Improved Nutrient Retention Research Articles

346 Nutritional Strategies to Enhance Nutrient Retention in Cattle, Fields, and Farms

Abstract Nutrient retention within livestock systems is a critical goal for enhancing efficiency of food production and promoting sustainable livestock farming. We define nutrient retention as the sequestering of C, N, and P within biotic elements of farming systems in sinks which have minimal loss to environmentally detrimental ends. Our objective is to summarize strategies to improve nutrient retention from ruminant animal production systems using nutritional management. Nutritional strategies for nutrient retention within animals and downstream food products include dilution of maintenance; precision feeding; and nutrient synchrony. Dilution of maintenance is a phenomenon where more efficient animals partition proportionally less of their consumed nutrients to maintenance processes, allowing proportionally greater quantities to be used for productive processes. Precision feeding encompasses numerous strategies, including amino acid feeding; precision carbohydrate feeding; individualized ration formulation; and precise feed delivery; among others. These strategies all precisely match nutrients supplied within a diet to nutrients required by an animal, thereby reducing nutrient overfeeding and waste. Nutrient synchrony is a feeding strategy promoting theoretically optimal microbial growth by ensuring appropriately matched supplies of carbohydrate and N substrates to facilitate fermentation. Improved microbial fermentation also serves to reduce nutrient loss to the environment through enhanced feed digestion efficiency. Evaluating animal feeding strategies and nutrient retention requires considering nutrient sinks beyond the animal and its productive outputs. Such sinks include soil and plant nutrient stores within the ecosystem. For pastured animals in particular, grazing strategies for enhanced forage production and soil C sequestration have been broadly reviewed. Sequestration of N and P within soils and plants have been less broadly reviewed but merit further discussion in the context of attempting to design management to create non-volatile sinks for multiple nutrients simultaneously. Whole-farm strategies for enhanced nutrient sequestration should be evaluated in a multi-nutrient environment to evaluate sustainability outcomes.

IFST vision for a UK‐wide national food strategy

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Electrohydrodynamic drying: Can we scale-up the technology to make dried fruits and vegetables more nutritious and appealing?

Electrohydrodynamic (EHD) drying is a promising technology to better preserve the nutritional content and sensory appeal of dried fruits and vegetables. To successfully scale up this technology, we need to rethink the current EHD dryer designs. There is also a significant potential to further enhance the nutritional content and sensory quality of the dried products by optimizing EHD process parameters. This study particularly highlights the current bottlenecks in scaling up the technology and improving nutrient retention and sensory appeal of the dried products. We discuss plausible future pathways to further develop the technology to produce highly nutritious dried products. Particular emphasis has been given to quantifying the residual nutritional and sensory properties of EHD dried products, and possible EHD dryer configurations for farmers and the industry. Concerning the nutritional content, EHD drying preserves vitamins, carotenes, and antioxidants significantly better than convective air drying. From the sensory perspective, EHD drying enhances the color of dried products, as well as their general appearance. With respect to scalability, placing the fruit on a grounded mesh electrode dries the fruit much faster and more uniformly than the grounded plate electrode. Future research should be directed toward simultaneous measurements of multiple food nutrients and sensory properties during EHD drying with a grounded mesh collector. Quantifying the impact of the food loading density on drying kinetics and energy consumption of the EHD drying process should also be a future research goal. Research comparing EHD drying with commercially available drying methods such as freeze-drying, microwave-drying, and infrared drying should also be carried out. This study gives promising insight toward developing a scalable novel thermal drying technology tailored to the requirements of the current and future society.

Effects of Loblolly Pine Biochar and Wood Vinegar on Poultry Litter Nutrients and Microbial Abundance.

