Chitin, Biochar, and Animal Manures Impact on Eggplant and Green Pepper Yield and Quality

The global obligation for food requires soil and plant management practices that provide valuable effects on the physical, chemical, and organic properties of soils. The use of animal manure, in agricultural production systems as alternative to synthetic elemental fertilizers has potential application to improve crop yield and fruit quality. A randomized complete block design (RCBD) was established to investigate the impact of nine soil treatments on yield and quality of bell pepper, Capsicum annuum and eggplant, Solanum melongena. The nine soil treatments included: chitin CH, biochar Bio, sewage sludge SS, chicken manure CM, SS mixed with biochar (SSBio), SS mixed with CH (SSCH), CM mixed with biochar (CMBio), CM mixed with CH (CMCH), and unamended (UN) native soil used as control treatment. At maturity, fruits from each treatment, were counted, weighed, and classified according to the USDA grades to U.S. Fancy, U.S. No.1, U.S. No.2, and culls. Overall number and weight of green pepper fruits collected from plants grown in SSCH were significantly greater (26.2 and 3.14 kg 5 plants-1) compared to fruits of plants grown in unamended control treatment (17.1 and 1.98 kg 5 Plants-1, respectively). Whereas CH alone was superior in increasing the number and weight of eggplant fruits compared to the control treatment. Average weight and number of eggplant fruits of plants grown in soil amended with chitin (4.46 kg and 11.5, respectively) were significantly (P ≤ 0.05) greater than weight and number of fruits obtained from plants grown in other soil treatments. Results also revealed a positive correlation coefficient (r) and high probability of significance (P) between number of fruits and weight of fruits among the nine soil treatments. Utilization of animal manures in agricultural systems is an inexpensive means for limited-resource farmers looking for improvements in crop yield and quality at affordable costs.

Combined Effect of Organic Manures and Inorganic Fertilizers on the Growth and Yield of Hybrid Rice (Palethwe-1)

We investigated the effect of combining organic and inorganic fertilizers on the growth and yield of hybrid rice (Palethwe-1) in the dry and wet seasons of 2015. Four quantities of inorganic fertilizer were used in the main plot [0%, 50%, 75%, and 100% nitrogen, phosphorus, and potassium (NPK)] based on the recommended amounts of 150 kg N ha-1, 70 kg P2O5 ha-1, and 120 kg K2O ha-1, while different organic manures were applied to subplots [no organic manure (O0), cow manure (Oc), poultry manure (Op), and vermicompost (Ov);all at 5 t·ha-1] as part of a split-plot experimental design with three replicates. In both seasons, significant differences in growth parameters including number of tillers hill-1, soil-plant analysis development (SPAD) values, total dry matter, yield, and yield components were observed in plants supplied with different inorganic fertilizers. The 100% NPK (I100) fertilizer produced the maximum yield but similar yields were achieved in plots supplied with 50% NPK (I50) and 75% NPK (I75). Significant differences in growth and yield parameters were also found in crops supplied with organic manures. Although identical quantities were supplied, Op produced the best growth parameters in both seasons including total dry matter, yield, and yield components. Oc also performed well. Combining inorganic and organic fertilizers demonstrated that I50 together with Op (5 t·ha-1) provided similar growth, total dry matter, and yield parameters to I100 in both seasons. Oc (5 t·ha-1) plus I75 also achieved similar yields to I100. This study demonstrates that the combined application of inorganic fertilizers and organic manures has the potential to reduce chemical fertilizer usage without decreasing the yield of hybrid rice, and can enhance the growth, yield, and yield components of Palethwe-1.

