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This article provides information on the effect of exogenous additives on heavy metal passivation and nitrogen retention in pig manure composting. It highlights the potential risks of high levels of heavy metals in pig manure and the importance of composting in reducing heavy metal pollution. The article discusses various additives, including physical, chemical, and microbial, that can contribute to heavy metal passivation and nitrogen retention during composting. It also emphasizes the need for further research to validate the effectiveness of these additives and assess their impact on soil health and microorganisms. Additionally, a list of references is provided for library patrons to explore these topics further. [Extracted from the article]

Introduction: Crude protein is a key element in regulating the diet of ruminants and is considered one of the most expensive nutrients needed by livestock. Feeding management plays an important role in the elimination of nitrogen in the production environment and the emission of greenhouse gases in animal husbandry systems (Avathar et al 2021). When there is excessive discharge of nitrogen in the environment, it causes the ecological balance in surface waters to be disrupted and the groundwater to be polluted (Dijkstra et al 2011). Excretion of these compounds in the environment will increase with fermentation, digestion and inefficient metabolism, and the increase in inefficiency in the rumen is caused by the complex and competitive metabolic pathways in the rumen microbial population. Therefore, increasing efficiency in the use of nutrients, especially nitrogen, to minimize their excretion from the animal's body should be considered. Various methods can be implemented in an animal husbandry unit to improve the use of nitrogen in ruminants. One of these solutions is to reduce the crude protein in the diet, but it has been reported that this method can have a negative effect on animal production (Chibisa and Motswangwa 2013). Another solution is nutrient synchronization or synchronizing the fermentation rate of dietary protein and energy sources, which has led to limited success (Yelchi et al. 2020). Another solution is to create oscillating in the concentration of crude protein in the diet and feed it intermittently at intervals of one to three days, and previous reports show that this method has improved nitrogen retention and its utilization in the body compared to eating constant amounts of crude protein daily in sheep and cattle (Rach et al., 2021). This study was conducted in order to investigate the effect of constant and intermittent feeding of dietary crude protein on ruminal parameters and microbial protein synthesis in sheep. Material and methods: Three diets were adjusted with 12, 14 and 16% crude protein but with the same metabolizable energy and protein. 8 male sheep were used in metabolic cages in a 4x4 Latin square design (four treatments with 2 squares and 8 replications). The first treatment received a diet with a crude protein level of 14% constantly. The second, third and fourth treatments received diets with 12 and 16% crude protein at intervals of 24, 48 and 72 hours, respectively. Nitrogen balance and retention, rumen and blood parameters, volatile fatty acids and microbial protein synthesis were measured. Results and discussion: The lowest total excreted nitrogen (via urine and feces) was observed in the treatment with 48-hour raw protein consumption interval (P<0.05). The retained nitrogen showed a significant increase in this treatment as compared to the constant crude protein feeding treatment (P<0.05). It has been reported that the increase in nitrogen retention in ruminants that received diets with oscillating crude protein levels is due to increased urea recycling in the rumen (Cole 1999). It seems that the transfer of urea from the blood to the rumen during the consumption of diets with low crude protein level (times 24, 48 and 72 hours) in oscillating diets increased and it compensates for the shortage of nitrogen in the rumen. In this condition, nitrogen excretion through urine also decreases and the efficiency of nitrogen use increases. The highest rumen liquid ammonia nitrogen was observed in the treatment with 48-hour crude protein consumption interval, but the pH and concentration of volatile fatty acids did not show any significant difference among the experimental treatments. Comparing the treatment of constant crude protein feeding (14%) with the treatments with intermittent consumption of crude protein (12 and 16%) in terms of the concentration of volatile fatty acids in the rumen fluid of the experimental sheep, including acetate, propionate and butyrate, as well as total volatile fatty acids, there is not a significant difference. The same ratio of concentrate to fodder and the similarity of the feed ingredients in the diets can be a reason for the lack of significance between the experimental treatments, which is in line with the results of previous researches (Khattab and Abdulwahid 2018). A significant difference was observed between the experimental treatments in terms of allantoin, total purine bases excreted, as well as nitrogen and microbial protein production, and the treatment with oscillating consumption of raw protein at a time interval of 48 hours had the highest amount. Albumin and total blood protein measured between the experimental treatments showed no significant difference, but blood urea nitrogen was the highest in the treatment with 48- hour crude protein consumption interval (P<0.01). Microbial protein synthesis in the rumen is affected by many animal and dietary factors, including nitrogen amounts, nitrogen sources, carbohydrate and nitrogen degradation rates, type and amount of carbohydrates in the diet, dry matter consumption, stability of fermentation in the rumen, and synchronization between nitrogen and energy (Hall 2013). It seems that in diets that cause fluctuation in the entry of protein sources into the rumen, the recycling of nitrogen to the rumen is done more effectively through the blood vessels and the liver, which in addition to reducing the excretion of nitrogen from the body also increases the production of microbial protein, in other words, the efficiency of using feed nitrogen increases, which is evident in the results of this research. Conclusion: The results showed that using the strategy of oscillating dietary crude protein concentration in sheep's diet improved nitrogen retention, rumen fermentation activities and microbial protein synthesis. [ABSTRACT FROM AUTHOR]

Forests are the largest carbon sink in terrestrial ecosystems, and the impact of nitrogen (N) deposition on this carbon sink depends on the fate of external N inputs. However, the patterns and driving factors of N retention in different forest compartments remain elusive. In this study, we synthesized 408 observations from global forest 15N tracer experiments to reveal the variation and underlying mechanisms of 15N retention in plants and soils. The results showed that the average total ecosystem 15N retention in global forests was 63.04 ± 1.23%, with the soil pool being the main N sink (45.76 ± 1.29%). Plants absorbed 17.28 ± 0.83% of 15N, with more allocated to leaves (5.83 ± 0.63%) and roots (5.84 ± 0.44%). In subtropical and tropical forests, 15N was mainly absorbed by plants and mineral soils, while the organic soil layer in temperate forests retained more 15N. Additionally, forests retained more N15H4+$$ {}^{15}\mathrm{N}{\mathrm{H}}_4^{+} $$than N15O3−$$ {}^{15}\mathrm{N}{\mathrm{O}}_3^{-} $$, primarily due to the stronger capacity of the organic soil layer to retain N15H4+$$ {}^{15}\mathrm{N}{\mathrm{H}}_4^{+} $$. The mechanisms of 15N retention varied among ecosystem compartments, with total ecosystem 15N retention affected by N deposition. Plant 15N retention was influenced by vegetative and microbial nutrient demands, while soil 15N retention was regulated by climate factors and soil nutrient supply. Overall, this study emphasizes the importance of climate and nutrient supply and demand in regulating forest N retention and provides data to further explore the impacts of N deposition on forest carbon sequestration. [ABSTRACT FROM AUTHOR]

Perennial tall grasses show promise as bioenergy crops due to high productivity and efficient nutrient use. Ongoing research on bioenergy grasses seeks to reduce their reliance on synthetic nitrogen (N) fertilizer, the manufacture of which relies on fossil fuel combustion. Excessive use of fertilizers also causes adverse environmental consequences and leads to the evolutionary loss of plant traits beneficial to sustainable N cycle. Notably, perennial tall grasses have exhibited the potential to maintain high biomass yield without the need for N fertilizer or causing soil N depletion. Perennial grasses can be adept at interacting with their microbial partners to facilitate N acquisition and retention via mechanisms such as biological N fixation and nitrification inhibition. These inherent N management traits should be preserved and optimized at the this early stage of bioenergy grass breeding programs. This review examines the impact of external N on bioenergy grass production and explores the potential of leveraging advantageous N‐cycling attributes of perennial tall grasses, laying groundwork for future management and research efforts. With minimized dependency on external N input, the cultivation of perennial energy grasses will pave the way toward more resilient agricultural systems and play a significant role in addressing key global energy and environmental challenges. [ABSTRACT FROM AUTHOR]