Simple SummaryDeveloping a sustainable agroforestry system requires the utilization of byproducts. Poultry production and forestry are the two largest agricultural industries in Mississippi (USA) with loblolly pine being one of the most predominant timber species in the southeast. Poultry litter is a high-nutrient waste generated in poultry systems that is used as a fertilizer. However, poultry litter can release pollutants that reduce air and water quality and carries a heavy microbial load. Biochar and wood vinegar effects on nutrient retention and microbial activity vary due to the source material, production conditions, and application rate. This research evaluated how loblolly pine biochar and wood vinegar influence nutrients and microbial activity over time. The study found that wood vinegar reduced microbial growth in poultry litter-biochar blends. Fungi thrived in higher biochar proportions and bacteria preferred less biochar. Nitrogen and phosphorous were retained in 10% and 20% biochar blends. Furthermore, 10% and 20% biochar treatments were observed to be less odorous and compact, and the high pH of the biochar would be an effective conditioner for acidic soils. This study provides valuable information to stakeholders on how to utilize these materials to meet their objectives using regionally generated waste streams in the southeastern USA.Biochar, wood vinegar, and poultry litter are waste streams that can be utilized as soil amendments and fertilizers. However, poultry litter releases several pollutants through nutrient leaching and carries heavy microbial loads, including potential human pathogens. Improving nutrient retention and reducing microbial load in poultry litter may help protect environmental and human health and improve its value as a soil amendment. The objectives of this study were to determine how blending varying proportions of loblolly pine (Pinus taeda L.) biochar, wood vinegar, and poultry litter affected nutrient profiles and microbial abundance over time. Biochar inclusion rates were 0%, 5%, 10%, and 20%, and wood vinegar was applied at 2% w/w. Samples were taken at Day 0, 57, and 112 to measure nitrogen, phosphorus, potassium, pH, total fungi, and total bacteria. Nutrient levels generally decreased with increasing biochar level; however, biochar inclusion rates of 10% and 20% retained nitrogen and phosphorus and exhibited improved physical properties. Overall, adding wood vinegar decreased nutrient concentrations and showed a biocidal effect for bacteria and fungi. Bacteria and fungi showed different relationships with biochar inclusion rates, with fungi preferring higher biochar inclusion rates and bacteria flourishing at lower biochar inclusion rates.

Coconut fiber biochar alters physical and chemical properties in sandy soils

This work aimed to characterize the biochar produced from residues of coconut fruit and to evaluate how it might beneficially alter the retention capacity of water and nutrients in soils with a sandy texture. The biochar was produced in a retort furnace and later analyzed to determine its chemical and physical characteristics. Experiments to analyze the retention potential of the biochar for water and nutrients were performed in PVC columns filled to a 400 mm depth, with the upper 300 mm receiving treatments that consisted of 0, 1, 2, 3, 4, and 5% (p p-1) biochar mixed with soil. For the nutrient retention experiment, in addition to the biochar concentrations, the treatments received the same NPK fertilization. The experiments were performed in a completely randomized design with four replications. The water retention in the upper 300 mm, as well as the pH, effective cation exchange capacity (ECEC) of the substrate, base saturation, and concentrations of P and K, increased with increasing biochar concentration. Coconut biochar demonstrated potential for increasing water retention and improving nutrient retention in sandy soils.

A Review of Potassium-Rich Crop Residues Used as Organic Matter Amendments in Tree Crop Agroecosystems

Ecosystem-based approaches to nutrient management are needed to satisfy crop nutrient requirements while minimizing environmental impacts of fertilizer use. Applying crop residues as soil amendments can provide essential crop nutrient inputs from organic sources while improving nutrient retention, soil health, water conservation, and crop performance. Tree crop hulls, husks, and shells have been found to contain high concentrations of potassium across species including almond, cacao, coffee, pecan, and hazelnut. The objective of this review is to characterize organic sources of potassium focusing on lignocellulosic pericarps and discuss reported effects of surface application on potassium cycling, water dynamics, soil functionality, and crop yield. Research indicates potassium ions solubilize readily from plant material into soil solution due to potassium’s high mobility as a predominately unbound monatomic cation in plant tissues. Studies evaluating tree crop nutshells, field crop residues, and forest ecosystem litter layers indicate this process of potassium release is driven primarily by water and is not strongly limited by decomposition. Research suggests orchard floor management practices can be tailored to maximize the soil and plant benefits provided by this practice. Contextual factors influencing practice adoption and areas for future study are discussed.

