Nutrient Production Research Articles

94 The Present and Future of Nasem Beef Nutrient Requirement Modeling

Abstract The precise and accurate prediction of animal nutrient requirements, feed intake, water intake, environmental impacts, and production efficiency is an essential function of nutrient requirement models when leveraged as tools to enhance the sustainability of livestock production systems. Historically, the legal standard for determining nutrient requirements of livestock within the United States has leveraged the National Academies of Sciences, Engineering, and Medicine (NASEM) nutrient requirement series (formerly referred to as the National Research Council (NRC) models). The objective of this work is to review the present advantages and future needs for the NASEM Beef Nutrient Requirement Models. Due to current production conditions prevalent within the United States beef industry, the adequate prediction of performance outcomes in commercial cattle in group feeding situations is arguably of the greatest importance. However, as the climate changes and interest in new genetics, production strategies, and feeding approaches expand, there will be an increasing need to additionally provide precise and accurate predictions of individual animals based on genetic potential, production system, and climate conditions. The NASEM 2016 Nutrient Requirements of Beef Cattle presented a stepwise improvement in model sophistication and customizability though the inclusion of a number of individually adjustable constants to adapt model predictions to animal performance in production settings, and through the expanded use of mechanistic solutions in estimating nutrient requirements. Another major advancement of this model release was the opportunity to push model updates and fixes as users identify challenges or issues with the model. The capacity to update nutrient requirement models in a more agile manner greatly contributes to the long-term need for more adaptable and flexible ration formulation tools. Although these improvements may enhance usability of the NASEM models, there are some additional opportunities for future iterations, including better capacity to explore individual animal requirements, leverage precision livestock farming technologies, and design rations to adapt animals to climate change.

Ayurvedic Management of Emesis Gravidarum - A Case Report

Emesis is a common experience in first trimester of pregnancy affecting 70 to 80% of all pregnant women. Altered immunological endocrinological and psychological states are responsible for initiation of symptoms. Mild to moderate emesis gravidarum have a significant adverse effect on quality of women's life. Even though onset is physiological its morbidity has to be reduced to minimize disease burden, enhance maternal health and to prevent hyper emesis gravidarum. Anti-emetic and anti-histamines are used in conventional Allopathic practice. Ayurvedic principle is early intervention and prevention of hyperemesis gravidarum with lifestyle modifications and adopting Pathya ahara. This is a case report of emesis gravidarum managed with pharmaco nutrient product –Malarinji modaka

Nutrient and Maillard reaction product concentrations of commercially available pet foods and treats.

Thermal processing is used to produce most commercial pet foods and treats to improve safety, shelf life, nutritional characteristics, texture, and nutrient digestibility. However, heat treatments can degrade protein quality by damaging essential amino acids, as well as contribute to the Maillard reaction. The Maillard reaction forms melanoidins that favorably improve food qualities (e.g., color, flavor, aroma), but also form Maillard reaction products (MRP) and advanced glycation end-products that may negatively affect health. Because commercial pet diets are frequently fed to domestic cats and dogs throughout their lifetimes, it is critical to quantify MRP concentrations and understand the variables that influence their formation so future diets may be formulated with that in mind. Because few research studies on MRP in pet diets have been conducted, the goals of this study were to measure the MRP in commercial pet foods and treats, estimate pet MRP intake, and correlate MRP with dietary macronutrient concentrations. Fifty-three dry and wet dog foods, dog treats, and cat foods were analyzed for dry matter, organic matter, crude protein, acid-hydrolyzed fat, total dietary fiber, and gross energy using standard techniques. MRP were analyzed using high-performance liquid chromatography and gas chromatography-mass spectrometry. Data were analyzed using the Mixed Models procedure of SAS 9.4. Dry foods had lower reactive lysine concentrations and reactive lysine: total lysine ratios (indicator of damage) than wet foods. Wet foods had more fructoselysine (FRUC) than dry foods; however, dry dog treats contained more FRUC than wet dog treats. The greatest 5-hydroxymethyl-2-furfural (HMF) concentrations were measured in dry and wet dog foods, whereas the lowest HMF concentrations were measured in dry and wet cat foods. Based on dietary concentrations and estimated food intakes, dogs and cats fed wet foods are more likely to consume higher carboxymethyllysine and FRUC concentrations than those fed dry foods. However, dogs fed wet foods are more likely to consume higher HMF concentrations than those fed dry foods. In cats, those fed dry foods would consume higher HMF concentrations than those fed wet foods. We demonstrated that pet foods and treats contain highly variable MRP concentrations and depend on diet/treat type. In general, higher MRP concentrations were measured in wet pet foods and dry treats. While these findings are valuable, in vivo testing is needed to determine if and how MRP consumption affect pet health.