Analysis and comparison of nutrient contents in different animal manures from Beijing suburbs

Manure samples were collected by floor scrapings in animal stables from Beijing suburbs. Total nitrogen (TN), total phosphorus (TP), and total potassium (TK) were analyzed by conventional wet chemical methods. All manures showed a high variability in nutrient contents. Nutrients contents in different animal manures were significantly different. TN and TK contents in layer manures were higher than swine and dairy manures

Influence of Organic Manures on Yield and Quality of Rice (<i>Oryza sativa</i>L.) and Blackgram (<i>Vigna mungo</i>L.) in Rice-Blackgram Cropping Sequence

Field experiments were conducted at Tamil Nadu Agricultural University, Coimbatore during rabi and summer seasons of 2007-2008 and 2008-2009 to study the influence of organic manures (enriched farmyard manure compost, vermicompost, farmyard manure + neem cake, enriched farmyard manure compost + vermicompost + farmyard manure, composted poultry manure and enriched poultry manure compost) and recommended NPK fertilizers on yield and quality of rice and blackgram in rice-blackgram cropping sequence. Based on field experiments, it was found that the application of enriched poultry manure compost on equal N basis (2.3 t·ha-1) recorded higher yield attributes and grain yield of rice (4675 kg·ha-1 in 2007 and 4953 kg·ha-1 in 2008), which was however comparable with composted poultry manure. The application of recommended NPK fertilizers recorded higher physical characteristics and cooking qualities of rice, which was comparable with enriched poultry manure compost. Higher sensory score was registered in enriched poultry manure compost as compared to recommended NPK through fertilizers. After harvesting of rice, the residual effect of enriched poultry manure compost and composted poultry manure applied to preceding rice crop improved yield attributes and yield of succeeding blackgram.

Heavy metals pollution in poultry and livestock feeds and manures under intensive farming in Jiangsu Province, China

The heavy metals pollution in poultry and livestock feeds and manures under intensive farming in Jiangsu Province was investigated. 97 feed and manure samples were sampled from 31 farming plants in 10 major cities of Jiangsu. 14 metals, including Zn, Cu, Pb, Cd, Cr, Ni, Mo, Mn, Ba, Co, Sr, Ti, As and Hg, were analyzed after samples acid digestion. The results showed that the most feed samples contained high concentration of metals exceeding National Hygienical Standard for Feeds. Meanwhile, it was found that Cu, Zn, Pb, Cd and Cr concentrations in animal manures were also high, for example, Cu concentration in a manure sample reached to as much as 1726 3 mg/kg. Heavy metals loading quantities in soil per year were then calculated when metals contaminated organic fertilizers were applied, and its effects on soil environmental quality were further evaluated.

Nitrogen Mineralization from Animal Manures and Its Relation to Organic N Fractions

Laboratory aerobic incubation was conducted for 161 d to study N mineralization and the changes of organic N fractions of nine different manures（3 chicken manures, 3 pig manures and 3 cattle manures） from different farms/locations. Results indicated that significant（P〈0.01 or P〈0.001） difference existed in N mineralization between manures. The rapid N mineralization in manures occurred during 56 to 84 d of incubation. First order exponential model can be used to describe N mineralization from chicken manures and pig manures, while quadratic equation can predict mineralization of organic N from cattle manures. An average of 21, 19 and 13% added organic N from chicken manure, pig manure and cattle manure was mineralized during 161 d of incubation. Amino acid-N was the main source of N mineralization. The changes of amino acid-N together with ammonium N could explain significantly 97 and 96% of the variation in mineralized N from manured soils and manures. Amino acid-N and ammonium N are two main N fractions in determining N mineralization potential from manures. Amino acid-N contributed more to the mineralized N than ammonium N.

Effects of long-term application of different green manures on ferric iron reduction in a red paddy soil in Southern China