The improvement of paddy soil chemical properties following the application of rice husk derived biocharin the Regency of Sijunjung

The district of Dharmasraya, Sijunjung and Pasaman Barat are the three main locations of illegal gold mining in West Sumatra. This kind of activity triggers a lot of land-use changes and the loss of agricultural land within those areas and creates environmental problems as well. Decreasing agricultural land will bring a significant impact on food availability within the region. To protect the scarcity of food, we conducted remediation of ex-gold mining land on those three locations by using biochar made from rice husk. This study was carried on at Batu Manjulur village, Kupitan sub-district in Sijunjung for four months, where soil sample was analyzed at Soil Science Department, Faculty of Agriculture, Andalas University. The experiment use 6 level of biochar application, run from A [without biochar]; B [fulfil of 2% soil organic matter content [SOM]]; C [fulfil 3% SOM]; D [fulfil 4% SOM], E [fulfil 5% SOM] and F [fulfil 6% SOM] with three replication. The result shows the application of rice husk-derived biochar increased soil quality including the chemical properties of the soil and improving nutrient retention and land productivity.

Respuesta productiva y balance de nitrógeno en pollos adicionados con sustancias húmicas en el agua de bebida

Humic substances obtained from vermicompost are an option to improve productivity and reduce ammonia emissions in broiler houses. The objective of the study was to evaluate the addition of 20% raw (RWL) or pasteurized (PWL) vermicompost leachate in the drinking water on production and carcass variables, broiler and litter chemical composition and gain, and nitrogen retention and losses in broilers from 21 to 45 days of age. A conventional diet supplemented with antibiotic growth promoters was offered throughout the experiment. Results indicate that breast performance was improved (P < 0.05) in broilers fed 20 % PWL in the drinking water compared to broilers that drank the RWL or water alone. The addition of 20 % RWL or PWL did not improve nutrient retention in chicks or litter or nitrogen balance or losses in 21- to 45-day-old chicks. PWL can be added to broiler drinking water to improve breast performance.

Nano-based slow releasing fertilizers for enhanced agricultural productivity

Nutrient losses from conventional fertilizers are one of the challenges being faced in the agricultural sector. Nano fertilizers are promising candidates for the fertilizer industry with a huge potential to improve nutrient retention for optimal growth. We report the synthesis and application of a slow releasing nanocomposite fertilizer with a high potential to sustain crop production. Nanotechnology is an emerging technology with a potential to improve agricultural yield by taking advantage of the salient features of nanostructured materials. Nano-encapsulated conventional fertilizers help in slow and sustained release of nutrients over an extended period of time. Comparative studies on the performance of the nanocomposite fertilizer and a conventional Compound D. Nitrogen, Phosphorus and Potassium (NPK) fertilizer were done. The nanocomposite fertilizer was characterized using Field Emission Scanning Electron Microscopy (FESEM) for surface studies and particle size analysis, Fourier Transform Infrared Spectroscopy (FTIR) for chemical composition studies, Powder X-ray Diffraction (P’XRD) for structural analysis and Energy Dispersive Spectroscopy (EDAX/EDS) for elemental composition analysis, Brunauer-Emmett-Teller (BET) for surface analysis. The slow release fertilizer exhibited a superior performance over the bulk or conventional fertilizers for instance, phosphate leaching tests conducted for a period of 50 min showed a leached phosphate concentration of 0.002 mol/dm3 and 0.008 mol/dm3 respectively for the slow release nano fertilizer and conventional NPK fertilizer respectively. The research work has revealed the huge capability of nano-based slow releasing fertilizers in improving plant nutrient availability for enhanced growth. It was realized that nanotechnology can stimulate the generation of much more cost effective and smarter fertilizers for improved crop yield copyright information to be updated in production process.

Stabilization of anaerobic co-digestion of biowaste using activated carbon of coffee ground biomass

Process instability commonly encountered in anaerobic co-digestion (AcoD) of organic fractions of municipal solid wastes (OFMSWs) is addressed by utilizing hydrochar (CB-HTC) and activated hydrochar (ACB-HTC) derived from coffee ground biomass. Addition of CB-HTC or ACB-HTC shortened the lag phase resulting in high biogas yield of 68.57 Nl/kg oTS or 102.86 Nl/kg oTS, respectively within the first week. Improvement in biogas yield (~5% higher than the control) was due to unique properties which prevented washout of consortia of bacteria useful for AcoD and subsequently led to a more stable process. An increase in either OLR [1.0 kg oTS/(m3*d) to 1.5 kg oTS/(m3*d)] or temperature (36.5 °C to 42.5 °C) did not lead to increase in ammonium-nitrogen or TKN in reactors amended with hydrochars. Likewise, ratio of VFA/TA was within 0.2–0.3 after the fourth week in ACB-HTC treated reactor. Addition of ACB-HTC greatly improved nutrient retention in the digestate.