Riboflavin synthesis from gaseous nitrogen and carbon dioxide by a hybrid inorganic-biological system

Microbes can provide a more sustainable and energy-efficient method of food and nutrient production compared to plant and animal sources, but energy-intensive carbon (e.g., sugars) and nitrogen (e.g., ammonia) inputs are required. Gas-fixing microorganisms that can grow on H2 from renewable water splitting and gaseous CO2 and N2 offer a renewable path to overcoming these limitations but confront challenges owing to the scarcity of genetic engineering in such organisms. Here, we demonstrate that the hydrogen-oxidizing carbon- and nitrogen-fixing microorganism Xanthobacter autotrophicus grown on a CO2/N2/H2 gas mixture can overproduce the vitamin riboflavin (vitamin B2). We identify plasmids and promoters for use in this bacterium and employ a constitutive promoter to overexpress riboflavin pathway enzymes. Riboflavin production is quantified at 15 times that of the wild-type organism. We demonstrate that riboflavin overproduction is maintained when the bacterium is grown under hybrid inorganic-biological conditions, in which H2 from water splitting, along with CO2 and N2, is fed to the bacterium, establishing the viability of the approach to sustainably produce food and nutrients.

A comprehensive review on enhancing nutrient use efficiency and productivity of broadacre (arable) crops with the combined utilization of compost and fertilizers.

Broadacre (arable) crops generally require a relatively higher nutrient input toward yield targets. The efficient use of nutrients in arable farmlands is very vital to this endeavor. It minimizes fertilizer input and adverse soil and environmental implications that may arise from the incremental use of fertilizers. It is understood that enhancing the natural capacity of the soil (i.e., the soil's physical, chemical, and biological quality), may effectively improve soil nutrient dynamics, availability, and efficient use by crops. The adoption of integrated nutrient management (INM) approaches such as the organic amendment of the soil in addition to fertilizer use has shown positive impacts on maintaining and recovering soil quality, hence lowering excessive fertilizer use in farmlands. Therefore, this review contextualized the effect of compost and fertilizer on nutrient use efficiency (NUE) and productivity of broadacre crops. The use of compost as an organic soil amendment material has shown some inherently unique advantages and beneficial impacts on soil health and fertility such as improved soil structure, nutrient retention, mobilization, and bioavailability. Several studies have explored these comparative advantages by either blending compost with chemical fertilizer before soil application or a co-application and have noted the observed amelioration of unfavorable soil conditions such as low porosity, high bulk density, low organic matter (OM), unfavorable pH, and cation exchange capacity (CEC), low biological activities with different doses of compost. Consequently, the co-utilization of composts and chemical fertilizers may become viable substitutes for chemical fertilizers in maintaining soil fertility, improving NUE, and crop yield in farmlands. The review further described the comparative environmental and economic implications of adopting the combined utilization of compost and fertilizers in farmlands.

