ongoing decomposition. Human-associated Bacteroides were only detected at the base of the grave where anoxic conditions prevailed. Nematode community abundance and richness were reduced at 70-75 cm and not detectable below 85-90 cm. Further, we identified certain Plectus spp. as potential indicators of enrichment due to decomposition. Here we demonstrate that human decomposition influences soil biogeochemistry, microbes, and microfauna up to four years after burial.

Nitrogen is cycled throughout ecosystems by a suite of biogeochemical processes. The high complexity of the nitrogen cycle resides in an intricate interplay between reversible biochemical pathways alternatively and specifically activated in response to diverse environmental cues. Despite aggressive research, how the fundamental nitrogen biochemical processes are assembled and maintained in fluctuating soil redox conditions remains elusive. Here, we address this question using a kinetic modelling approach coupled with dynamical systems theory and microbial genomics. We show that alternative biochemical pathways play a key role in keeping nitrogen conversion and conservation properties invariant in fluctuating environments. Our results indicate that the biochemical network holds inherent adaptive capacity to stabilize ammonium and nitrate availability, and that the bistability in the formation of ammonium is linked to the transient upregulation of the amo-hao mediated nitrification pa...

The effects of calcium hydrogen phosphate on lead (Pb) uptake by cowpea (Vigna unguiculata) were investigated in a growth chamber experiment coupled with atomic absorption spectrophotometry (AAS) and colorimetry analyses. Cowpea seeds were planted and harvested in soil samples treated with Pb+2 added as lead nitrate at the rates of 0, 1000 and 3000 mg/kg followed by calcium hydrogen phosphate (CaHPO4) at 0, 10, 50 and 250 mg/kg. Increases in shoot yield brought about by phosphate fertilization were observed to oppress the shoot lead concentration as a result of growth dilution, where the actual amount of lead in shoots was unaffected by phosphate treatment. This work revealed that there is no substantial effect on lead uptake by cowpea, as a result of phosphate fertilization. Therefore, phosphate fertilization is a good means of cowpea production with minimal lead uptake and hence safe for human consumption

Mangrove plays a pivotal role in the nutrient biogeochemical processes by behaving as both source and sink for nutrients and other materials. Litter from mangroves added major part ofthe carbon and fresh water sources from estuary enrich them with nutrients. Microbial processes playa vital role in the dynamics of nutrients and its cycling. In the anoxic condition microbes convert organic carbon into methane and other gases. Spatial and temporal variation of methane emission is dependent on complex biogeochemical processes as well as the climatic conditions existing in the mangrove ecosystem. Methane emission from mangrove ecosystems is perceived to be the major source of green house gases in the environment.

Purpose Biochar and inorganic fertilizer when co-applied have been reported to increase crop yield and enhance soil fertility. However, studies on this complementary effect on soil properties and rain-fed upland rice performance in Sub-Saharan Africa are still scanty. Methods Field factorial studies conducted over 2 years was set up to investigate the interactions between rice husk biochar and inorganic nitrogen (N) fertilizer on a sandy clay loam Alfisol. A two-factor (4 × 4) in RCBD where rice husk biochar was incorporated at four doses, 0, 3, 6, and 12 t/ha −1 , inorganic N fertilizer (urea) at four rates, 0, 30, 60 and 90 N kg/ha −1 , and their combinations was adopted. Results Results showed that combination of biochar and N fertilizer exerted significant (P > 0.05) interactive effect on rice harvest index, grain and straw yield and N-use efficiency. Interaction between biochar and N fertilizer increased agronomic efficiency by 140% and grain nutrient recovery by 191% over 2 years. Combination of biochar and N fertilizer reduced soil bulk density, increased water holding capacity and soil chemical status such as pH, N, P, K, Corg, Ca, ECEC and base saturation, all within the top 10 cm depth of the soil. Conclusions Overall, the results established that rice husk biochar can be used as a soil conditioner to enhance upland rice yield on an Alfisol. The combined dose of 3-6 t/ha −1 biochar and 30 kg/ha −1 of N fertilizer is thus recommended for upland rice farmers in the study area.