Dissimilatory Fe（Ⅲ） reduction is an important process in the geochemical cycle of iron in anoxic environment. As the main products of dissimilatory iron reduction, the Fe（Ⅱ） species accumulation could indicate the reduction ability. The effects of different green manures on Fe（Ⅲ） reduction in paddy soil were explored based on a 31-year rice-rice-winter green manure cropping experiment. Four treatments were involved, i.e., rice-rice-milk vetch （RRV）, rice-rice-rape （RRP）, rice-rice-ryegrass （RRG） and rice-rice-winter fallow （RRF）. Soils were sampled at flowering stage of milk vetch and rape （S1）, before transplantation （S2）, at tillering （S3）, jointing （S4）, and mature （S5） stages of the early rice, and after the harvest of the late rice （S6）. The contents of TFeHa （HCI-extractable total Fe）, Fe（Ⅱ）HCI （HCI-extractable Fe（Ⅱ） species） and Fe（Ⅲ）HCI （HCI- extractable Fe（Ⅲ） species） were measured. The correlations among those Fe species with selected soil environmental factors and the dynamic characteristics of Fe（Ⅱ）HCI accumulation were investigated. The results showed that TFeHc~ in RRF was significantly higher than those in the green manure treatments at most of the sampling stages. Fe（II）Ha increased rapidly after the incorporation of green manures in all treatments and kept rising with the growth of early rice. Fe（Ⅱ）Ha in RRG was quite different from those in other treatments, i.e., it reached the highest at the S2 stage, then increased slowly and became the lowest one at the S4 and S5 stages. Fe（Ⅲ）Ha showed oppositely, and Fe（Ⅱ）HCI/Fe（Ⅲ）HCI performed similarly to Fe（Ⅱ）HCI The maximum accumulation potential of Fe（Ⅱ）HCI was significantly higher in RRF, while the highest maximum reaction rate of Fe（Ⅱ）Ha accumulation appeared in RRG. Significant correlations were found between the indexes of Fe（Ⅱ）HCI accumulation and soil pH, oxidation-reduction potential （Eh） and total organic acids, respectively. In together, we found that long-term application of green manures decreased the TFeHa in red paddy soils, but promoted the ability of Fe（lll） reduction, especially the ryegrass; Fe（Ⅱ）Ha increased along with the growth of rice and was affected by soil conditions and environmental factors, especially the water and redox ability.

Effect of Zinc and Composting Time on Dynamics of Different Soluble Copper in Chicken Manures

Chicken manures added with Cu and Zn were used for composting experiment to study the dynamics of different soluble humus complexed copper （H2O-Cu,NaOH-Cu and NaOH-Na4P2O7-Cu）.The effect of zinc in compost on humus complexed copper and the relationship between humus complexed copper were also revealed.The results showed that H2O-Cu increased before the 45 d of composting and decreased thereafter.In the treatments of 1：1,2：1 and 3：1 with the added copper content increasing,H2O-Cu increased with decomposition process.Added high level zinc in manure could decrease the relative H2O-Cu content at the last stage of composting.NaOH-Cu decreased greatly with the compost proceeding.With the added copper content increasing in manure,the percentage of NaOH-Cu to total copper decreased.Added zinc had no significant impact on NaOH-Cu concentration.NaOH-Na4P2O7-Cu increased with composting.With the added copper content increasing in compost manure,the percentage of NaOH-Na4P2O7-Cu to total copper increased,and showed an increase trend with composting proceeding.Added zinc in manure increased NaOH-Na4P2O7-Cu.In composts,55-80% of extracted copper was present in NaOH fraction,10-30% in NaOH-Na4P2O7-Cu fraction,and 0-10% in H2O fraction.Whatever the added copper or zinc contents increased in manures,the distribution percent of NaOH- Na4P2O7-Cu （pressed as percent of extracted Cu） increased and that of H2O-Cu and NaOH-Cu decreased.Three extracted Cu （H2O,NaOH and Na4P2O7） were strongly correlated to each other,H2O-Cu and NaOH-Na4P2O7-Cu were significantly correlated to H2O-extracted organic C and NaOH-Na4P2O7-extracted organic C,respectively.