Much progress has been made in understanding the conditions of biochar production related to biochar properties and carbon (C). Still, very little knowledge has been gained regarding the effects on nitrogen (N), one of the most critical nutrients affected by pyrolysis temperature (PT). Analysis of N in biochar is costly, and alternative methods should be developed to estimate the N content in biochar quickly under different pyrolysis conditions. We hypothesized that there was a correlation between biochar N content and its electrical conductivity (EC). We aimed to evaluate total N and the effect of PT through the correlation with EC, a parameter that can be easily measured. Biochar products derived from coffee husk (CH) and chicken manure (CM) produced at increasing PT (300 to 750 °C) were used for the study and measured for total N and EC. The increase in PT caused significant N loss, consequently reducing total N content in biochars, with the highest loss (82%) and lowest total N content (1.2 g kg−1) found in CM biochar pyrolyzed at 750 °C. The lowest N loss (21% for CH biochar and 36% for CM biochar) was observed at a PT of 300 °C. A negative correlation between EC and total N and a positive correlation with N loss were found in both biochar products across the wide range of PT investigated. To preserve the N content in biochars, the PT should not exceed 400 °C. Our results indicate that EC is a fast and accurate biochar proxy attribute capable of predicting the N content and its loss in coffee husk and chicken manure-derived biochars as the pyrolysis temperature increased from 300 °C to 750 °C and could be used as an alternative to predict the N in biochar easily. A more extensive set of biochar samples and pyrolysis conditions should be tested to validate this approach. [ABSTRACT FROM AUTHOR]

Inclusion of a source of non-protein nitrogen (NPN) may improve essential amino acid (EAA) and nitrogen (N) utilization in N-limiting diets. Growing barrows (20.4 ± 0.5 kg) were randomly assigned to 1 of 10 dietary treatments (n = 9 pigs/treatment) in nine blocks. Diets contained no ammonium phosphate (NAP) or 1.7% ammonium phosphate (AP) to have an EAA-N:total N ratio of 0.36 and 0.33, respectively, with graded levels of dietary lysine (Lys; 0.8%, 0.9%, 1.0%, 1.1%, and 1.2% standardized ileal digestible (SID)). Following a 7-day dietary adaptation, a 4-day N-balance collection period was conducted. Blood samples were obtained on day 2 of the collection period. Nitrogen retention (NR) increased and urinary N output decreased with inclusion of NPN and increasing Lys (P < 0.01). Plasma urea N decreased with increasing Lys (P < 0.05). Total plasma EAA content was reduced with NPN supplementation (P < 0.05), while content of Arg, Asp, Gln, and Glu was increased (P < 0.01). The linear breakpoint model indicated that NR was maximized at 1.00% SID Lys in NAP-fed pigs and at 1.09% SID Lys in AP-fed pigs. These results indicate that diets deficient in dietary N reduce NR and Lys requirement, which were in turn increased with NPN supplementation. [ABSTRACT FROM AUTHOR]

Nutrient pollution—mainly nitrogen and phosphorus—caused by organic waste continues to impact the environment. The implementation of a circular economy is integral to alleviating these effects. Liquid digestate, which is a byproduct of anaerobic digestion (a waste-valorising process), is a nutrient-dense organic fertiliser with vast applications in agriculture. Using an aerobic polishing unit, this study developed a viable method for the preparation of a hydroponic fertiliser by investigating the effect of pH on the nutrient recycling capabilities of said system. The heterotrophic bacteria present in the biofilm, identified by 16S gene sequencing, are responsible for 90% of organic carbon (as TOC) removal with minimal ammonium loss. This is ideal for promoting optimal nitrification in hydroponic systems in the absence of organic carbon to ensure plant growth is not affected. Although pH 8 was found to be ideal for batch operation, this pH condition resulted in decreased microbial longevity and, therefore, increased ammonification due to microbial decay. Therefore, continuous operation at pH 7 proved to be a better option owing to the ammonium-rich effluent (>220 mg/L) which was produced, which is on par with the nitrogen concentration of a Hoagland solution. The continuous carbon polishing of liquid digestate provides an efficient way of utilising organic fertilisers in hydroponic systems. [ABSTRACT FROM AUTHOR]

The effects of nitrogen (N) deposition on forests largely depend on the ecosystem N status and the fates of deposited N. Boreal forests are typically N-limited ecosystems and are considered to be more efficient in retaining deposited N relative to temperate and tropical forests. As a primary disturbance in boreal forests, wildfires may alleviate N limitation in the burned ecosystem and increase mineralization, resulting in the altered outcomes of the N deposition. In order to explore the effects of a severe wildfire on the retention of deposited N, we investigated the fates of newly deposited N in burned and unburned boreal larch forests by applying 15NH4NO3 tracers to the forest floors. Results showed that total ecosystem retention for the deposited N was 60% in the forest recovering from a severe wildfire burned five years ago, significantly lower than in the unburned mature forest (89%). The difference was mainly attributed to the substantially lower retention in vegetation (8.3%) in the burned site than in the unburned forest (32.4%), as tracer recoveries in soil were similar (51.2 and 56.6%, respectively). Although most 15N tracer was immobilized in organic soil in both burned and unburned forests (33 and 47%, respectively), a noticeably higher amount of 15N was found in mineral soil in the burned forest (19%) than in the unburned forest (10%), suggesting mineral soil as a significant sink for N deposition in the burned forest. A higher total 15N retention in the unburned forest implies that more new N input may stimulate C sequestration and promote the productivity of the Eurasian boreal forest under the background of atmospheric N deposition. However, a considerable amount of deposited N may be lost from the disturbed boreal larch forest ecosystem after a severe wildfire. [ABSTRACT FROM AUTHOR]

Much progress has been made in understanding the conditions of biochar production related to biochar properties and carbon (C). Still, very little knowledge has been gained regarding the effects on nitrogen (N), one of the most critical nutrients affected by pyrolysis temperature (PT). Analysis of N in biochar is costly, and alternative methods should be developed to estimate the N content in biochar quickly under different pyrolysis conditions. We hypothesized that there was a correlation between biochar N content and its electrical conductivity (EC). We aimed to evaluate total N and the effect of PT through the correlation with EC, a parameter that can be easily measured. Biochar products derived from coffee husk (CH) and chicken manure (CM) produced at increasing PT (300 to 750 °C) were used for the study and measured for total N and EC. The increase in PT caused significant N loss, consequently reducing total N content in biochars, with the highest loss (82%) and lowest total N content (1.2 g kg−1) found in CM biochar pyrolyzed at 750 °C. The lowest N loss (21% for CH biochar and 36% for CM biochar) was observed at a PT of 300 °C. A negative correlation between EC and total N and a positive correlation with N loss were found in both biochar products across the wide range of PT investigated. To preserve the N content in biochars, the PT should not exceed 400 °C. Our results indicate that EC is a fast and accurate biochar proxy attribute capable of predicting the N content and its loss in coffee husk and chicken manure-derived biochars as the pyrolysis temperature increased from 300 °C to 750 °C and could be used as an alternative to predict the N in biochar easily. A more extensive set of biochar samples and pyrolysis conditions should be tested to validate this approach.

Biochar is produced by burning biomass under oxygen‐limited conditions, and it has been widely used as a soil amendment to improve soil functions such as nutrient retention. However, whether the impact of biochar application on soil nitrogen (N) transformation and N2O emission varies with the pyrolysis temperature remains unclear, especially in different forest types in subtropical regions. In this study, a 60‐day laboratory incubation experiment was conducted to evaluate the impact of biochar with different pyrolysis temperatures (300°C [BC300], 500°C [BC500], and 800°C [BC800]) on net N transformation rates and N2O emission in soils collected from Castanopsis kawakamii dominated natural forest (NF) and Chinese fir (Cunninghamia lanceolate, CF) plantation in subtropical China. The results showed that the application of biochar significantly increased soil ammonium (NH4+) content (p < 0.001) but reduced nitrate (NO3−) content (p < 0.001) compared with the control. The soil NH4+ content of the BC800 treatment was significantly higher than that of other treatments (p < 0.001). Biochar application significantly reduced soil net N mineralization (NRmin) and nitrification (NRnit) rate (p < 0.001), but increased net ammonification (NRamm) rate (p < 0.001). The application of biochar led to a remarkable decrease in cumulative N2O emission compared to the control (p < 0.001). In particular, soils treated with high‐temperature biochar emitted significantly lower N2O compared to other treatments (p < 0.001). The partial least squares path model demonstrated that biochar influenced N2O emission through a direct effect in NF soil and an indirect effect in CF soil. This study highlights the distinct role of biochar, particularly that produced under high pyrolysis temperatures as a soil amendment to mitigate N2O emission and promote N retention in both subtropical natural and planted forests. [ABSTRACT FROM AUTHOR]

Denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) are three competing processes of microbial nitrate reduction that determine the degree of ecosystem nitrogen (N) loss versus recycling. However, the global patterns and drivers of relative contributions of these N cycling processes to soil or sediment nitrate reduction remain unknown, limiting our understanding of the global N balance and management. Here, we compiled a global dataset of 1570 observations from a wide range of terrestrial and aquatic ecosystems. We found that denitrification contributed up to 66.1% of total nitrate reduction globally, being significantly greater in estuarine and coastal ecosystems. Anammox and DNRA could account for 12.7% and 21.2% of total nitrate reduction, respectively. The contribution of denitrification to nitrate reduction increased with longitude, while the contribution of anammox and DNRA decreased. The local environmental factors controlling the relative contributions of the three N cycling processes to nitrate reduction included the concentrations of soil organic carbon, ammonium, nitrate, and ferrous iron. Our results underline the dominant role of denitrification over anammox and DNRA in ecosystem nitrate transformation, which is crucial to improving the current global soil N cycle model and achieving sustainable N management. [ABSTRACT FROM AUTHOR]

Abstract Perennial tall grasses show promise as bioenergy crops due to high productivity and efficient nutrient use. Ongoing research on bioenergy grasses seeks to reduce their reliance on synthetic nitrogen (N) fertilizer, the manufacture of which relies on fossil fuel combustion. Excessive use of fertilizers also causes adverse environmental consequences and leads to the evolutionary loss of plant traits beneficial to sustainable N cycle. Notably, perennial tall grasses have exhibited the potential to maintain high biomass yield without the need for N fertilizer or causing soil N depletion. Perennial grasses can be adept at interacting with their microbial partners to facilitate N acquisition and retention via mechanisms such as biological N fixation and nitrification inhibition. These inherent N management traits should be preserved and optimized at the this early stage of bioenergy grass breeding programs. This review examines the impact of external N on bioenergy grass production and explores the potential of leveraging advantageous N‐cycling attributes of perennial tall grasses, laying groundwork for future management and research efforts. With minimized dependency on external N input, the cultivation of perennial energy grasses will pave the way toward more resilient agricultural systems and play a significant role in addressing key global energy and environmental challenges.

Identifying tipping points in the relationship between aridity and gross nitrogen (N) cycling rates could show critical vulnerabilities of terrestrial ecosystems to climate change. Yet, the global pattern of gross N cycling response to aridity across terrestrial ecosystems remains unknown. Here, we collected 14,144 observations from 451 15N‐labeled studies and used segmented regression to identify the global threshold responses of soil gross N cycling rates and soil process‐related variables to aridity index (AI), which decreases as aridity increases. We found on a global scale that increasing aridity reduced soil gross nitrate consumption but increased soil nitrification capacity, mainly due to reduced soil microbial biomass carbon (MBC) and N (MBN) and increased soil pH. Threshold response of gross N production and retention to aridity was observed across terrestrial ecosystems. In croplands, gross nitrification and extractable nitrate were inhibited with increasing aridity below the threshold AI ~0.8–0.9 due to inhibited ammonia‐oxidizing archaea and bacteria, while the opposite was favored above this threshold. In grasslands, gross N mineralization and immobilization decreased with increasing aridity below the threshold AI ~0.5 due to decreased MBN, but the opposite was true above this threshold. In forests, increased aridity stimulated nitrate immobilization below the threshold AI ~1.0 due to increased soil C/N ratio, but inhibited ammonium immobilization above the threshold AI ~1.3 due to decreased soil total N and increased MBC/MBN ratio. Soil dissimilatory nitrate reduction to ammonium decreased with increasing aridity globally and in forests when the threshold AI ~1.4 was passed. Overall, we suggest that any projected increase in aridity in response to climate change is likely to reduce plant N availability in arid regions while enhancing it in humid regions, affecting the provision of ecosystem services and functions. [ABSTRACT FROM AUTHOR]

The objective of the study was to investigate the effects of inclusion of Pleurotus florida treated wheat straw in the total mixed rations (TMRs) on feed intake, growth performance, nutrient digestibility, and nitrogen retention in male buffalo calves. As a pilot study, four TMRs, i.e., TMR1 having 0% P. florida treated wheat straw (FTWS), TMR2 (20% FTWS), TMR3 (40% FTWS), and TMR4 (60% FTWS) with berseem hay as basal diet, were formulated. Sixteen Nili-Ravi male buffalo calves (aged 10–12 months, weighing 73 ± 2.50 kg) were divided into four equal groups and randomly assigned one of four TMRs. A significant increase (P < 0.05) was observed in all nutrients intake, their digestibility, weight gain, and nitrogen retention with TMRs incorporated with FTWS. Highest feed conversion ratio (FCR) of 2.63 was noted with TMR1-0% and the lowest FCR (1.80) with TMR4-60%, on the other hand. In conclusion, the TMR4 (60% FTWS) has the potential to increase the weight gain, nutrient digestibility, nitrogen retention, and feed efficiency in buffalo calves. Therefore, inclusion of 60% Pleurotus florida treated wheat straw is recommended as TMRs with berseem hay based basal diet for feeding buffaloes calves. [ABSTRACT FROM AUTHOR]

Abstract Biochar is produced by burning biomass under oxygen‐limited conditions, and it has been widely used as a soil amendment to improve soil functions such as nutrient retention. However, whether the impact of biochar application on soil nitrogen (N) transformation and N2O emission varies with the pyrolysis temperature remains unclear, especially in different forest types in subtropical regions. In this study, a 60‐day laboratory incubation experiment was conducted to evaluate the impact of biochar with different pyrolysis temperatures (300°C [BC300], 500°C [BC500], and 800°C [BC800]) on net N transformation rates and N2O emission in soils collected from Castanopsis kawakamii dominated natural forest (NF) and Chinese fir (Cunninghamia lanceolate, CF) plantation in subtropical China. The results showed that the application of biochar significantly increased soil ammonium (NH4+) content (p

Abstract Background Soil fauna is an important driver of carbon (C) and nitrogen (N) release from decomposing litter in forest ecosystems. However, its role in C and N cycling concerning climate and litter traits remains less known. In a 4-year field experiment, we evaluated the effects of soil fauna on litter C and N release across an elevation gradient (453, 945, 3023, and 3582 m) and litter traits (coniferous vs. broadleaf) in southwestern China. Results Our results showed that N was retained by –0.4% to 31.5%, but C was immediately released during the early stage (156–516 days) of decomposition for most litter species. Soil fauna significantly increased the peak N content and N retention across litter species, but reduced the C/N ratio for certain species (i.e., Juniperus saltuaria, Betula albosinensis, Quercus acutissima, and Pinus massoniana litter), leading to more C and N being released from decomposing litter across the elevation gradient. Contributions of soil fauna to C and N release were 3.87–9.90% and 1.10–8.71%, respectively, across litter species after 4 years of decomposition. Soil environment and initial litter quality factors caused by elevation directly affected litter C and N release. Changes in soil fauna resulting from elevation and fauna exclusion factors had a direct or indirect impact on C and N release during litter decomposition. Conclusions Our findings suggest that soil fauna promote C and N release from decomposing litter in different magnitudes, mainly controlled by environmental conditions (i.e., temperature and moisture), litter quality (i.e., lignin and cellulose content, and lignin/cellulose), and its diversity across the elevation gradient.

An N-balance experiment was conducted to test the hypothesis that d-Methionine (d-Met) has the same bioavailability and efficacy as l-Methionine (l-Met) when fed to weanling pigs. A Met-deficient basal diet containing 0.24% standardized ileal digestible (SID) Met was formulated. Six additional diets were formulated by adding 0.036%, 0.072%, or 0.108% d-Met or l-Met to the basal diet, and these diets, therefore, contained 77%, 87%, or 97% of the requirement for SID Met. Fifty-six barrows (10.53 ± 1.17 kg) were housed in metabolism crates and allotted to the seven diets with eight replicate pigs per diet. Feces and urine were collected quantitatively with 7-d adaptation and 5-d collection periods. Blood and tissue samples from pigs fed the basal diet and pigs fed diets containing 0.108% supplemental Met were collected on the last day. Results indicated that N retention (%) linearly increased (P < 0.01) as supplemental d-Met or l-Met increased in diets. Based on N retention (%) as a response, the linear slope-ratio regression estimated the bioavailability of d-Met relative to l-Met to be 101% (95% confidence interval: 57%-146%). The villus height and crypt depth in the jejunum were not affected by the Met level or Met source. Total antioxidant capacity or thiobarbituric acid reactive substance concentrations in plasma or tissue samples from pigs fed the control diet or diets containing 0.108% supplemental d-Met or l-Met were not different. Abundance of mRNA for some AA transporters analyzed in intestinal mucosa of pigs also did not differ. Therefore, it is concluded that d-Met and l-Met are equally bioavailable for weanling pigs.