While there is significant evidence that the addition of organic residues to soils can improve overall soil fertility, it is unclear as to what organic residues will have the most beneficial impact. The use of residue chemistry as an index for assessing organic resource quality is highly reported and has been linked to organic matter decomposition and nutrient release patterns. However, less is reported on the direct linkages between organic residue chemistry and soil biogeochemistry and how the impact varies between sole and mixed organic residues. In this research,

This study was conducted to assess the potentials of Azadirachta indica (L.) in the removal of heavy metal from soil contaminated with lead poisoning in Anka, Zamfara State. Soil and Azadirachta indica samples were collected and analyzed for physico-chemical and heavy metals. Contamination and transfer factors were also calculated. The results of physico-chemical parameters revealed that Anka (control) has highest pH H20 (1:2.50); 7.63, Organic Carbon (OC); 1.54%, Total Nitrogen (TN); 1.91%; Cationic Exchange Capacity (CEC); and 5.52cmol kg −1. Abare has the highest values of Available Phosphorus (AP); 32.55 mg/kg, Electrical Conductivity (CEe); 1.33d/sm. The textural classes were Loamy Sand (LS). The highest concentrations of heavy metals were in Abare; Zn (54.68mg/kg), Mn (51.19mg/kg), Pb (493.85mg/kg) and Cd (3.78mg/kg). The highest CF of all the heavy metals was found in Abare with Zn (0.18), Mn (0.03), Pb (4.94) and Cd (1.26). Bagega has the highest concentrations of transfer factor (TF) of Mn (2.10), Pb (1.48) and Cd (0.75) while Anka town has the highest TF of Zn (2.53). The results obtained showed that soil physico-chemical properties enhance mobility and availability of heavy metals. Azadirachta indica can accumulate heavy metals from contaminated soils as the concentrations of the heavy metals were reduced in the polluted soils. The contamination factors revealed that most values fall within none to medium contamination due to the phytoremediation potential of the plant. Thus Azadirachta indica posses high phytoremediation potentials as it helps in reducing the high amount of heavy metals in the soil.

Snowmelt dynamics are a significant determinant of microbial metabolism in soil and regulate global biogeochemical cycles of carbon and nutrients by creating seasonal variations in soil redox and nutrient pools. With an increasing concern that climate change accelerates both snowmelt timing and rate, obtaining an accurate characterization of microbial response to snowmelt is important for understanding biogeochemical cycles intertwined with soil. However, observing microbial metabolism and its dynamics non-destructively remains a major challenge for systems such as soil. Microbial volatile compounds (mVCs) emitted from soil represent information-dense signatures and when assayed non-destructively using state-of-the-art instrumentation such as Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-TOF-MS) provide time resolved insights into the metabolism of active microbiomes. In this study, we used PTR-TOF-MS to investigate the metabolic trajectory of microbiomes from a subalpine forest soil, and their response to a simulated wet-up event akin to snowmelt. Using an information theory approach based on the partitioning of mutual information, we identified mVC metabolite pairs with robust interactions, including those that were non-linear and with time lags. The biological context for these mVC interactions was evaluated by projecting the connections onto the Kyoto Encyclopedia of Genes and Genomes (KEGG) network of known metabolic pathways. Simulated snowmelt resulted in a rapid increase in the production of trimethylamine (TMA) suggesting that anaerobic degradation of quaternary amine osmo/cryoprotectants, such as glycine betaine, may be important contributors to this resource pulse. Unique and synergistic connections between intermediates of methylotrophic pathways such as dimethylamine, formaldehyde and methanol were observed upon wet-up and indicate that the initial pulse of TMA was likely transformed into these intermediates by methylotrophs. Increases in ammonia oxidation signatures (transformation of hydroxylamine to nitrite) were observed in parallel, and while the relative role of nitrifiers or methylotrophs cannot be confirmed, the inferred connection to TMA oxidation suggests either a direct or indirect coupling between these processes. Overall, it appears that such mVC time-series from PTR-TOF-MS combined with causal inference represents an attractive approach to non-destructively observe soil microbial metabolism and its response to environmental perturbation. .