Developing the nitrogen handprint approach to quantify the positive impacts of industrial symbiosis on nitrogen cycles

Excessive nitrogen (N) uptake for nutrient use in food production and industry and increased N losses to the environment severely interfere with nutrient cycles and harm the environment and thus, closing N cycles through N recovery and recycling is required to improve N use efficiency. To quantify positive impacts enhancing N cycles, this study suggests a novel N handprint approach, which combines life cycle assessment based nutrient footprint and carbon handprint approaches. The N handprint comprises of a set of indicators providing a wide systemic view on changes in N cycles. The case study demonstrates that the N handprint is created when a recycled N nutrient product is used instead of a virgin N nutrient for the needs of a pulp and paper mill wastewater treatment. According to our results, the handprint equals a reduction of 454 kg of virgin N inputs, and 5.6 kg of total N inputs for daily treated wastewater. Additionally, global warming potential is 91%, and the eutrophication potential 48% lower for the recycled N nutrient than for the virgin N nutrient. These results can be used to promote the use of recycled N on similar occasions in order to improve nutrient use efficiency. • The nitrogen (N) handprint approach aims to highlight efficient nutrient use. • The approach is combining carbon handprint and nutrient footprint. • The approach is applied to N recycling in an industrial symbiosis. • N handprint enables to show positive environmental impacts of circular N solutions.

Deciphering the environmental drivers throughout the 20th and 21st centuries in the paleolimnological record of Laguna del Plata, Laguna Mar Chiquita system, Northern Pampean plain, Argentina

Laguna del Plata (LP) is a small, shallow hypereutrophic saline lake which is part of the hydrological system of Laguna Mar Chiquita (LMC) (Córdoba, Argentina). Environmental variability of LP occurred in the last ca. 80 years, was reconstructed through a multi-proxy approach in LP-17-I sedimentary core.The synchronic correspondence of lithological units and physicochemical proxies throughout the paleolimnological record made it possible to identify two main environmental stages. Stage I (1934–1977 CE) records a long drought resulting in low water levels and high-water salinities, while stage II (1977–2017 CE) records a humid phase, high water levels and low water salinity. In stage II we distinguish three sub-stages related to changes in the nutrient load: sub-stage II A (1977–1983 CE), sub-stage II B (1983–2010 CE) and sub-stage II C (2010–2017 CE). Sub-stage II A is characterized by an increase in TN, carbonates, TOC, CD and TC, related to humid context and reduced water salinities rather than anthropic influence. During sub-stage II B, there is a synchronous increase of nutrients and primary production proxies which matches the urban population growth of Córdoba city and the expansion of the agricultural activity after the 1980s, during a favorable hydroclimatic context. During sub-stage II C, the increase of nutrient and primary production proxies was maintained, despite water lake level variability, as a consequence of anthropic influence. Results show that regional hydroclimatic variability can act synergistically with anthropic influence ruling the nutrient fluxes to LP and therefore influencing the eutrophication and primary productivity of the lake. However, our results allowed us to distinguish that stage I and sub-stage II A were mainly dominated by hydroclimatic variability while sub-stage II B and sub-stage II C were mostly governed by anthropic influence.This study contributes to the understanding of the role of natural and anthropic drivers on the environmental dynamics of the LMC hydrological system during the 20th and 21st centuries. These results provide tools for planning activities and improving watershed management policies in the Pampean plain region of Argentina.

Field test of water-net based wastewater treatment for nutrient removal and bioethanol production.

In this study, an open pond constructed in Myanmar, a region with tropical climate and favorable environmental conditions for algae growth, was considered to conduct field experiments on sewage inflow river water. The nutrient removal efficiency and productivity of Hydrodictyon reticulatum (H. reticulatum) were analyzed, and the maximum fermentation limit concentration for bioethanol production was determined. Three ponds were operated in batch mode to investigate the effect of light intensity. Photoinhibition was caused due to excessive light intensity in summer season in the region with tropical climate resulting in reduced facility efficiency in the absence of shade. For light blocking, a transparent film was found to be more effective than a translucent film. In the transparent film shading facility, the nitrogen and phosphorus removal efficiencies were maintained above 76% and 81%, respectively, and the productivity of H. reticulatum was 2.27gm-2 d-1. For a raceway open pond facility shaded with transparent film, the performance was evaluated based on hydraulic retention time (HRT), and the productivity of algae was found to increase with increasing supply of nitrogen and phosphorous. Maximum biomass production of 3.21gm-2 d-1 was observed with an HRT of 3d, suggesting the possibility of long-term operation. As a result of evaluating the ethanol production based on the initial concentration of H. reticulatum, the yield of bioethanol at the initial reducing sugar content of 120gL-1 was 89.4%, but bioethanol production was only 8.9gL-1.