Background: Soil fauna is an important driver of carbon (C) and nitrogen (N) release from decomposing litter in forest ecosystems. However, its role in C and N cycling concerning climate and litter traits remains less known. In a 4-year field experiment, we evaluated the effects of soil fauna on litter C and N release across an elevation gradient (453, 945, 3023, and 3582 m) and litter traits (coniferous vs. broadleaf) in southwestern China. Results: Our results showed that N was retained by –0.4% to 31.5%, but C was immediately released during the early stage (156–516 days) of decomposition for most litter species. Soil fauna significantly increased the peak N content and N retention across litter species, but reduced the C/N ratio for certain species (i.e., Juniperus saltuaria, Betula albosinensis, Quercus acutissima, and Pinus massoniana litter), leading to more C and N being released from decomposing litter across the elevation gradient. Contributions of soil fauna to C and N release were 3.87–9.90% and 1.10–8.71%, respectively, across litter species after 4 years of decomposition. Soil environment and initial litter quality factors caused by elevation directly affected litter C and N release. Changes in soil fauna resulting from elevation and fauna exclusion factors had a direct or indirect impact on C and N release during litter decomposition. Conclusions: Our findings suggest that soil fauna promote C and N release from decomposing litter in different magnitudes, mainly controlled by environmental conditions (i.e., temperature and moisture), litter quality (i.e., lignin and cellulose content, and lignin/cellulose), and its diversity across the elevation gradient. [ABSTRACT FROM AUTHOR]

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Simple Summary: The inclusion of morula kernel cake (MKC) as a source of protein in finishing diets of Tswana lambs positively supported growth and enhanced sensory attributes of cooked meat steaks. Feed intake, average daily gain (ADG), feed conversion ratio (FCR), and carcass traits were similar for lambs fed on diets containing Lucerne (commercial diet), sunflower seedcake, or MKC. However, lambs from a commercial diet (CD) had a better nitrogen retention than lambs from a sunflower seedcake diet (SCD). Nitrogen retention in lambs fed a morula kernel cake diet (MKCD) was numerically better than those from SCD. The nutritional meat quality parameters were similar across the dietary treatments and were within the recommended reference values. Additionally, meat steaks of lambs that consumed MKCD were rich in oleic acid while meat steaks of lambs that ate SCD had no oleic acid. Furthermore, the gross margins from lambs fed either MKCD or SCD were better than those fed CD. This was attributed to lower variable costs of feed that accounted to 51% of production costs in lambs fed either MKCD or SCD when compared to lambs fed CD, which had variable costs of 71% apportioned to feed. A trial evaluated growth performance, carcass characteristics, meat quality, and economic returns of fattened lambs fed on diets containing different protein sources. Six castrated male Tswana lambs per treatment were used in a completely randomised design (CRD) trial and fed on complete diets containing Lucerne (CD; commercial diet), morula kernel cake (MKC), or sunflower seedcake (SC) as protein sources over a 103-day experiment. No significant differences (p > 0.05) were observed in the dry matter intake, final body weight, average daily gain, and FCR. This was attributable to all the diets providing an equal supply of nutrients to the lambs. Meat quality attributes and proximate composition values were similar (p > 0.05) across the treatments. Longissimus dorsi muscle organoleptic quality did not differ (p > 0.05) across the treatments. The gross margin analysis was significantly greater (p < 0.05) when feeding SCD than feeding CD and was intermediate for lambs fed MKCD. Morula kernel cake (Sclerocarya birrea) can be used for fattening lambs when common protein sources are either not available or expensive. [ABSTRACT FROM AUTHOR]

Inoculation with microorganisms is an effective method for promoting compost maturity and quality. This study investigated the effects of different microbial inoculants on compost maturity, nitrogen retention, and the diazotroph community during cotton straw composting. Results revealed that inoculation improved organic matter degradation and compost maturity, increasing the total nitrogen masses by 6.6–33.0% and the total nitrogen by 84.6–112.1%. Particularly, the microbial inoculants containing Anoxybacillus rupiensis, Paenibacillus illinoisensis, and Bacillus velezensis (1:1:1, T1 treatment) exhibited the highest total nitrogen masses and total nitrogen content. Furthermore, inoculation enhanced nitrogenase activity and nifH abundance, and markedly influenced the succession of the diazotroph community, increasing their sensitivity to environmental variables during composting. Furthermore, the total nitrogen, C/N ratios, and moisture content significantly affected the diazotroph community. Results from a network analysis indicated that inoculation affected the co-occurrence patterns among the diazotroph species and increased complexity between diazotrophs. In conclusion, this study provided three promising microbial inoculants for high-quality compost production and a reference for promoting nitrogen retention in cotton straw composting. [Display omitted] [ABSTRACT FROM AUTHOR]

This study was carried out to evaluate how broiler chickens respond to corn-soybean meal-based diets enriched with creatine monohydrate (CMH). The effects of CMH at protein levels were observed on performance, nutrients retention, meat water holding capacity (WHC) and blood biochemical parameters in broiler chickens. Three hundred twenty-day-old chicks (Ross 308) were organized in a 2 × 4 factorial arrangement in a completely randomized design, having 4 replicates and 10 birds in each cage (repeat). Diets formulated for two levels of protein (at an amount recommended for Ross 308 and also an amount being 10% higher than the recommendation catalog Ross 308, 2019). Four levels of CMH were used, amounting to 0, 0.1, 0.3 and 0.5% of the diet. In all of the experiment periods the performance results showed that the highest bodyweight gain and the lowest feed conversion ratio were observed in high levels of CMH (0.3 and 0.5%) (P<0.05). Feeding the birds with a diet containing protein (high level) led to the highest growth performance (P<0.05). Regarding N loss and nitrogen retention (g bird-1 day-1), the interaction between CMH and protein was significant. Apparent metabolizable energy (AME), N intake (g bird-1 day-1) and N retention (% intake) were affected by protein (P<0.05). The highest WHC was observed in birds that were fed on a diet containing higher amount of protein (P<0.05). Birds fed with 0.3% or 0.5% CMH showed an increase in blood creatinine (P<0.05), as compared to birds fed with 0 or 0.1% CMH. In conclusion, the growth performance of broilers improved by adding 0.3% CMH to the diet, and also birds fed to protein (high level) increased their growth performance. [ABSTRACT FROM AUTHOR]

We investigated the utility of using synchronous measurements to create nitrogen (N) emission and retention maps of agricultural areas. Total N (TN) emissions from agricultural areas in three different Danish pilot catchments (1800–3737 ha) and within sub-catchments (100–1200 ha) were determined by a source apportionment approach. Intensive daily (main gauging stations) and fortnightly (synchronous stations) monitoring of discharge, TN, and nitrate-N (NO3-N) concentrations was conducted for two years. The groundwater N retention was calculated as the difference between a model-calculated NO3-N leaching from agricultural fields and the calculated agricultural N emission. The average annual N leaching and N emission in the three catchments amounted to 68, 48, and 58 kg N/ha and 6, 30, and 40 kg N/ha, respectively. The N retention in groundwater in the three catchments, calculated based on either TN or NO3-N emissions, amounted to 26 and 44%, 44 and 57%, and 93 and 97%, respectively, with large variations within two of the main catchments. From this study, we conclude that synchronous measurements in streams provide a good opportunity for developing local N emission and N retention maps. However, NO3-N should be used when dealing with N retention calculation at the finer resolution scale of 100–300 ha catchments. [ABSTRACT FROM AUTHOR]