Reduction of Nutrient Leaching Potential in Coarse-Textured Soil by Using Biochar

Background: Loss of nutrients and organic carbon (OC) through leaching or erosion may degrade soil and water quality, which in turn could lead to food insecurity. Adding biochar to soil can effectively improve soil stability, therefore, evaluating the effects of biochar on OC and nutrient retention and leaching is critical. Methods: We conducted a 42-day column leaching experiment by using sandy loam soil samples mixed with 2% of biochar pyrolyzed from Honduran mahogany (Swietenia macrophylla) wood sawdust at 300 °C (WB300) and 600 °C (WB600) and a control sample. Leaching was achieved by flushing the soil column on day 4 and every week during the 42-day experiment and adding a water volume for each flushing equivalent to the field water capacity. Results: Biochar application increased the final soil pH and OC, NH4+-N, NO3−-N, available P concentrations but not exchangeable K concentrations. In particular, WB600 exhibited superior performance in alleviating soil acidification; WB300 engendered high NO3−-N concentrations. Biochar application effectively retained water in soil and inhibited the leaching of the aforementioned nutrients and dissolved OC. WB300 reduced NH4+-N and K leaching by 30%, and WB600 reduced P leaching by 68%. Conclusions: Biochar application can improve nutrient retention and reduce the leaching potential of soils and connected water bodies.

Growth performance and gastrointestinal responses in heavy Tom turkeys fed antibiotic free corn−soybean meal diets supplemented with multiple doses of a single strain Bacillus subtilis probiotic (DSM29784)

Growth performance and gastrointestinal (GIT) responses to a single-strain of Bacillus subtilis (SSB) were investigated using 960 Hybrid Converter Toms. A total of 4 iso-caloric and iso-nitrogenous corn-soybean meal-based diets were allocated to 12 replicate cages/pens and fed (ad libitum) in a four-phase feeding program (starter; days 0 to 28, grower-1; days 29 to 56, grower-2; days 57 to 84, and finisher; days 85 to 126). The diets had either 0 (control), 1E+08 (low), 2E+08 (mid) or 1E+09 (high) cfu B. subtilis/kg. Feed intake (FI) and BW were recorded by phase. Excreta samples were collected towards the end of starter and grower-1 phases for apparent retention (AR) of components by marker method and litter moisture, respectively. Selected birds were necropsied on days 28 and 56 for GIT weight and samples for jejunal histomorphology and ceca digesta short chain fatty acids (SCFA). Supplemental SSB had linear and non-linear (P < 0.05) response on BW gain (BWG). Specifically, relative to the control, birds fed low SSB had higher BWG in starter and grower-1 phases whereas bird fed mid and high SSB had lower BWG in grower-2 and birds fed low and mid SSB had higher BWG in finisher phase. Consequently, birds fed low and mid SSB doses were heavier (P < 0.05) than control fed birds at the end of trial. The FCR response to SSB was linear and non-linear (P < 0.05) with birds fed low SSB showing lower FCR than control fed birds in starter, grower-1 and finisher phases. Supplemental SSB had linear and non-linear (P<0.05) effects on AR of components (DM, ash, crude protein, crude fat, neutral detergent fiber, and gross energy), litter moisture, GIT weight, jejunal histomorphology, and SCFA. Relative to control, birds fed high SSB showed higher AR of components, villi height, day 56 ceca digesta total SCFA concentration, and lower litter moisture. In conclusions, under condition of the current study, growth performance was optimized by low to mid SSB. Improved nutrient retention and indices of gut health suggested higher SSB doses may optimize growth performance under challenging farm conditions.