Snowmelt dynamics are a significant determinant of microbial metabolism in soil and regulate global biogeochemical cycles of carbon and nutrients by creating seasonal variations in soil redox and nutrient pools. With an increasing concern that climate change accelerates both snowmelt timing and rate, obtaining an accurate characterization of microbial response to snowmelt is important for understanding biogeochemical cycles intertwined with soil. However, observing microbial metabolism and its dynamics non-destructively remains a major challenge for systems such as soil. Microbial volatile compounds (mVCs) emitted from soil represent information-dense signatures and when assayed non-destructively using state-of-the-art instrumentation such as Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-TOF-MS) provide time resolved insights into the metabolism of active microbiomes. In this study, we used PTR-TOF-MS to investigate the metabolic trajectory of microbiomes from a sub...

Para analizar la dinámica del carbono orgánico de los suelos (COS) asociada a su cambio de uso, de vegetación y prácticas de manejo, es necesario desarrollar modelos para usarse en forma predictiva. Un enfoque de modelación es la distribución del COS presente en los complejos organominerales primarios (arcillas, limos y arenas) ligado a las fracciones físicas. Para la separación de las fracciones físicas se emplea la dispersión del suelo por ultrasonido, paso que requiere optimizar las energías de sonicación para lograr la completa dispersión del suelo. En este trabajo se discute el modelo COLPOS y su hipótesis, así como sus posibles extensiones que consideran las masas y los enriquecimientos de las fracciones físicas del suelo, adicionalmente al análisis de las relaciones entre esas fracciones. Para analizar los patrones asociados al modelo COLPOS y sus extensiones, se analizan resultados disponibles de fraccionamientos de suelos mexicanos realizados con ultrasonido, además de tres...

This study attempted to examine the effects of biochar amendment together with bio-fertilizer on soybean yield and its qualitative properties, as well as a few chemical properties of soil through a factorial randomized complete block design at three replications in east of Golestan Province (Iran) during 2014. The two factors under study included the following: (1) biochar amendment (in four levels of 0, 2.5, 8, and 16 tons per hectare), (2) bio-fertilizer containing phosphorus and sulfur growth-promoting rhizobacteria (in two levels of inoculation and non-inoculation) applied through foliar feeding. The results of analysis of variance indicated that interactions of biochar amendment and bio-fertilizer on harvest index and grain yield were significant (p ≤ 0.01). According to the results of this study, the highest harvest index and oil content were 56.9, and 17.7%, respectively, in the treatment of 8 tons per hectare biochar and inoculation with biofertilizer. The lowest harvest index and the lowest oil content were in the control treatment. The interaction of biochar and bio-fertilizer on bulk density and cation exchange capacity was significant (p ≤ 0.01). The results of this study demonstrated that biochar affected the amount of residual nitrogen in the soil after harvest, cation exchange capacity (CEC), acidity (pH), and electrical conductivity (EC). The highest grain yield (3440 kg/ha) was in the 8-ton biochar treatment with inoculated bio-fertilizer. Our study concludes that the biochar and bio-fertilizers can improve grain yield of soybean till 51% relative to the control.

The need to maintain the rising numbers of both serviceable and degenerating automobiles in Nigeria has led to the springing up of vehicle workshops in approved and unapproved locations, where mechanics discharge spent engine oil indiscriminately into the soil and water environments. It is therefore desirable to explore potentially affordable and sustainable remediation methods. This study examined the efficacy of vermicast tea for the remediation of spent engine oil contaminated soil. Spent engine oil contaminated soil was collected from an automobile workshop, and mixed with different concentrations (20%, 50%, and 100%) of vermicast tea. The total petroleum hydrocarbon (TPH), moisture content, organic matter content, pH, and cation exchange capacity (CEC) in the contaminated soils were determined on day one, day 21, and day 42, using standard procedures. It was found that the TPH concentrations reduced in both vermicast tea treated and untreated soils, but percentage reductions we...