Crop productivity on tropical peat soils is poor partly because of their nutrient deficiency and the acidic nature of tropical peat soils. Ammonium (NH4+) and nitrate (NO3– ) ions are commonly leached from tropical peat soils principally because of high rainfall and lack of clay to retain these nutrients. Leaching of these ions into water bodies causes water pollution through eutrophication which has been implicated in disrupting productive aquatic life. To reverse this act of environmental quality degradation, clinoptilolite zeolite (CZ) could be used to retain nutrients including NH4+ and NO3– in tropical peat soils for crop use because of the alkalinity and high affinity of CZ for retention of macronutrients. Moreover, this approach could be used as an innovative and sustainable alternative for high use of lime (CaCO3 ) because of the liming effect of CZ. However, information on using CZ on tropical peat soils is scarcely explored. Thus, CZ was tested in a leaching study to determine its effects on soil total nitrogen (N), exchangeable ammonium, and nitrate retention in a tropical peat soil. Treatments evaluated were: (i) soil only, (ii) nitrogen, phosphorus, potassium (NPK) fertilizer alone, and (iii) combination of different amounts of clinoptilolite zeolite (25%, 50%, 75%, and 100%) and different amounts of NPK fertilizer (50%, 75%, and 100%). The peat soils with CZ improved soil pH, exchangeable NH4+, and available NO3– . The mixture of CZ and NPK fertilizer reduced NH4+ and NO3– loss because CZ has high affinity for NH4+ whereas NO3– was absorbed into the channels of CZ. Co-application of 100% CZ with 100%, 75%, and 50% NPK fertilizer, together with 75%, 50%, and 25% CZ with 100% fertilizer increased total N of the peat soil. Ability of CZ to buffer the soil pH reduces the need for liming. This alternative way of retaining N in tropical peat soils is practical and a sustainable approach for improving peat soil productivity. [ABSTRACT FROM AUTHOR]

Introduction: Promoting crop growth and regulating denitrification process are two main ways to reduce soil N2O emissions in agricultural systems. However, how biochar and arbuscular mycorrhizal fungi (AMF) can regulate crop growth and denitrification in soils with different phosphorus (P) supplies to influence N2O emission remains largely unknown. Method: Here, an eight-week greenhouse and one-year field experiments biochar and/or AMF (only in greenhouse experiment) additions under low and high P environments were conducted to characterize the effects on wheat (Triticum aestivum L.) growth and N2O emission. Results: With low P supply, AMF addition decreased leaf Mn concentration (indicates carboxylate-releasing P-acquisition strategies), whereas biochar addition increased leaf Mn concentration, suggesting biochar and AMF addition regulated root morphological and physiological traits to capture P. Compared with low P supply, the high P significantly promoted wheat growth (by 16-34%), nutrient content (by 33218%) and yield (by 33-41%), but suppressed soil N2O emissions (by 32-95%). Biochar and/or AMF addition exhibited either no or negative effects on wheat biomass and nutrient content in greenhouse, and biochar addition promoted wheat yield only under high P environment in field. However, biochar and/or AMF addition decreased soil N2O emissions by 24-93% and 32% in greenhouse and field experiments, respectively. This decrease was associated mainly with the diminished abundance of N2O-producing denitrifiers (nirK and nirS types, by 17-59%, respectively) and the increased abundance of N2O-consuming denitrifiers (nosZ type, by 35-65%), and also with the increased wheat nutrient content, yield and leaf Mn concentration. Discussion: These findings suggest that strengthening the plant-soil-microbe interactions can mitigate soil N2O emissions via manipulating plant nutrient acquisition and soil denitrification. [ABSTRACT FROM AUTHOR]

IntroductionPromoting crop growth and regulating denitrification process are two main ways to reduce soil N2O emissions in agricultural systems. However, how biochar and arbuscular mycorrhizal fungi (AMF) can regulate crop growth and denitrification in soils with different phosphorus (P) supplies to influence N2O emission remains largely unknown.MethodHere, an eight-week greenhouse and one-year field experiments biochar and/or AMF (only in greenhouse experiment) additions under low and high P environments were conducted to characterize the effects on wheat (Triticum aestivum L.) growth and N2O emission.ResultsWith low P supply, AMF addition decreased leaf Mn concentration (indicates carboxylate-releasing P-acquisition strategies), whereas biochar addition increased leaf Mn concentration, suggesting biochar and AMF addition regulated root morphological and physiological traits to capture P. Compared with low P supply, the high P significantly promoted wheat growth (by 16-34%), nutrient content (by 33-218%) and yield (by 33-41%), but suppressed soil N2O emissions (by 32-95%). Biochar and/or AMF addition exhibited either no or negative effects on wheat biomass and nutrient content in greenhouse, and biochar addition promoted wheat yield only under high P environment in field. However, biochar and/or AMF addition decreased soil N2O emissions by 24-93% and 32% in greenhouse and field experiments, respectively. This decrease was associated mainly with the diminished abundance of N2O-producing denitrifiers (nirK and nirS types, by 17-59%, respectively) and the increased abundance of N2O-consuming denitrifiers (nosZ type, by 35-65%), and also with the increased wheat nutrient content, yield and leaf Mn concentration.DiscussionThese findings suggest that strengthening the plant-soil-microbe interactions can mitigate soil N2O emissions via manipulating plant nutrient acquisition and soil denitrification.

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Purpose: Knowledge of nitrogen (N) dynamics of organic fertilisers as partial substitutes for chemical fertilisers could improve the retention of mineral N and optimise fertilisation practices in paddy soils. Materials and methods: 15 N tracing was performed to quantify the effect of 36 years of partial substitution of chemical N by organic N on gross N transformation rates in soils, and its relationship to organic N fractions. Treatments were chemical fertilisation (NPK), substitution of chemical N with 30%, 50% and 70% organic N (70F + 30 M, 50F + 50 M and 30F + 70 M), and no fertilisation (control). Results and discussion: Partial substitution elevated N mineralisation, ammonium immobilisation, autotrophic nitrification and nitrate consumption rates by 58.4–609.3%, 36.0–304.2%, 0.5–320.0% and 51.4–112.6%, respectively, compared to NPK treatment. However, gross N transformation rates differed with varying organic N substitution proportions. Fifty percent substitution increased mineralisation and immobilisation of the labile organic N pool by increasing the level and distribution of amino acid N fractions in acid-hydrolysable N, resulting in the highest N supply and retention capacity and the lowest N loss potential. Thirty percent substitution also increased the supply and retention capacity of nitrogen, but its integrated effect was inferior to the 50% substitution treatment. However, 70% substitution increased the potential loss of nitrate by increasing the ratio of gross nitrification rate to gross ammonia immobilisation rate (N/I). Partial substitution also increased the yield by 4.26–6.91% (p < 0.05), but there were no significant differences between organic N substitution proportions. Conclusion: Thus, accumulating active fractions of the soil organic N pool enhanced soil N supply and mineral N retention in acidic rice fields. Given optimal sustainable agricultural practices, and considering yield, N retention and potential N losses, a 50% substitution of chemical N with organic N can be recommended for the study region. [ABSTRACT FROM AUTHOR]

Conventional composting faces challenges of nitrogen loss, product instability, and limited humic substance formation. This study investigated the effects of nanoscale biochars (nano-BCs) derived from rice straw (nano-RSB) and corn stover (nano-CSB) on manure composting. A randomized design with five treatments was used: control, regular biochars (RSB and CSB), and nano-BCs. Nano-BCs, especially nano-CSB, significantly improved compost maturity and reduced phytotoxicity, achieving a 146.20 % germination index. They increased total nitrogen (55.09-63.64 %) and phosphorus (10.25-12.33 %) retention, reduced NH 4 + -N loss, and promoted nitrification. Nano-CSB showed the highest final NO 3 - -N content (8.63 g/kg). Bacterial richness and diversity increased by 25-30 % in nano-BC treatments, with selective enrichment of beneficial species. The unique properties of nano-BCs, including high surface area and microporous structure, improved nutrient retention and compost quality. Nano-BCs offers a promising solution for sustainable waste management and high-quality compost production in agriculture, significantly enhancing nutrient retention and microbial community regulation during composting process., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The objectives of the experiment were to study the effects of adding polyethylene glycol (PEG) to steer ration containing high sorghum tannins on rumen fermentation, nutrient digestion, nitrogen (N) balance and plasma biochemical parameters. Eight growing steers at 16 months of age were allotted to a replicated 4 × 4 Latin square design with 4 treatments and 4 periods (19 d each). Polyethylene glycol at 0, 1.75, 3.50 and 7.00 g/kg dry matter (DM) were added to a basal ration containing 27.82% DM of sorghum grain (total tannins 3.3 g/kg DM) as the treatments. The results indicated that adding PEG quadratically increased the ruminal pH (P = 0.049), tended to linearly increase the ruminal concentration of total volatile fatty acids (P = 0.070), increased the molar proportion of acetate (P = 0.016), linearly decreased the molar proportion of butyrate (P = 0.015), and tended to increase the molar proportion of iso-valerate (P = 0.061) and the ruminal concentration of ammonia N (P = 0.092). Adding PEG tended to quadratically decrease the relative abundance of methanogenic archaea (P = 0.082), linearly decreased the relative abundance of Fibrobacter succinogenes (P = 0.008) and decreased the relative abundance of Butyrivibrio fibrisolvens (P = 0.048) at 7.00 g/kg DM. Dietary addition with PEG increased the crude protein (CP) digestibility (P 0.05). It was concluded that adding PEG effectively improved the CP digestibility of the ration containing high sorghum tannins but increased the urinary urea excretion without improving the N retention and N retention rate in steers.