Nitrogen transformation in maize soil after application of different organic manures

The nitrogen transformation in maize soil after application of different organic manure was studied. The nitrogen mineralization in surface soil, NO - 3-N dynamics and distribution in soil profile, and N 2O emission were investigated. Eight treatments were laid out randomizing with three replications in 24 plots: maize plantation without fertilizer(CK1), bare soil without maize plantation and fertilization(CK2), swine manure(S1, S2), poultry manure(P1, P2), and cattle manure(C1, C2). Three manures were applied at two application levels(15 t/hm 2 and 30 t/hm 2). The results indicated that NH + 4-N in surface soil showed the same temporal pattern without much variation among different treatments. But NO - 3-N in the same layer exhibited large temporal pattern in all treatments, which was mainly due to its easy eluviations of NO - 3-N in soil, its transformation to N 2O and the influence of precipitation. The distribution of NO - 3-N in the soil profile during maize growing season showed the leaching tendency from surface soil to subsoil, which was different among the treatments. The poultry treatments showed the largest leaching tendency. The study also revealed that the emissions of N 2O were affected by the application of organic manures in the order of P2>S2>C2>P1>S1>C1>CK1>CK2. All these results showed that organic manure applications significantly affect nitrogen transformation and distribution in maize soil. Considering N 2O emission and NO - 3-N leaching, the management of organic manure in the agriculture needs further studies.

Effects of Organic Manures in Changes of Some Soil Properties at Different Incubation Periods

A laboratory incubation experiment of 60 days was carried out to observe the changes of soil pH, electrical conductivity (EC), soil organic carbon (SOC), and potassium chloride extractable nitrogen () in a soil to which three animal manures viz. cow dung (CD), chicken manure (CM) and a combination of CD and CM had been applied at a rate of 10 t·ha-1. The effects of manures varied with manure type and incubation period. Soil pH slightly increased with the incubation period up to 30 days there after it declined with time significantly (p < 0.05). There was a significant (p < 0.05) increase in EC as days of incubation increased. Organic carbon contents of manure treated soils reached its peak at 15 days of incubation and decreased thereafter with time. The content of increased significantly (p < 0.05) as incubation period increased in control and cow dung amended soils whereas there was no significant difference in contents when either chicken manure alone or cow dung and chicken manure mixed in combination. After 60 days of incubation, the highest amount of was found in cow dung plus chicken manure treated soil followed by chicken manure treatment.

General Situation of Green Manure Germplasm Resources in China and Research Progress on Decomposition Characteristics and Fertility Improvement of Green Manures

As a kind of biological fertilizer sources, green manure can improve soil fertility and the quality of agricultural products. This paper introduced the germplasm resource of green manures in the major provinces in China, mainly summarized the characteristics of decomposition and nutrients release of returning green manures to soils, as well as the influence on soil fertility and succeeding crops, with the aim to provide references for rational utilization of green manures and the scientific management of farmland nutrients.

Enhancing Biogas Production: Influence of Mixing Cow and Chicken Manures

The objectives of this study were to enhance the production of biogas through using a mixture of cow and chicken manure and to investigate the effect of digested manure on plant growth. Biogas digester consisted of a plastic polyethylene tank with a volume of 0.25 cubic meters. Cow and chicken manures were collected from certified animal and chicken farms. Mixture of manure was prepared by mixing 5 kg of chicken manure and 5 kg of cow manure together in 100 L plastic tank containing 90 L water free from chlorine. Percentage of manure in all cases was 10% (w/v). The manures were transferred to the digesters and kept in greenhouse to insure warm conditions (30°C - 39°C). Produced biogas was measured each two days and digestate samples were taken every two days for pH, EC, BOD, COD determination. Results showed increased biogas production and reached the highest quantity after 28 days and the amount of biogas produced from the mixture of cow and chicken manures was higher than the amount produced from each manure individually. Decreases in pH values were observed during biogas production followed by BOD, COD reduction. On the other hand, increases on EC values were observed. Application of digested manure in agriculture increased yield of lettuce by 75% comparing with the control sample. The study recommended using cow manure mixed with chicken manure to increase the production of biogas and to use the digested manure in agricultural.