Effect of Integrated Use of Rapeseed Cake, Biochar and Chemical Fertilizers on Root Growth, Nutrients Use Efficiency and Productivity of Tea

The tea root system plays a key role in the uptake of nutrients and water from the soil. The effect of integrated fertilizers (Control (CK) (no fertilizers), 100% NPK, 100% NPK withbiochar (NPK + B), 50% NPK with 50% rapeseed cake (NPK + RC), and 100% rapeseed cake (RC))on alterations in root growth characteristics and soil physical properties, nutrient uptake, NUE, and biomass production of tea (Longjing 43) was studied in an Alfisol at the greenhouse of the China Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, during 2020–2021. The results showed that the conjunctive application of mineral fertilizers with rapeseed cake (NPK + RC) resulted in significant (p < 0.05) reductions in soil penetration resistance (14.8%) and bulk density (8.7%) and improvement in porosity (9.9%) compared to the control. NPK + RC recorded significantly higher (p < 0.05) root surface area, root volume, root tips, root length, and root CEC of tea than NPK (15%, 20%, 27%, 6%, and 11%) and control (40%, 165%, 49%, 68%, and 12%). The combinedapplication of RC and NPK fertilizer significantly decreased the specific root surface area (137%) and specific root length (66.8%) compared to the control. Root, stem, leaves, and total biomass were improved by integrated fertilization compared to the control and mineral fertilization. The nutrient content (N,P,K), nutrient uptake, NUE, nutrient uptake per root length, volume, and surface area of tea plants under NPK + RC and NPK + B were significantly (p < 0.05) higher than RC and CK. Therefore, the integrated use of rapeseed cake with mineral fertilization in Alfisol should be practiced in tea plantations to improve soil physical environment, root proliferation and root CEC, nutrient uptake, and NUE and achieve higher tea biomass production through the efficient exploitation of nutrients.

Alleviation of salt stress in rapeseed (Brassica napus L.) plants by biochar-based rhizobacteria: new insights into the mechanisms regulating nutrient uptake, antioxidant activity, root growth and productivity

ABSTRACT Amendment of saline soils with biochar and rhizobacteria is a new technique to diminish the negative impacts of salt stress on plants. Hence, an original pot experiment was conducted in a glass greenhouse at the University of Tabriz to investigate the performance of salt-stressed (0, 6 and 12 dS m−1 NaCl) rapeseed (Brassica napus L.) plants in response to different biochar-related treatments (non-biochar, biochar, biochar-based Pseudomonas putida RS-198, biochar-based Azotobacter chroococcum RS-106 and both bacteria). The biochar-related treatments reduced sodium content, generation of reactive oxygen species, lipid peroxidation and enzymatic antioxidants in plant tissues while enhanced nutrient content, non-enzymatic antioxidants, main and lateral roots lengths and weights, main/lateral root length ratio, specific root length, root diameter, shoot length and weight, leaf area, chlorophyll content and seed and oil yields under saline conditions. The biochar-based Pseudomonas + Azotobacter was the superior treatment for reducing the harmful impacts of salt stress on rapeseed plants, which resulted in 83–109% and 69–115% improvements in seed and oil yields of this crop under moderate and high salinities, respectively. Therefore, inoculation of biochar with both rhizobacteria might be a novel approach for improving salt tolerance and productivity of rapeseed plants.