Background and Objectives: Nitrogen (N) fertilizer management with other soil amendments is crucial for optimal growth and productivity of grain crops. There has been increasing interest on converting rice straw to biochar and examining its use as a soil amendment. This study was conducted to evaluate the effects of different nitrogen fertilizer managements combined with rice straw derived biochar on rice growth and yield attributes. Materials and Methods: This greenhouse pot study was performed in a randomized complete block design with 4 replications. Treatments comprised of 150 kg ha-1 N fertilizer as a control (T1), 9 t ha-1 rice straw biochar added to 30, 60, 90, 120 and 150 kg N ha-1 (T2, T3,T4, T5 and T6, respectively). Growth measurement was carried out at week 2, 6 and 10 after transplanting, while yield attributes were obtained upon harvesting at 110 days. The effects of N and biochar treatments data were analysed using two-way analysis of variance (ANOVA) in PROC ANOVA in SAS Ver. 9.4 while treatments means differences were compared using least significant difference (LSD), both at p<0.05. Results: Treatment 5 (120 kg N ha-1 with biochar) was able to promote more plant growth and yield attributes than the other treatments, especially in plant height, leaf area, relative chlorophyll content and tiller number. Increased yield over the control treatment was found similar to 90 and 120 kg N ha-1 with biochar, reducing fertilization up to 40% and resulted in 20% grain yield improvement compared to the control. Therefore, rice straw biochar addition at 9 t ha-1 with 90-120 kg N ha-1 can be recommended for sustainable rice productivity and improvement of rice yield and farmers' profits. Conclusion: The use of biochar in addition to the chemical fertilizers in rice production systems is an economically feasible and practical nutrient management practice.

It is well known that the hydrolysable tannin (tannin acid) and condensed tannins in a plant can influence the availability of soil nitrogen (N) through the formation of tannin-organic N complexes. However, the lack of research on the effect of tannin acid-organic N complexes on soil N hinders our understanding of the subsequent role of these complexes. In this line, an incubation experiment was carried out with the addition of tannin acid-arginine and tannin-bovine serum albumin (BSA) complexes, where tannin acid was represented as the hydrolysable tannin. For the necessary comparisons, tannin acid, arginine, or BSA was added to the soil samples. The results showed that tannic acid addition quickly decreased protein contents at the beginning of incubation and decreased soluble organic N (SON) after 3 days to produce the inorganic N in the soil as compared to control. Tannin-arginine complexes increased NH 4 +-N compared with control and this increased degree was found lower than arginine treatment. Moreover, the addition of tannin-BSA complexes did not significantly increase soil NH 4 +-N as BSA alone treatment did. NO 3 −-N and N 2 O emission increased in each treatment compared with control indicating nitrification was not limited. The increase of NH 4 +-N was mainly attributed to the decrease of SON after 3 days of incubation. These results suggested that tannin acid quickly formed the complexes with protein to impact soil N. While, the effects of tannin-arginine and tannin-BSA complexes on soil N transformation were quite dissimilar. Thus, this study highlighted the subsequent role of tannin-organic N complexes under the influence of tannin. Tannin and tannin-organic N complexes naturally coexist in the ecosystem to impact soil N dynamics and may interact with each other as well.

Several studies in the temperate region have indicated that biofertilizer have the potential to improve soil properties but may also cause serious reduction in soil productivity. We studied the effects of biofertilizer and nutrient solution application on soil properties and yield of spinach (Spinacea oleracea L.) on four soil types of Chengdu, Hunan, Shannxi and Xiaotangshan, Beijing, China. Two profile pits were sited on each of the location of the soil unit and were described before soil samples collection from the genetic horizons of each pit for analysis of soil properties. Soil total nitrogen, available phosphorus, calcium, magnesium, potassium and CEC were significantly (p<0.05) enhanced with biofertilizer treated soils of Chengdu and Hunan and spinach performance was significant compared to nutrient solution treated soils. The growth of salt-sensitive spinach was very poor on Shannxi and Xiaotangshan soils with biofertilizer. Spinach height and dry matter yield after six weeks were significantly improved (p<0.05) on the biofertilizer treated soils of Chengdu and Hunan compared to Shannxi and Xiaotangshan soils and soil with nutrient solution. These results indicated that the application of biofertilizer and nutrient solution application should done with better understanding of soil properties because of its negative effects on soils and crops.

A field experiment was conducted for 2 years (2019 and 2020) to determine the response to the application of Biochar (BC) obtained from the coffee pulp in combination with chemical fertilization (CF) in coffee trees. The established treatments were the edaphic application of different doses of BC (0, 4, 8, and 16 t ha−1) and levels of CF (0, 33, 66, and 100% of the nutritional requirements) on the physical (bulk density (ρa), stable aggregates), chemical (nutrient availability), and biological (respiration) properties of soil from a coffee crop. Regarding the physical properties, it was mainly observed that BC doses of 8 or 16 t ha−1 reduced ρa (0.82 and 0.83 g cm−3, respectively) and increased the aggregation status (96.5% and 96.84%, respectively) in comparison to 0 t ha−1 in 2020. The chemical properties showed that the application of 16 t ha−1 BC decreased about 60% of the exchangeable acidity (EA) compared to the control (0 t ha−1) whereas the pH (4.96 and 4.92) and organic car...