Ammonium Dissociation for Swine and Dairy Cattle Manures

The dissociation of ammonium (NH4+) into ammonia (NH3) in wastewaters is a key factor governing atmospheric nitrogen volatilization. Relatively rich in total ammoniacal nitrogen (TAN or NH4+ plus NH3), livestock manures are most susceptible to NH3 volatilization, although indirect measurements report 5 times less NH4+ dissociation as compared to theoretical values. The objective of this study was therefore to directly measure NH4+ dissociation of two standard NH4Cl solutions (1750 and 3500 mg TAN/L), and of swine and dairy cattle manures at various dilutions and temperatures using a ammonia selective electrode (hydrogen and silver-silver chloride electrode couple) at various pH and temperatures. All solutions demonstrated NH4+ dissociation varying from theory, especially because of dissolved compounds such as atmospheric CO2. At a neutral pH, ratios of theoretical to measured [NH3-N] ranged from 1.5 to 3.5, with higher ratios corresponding to higher TAN levels. At a pH below 6, NH3 volatilization was enhanced by the shift of HCO3- to H2CO3 and CO2. With previous research projects reporting 5 times less NH3 volatilization as compared to theory, the present indicates that dissociation activity account for half of this drop with gas diffusion accounting for the other half.

Seed Potential of Ruminants Organic Manures in Sahelian Agro-Pastoral Systems

In degraded Sahelian agro-systems, livestock manures increase agricultural production and ensure natural regeneration through their selective seed potential. Yet, this seed potential that contributes to species dissemination is still poorly known. This study aimed to determine the seed potential of different livestock ruminant manures. To this end, cattle (Bos indicus), goat (Capra hircus) and sheep (Ovis aries) manures were collected in 45 distinct enclosures in the Sahelian zone of Burkina Faso following the three seasonal periods of the year. A total of 36 species in 13 families and 26 genera was identified in the coarse fraction of the three type of manure. The most abundant seeds in the manure are those of Fabaceae-mimosoideae, Fabaceae-caesalpinoideae, Rhamnaceae and Balanitaceae. The results showed that the contribution of goats to the total seed potential was 61% against 36% for sheep and 3% for cattle. The average number of seeds was 205 seeds/Kg of manure for goats, 125 seeds/Kg for sheep and 11 seeds/Kg for cattle. Depending on the collection period, the cold-dry season contributed 70% to the total annual seed potential against 22% of the hot-dry season and 8% for the rainy season. Following the species functional traits, goat spread more seeds of woody indehiscent pods (barochores species) containing one, 4 to 10 seeds with hard cores and integuments. Sheep spread more seeds of annual legumes having dehiscent pods (autochores) and more than 10 seeds. The most abundant seeds in the manure are those of agroforestry (Vachellia nilotica, Faidherbia albida, Piliostigma reticulatum), ruderal (Ipomoea eriocarpa) or invasive (Senna obtusifolia) species. The most frequently (RI Dactyloctenium aegyptium, Eleusine indica, Corchorus tridens, Sporobolus festivus and Ipomoea eriocarpa. Taxonomic and functional characteristics of the seed potential of ruminants manures shape the regeneration traits of agro-ecosystems through selective seed dissemination.

Combustion Characteristics of Animal Manures

A huge amount of waste from the cattle livestock and bird poultry are generated using as manure and solid fuel. In this work, the heat value and proximate parameters of livestock and poultry manures are described. The calorific value of manures (n = 22) was ranged from 2580 - 11,200 kcal/kg with mean value (p = 0.05) of 5333 ± 1073 kcal/kg. The effect of cattle age and additives i.e. NaNO3 and Na2WO4 in the heat value of the manures are discussed. The chemical characteristics of the emitted particulate matters (PM) and ash residues are highlighted.