Bluefin Larvae in Oligotrophic Ocean Foodwebs, investigations of nutrients to zooplankton: overview of the BLOOFINZ-Gulf of Mexico program

Abstract Western Atlantic bluefin tuna (ABT) undertake long-distance migrations from rich feeding grounds in the North Atlantic to spawn in oligotrophic waters of the Gulf of Mexico (GoM). Stock recruitment is strongly affected by interannual variability in the physical features associated with ABT larvae, but the nutrient sources and food-web structure of preferred habitat, the edges of anticyclonic loop eddies, are unknown. Here, we describe the goals, physical context, design and major findings of an end-to-end process study conducted during peak ABT spawning in May 2017 and 2018. Mesoscale features in the oceanic GoM were surveyed for larvae, and five multi-day Lagrangian experiments measured hydrography and nutrients; plankton biomass and composition from bacteria to zooplankton and fish larvae; phytoplankton nutrient uptake, productivity and taxon-specific growth rates; micro- and mesozooplankton grazing; particle export; and ABT larval feeding and growth rates. We provide a general introduction to the BLOOFINZ-GoM project (Bluefin tuna Larvae in Oligotrophic Ocean Foodwebs, Investigation of Nitrogen to Zooplankton) and highlight the finding, based on backtracking of experimental waters to their positions weeks earlier, that lateral transport from the continental slope region may be more of a key determinant of available habitat utilized by larvae than eddy edges per se.

Modelling and techno-economic assessment of (bio)electrochemical nitrogen removal and recovery from reject water at full WWTP scale

At conventional wastewater treatment plants (WWTPs), reject waters originating from the dewatering of anaerobically digested sludge contain the highest nitrogen concentrations within the plant and thereby have potential for realising nitrogen recovery in a reusable form. At the same time, nitrogen removal from reject waters has potential to reduce the energetic and chemical demands of the WWTP due to a reduced nutrient load to the activated sludge process. In recent years, (bio)electrochemical methods have been extensively studied for nitrogen recovery from reject waters in laboratory-scale but not yet implemented in real WWTP environments, particularly due to concerns about the need for large capital investments. This study assessed the techno-economic feasibility of retrofitting a (bio)electrochemical nitrogen removal and recovery (NRR) unit into the reject water circulation line of a full-scale WWTP through modelling. Data from laboratory-scale (bio)electroconcentration ((B)EC) experiments was used to construct a simple, semi-empirical model block integrated into the Benchmark Simulation Model No. 2 (BSM2) simulating a generalised WWTP. The effects of nitrogen removal from the reject water on both the effluent quality and operational costs of the WWTP were assessed and compared to the BSM2 performance without an NRR unit. In all studied scenarios, the effluent quality index was improved by 4–11%, while both the aeration (7–19% decrease) and carbon (24–71%) requirements were reduced. The additional energy consumed by the NRR unit increased the total operational cost index by >18%, but the revenue assumed for the generated nutrient product (20 EUR kgN−1) was enough to make the BEC-NRR scenarios at realistically low current densities (1 and 5 A m−2) economically attractive compared to the control. A sensitivity analysis revealed that electricity price and nutrient product value had the most notable effects on the feasibility of the NRR unit. The results suggest a key factor in making (bio)electrochemical NRR economically viable is to reduce its electricity consumption further, while the anticipated increases in nitrogen fertiliser prices can help accelerate the adoption of these methods in larger scale.