A field experiment was conducted during kharif 2017-18 to investigate the impacts of azolla (Azolla pinnata) biofertilizer and urea on rice (Oryza sativa L.) yield, temporal soil P availability and improvement in soil acidity indices under low land acidic soil of Meghalaya. Six treatments viz., control (T1), fresh azolla incorporation @ 16000 kg ha-1 (T2), 30 kg N ha-1 through urea (T3), 60 kg N ha-1 through urea (T4), 30 kg N ha-1 through urea + azolla incorporation @ 16000 kg ha-1 (T5) and 60 kg N ha-1 through urea with azolla incorporation @ 16000 kg ha-1 (T6) were tested in Randomized Block Design with four replications. Application of 60 kg N ha-1 through urea along with azolla incorporation @ 16000 kg ha-1 (T6) produced highest grain yield (4.2 t ha-1) followed by T5 and T4. It had significantly greater available phosphorus at 30 DAT (24.13 P2O5 kg ha-1) and at maturity (20.63 P2O5 kg ha-1) followed by 30 kg N ha-1 through urea + azolla incorporation @ 16000 kg ha-1 (T5), compared to control and other treatment plots. Available phosphorus in T6 was statistically significant over T4 (60 kg N ha-1 through urea) whereas T5 was significant over T3 (30 kg N ha-1 through urea) with respect to advancement in crop age. The soil acidity indices reflected highest improvement with azolla bio-fertilizer incorporation @ 16000 kg ha-1 (T2) over all other treatments indicating that azolla bio-fertilizer can be an alternative option for acid soil management.

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Soybean is grown in many parts of Northern Nigeria, with little climatic challenges and soil organic matter. There is need to investigate possible influence of planting date of the crop in Southeastern Nigeria, an environment that is rather foreign to the crop. A study was carried out in 2018 and 2019 cropping seasons at Federal College of Agriculture, Ishiagu, Ebonyi State, to evaluate the influence of different planting dates and fertilizer types on selected soil physical and chemical properties, growth and yield of soybean. A split plot in a randomized complete block design was used with planting date (May and June) as the main plots, while six fertilizer types (poultry-droppings manure 5 t ha–1, swine-droppings manure 5 t ha–1, rice-husk dust 5 t ha–1, NPK 15:15:15 at 150 kg ha–1, urea at 100 kg ha–1 and the control) constituted the sub-plots. At crop maturity, some soil quality indices and pod and grain yields (t ha–1) of soybean were assessed. Soil organic carbon (SOC) and tot...

Lead (Pb) accumulation in parts of maize plant as a possible route for Pb poisoning was investigated. Experimental design adopted was a 3 factorial combination (4 x 1 x 1). Prior to planting of seeds, soil sample was analyzed for its physicochemical properties. At maturity, maize crop and parts of the plants were harvested and analyzed for their Pb contents. TF, BCF and BAF were as well determined. Physicochemical properties’ results revealed that pH was 6.75, Ec = 1.62 dSm-, K = 1.66 %, Mg =12.87 cmol/kg, Ca =1.9 cmol/kg, N = 0.6%, P = 0.98%, BD = 1.25 g/cm3 and MC = 40.84%. TF, BCF and BAF value obtained were &lt; 1. Similarly, Pb found in the grains, leaves, shots, roots and soil were within 0.3133 - 1.0533 ppm; 4.7133 - 7.100 ppm; 8.070 - 14.09 ppm; 14.02 - 26.00 ppm and 172 - 551.34 ppm for grains, leaves, shoots, roots and soil Pb concentration respectively. However, consumption of vegetables and crops cultivated in Pb contaminated soil will pose serious health risk to the con...