Nitrogen recycling between Earth's interior and exterior determines the evolution of the atmosphere and habitability of the planet. However, the contribution of subduction to the deep nitrogen recycling is still highly debated. Ammonium‐bearing silicate minerals are the main nitrogen carriers in subduction zones. Nitrogen retention in subduction‐zone minerals determines the subducted nitrogen fluxes to the deep Earth. Here, we reveal ammonium behavior in a natural ammonium‐bearing feldspar at elevated temperatures to 1000°C and pressures to 19.99 GPa. With increasing temperature and pressure, ammonium interacts with the silicate framework and forms hydrogen bonding. The ammonium loss rates are on the order of 10−15, 10−14, and 10−13 at 800, 900, and 1000°C, respectively, with activation energy of 271 ± 13 kJ/mol. The activation energy of ammonium loss in feldspar is higher than that in phengite. Moreover, the ammonium diffusivities are similar to that of hydrogen in feldspar, but much slower than that of molecular water and faster than those of K and Ar. The results imply that most of nitrogen can be potentially retain in the feldspar structure before feldspar breakdown. Considering that feldspar could be stable to a great depth along cold subduction, it could be a potential carrier for nitrogen transport to the deep Earth. Plain Language Summary: Feldspar is an important constituent of Earth's crust and has a large affinity of nitrogen as ammonium in the structure. Here, we report nitrogen retention in feldspar at high temperature and high pressure. Our data show that ammonium interacts with the silicate framework and forms hydrogen bonding with increasing temperature and pressure. Ammonium is more stable in feldspar than in phengite, with similar diffusion kinetics to hydrogen in feldspar. Therefore, ammonium may be carried by feldspar to a great depth along cold subduction. Key Points: Ammonium interacts with the silicate framework and forms hydrogen bonding with increasing temperature and pressureAmmonium loss has the similar kinetics to hydrogen in feldspar, with larger activation energy in feldspar than that in phengiteFeldspar is a potential carrier for nitrogen transport in subduction zones [ABSTRACT FROM AUTHOR]

Abstract Background The aim of this study was to determine the effect of dietary inclusion of silkworm pupae meal (SPM) on nutrient digestibility, nitrogen utilization, gastrointestinal physiology and blood biochemical parameters in rabbits. Thirty Termond White rabbits were divided into three groups: SBM – fed a diet containing 10% soybean meal (SBM), SPM5 – fed a diet containing 5% SBM and 5% SPM, and SPM10 – fed a diet containing 10% SPM. Results Nutrient digestibility and nitrogen retention decreased with increasing SPM inclusion levels in rabbit diets. The dietary inclusion of SPM caused a significant increase in the stomach pH. Group SPM10 rabbits were characterized by the highest cecal tissue and digesta weights. The lowest cecal pH was noted in group SPM5. The relative weights of colonic tissue and digesta tended to increase with increasing levels of SPM. The total and intracellular activity of bacterial α-galactosidase decreased significantly in both SPM groups. The replacement of SBM with SPM led to a decrease in the activity of bacterial β-glucuronidase in the cecal digesta. The intracellular activity of bacterial α-arabinofuranosidase increased, and its release rate decreased in the cecum of rabbits in SPM groups. The extracellular activity of bacterial β-xylosidase in the cecal digesta tended to decrease in group SPM10. The highest extracellular and intracellular activity of bacterial β-cellobiosidase in the cecal digesta was noted in the SPM5 treatment. The lowest and the highest activity of bacterial N-acetyl-β-D-glucosaminidase (NAGase) was observed in groups SBM and SPM10. The SPM10 treatment contributed to a decrease in the cecal concentrations of butyric, iso-valeric and valeric acids. The lowest total concentration of putrefactive short-chain fatty acids (PSCFAs) was observed in group SPM10. The cecal concentration of propionic acid tended to increase in group SPM5, whereas the cecal concentration of iso-butyric acid tended to decrease in group SPM10. The colonic concentration of iso-valeric acid was lowest in group SPM5. SPM treatments resulted in a significant increase in plasma albumin concentration. Plasma urea concentration was significantly higher in group SPM10 than in SBM and SPM5. Conclusions The results of this study suggest that rabbit diets can be supplemented with SPM at up to 5%.

The impacts of biochar application on the carbon (C) and nitrogen (N) cycles in soil profiles in vegetable fields have rarely been reported. A three-year field experiment (CK, control; BC, biochar; N, nitrogen fertilizer; BCN, biochar and nitrogen fertilizer) was conducted in fluvo-aquic soil with a wild cabbage-Chinese cabbage rotation to investigate biochar effects on soil organic carbon (SOC) sequestration, N retention, and nitrate (NO 3 −) leaching in the soil profile (topsoil, 0–20 cm; subsoil, 20–50 cm; third-layer soil, 50–100 cm). The results showed that the biochar-induced increase in topsoil SOC under N fertilization was greater for Chinese cabbage season than for wild cabbage season. Excluding biochar-N, biochar application caused an extra increase in topsoil total nitrogen (TN) under N fertilization. Biochar decreased the NO 3 −-N concentration of third-layer soil solution, particularly under N fertilization, indicating that biochar reduced the potential source of NO 3 − leaching. Under N fertilization, biochar reduced the abundances of carbon-degrading bacteria (Streptomyces , Bacillus , Mycobacterium, and Sphingomona s) and genes (sga , xylA , lig, and pgu) in the topsoil, as well as the abundances of ammonia-oxidizing bacteria (Nitrosospira and Nitrosomonas) and gene (amoA) in the third-layer soil. However, biochar increased the abundance of ammonia-assimilating bacteria (Rhodococcus) and gene (glnA) in the topsoil. Biochar inhibited the microbial function associated with C degradation by affecting soil TN, thus enhancing topsoil SOC sequestration. Biochar promoted the soil microbial function related to ammonia assimilation by affecting dissolved organic carbon (DOC), subsequently enhancing ammonia assimilation. Moreover, biochar initially inhibited ammonia oxidation in the third-layer soil by increasing soil DOC, subsequently affecting nitrite oxidation and ultimately reducing soil NO 3 − leaching. Biochar significantly increased the N use efficiency of vegetables in the last two years. This study provides insights into biochar effects on the changes in soil microbial function, which promoted SOC sequestration, enhanced N retention and mitigated nitrate leaching in a vegetable rotation field. [Display omitted] • Biochar favored SOC sequestration at 0–20 cm in Chinese cabbage season by limiting C degradation compared with wild cabbage. • Biochar increased soil N retention at 0–20 cm by promoting ammonia assimilation. • Biochar reduced NO 3 − leaching by inhibiting ammonia oxidation in 50–100 cm soil and improving N uptake and N retention. [ABSTRACT FROM AUTHOR]

[Display omitted] • Superphosphate (CP) and 'Mg(OH) 2 &H 3 PO 4 ′ increased NH 4 +-N by 75 % and 44 % respectively. • CP increased nitrogen ratio of humic acid to total by 49% compared to the control. • Phosphate additives improved the humification degree and the polymerization of humus. • Preserved NH 4 +-N due to phosphate additives was converted to nitrogenous humic acid. • Clustered bacterial positive relations in CP help to convert precursor to humic acid. This study aimed to compare the effect of different phosphate additives including superphosphate (CP) and MP [Mg(OH) 2 + H 3 PO 4 ] on nitrogen conversion, humus fractions formation and bacterial community in food waste compost. The results showed the ratio of humic acid nitrogen in total nitrogen (HA-N/TN) in CP increased by 49 %. Ammonium nitrogen accumulation was increased by 75 % (CP) and 44 % (MP). Spectroscopic techniques proved that phosphate addition facilitated the formation of complex structures in HA. CP enhanced the dominance of Saccharomonospora , while Thermobifida and Bacillus were improved in MP. Structural equation modeling and network analysis demonstrated that ammonium nitrogen can be converted to HA-N and has positive effects on bacterial composition, reducing sugars and amino acids, especially in CP with more clustered network and synergic bacterial interactions. Therefore, the addition of phosphate provides a new idea to regulate the retained nitrogen toward humification in composting. [ABSTRACT FROM AUTHOR]

A trial evaluated growth performance, carcass characteristics, meat quality, and economic returns of fattened lambs fed on diets containing different protein sources. Six castrated male Tswana lambs per treatment were used in a completely randomised design (CRD) trial and fed on complete diets containing Lucerne (CD; commercial diet), morula kernel cake (MKC), or sunflower seedcake (SC) as protein sources over a 103-day experiment. No significant differences (p > 0.05) were observed in the dry matter intake, final body weight, average daily gain, and FCR. This was attributable to all the diets providing an equal supply of nutrients to the lambs. Meat quality attributes and proximate composition values were similar (p > 0.05) across the treatments. Longissimus dorsi muscle organoleptic quality did not differ (p > 0.05) across the treatments. The gross margin analysis was significantly greater (p < 0.05) when feeding SCD than feeding CD and was intermediate for lambs fed MKCD. Morula kernel cake (Sclerocarya birrea) can be used for fattening lambs when common protein sources are either not available or expensive.