Comparative Genomics and In Silico Evaluation of Genes Related to the Probiotic Potential of Bifidobacterium breve 1101A

Bifidobacterium breve is among the first microorganisms colonizing the intestinal tract in humans and is a predominant species in the gut microbiota of newborns and children. This bacterium is widely used in the probiotic industry due to its capacity to improve host health. The search for new targets with probiotic properties is an increasing trend with the help of next-generation sequencing as they facilitate the characterization of the bacterial features. B. breve 1101A was isolated from the faeces of healthy children in Brazil and therefore could play a protective role in the gut. To investigate the beneficial properties of this strain, the present study performed a comprehensive characterization of the genetic features involved in the bacterium resistance and adaptation to gastrointestinal conditions, production of nutrients, and immunomodulatory compounds. Furthermore, this study carried out the prediction of genomic elements (plasmids, prophages, CRISPR-Cas systems, insertion sequences, genomic islands, antibiotic resistance genes) to evaluate the safety of B. breve 1101A. A comparative genomics approach using 45 B. breve complete genomes based on pangenome and phylogenomic analysis was also performed to identify specific genes in B. breve 1101A. The prediction of genetic elements, possibly safety-related, did not detect plasmids, but only one incomplete prophage, two non-functional CRISPR systems, and seven genomic islands. Additionally, three antibiotic resistance genes were identified: ileS (resistance to mupirocin), rpoB, and erm(X). In the comparative genomic analysis, the pangenome was revealed to be open, and B. breve 1101A presented 63 unique genes associated with several processes, such as transmembrane transport, membrane components, DNA processes, and carbohydrate metabolism. In conclusion, B. breve 1101A is potentially safe and well-adapted for intestinal disorder therapeutics, although the role of its unique genetic repertoire needs further investigation.

Sensing Host Health: Insights from Sensory Protein Signature of the Metagenome.

The human microbiota, which comprises an ensemble of taxonomically and functionally diverse but often mutually cooperating microorganisms, benefits its host by shaping the host immunity, energy harvesting, and digestion of complex carbohydrates as well as production of essential nutrients. Dysbiosis in the human microbiota, especially the gut microbiota, has been reported to be linked to several diseases and metabolic disorders. Recent studies have further indicated that tracking these dysbiotic variations could potentially be exploited as biomarkers of disease states. However, the human microbiota is not geography agnostic, and hence a taxonomy-based (microbiome) biomarker for disease diagnostics has certain limitations. In comparison, (microbiome) function-based biomarkers are expected to have a wider applicability. Given that (i) the host physiology undergoes certain changes in the course of a disease and (ii) host-associated microbial communities need to adapt to this changing microenvironment of their host, we hypothesized that signatures emanating from the abundance of bacterial proteins associated with the signal transduction system (herein referred to as sensory proteins [SPs]) might be able to distinguish between healthy and diseased states. To test this hypothesis, publicly available metagenomic data sets corresponding to three diverse health conditions, namely, colorectal cancer, type 2 diabetes mellitus, and schizophrenia, were analyzed. Results demonstrated that SP signatures (derived from host-associated metagenomic samples) indeed differentiated among healthy individual and patients suffering from diseases of various severities. Our finding was suggestive of the prospect of using SP signatures as early biomarkers for diagnosing the onset and progression of multiple diseases and metabolic disorders. IMPORTANCE The composition of the human microbiota, a collection of host-associated microbes, has been shown to differ among healthy and diseased individuals. Recent studies have investigated whether tracking these variations could be exploited for disease diagnostics. It has been noted that compared to microbial taxonomies, the ensemble of functional proteins encoded by microbial genes are less likely to be affected by changes in ethnicity and dietary preferences. These functions are expected to help the microbe adapt to changing environmental conditions. Thus, healthy individuals might harbor a different set of genes than diseased individuals. To test this hypothesis, we analyzed metagenomes from healthy and diseased individuals for signatures of a particular group of proteins called sensory proteins (SP), which enable the bacteria to sense and react to changes in their microenvironment. Results demonstrated that SP signatures indeed differentiate among healthy individuals and those suffering from diseases of various severities.

Production of high nutrients and antioxidans gluten and lactose- free cupcake using beetroot powder and coconut milk.

Production of high nutrients and antioxidans gluten and lactose- free cupcake using beetroot powder and coconut milk.