Purpose Rice is a staple food in Nigeria, but its cultivation faces constraints of soil acidity, low soil fertility and rainfall variability. Research has shown that biochar has the potential to alleviate the effects of these conditions, but responses vary depending on soil and climate factors. Therefore, this study was conducted to evaluate the effects of different application rates of rice husk biochar on upland rice growth and yield. Method Two field experiments were conducted within two years in Kwara State located in the southern Guinea savanna agroecological zone of Nigeria. Four biochar rates (0, 5, 15 and 25 t/ha) were used and replicated thrice in a randomised complete block design set up on three soils in three locations. Agronomic data were subjected to analysis of variance (ANOVA) to quantify variations in treatment responses, followed by a separation of significantly different means using the least significant difference (LSD) at p≤ 0.05. Results Better growth was recorded in the first year compared to the second year. Percentage decreases of 9.4 and 11.4% were recorded in plant height (12 weeks after planting), and tiller productivity from the first to the second year, respectively. Biochar amendment significantly (p≤0.01) improved rice seedling emergence (34.6%) and seed weight (5.8%) relative to control. The highest grain yield of 5.24 t/ha was recorded under 15 t/ha biochar application rate compared to 2.37 t/ha under control. Conclusion The application rate of 15 t/ha increased rice yield by 55.0% relative to the control, whereas at 25 t/ha the rice growth and yield were reduced.

The impact of plastic enriched composting on soil structure, fertility and growth of maize (Zea mays L.) was examined in this study. A completely randomized blocked design (RCBD) consisting of five treatments viz., A (Control, untreated soil), B (0.83% treatment level), C (1.67% treatment level), D (2.50% treatment level) and E (3.33% treatment level) with three replicates each was used. The result of the physico-chemical parameters of the soil revealed that the addition of plastic granules to the soil resulted to increase in the total organic carbon content and bulk density of the soil. However, other nutrient elements of the soil were not affected. Among the treatments, there was no significant difference (P<0.05) on the germination of Zea mays seedlings. The result of impact of plastic on the growth showed that the higher the plastic granules the more its negative impact on Zea mays growth. A (36.51 ± 1.30 cm) had the highest growth while the least growth was observed in D (28.50 ± 0.74 cm) and E (28. 78 ± 1.64 cm) treatments after eight weeks of planting.

A field experiment was conducted to evaluate effect of biochar amended urea on nitrogen economy of soil for improving growth and yield of wheat under field condition. Experiment plan was comprised of twelve treatments with four replications including treatments without application of urea and biochar (control) and urea only. Biochar was applied @1 to 10% of the weight of urea fertilizer applied each treatment. Results showed that application of biochar @10% with recommended dose of urea significantly improved plant height, spike length, number of tillers, number of spikelet per spike, 1000 grain weight, grain yields, biomass yield, harvesting index, nitrogen (N) concentration and uptake in grain and straw and agronomic efficiency of nitrogen (AEN) by 6.0

This study was conducted to monitor some area carbon in Adekunle Ajasin University Akungba (AAUA) Campus to encourage tree planting alongside her edifice and discourage high rate of deforestation. This study relies solely on the use of remote sensing data to estimate carbon sequestration between year 2014 and 2020. The objective of this study is to estimate the carbon sequestration capacity in the study area using remote sensing (RS) and geographical information system (GIS) with a view to enkindling the importance of trees or forest within the University campus. Consequently, Landsat 8 TM Satellite images of year 2014 and 2020 of the study area were obtained from United States Geological Survey (USGS). The spectral vegetation index (normalised difference vegetation index) was estimate using spectral bands 4 and 5. Ten areas were chosen for this study and their coordinates obtained using GPS receiver when visited. These areas were not developed in 2014 and not fully developed as at ...

A field experiment was conducted during kharif 2017-18 to investigate the impacts of azolla (Azolla pinnata) biofertilizer and urea on rice (Oryza sativa L.) yield, temporal soil P availability and improvement in soil acidity indices under low land acidic soil of Meghalaya. Six treatments viz., control (T1), fresh azolla incorporation @ 16000 kg ha-1 (T2), 30 kg N ha-1 through urea (T3), 60 kg N ha-1 through urea (T4), 30 kg N ha-1 through urea + azolla incorporation @ 16000 kg ha-1 (T5) and 60 kg N ha-1 through urea with azolla incorporation @ 16000 kg ha-1 (T6) were tested in Randomized Block Design with four replications. Application of 60 kg N ha-1 through urea along with azolla incorporation @ 16000 kg ha-1 (T6) produced highest grain yield (4.2 t ha-1) followed by T5 and T4. It had significantly greater available phosphorus at 30 DAT (24.13 P2O5 kg ha-1) and at maturity (20.63 P2O5 kg ha-1) followed by 30 kg N ha-1 through urea + azolla incorporation @ 16000 kg ha-1 (T5), compared to control and other treatment plots. Available phosphorus in T6 was statistically significant over T4 (60 kg N ha-1 through urea) whereas T5 was significant over T3 (30 kg N ha-1 through urea) with respect to advancement in crop age. The soil acidity indices reflected highest improvement with azolla bio-fertilizer incorporation @ 16000 kg ha-1 (T2) over all other treatments indicating that azolla bio-fertilizer can be an alternative option for acid soil management.