Phosphorus and Nitrogen Adsorption by Clinoptilolite Zeolite Coated with Iron-Oxide

ABSTRACTClinoptilolite zeolite coated with hydrous ferric oxide (FeZeo) may improve nutrient retention when blended into sand-based root zones. The objective of this study was to evaluate the effects of nutrient-charged FeZeo on nitrogen (N) and phosphorus (P) leaching and on growth of creeping bentgrass (Agrostis palustris Huds.). FeZeo was pre-loaded with 255 mg kg−1 N and 224 mg kg−1 P using a water-soluble fertilizer. Then, root zone mixes (RZM) containing 0, 5, 10, and 20% fertilizer-loaded FeZeo were packed into lysimeters and seeded with creeping bentgrass at a rate of 49 kg ha−1. RZMs with 20% FeZeo received no additional fertilization whereas those containing 0, 5, and 10% FeZeo received four additional fertilizer applications during the next 8 months so that the cumulative N and P rates for every lysimeter were equivalent to 149 kg ha−1 and 131 kg ha−1, respectively. Lysimeters were irrigated every 2 to 3 days and leachate was collected and analyzed. Compared to putting green sand, the 5, 10 and 20% FeZeo treatments reduced the quantity of leached P by 96.2%, 91.3%, and 90.3%, and the quantity of leached N by 88.6%, 82.7% and 76.7%, respectively. Results suggest that pre-fertilized FeZeo applied to sand-based root zone mixes at 5 to 10% can significantly reduce nutrient leaching while maintaining acceptable plant growth, but higher rates of FeZeo can reduce plant growth. An alternative use for higher rates of FeZeo might include a filtering material for agricultural tile drainage.Abbreviations: cation exchange capacity (CEC), electrical conductivity (EC), iron-oxide coated clinoptilolite zeolite FeZeo, nitrogen (N), RZM, root zone mix

Insoluble fiber sources in mash or pellets diets for young broilers. 2. Effects on gastrointestinal tract development and nutrient digestibility

The effects of feed form and dietary fiber on the development of the gastrointestinal tract (GIT) and nutrient digestibility were studied in broilers at 8 and 21 d of age. The experiment included 14 treatments arranged as a 2 × 7 factorial with 2 feed forms (mash vs. pellet) and 7 diets that consisted in a low fiber diet and 6 extra diets resulting from the combination of 3 insoluble fiber sources [oat hulls (OH), rice hulls, and sunflower hulls] and 2 levels of inclusion (2.5 and 5.0%). Pelleting decreased the relative weight (% BW) of the full GIT, and empty gizzard (P < 0.001) and the relative length (cm/kg empty BW) of the small intestine and ceca (P < 0.001) and increased full crop (P < 0.001) and liver (P < 0.05) weights. Fiber inclusion increased the empty weight and the fresh digesta content of the gizzard (P < 0.001) but had limited and inconsistent effects on the weight of the full GIT or the length of the small intestine and ceca. Gizzard pH decreased with mash feeding and fiber inclusion (P < 0.001). Pelleting decreased ether extract retention (P < 0.05) but did not affect N retention or AMEn of the diets. Fiber inclusion improved nutrient retention (P < 0.05 to P < 0.001) with more pronounced effects with OH than with sunflower hulls or rice hulls inclusion. The AMEn of the diets increased (P < 0.05) with 2.5% of fiber inclusion but no extra benefits were obtained with a further increase to 5.0%. Starch ileal digestibility increased with mash feeding (P < 0.001) and fiber supplementation (P < 0.05). In summary, pelleting increases full crop weight and gizzard pH and decreased full gizzard weight and starch ileal digestibility. Moderate amounts of insoluble fiber, especially OH, increases gizzard weight, reduces gizzard pH, and improves nutrient digestibility in young broilers.

Current Insights into the Effectiveness of Riparian Management, Attainment of Multiple Benefits, and Potential Technical Enhancements.