The efficiency of microalgae-based remediation as a green process for industrial wastewater treatment

Wastewater treatment including microalgae is an economically promising and environmentally friendly alternative to conventional wastewater treatment due to the concurrent nutrient removal and production of high-value biomass. This work aimed to choose the most suitable type of wastewater and its appropriate dilution for sustaining microalgal growth by testing unialgal versus mixed microalgae cultures and raw versus autoclaved wastewater. Based on pilot experiments including microplate screening, unialgal cultures of Chlorella emersonii grown in 1:5 diluted, non-autoclaved wastewater were selected as the optimum scenario for further testing. In the main experiments, Chlorella emersonii was cultivated in Erlenmeyer flasks and bubble column reactors. Additionally, a photoautotrophic biofilm was grown in flumes. We studied three types of wastewater originating from a large municipal wastewater treatment plant, a brewery, and a dairy. Dairy wastewater performed best in all cultivation systems and resulted in a maximum biomass per irradiated area of around 145 μg cm−2 chlorophyll-a of Chlorella cultures in bubble columns, followed by 105 μg cm−2 in flumes run by a photoautotrophic biofilm. Furthermore, phosphorus reduction of 96 % for dairy, 40 % for the brewery, and 43 % for municipal wastewater were achieved in the flumes. Due to the easy harvest of algae biomass, low construction and operation costs, flumes represent a recommendable cultivation system for dairy wastewater treatment on a larger scale.

Effectiveness of Dyella japonica and Enterobacter cloacae as biofertilizers to increase maize (Zea mays) production on andisol soil

Abstract. Sembiring M, Sabrina T. 2022. Effectiveness of Dyella japonica and Enterobacter cloacae as biofertilizers to increase maize (Zea mays) production on andisol soil. Biodiversitas 23: 3338-3343. Nitrogen is a very important nutrient in plant growth because it is one of the constituents of plant cells. The availability of nitrogen nutrients in the soil is very low, and this is because nitrogen is easily leached and easy to evaporate. Application of N-fixing microbes is one way to increase the availability of nitrogen in the soil. This study aims to utilize nitrogen-fixing microbes to increase nutrient uptake, production, and efficiency of urea fertilization. The study used a factorial randomized block design (RBD) consisting of Factor I, namely biofertilizer consisting of 4 treatments, namely without the application of bacteria (N0), Dyella japonica 5g (N1), Enterobacter cloacae 5g (N2) and D. japonica 2.5g + E. cloacae 2.5g (N3). Factor II is urea fertilizer with 5 levels U0 = No urea fertilizer, U1 = 1.25 g, U2 = 2.50 g, U3 = 3.75g and U4 = 5g. Parameters observed were plant height observed in weeks I-VIII, plant nitrogen (N) uptake (mg/plant), phosphorus (P) uptake (mg/plant), potassium (K) uptake (mg/plant), and plant production (g). Sampling of plants for analysis of nutrient uptake was carried out at the end of the vegetative period, namely the 8th week, while for plant production parameters, plant samples were taken at the 12th week. The results showed that the applications of nitrogen-fixing bacteria could increase N uptake up to 89.35%, P uptake up to 79.57%, K uptake up to 48.81%, and crop production increase up to 49.76%. The applications of nitrogen-fixing microbes can streamline the use of urea fertilizer by up to 50%. In general, the best treatment is the applications of D. japonica and E. cloacae plus 2.5g urea (N3U2).