Nitrogen is cycled throughout ecosystems by a suite of biogeochemical processes. The high complexity of the nitrogen cycle resides in an intricate interplay between reversible biochemical pathways alternatively and specifically activated in response to diverse environmental cues. Despite aggressive research, how the fundamental nitrogen biochemical processes are assembled and maintained in fluctuating soil redox conditions remains elusive. Here, we address this question using a kinetic modelling approach coupled with dynamical systems theory and microbial genomics. We show that alternative biochemical pathways play a key role in keeping nitrogen conversion and conservation properties invariant in fluctuating environments. Our results indicate that the biochemical network holds inherent adaptive capacity to stabilize ammonium and nitrate availability, and that the bistability in the formation of ammonium is linked to the transient upregulation of the amo-hao mediated nitrification pa...

Two coryneform bacteria Arthrobacter sp. PI/1-95 (Arth1) and Arthrobacter sp. PI/3-95 (Arth3) were isolated from forest soil characterized and investigated with respect to their reaction towards aluminium (Al). Sigmoid functions were used to describe dose-response relationships between Al concentration and microbial growth and to calculate EC-values. EC 100-indicating a complete inhibition of microbial growth-varied between 185 µM Al for Arth1 and 11 mM Al for Arth3. A pure pH effect seems probable in connection with the sensitive Arth1 but not with the tolerant species Arth3. Temperature was shown to distinctly increase the toxic effects of Al towards Arth3 whereas only a moderate modification in Al-toxicity was observed with Arth1.

Purpose Soil acidity and nutrients deficiency are the major constraints causing low crop yield and food insecurity in the highlands of Ethiopia. A field experiment was conducted in northwestern Ethiopia during 2018 and 2019 cropping seasons to study effects of compost and lime application on soil properties and wheat yield. Method The treatments consisted of three compost levels (0, 3 and 6 t ha-1) and three lime rates (0, 1 and 2 t ha-1) arranged in a randomized complete block design with three replications. Before planting and after harvest, soil samples were collected from each experimental plot to analyze soil properties. Results Combination of lime and compost significantly (p<0.05) increased soil pH, soil organic carbon, total nitrogen, available phosphorus and exchangeable base cations. In contrast, exchangeable acidity and aluminum levels decreased substantially compared to individual application of amendments. Compared to the control, application of 2 t ha-1 lime, 6 t ha-1 compost alone and their combination increased wheat grain yield by 24.6%, 42% and 97.5%, respectively. Besides, the combined application of compost and lime provided the highest net benefit (1915.90 US$ ha-1), which was noticeably greater than the control (1034.44 US$ ha-1). Conclusion The application of lime and compost in combination is an effective option to curb soil acidity while enhancing soil nutrients availability and crop yields at lower input costs. However, to determine the application frequency, long-term effects of compost and lime in combination on acidic soil properties and crop yield need to be investigated through further research.