Urea–nitrogen is commonly lost through ammonia (NH3) volatilization, denitrification, and nitrate (NO3−) leaching. Rejected sago starch (RSS), which is a by-product of sago flour extraction, could be used to minimize NH3 volatilization from urea. Urea granules were coated with different concentrations of RSS (2%, 3%, 4%, 5%, and 6%), and their effects on NH3 emission, soil pH, exchangeable ammonium (NH4+), and available NO3− were determined. The urea was coated with RSS and homogenized using a mini rotary machine. The RSS-coated urea granules were dyed to differentiate their concentrations. The effectiveness of the RSS as a coating material was determined using a closed-dynamic air flow system. The soil used in the NH3 volatilization was the Bekenu series (Sandy loam, Typic Paleudults). This study compared seven different mixture treatments: soil alone (S), 5 g of uncoated urea (U), 5 g of 2% RSS-coated urea (CU1), 5 g of 3% RSS-coated urea (CU2), 5 g of 4% RSS-coated urea (CU3), 5 g of 5% RSS-coated urea (CU4), and 5 g of 6% RSS-coated urea (CU5). Urea coated with RSS, particularly CU1, effectively minimized NH3 loss and improved the retention of soil exchangeable NH4+ and available NO3− compared with uncoated urea because the RSS serves as a barrier to minimizing the concentration of NH3 from urea hydrolysis. Urea could be coated with RSS at the 2% concentration to enhance urea–N efficiency through a reduction in NH3 emission from urea. RSS-coated urea could be an alternative for farmers because of its controlled release of N and economical benefits. Field planting using rice as a test crop to solidify the effectiveness of RSS-coated urea in improving N retention from urea is still ongoing. [ABSTRACT FROM AUTHOR]

Purpose: A controlled study evaluated the effect of condensed tannins (CT) from Gymnopodium floribundum leaf meal (GF), infection with Haemonchus contortus (I) and their interaction, on feed intake, diet digestibility and retention of N (NR) and energy (ER) in hair sheep lambs. Methods: Thirty-six, worm-free hair sheep lambs (14.9 ± 1.56 kg body weight) were housed in metabolic cages. Eighteen animals were infected with 6000 H. contortus L3, while other 18 lambs were kept non-infected. On day 28th post-infection (PI), infected lambs were assigned to three diet groups: a diet without GF (I-NONGF), a diet with GF (I + GF) and a diet with GF + polyethylene glycol (PEG) (I + GF + PEG). Non-infected (NI) lambs were assigned to similar diet groups: NI-NONGF, NI + GF and NI + GF + PEG. The packed cell volume (% PCV), ante-mortem faecal egg counts and post-mortem worm burdens were also evaluated. Results: Infection did not affect digestibility, NR and ER. Meanwhile, CT intake from the GF diet reduced the digestibility of dry matter, organic matter and crude protein, as well as NR, compared to lambs consuming the NONGF and GF + PEG diets (P < 0.05). Although, the digestible energy was similar between lambs consuming NONGF and GF + PEG diets, the ER was higher for lambs consuming the control NONGF diet. Diets did not affect the PCV, or the ante-mortem and post-mortem parasitological variables. Conclusion: The costs on N and energy metabolism were mainly associated with the CT content of the GF diet, but other features of the diet such as the high lignin content, seemed to affect animals consuming GF meal. Meanwhile, the H. contortus infection had a non-significant impact. [ABSTRACT FROM AUTHOR]

The research aims to examine the effect of differences in house length and placement zones inside a closed house on the utilization of broiler chicken feed protein in the dry season. The research material is 600 broiler chickens (strain cobb) divided into 20 experimental units and 2 closed houses with a length of 60 m with a capacity of 11,000 and a length of 120 m with a capacity of 22,000. This research used a randomized block design with a split-plot pattern and two factors. The main plot is closed house with length 60 and 120 meters, the subplot is the zone placement of chicken which are divided into 4 zones: zone 1 is parallel to the inlet, zone 2 is measured at 1/4 of the house length, zone 3 is measured at 1/2 the house length, zone 4 is measured at 3/4 the house length from the inlet. The parameters observed were protein digestibility, the protein efficiency ratio (PER), and nitrogen retention (NR). Macroclimate, microclimate, and microclimatic ammonia observed as supporting data and an overview of the research conditions. Longer house and placement zone of chicken further from the inlet increase temperature, humidity, and microclimatic ammonia inside the closed house. The results showed an interaction between the house length and placement zone of chicken against NR. The housing length of 120 m and zone 4 was significantly (P≤0,05) having lower protein digestibility, PER, and NR values. Protein digestibility began to decrease significantly (P≤0,05) in zone 3, while PER and NR significantly decrease from zone 2. It concludes that longer closed house and placement zones further from the inlet decrease the ability of broilers to utilizing feed protein in the dry season.

Wildfire is a major driver of nitrogen (N) cycling and export from terrestrial to aquatic systems. While fire is a natural process in many watersheds, it can still degrade water quality by rapidly flushing N to streams. This can be particularly problematic in watersheds that experience high levels of N deposition or where climate change is promoting larger and more severe fires. The extent and duration of postfire N export, and the potential consequences for downstream water quality, depend on how N inputs, internal cycling, and outputs vary before, during, and after fire. Here we review the major factors controlling N cycling and retention in forests and adjacent shrublands, and how fire modifies these controls. We connect burned slopes to streams to describe how fire exports N to aquatic environments. We also consider the implications for municipal watersheds and water resources management. We close by identifying critical knowledge gaps in projecting how fire will affect watershed N cycling and retention in the future. [ABSTRACT FROM AUTHOR]

This study objective was to assess the effect of time of feeding on nutrients intake and haemato-biochemical indices of West African dwarf (WAD) bucks. Fifteen bucks with an initial live-weight of 7.50 ± 0.35 kg aged between 8 - 12 months were grouped into three treatments and five replicates for 115 days. The bucks were fed once daily in the morning, noon or evening either at 06:00, 12:00 or 18:00 hour for 90 days respectively under natural light-dark cycles. The experimental diets were Panicum maximum (Guinea grass) and concentrate diets at 50:50 % DM ratio. Serum glucose in evening fed-bucks was significantly higher (p<0.02) than noon and morning-fed buck. Nitrogen retention also increased from dawn to dusk with the morning-fed bucks (64.31 ± 3.79 %) having significantly lowest (p<0.02) value, while evening-fed bucks had the highest (74.73 ± 1.15 %) nitrogen retention. However, time of feeding did not significantly affect (p>0.05) nutrient digestibility, haematological parameters, total protein, lipid profile, and mineral utilization. Feeding animals in the evening or early hours of the morning may be healthy for livestock in a changing climate. [ABSTRACT FROM AUTHOR]