Buffer strips between land and waters are widely applied measures in diffuse pollution management, with desired outcomes across other factors. There remains a need for evidence of pollution mitigation and wider habitat and societal benefits across scales. This paper synthesizes a collection of 16 new primary studies and review papers to provide the latest insights into riparian management. We focus on the following areas: (i) diffuse pollution removal efficiency of conventional and saturated buffer strips, (ii) enhancing biodiversity of buffers, (iii) edge-of-field technologies for improving nutrient retention, and (iv) potential reuse of nutrients and biomass from buffers. Although some topics represent emerging areas, for other well-studied topics (e.g., diffuse pollution), it remains that effectiveness of conventional vegetated buffer strips for water quality improvement varies. The collective findings highlight the merits of targeted, designed buffers that support multiple benefits, more efficiently interrupting surface and subsurface contaminant flows while enhancing diversity in surface topography, soil moisture and C, vegetation, and habitat. This synthesis also highlights that despite the significant number of studies on the functioning of riparian buffers, research gaps remain, particularly in relation to (i) the capture and retention of soluble P and N in subsurface flows through buffers, (ii) the utilization of captured nutrients, (iii) the impact of buffer design and management on terrestrial and aquatic habitats and species, and (iv) the effect of buffers (saturated) on greenhouse gas emissions and the potential for pollution swapping.

Effect of temperature, oxygen and light on the degradation of β-carotene, lutein and α-tocopherol in spray-dried spinach juice powder during storage

The aim of this study was to evaluate the interaction between packaging parameters (transmission of light and oxygen) and storage temperatures (4, 20, 40 °C) on nutrient retention of Spinach (Spinacia oleracea) juice, spray-dried in the absence of an added encapsulant. β-Carotene was more susceptible to degradation compared with lutein and α-tocopherol. Under our experimental conditions, it was observed that excluding low fluorescent light intensity and air by vacuum packaging at 20 °C did not seem to improve nutrient retention loss over time (p > 0.05). The rate of β-carotene, lutein and α-tocopherol loss displayed first order reaction kinetic with low activation energy of 0.665, 2.650 and 13.893 kJ/mol for vacuum, and 1.089, 4.923 and 14.142 kJ/mol for non-vacuum, respectively. The reaction kinetics and half-life for β-carotene, lutein and α-tocopherol at 4 °C and non-vacuumed were 2.2 × 10−2, 1.2 × 10−2, and 0.8 × 10−2 day−1, and 32.08, 58.25 and 85.37 day, respectively.

367 Regulating Livestock Waste in Nebraska – a Brief Overview.

The Department of Environmental Quality (Department) is tasked with regulating livestock waste control facilities in the state of Nebraska. The purpose of the Livestock Waste Management Act, the primary enabling legislation behind Title 130, Livestock Waste Control Regulations, is to protect waters of the state from being negatively impacted by livestock waste. The Department oversees both the state Construction and Operating Permit program and the federal National Pollutant Discharge Elimination System (NPDES) permitting program via delegation by the United States Environmental Protection Agency. The Department seeks voluntary compliance from livestock producers and promotes engagement with the general public through educational outreach and the solicitation of public comments regarding permitting decisions. The Department faces a number of challenges in accomplishing these tasks including: public perceptions and misconceptions of the beneficial use of manure; a lack of understanding of the regulations that are in place and the requirements placed on the livestock industry; changes in production practices that have improved nutrient retention; and emerging practices that have yet to be addressed by current regulations.

Effect of cereal type and Xylanase supplementation on nutrient retention and growth performance of broilers