Changes in heavy metal contents in animal feeds and manures in an intensive animal production region of China

The 360 feed and manure samples were collected from 150 animal farms in Jiangsu Province, China and analyzed for heavy metals. Concentrations of Zn and Cu in animal feeds were 15.9-2041.8 and undetected-392.1 mg/kg respectively, while Hg, As, Pb, Cd, and Cr in all feeds were below 10 mg/kg. Concentrations of Cu, Zn, and Cr in animal manures were 8.4-1726, 39.5-11379, and 1.0-1602 mg/kg respectively, while As, Cd, Hg, and Pb were 〈 10 mg/kg. The concentration of Cu, Zn, As and Cr in animal feed and manure were positively correlated （p 〈 0.001）, but the Cd, Hg, and Pb were not statistically correlated between the feed and the manure. Concentrations of Cu and Zn were highest in pig feed and manure, followed by poultry and dairy feeds and manures. During 1990- 2008, Cu, Zn, As, Cr, Cd contents increased by 771%, 410%, 420%, 220%, and 63% in pig manure, 212%, 95%, 200%, 791%, and -63% in dairy manure, and 181%, 197%, 1500%, 261, and 196% in poultry manure. Most of the increases occurred from 2002 to 2008, which reflects the extensive use of feed additives after 2002. In contrast, Pb and Hg in manures continuously decreased from 1990 to 2008. The results suggest that the heavy metal contents in animal manure have been greatly increased over 18 years and the contribution of manures to soil should be considered.

Manure substitution improves maize yield by promoting soil fertility and mediating the microbial community in lime concretion black soil

Synthetic nitrogen(N)fertilizer has made a great contribution to the improvement of soil fertility and productivity,but excessive application of synthetic N fertilizer may cause agroecosystem risks,such as soil acidification,groundwater contamination and biodiversity reduction.Meanwhile,organic substitution has received increasing attention for its ecologically and environmentally friendly and productivity benefits.However,the linkages between manure substitution,crop yield and the underlying microbial mechanisms remain uncertain.To bridge this gap,a three-year field experiment was conducted with five fertilization regimes:i)Control,non-fertilization;CF,conventional synthetic fertilizer application;CF_(1/2)M_(1/2),1/2 N input via synthetic fertilizer and 1/2 N input via manure;CF_(1/4)M_(3/4),1/4 N input synthetic fertilizer and 3/4 N input via manure;M,manure application.All fertilization treatments were designed to have equal N input.Our results showed that all manure substituted treatments achieved high soil fertility indexes(SFI)and productivities by increasing the soil organic carbon(SOC),total N(TN)and available phosphorus(AP)concentrations,and by altering the bacterial community diversity and composition compared with CF.SOC,AP,and the soil C:N ratio were mainly responsible for microbial community variations.The co-occurrence network revealed that SOC and AP had strong positive associations with Rhodospirillales and Burkholderiales,while TN and C:N ratio had positive and negative associations with Micromonosporaceae,respectively.These specific taxa are implicated in soil macroelement turnover.Random Forest analysis predicted that both biotic(bacterial composition and Micromonosporaceae)and abiotic(AP,SOC,SFI,and TN)factors had significant effects on crop yield.The present work strengthens our understanding of the effects of manure substitution on crop yield and provides theoretical support for optimizing fertilization strategies.

Application of organic manure as a potential strategy to alleviate the limitation of microbial resources in soybean rhizospheric and bulk soils