Protein sources from cereals are used in broiler diets, usually in order to reduce feeding costs. However, their efficient use in poultry diets is limited by the level of fiber whose compounds are resistant to digestion in the small intestine; due to this sugars are not digested by endogenous poultry enzymes. The aim of this study was to determine the effect of multi-carbohydrase (MC) and phytase (Phy) on the total retention of nutrients, retention of apparent metabolizable energy corrected for nitrogen (AMEN) (trial 1) and apparent and standardized ileal digestibility of amino acids (trial 2) of rice bran (RB). A total of 245-day-old male broilers (Cobb 500) was distributed at 21-day-old in a completely randomized design in a 2 × 2 + 1 (0 and 200 mg/kg MC; 0 and 50 mg/kg Phy, and basal diet – BD) factorial arrangement of treatments, to give seven replicates and seven birds per replicate. The BD based on corn (trial 1) and cornstarch and casein (trial 2) was used only to determine the coefficients of retention of nutrients and energy, and coefficients of digestibility of amino acids of the RB. The test diets were made by mixing BD and RB 7 : 3 wt/wt basis. There was interaction (P0.05) for ash, calcium, phosphorous and NDF was observed. Enzymes interacted (P

Lupine seeds have the potential to be an alternative to imported dietary proteins. In rabbits, it has been indicated that White lupine seed (WLS) is a suitable protein source. Other lupine species, for example, narrow-leaved lupine seed (NLS), have not yet been tested in rabbit diets. Two experiments were carried out to evaluate the effect of the dietary inclusion of NLS on growth performance, sanitary risk index (SRI), coefficients of total tract apparent digestibility (CTTAD) and nitrogen output in fattening rabbits. Narrow-leaved lupine was compared with WLS as a main protein source. For Experiment I, a total of 198 Hyplus rabbits (37 days of age) were allocated into two groups (99 rabbits per group), fed the WLS I diet (120 g/kg of WLS cv. Amiga) or the NLS I diet (150 g/kg of NLS cv. Probor), and used for performance and carcass trait evaluations. In addition, the CTTAD of the diets and the nitrogen output were determined in 10 Hyplus rabbits per treatment (37 days of age). For Experiment II, a total of 180 Hyplus rabbits (32 days of age) were allocated into two groups (90 rabbits per group), fed the WLS II diet (120 g/kg of WLS cv. Amiga) or the NLS II diet (130 g/kg of NLS cv. Primadona), and used for performance and carcass trait evaluations. In addition, the CTTAD of the diets was determined in 10 Hyplus rabbits per treatment (32 days of age). Regardless of the treatment, the dietary inclusion of NLS had a negative effect on growth of the rabbits. The nitrogen excretion and coefficients of nitrogen retention of rabbits were not affected by the treatments. In Experiment I, SRI (37 to 80 days of age) was higher in rabbits fed the NLS I diet than in those fed the WLS I diet (38.4% v. 23.2%, respectively; P = 0.031). Similarly, in Experiment II (32 to 74 days of age), SRI was higher in rabbits fed the NLS II diet than in rabbits fed the WLS II diet (37.8% v. 23.3%, respectively; P = 0.052). In conclusion, regardless of the variety, the dietary inclusion of NLS had no negative effect on the nitrogen output or dressing-out percentage of rabbits when compared to those of rabbits fed the WLS diets. With respect to the SRI and performance, however, NLS did not provide a satisfactory outcome.

Ruminants are one of the largest anthropogenic methane and nitrous oxide emissions. Therefore, the hypothesis was to study the effects of reducing dietary crude protein (CP) level on environmental contaminators when rumen-protected amino acids and choline chloride were supplemented. Sixty Holstein dairy cows were used during the experiment. Test diets were: (1) CD = Control diet with16.2 g of crude protein/ Kg of DM); (2) LM = Low protein diet with 14.2 g of crude protein/ Kg of DM + methionine ; (3) LL = Low protein diet with 14.2 g of crude protein/ Kg of DM + lysine; (4) LML = Low protein diet with 14.2 g of crude protein/ Kg of DM + methionine + lysine; (5) LMLC = Low protein diet with 14.2 g of crude protein/ Kg of DM + methionine + lysine + choline. Dry matter and NDF intake were not different, but the control group received higher CP and ADF compared with other groups (P < 0.05). Fecal CP and ADF of control group were lower (P < 0.05), but no differences were observed for fecal dry matter (DM) and NDF. Milk yield and protein content were higher for LML and LMLC like control group (P < 0.05). Nitrogen intake, urinary N, urinary urea N and total excreta N decreased (P < 0.05) when animals fed low protein. There was no difference in ruminal pH and acetate to propionate ratio, whereas the ruminal ammonia-N decreased with the low protein (P < 0.05). The 120-h gas production test, showed no difference on the kinetics of digestion and in vitro methane emission. However, the inclusion of DMI in the calculations revealed that low protein can reduce (P < 0.05) methane emission. Overall, our findings indicated that low protein can be compensated for by adding rumen-protected amino acids, not only to maintain the animal performance, but also to decrease nitrogen excretion and methane emission.

Wetlands protect downstream waters by filtering excess nitrogen (N) generated from agricultural and urban activities. Many small ephemeral wetlands, also known as geographically isolated wetlands (GIWs), are hotspots of N retention but have received fewer legal protections due to their apparent isolation from jurisdictional waters. Here, we hypothesize that the isolation of the GIWs make them more efficient N filters, especially when considering transient hydrologic dynamics. We use a reduced complexity model with 30 years of remotely sensed monthly wetland inundation levels in 3700 GIWs across eight wetlandscapes in the US to show how consideration of transient hydrologic dynamics can increase N retention estimates by up to 130%, with greater retention magnification for the smaller wetlands. This effect is more pronounced in semi-arid systems such as the prairies in North Dakota, where transient assumptions lead to 1.8 times more retention, compared to humid landscapes like the North Carolina Pocosins where transient assumptions only lead to 1.4 times more retention. Our results highlight how GIWs have an outsized role in retaining nutrients, and this service is enhanced due to their hydrologic disconnectivity which must be protected to maintain the integrity of downstream waters.

We investigated the utility of using synchronous measurements to create nitrogen (N) emission and retention maps of agricultural areas. Total N (TN) emissions from agricultural areas in three different Danish pilot catchments (1800–3737 ha) and within sub-catchments (100–1200 ha) were determined by a source apportionment approach. Intensive daily (main gauging stations) and fortnightly (synchronous stations) monitoring of discharge, TN, and nitrate-N (NO3-N) concentrations was conducted for two years. The groundwater N retention was calculated as the difference between a model-calculated NO3-N leaching from agricultural fields and the calculated agricultural N emission. The average annual N leaching and N emission in the three catchments amounted to 68, 48, and 58 kg N/ha and 6, 30, and 40 kg N/ha, respectively. The N retention in groundwater in the three catchments, calculated based on either TN or NO3-N emissions, amounted to 26 and 44%, 44 and 57%, and 93 and 97%, respectively, with large variations within two of the main catchments. From this study, we conclude that synchronous measurements in streams provide a good opportunity for developing local N emission and N retention maps. However, NO3-N should be used when dealing with N retention calculation at the finer resolution scale of 100–300 ha catchments.

Biochar is usually used as an agricultural soil amendment to improve soil nutrition availability and soil microbial environment. However, the effects of Moutai lees biochar on the migration and retention characteristics of nitrogen fertilizer and the changes of nitrifying microorganisms on yellow soil of southwest China are still not distinct. In this study, the migration distribution characteristics of nitrogen fertilizer, nitrogen retention capacity and microbial community structure were evaluated by a soil column leaching simulated experiment. Five application rates of biochar: 0%(BC0), 0.5%(BC0.5), 1.0%(BC1.0), 2.0%(BC2.0) and 4.0%(BC4.0) were respectively tried. The results showed that the application of Moutai lees biochar has significantly increased the total nitrogen (TN) and nitrate (NN) contents in yellow soil, but it has also significantly decreased the microbial biomass nitrogen (MBN) content. When compared with the BC0 treatment, it was found that the application of biochar increased nitrogen fertilizer retention rate (NF) to 49.84%–95.23%. Moreover, high biochar application rates (2.0% and 4.0%) were also able to improve the NF ratio, while low biochar application rates (0.5% and 1.0%) still had the risk of nitrogen leaching losses. Additionally, the application of biochar changed the bacterial community structure and the relative abundance of nitrogen-related microorganisms in yellow soil. Also, it was determined that Nitrite-oxidizing bacteria (NOB) played a major factor in affecting soil nitrogen, instead of ammonia-oxidizing archaea (AOA) and ammonium-oxidizing bacteria (AOB). Overall, research finally concluded that Moutai lees biochar decreased nitrite oxidation effect and changed ammoxidation to affect nitrogen nutrients availability in yellow soil and the biochar application rate of 4% has increased nitrogen fertilizer retention rate and decreased the risk of nitrogen leaching losses in yellow soil.