Application of mathematical optimization to exploit regional nutrient recycling potential of biogas plant digestate

Nutrients can be circulated back to agriculture from waste streams through anaerobic digestion and digestate processing. Digestate processing, however, is making slow progress as circulated nutrient products have not been cost competitive compared to fossil fertilizers and not designed from the farmer’s perspective to truly match with the regional nutrient need. In this study, the aim is to assess apply mathematical optimization to the design of a cost-optimal processing route for a biogas plant’s digestate to produce fertilizer products based on specified regional needs. Another aim is to analyze whether such a cost-optimal solution can fully exploit the nutrient recycling potential, that is, the efficiency of such a solution in returning nutrients to agriculture. The results indicate that mathematical optimization allows the design of a cost-optimal digestate production routes based on the region’s nutrient need and characteristics. The true cost optimum was found for a design combining three processing technologies and producing four nutrient products, which when mixed, would fulfil farmer’s fertilization needs. However, there seems to be a conflict between an optimal economic design and a full exploitation of recycling potential as only 25% of the digestate’s phosphorus was utilized within the case region. This is because only 29% of the digestate mass was used and processed as fertilizer, as the concentration of required nutrients was deemed too low for economic use. The proposed mathematical model could be implemented as tool to assist in biogas plant investment decisions.

Compost Based Bio-pesticide to Control the White Root Disease caused by Rigidoporus microporus of Rubber Growing Lands in Sri Lanka

White root disease caused by Rigidoporus microporus is the most destructive root disease in rubber plantations of Sri Lanka. Trichoderma is a useful, filamentous fungus, widely used as bio-control agents for controlling soil borne diseases of plants and as growth promoters. An attempt was taken to use a compost based bio-pesticide as environmental friendly and low cost substitution against R. microporus. Soil samples were collected from different rubber growing districts and antagonistic fungi were selected using dual plate culture test. Among the antagonistic fungi, the best performing two isolates, which showed more than 80% inhibition against R. microporus were identified. The two fungi were used for the production of the bio-pesticide. Fungi were inoculated in to compost media (7.5-7.8 log10CFUg-1 ) and shelf life time was monitored. The effectiveness of the media under field conditions was evaluated using a pot trial. The results of the study revealed that in compost based media, the most effective fungus was proven to be T. harzianum. Compost based formulations of Trichoderma have shelf life of 8 months. As the nutrient content of the compost medium is high, an increment of the CFUg-1 was observed within the first six weeks. The reduction of the nutrient content and production of toxic metabolites due to the high population could be the reason for the gradual decrease of CFUg-1 after ten weeks. The pot trial carried out using the compost based biopesticide gave promising results. Based on the results, handling convenience, additional nutrition of medium etc., compost based bio-pesticide has been identified as successful in the prevention of white root disease in rubber plants.

Drought changes litter quantity and quality, and soil microbial activities to affect soil nutrients in moso bamboo forest

Drought would significantly influence the forest soils through changing the litterfall production and decomposition process. However, comprehensive in situ studies on drought effects in subtropical forests, especially in bamboo forests, have rarely been conducted. Here, we conducted a throughfall exclusion experiment with a rainfall reduction of ~80% in moso bamboo (Phyllostachys edulis) forests to investigate effects of drought on litter quantity, quality, soil microbial and enzyme activities, and soil nutrients across two years in subtropical China. We observed that throughfall exclusion (TE) treatment significantly decreased soil moisture by 63% compared to ambient control treatment (CK). Drought significantly decreased the annual litterfall in the second treatment year, and the leaf litter decomposition rate (−30% relative to CK) over 2 years of decomposition. TE treatment significantly decreased net release rate of litter carbon (C) and the amount of litter nitrogen (N) immobilization during a 360-day decomposition period, leading an increased litter C: N ratio in TE compared to CK. There was a distinct difference in soil microbial community composition between TE and CK treatments, showing higher bacteria biomass in TE but no difference in fungal biomass between TE and CK. Structural equation modelling revealed that drought decreased the contribution of litter quantity to soil nutrients but increased that of litter quality and soil microbial community to soil nutrients. Our results suggest that increasing drought events in subtropical China will directly reduce litterfall quantity and quality on the one hand, and alter the soil enzyme activities and microbial composition on the other hand, all of which will consequently decrease litter decomposition rate, soil nutrient availability, growth rate and productivity, leading to changes in the functioning and services of subtropical bamboo forests.