The development and vigor of soil microorganisms in terrestrial ecosystems are frequently constrained by the limited availability of essential elements such as carbon(C),nitrogen(N),and phosphorus(P).In this study,we investigated the impact of long-term application of varying levels of organic manure,low(7.5 Mg ha^(−1)yr^(−1)),moderate(15.0 Mg ha^(−1)yr^(−1)),and high(22.5 Mg ha^(−1)yr^(−1)),on the stoichiometry of enzymes and the structures of the microbial communities in soybean rhizospheric and bulk soils.The main goal of this research was to examine how soil microbial resource limitations in the rhizosphere respond to different long-term fertilization strategies.The soil enzymatic activities were quantified,and the structure of the microbial community was assessed by analyzing phospholipid fatty acid profiles.When compared to the bulk soil,the rhizospheric soil had significant increases in microbial biomass carbon(MBC),nitrogen(MBN),and phosphorus(MBP),with MBC increasing by 54.19 to 72.86%,MBN by 47.30 to 48.17%,and MBP by 17.37 to 208.47%.Compared with the unfertilized control(CK),the total microbial biomasses of the rhizospheric(increased by 22.80 to 90.82%)and bulk soils(increased by 10.57 to 60.54%)both exhibited increases with the application of organic manure,and the rhizospheric biomass was higher than that of bulk soil.Compared with bulk soil,the activities of C-,N-and P-acquiring enzymes of rhizospheric soil increased by 22.49,14.88,and 29.45%under high levels of organic manure,respectively.Analyses of vector length,vector angle,and scatter plots revealed that both rhizospheric and bulk soils exhibited limitations in terms of both carbon(C)and phosphorus(P)availability.The results of partial least-squares path modelling indicated that the rhizospheric soil exhibited a more pronounced response to the rate of manure application than the bulk soil.The varying reactions of rhizospheric and bulk soils to the extended application of organic manure underscore the crucial function of the rhizosphere in mitigating limitations related to microbial resources,particularly in the context of different organic manure application rates.

Excessive manure application stimulates nitrogen cycling but only weakly promotes crop yields in an acidic Ultisol:Results from a 20-year field experiment

Population growth and growing demand for livestock products produce large amounts of manure,which can be harnessed to maintain soil sustainability and crop productivity.However,the impacts of excessive manure application on crop yields,nitrogen(N)-cycling processes and microorganisms remain unknown.Here,we explored the effects of 20-year of excessive rates(18 and 27 Mg ha^(–1)yr^(–1))of pig manure application on peanut crop yields,soil nutrient contents,N-cycling processes and the abundance of N-cycling microorganisms in an acidic Ultisol in summer and winter,compared with none and a regular rate(9 Mg ha^(–1)yr^(–1))of pig manure application.Long-term excessive pig manure application,especially at the high-rate,significantly increased soil nutrient contents,the abundance of N-cycling functional genes,potential nitrification and denitrification activity,while it had a weaker effect on peanut yield and plant biomass.Compared with manure application,seasonality had a much weaker effect on N-cycling gene abundance.Random forest analysis showed that available phosphorus(AP)content was the primary predictor for N-cycling gene abundance,with significant and positive associations with all tested N-cycling genes.Our study clearly illustrated that excessive manure application would increase N-cycling gene abundance and potential N loss with relatively weak promotion of crop yields,providing significant implications for sustainable agriculture in the acidic Ultisols.

Breakthrough of Carbon-Ash Recalcitrance in Hydrochar via Molten Carbonate:Engineering Mineral-Rich Biowaste Toward Sustainable Platform Carbon Materials

The function-led design of porous hydrochar from mineral-rich biowaste for environmental applications inevitably suffers from carbon-ash recalcitrance.However,a method to alter the original carbon skeleton with ash remains elusive and hinders the availability of hydrochar.Herein,we propose a facile strategy for breaking the rigid structure of carbon-ash coupled hydrochar using phase-tunable molten carbonates.A case system was designed in which livestock manure and NaHCO3 were used to prepare the activated hydrochar,and NH3 served as the target contaminant.Due to the redox effect,we found that organic fractions significantly advanced the melting temperature of Na2CO3 below 800℃.The Na species steadily broke the carbon-ash interaction as the thermal intensity increased and transformed inorganic constituents to facilitate ash dissolution,rebuilding the hydrochar skeleton with abundant hierarchical channels and active defect edges.The surface polarity and mesopore distribution collectively governed the five cycles NH3 adsorption attenuation process.Manure hydrochar delivered favorable potential for application with a maximum overall adsorption capacity of 100.49 mg·g^(-1).Integrated spectroscopic characterization and theoretical computations revealed that incorporating NH3 on the carbon surface could transfer electrons to chemisorbed oxygen,which promoted the oxidation of pyridine-N during adsorption.This work offers deep insight into the structure function correlation of hydrochar and inspires a more rational design of engineered hydrochar from high-ash biowaste.