An experiment was conducted to study the effect of cereal (corn, wheat, barley and sorghum) and supplemental enzyme (a mono-component xylanase) in a 4 × 2 factorial arrangement. A 2-phase feeding program (0 to 21 and 21 to 42 d) was used and 4 iso-caloric, iso-nitrogenous diets were formulated containing corn, wheat, barley, or sorghum as the sole cereal. Diets based on each cereal were fed without or with supplemental xylanase (16,000 BXU/kg) to 8 replicate pens of 10 chicks (5 male : 5 female, Cobb 500) each. Growth performance was recorded at 21 or 42 d posthatch. Excreta was quantitatively collected from 18 to 21 and 38 to 41 d for the measurement of the total tract retention of dry matter (DM), nitrogen (N) and neutral detergent fiber (NDF) and apparent metabolizable energy (AME). Ileal digestible energy (IDE) was measured at the end of the study (42 d posthatch) using titanium dioxide as an indigestible marker. For the overall 42 d period, birds fed barley-based diets had lower feed intake (P < 0.05), lower body weight (P < 0.05) and converted feed into gain less efficiently (P < 0.05) compared with the diets based on corn, wheat or sorghum. Xylanase supplementation improved weight gain in diets based on corn, wheat, and sorghum with the exception of barley-based diets (cereal × xylanase interaction, P < 0.05). Xylanase improved the overall feed conversion ratio (1.885 vs. 1.939; P < 0.05) with the effect being independent of the cereal type. The N retention of barley-based diets was lower (P < 0.05) compared with the other cereals, while xylanase improved N retention (P < 0.05) regardless of the cereal type. NDF digestibility differed (P < 0.05) across cereal (barley > wheat > corn > sorghum) and was improved (P < 0.05) by xylanase supplementation. A significant cereal × xylanase interaction (P < 0.05) was observed for energy measurements, where xylanase improved IDE of the corn-based diet, and AME of corn- and wheat-based diets. Results of the current study demonstrate potential of xylanase in improving nutrient retention and growth performance of broilers fed diets based on variety of cereal grains.

Mitigating Negative Microbial Effects of p-Nitrophenol, Phenol, Copper and Cadmium in a Sandy Loam Soil Using Biochar

Biochars are adsorptive solids potentially of benefit to soil microbes by providing improved nutrient retention, a carbon substrate and contaminant adsorption. A 28-day incubation experiment gauged the interactive effects of biochar application and contaminants on the microbial biomass and respiration of a sandy loam soil. Soil was amended with 250 mg/kg phenol or p-nitrophenol (two toxic but nevertheless biodegradable organic contaminants) or 50 mg/kg cadmium or copper. Biochar application generally caused increased microbial respiration and biomass relative to non-amended controls. Of the heavy metal-amended soils, Cu effected significant reductions in microbial biomass carbon and basal respiration, which were improved with concurrent biochar amendment. The biochar’s functional groups are likely to have mitigated the metals’ negative effects via complexation and sorption, while the soil’s proportion of negative pH-dependent sites was increased by the pH rise induced by biochar application, allowing more cationic retention. Organic contaminant-spiked soils had higher microbial biomass-specific respiration without biochar amendment, indicating that surviving microbes utilised the compounds and necromass as substrates. Paranitrophenol proved to be particularly toxic without biochar application, causing marked reductions in the microbial quotient and biomass carbon. Remarkably, concurrent biochar and pNP application led to hugely increased microbial biomass carbon and nitrogen, significantly higher than those in contaminant-free replicates. It is likely this arose from biochar sorbing the contaminant and allowing its microbial utilisation as a carbon and nitrogen source, stimulating growth. Biochar application is a highly promising strategy for reducing the soil microbial toxicity of heavy metals and aromatic organic contaminants, particularly p-nitrophenol.

Mycorrhizal inoculation increases genes associated with nitrification and improved nutrient retention in soil

The effects of arbuscular mycorrhizal (AM) inoculation on prokaryote abundance within the maize rhizosphere and hyphosphere, and retention of nutrients were investigated. Maize plants were grown in pots with a membrane located at a soil depth of approximately 16 cm that allowed growth of fungal hyphae above and below the membrane, but did not allow growth of roots below the membrane. As expected, mycorrhizal inoculation significantly increased the contents of soil organic matter, Total Kjeldahl Nitrogen (primarily organic N), and Mehlich 1 phosphorus relative to the non-inoculated control. Copy numbers of 16S rRNA genes were significantly higher in the mycorrhizal compartments relative to non-mycorrhizal controls. Bacterial ammonia monooxygenase (AOB) genes, but not archaeal monooxygease genes (AOA), were significantly higher in planted treatments with and without addition of mycorrhizae, indicating that mycorrhizae stimulate prokaryotic growth and bacterial nitrification. The ecological relevance of increased NOx-N resulting from the growth of AOB in inoculated soils is not clear; however, increased mobility of NOx-N over NH4 + could result in a competition between leaching loss and increased uptake by mycorrhizae.