Purpose Scarcity of effective manures frustrates the adoption of organic-based soil fertility management in tropical agriculture. Cattle dung (CD) is hugely generated but underutilised due to its high carbon-nitrogen ratio and low mineralisation rate compared with poultry droppings (PD), hence the need to enhance CD's efficacy. Method Effects of CD utilisation options on fertility of sandy-loam Ultisols and maize growth were assessed under glasshouse conditions. Four options, CD in its cured form (CD), CD-derived biochar (BC), CD water-soaked CD fermentate (FM) and CD+urea (CDU), were assessed against cured PD and NPK-15:15:15 as reference manure and fertilizer, respectively, using 5-kg potted soils watered to and maintained at field capacity. Organic amendments were added at 10-t-ha-1 equivalents before sowing except FM added alongside CDU's urea at 250 kg ha-1 equivalent after sowing. Also, NPK-15:15:15 was added at 400 kg ha-1 equivalent after sowing. Results After 9 weeks, BC, CDU and PD had similar effects on soil pH, organic matter, total N and available P which increased by 49-51%, 30-34%, 200-333% and 164-176%, respectively relative to the control. The BC always showed maize plants similar to the tallest ones in PD. Maize dry matter was the highest in CDU/PD (35.06-35.56 g pot-1) and the lowest in control (9.56 g pot-1). Residual effects showed that BC and PD maintained the increases in soil pH, while CDU/PD always showed tallest plants and enhanced dry matter over the rest except BC. Soil pH, Mg 2+ and base saturation together caused 93% of treatments' effects on dry matter. Conclusion Converting CD to BC or supplementing it with urea (CDU) in coarse-textured tropical soils could have prolonged liming and/or biomass productivity-enhancing effects as PD.

This study aims to evaluate the impact of palm oil mill effluent treated with sodium carbonate on the growth of maize. The experiment consisted of eight treatments of concentrations of palm oil mill effluent viz 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0% and 8.0%. The treatment was carried out on potted maize plants with six replications. Four kilograms of soil was weighed into each pot. Six pots were labelled as control with untreated palm oil mill effluent added to them. Eight other groups consisting of six pots each were treated with 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0% and 8.0% concentrations of the effluent. The maize seeds were planted one in each pot to avoid overcrowding. The pots were transferred to greenhouse and moistened daily with the effluent. The growth rate, plant height and leaf length of the maize plants were thereafter determined. The 8.0% concentration of sodium carbonate in the effluent had the highest expected effect on the parameters whereas the control gave...

Human activities have degenerated nearly 40% of the universe soil through excessive chemical inputs, tilling and industrial activities. Biochar can increase soil fecundity, agricultural productivity and protects soil-borne diseases. This study aimed to assess the efficacy of rice husk biochar on the growth and yield of tomato plants. Biochar was produced through feedstock (rice-husk) pyrolysis and used as soil amendments at different concentrations (20 t/ha and 40 t/ha) and an unamend soil served as control. Physicochemical properties of the soil, rice husk, biochar and biochar soil before and after planting were determined using standard methods. Rhizospheric microflora of the plants were isolated and identified based on morphological and biochemical characterizations. Agronomic parameters such as plant height, stem girth, leaf area, number of leaves, flowers, fruits and weight of fruits were determined. Results revealed that rice husk biochar (40 t/ha) had the highest physical and...

The hydrogen isotope composition (δ&lt;sup&gt;2&lt;/sup&gt;H) of biomarkers produced by algae is strongly influenced by the δ&lt;sup&gt;2&lt;/sup&gt;H values of the water in which they grew. δ&lt;sup&gt;2&lt;/sup&gt;H values of algal biomarkers preserved in lake sediments are thus a useful tool for reconstructing past changes in lake water δ2H values, which can be used to infer hydroclimate variability. However, studies from laboratory cultures of marine algae have shown that a number of factors can influence the magnitude of hydrogen isotope fractionation between algal lipids and their source water, including temperature and growth rates. Quantifying the natural extent of these changes in freshwater lacustrine settings and identifying their causes is essential for robust application of δ&lt;sup&gt;2&lt;/sup&gt;H values of algal lipids as paleohydroclimate proxies, yet the influence of these factors remains poorly constrained.&lt;br&gt;&lt;br&gt; This work targets the effect of temp...

The effect of Bioremediation on Early Seedling growth of Amaranthus hybridus L. on oil palm effluent polluted soil was carried out in the field using perforated polythene bags. The soil samples were polluted with 0, 80, 120 and 240ml of oil palm effluent and amended with compost manure supplement (fermented oil palm spikelet) at 0, 40, 60 and 80 g respectively). The 0ml and 0g served as controls. The mean result obtained after 12 weeks showed that the addition of compost manure supplement (fermented oil palm spikelet) to the contaminated soil promotes growth of plant as there was increase in the growth parameters such as shoot height, petiole length, leaf area, number of nodes, number of branches, internode length, root length, and moisture content. This study recommends that contaminated soils should be amended with manure to improve the growth performance of plants.