Effect of different levels of nitrogen in nutrient solution and crop system on nitrate accumulation in endive

With the objective of studying the effect of two nutrient solutions and two crop systems (greenhouse and openfield) on nitrate accumulation, incidence of tipburn and chlorophyll content, endive (cv. Cuartana) was planted in 8 L pots, filled with a mixture of coconut coir:perlite (1:1) in three different cycles C1 (winter), C2 (spring) and C3 (summer). Plants were irrigated with two nutrient solutions of different nitrate content: S1, low ([NO^?₃] = 7.91 mmol L^?1) and S2 moderate nitrate content ([NO^?₃] = 16.91 mmol L^?1). Nitrate content was determined by reflectometry, tipburn was evaluated using a qualitative scale and chlorophyll content by soil plant analysis development(SPAD) values. Plants irrigated with S2 showed higher nitrate accumulation in leaves in all cycles, however, no influence of the nutrient solution was observed on the incidence of tipburn. Greenhouse-cultivated plants accumulated more nitrates than those cultivated in open field and also showed a higher incidence of tipburn and SPAD values.     

氰在土壤中的吸附与转化

氰(C2N2)是一种具有替代溴甲烷潜力的新熏蒸剂,明确C2N2在土壤中的吸附与转化行为对C2N2的安全应用具有重要的意义.利用静态法研究了C2N2在土壤中的吸附与转化过程,土壤对C2N2的吸附速率与土壤的理化性质有关,受环境温度、土壤含水量和土壤生物的影响较少,与熏蒸浓度无关.采用气相色谱(GC)和流动注射分析仪(FIA)测定了土壤对C2N2的吸附率和C2N2在土壤中的可能转化产物.结果表明,土壤对C2N2的吸附能力很强,熏蒸2h吸附率在75％以上,熏蒸24 h吸附率在98％以上,并可快速转化为HCN、NH4+和NO3-.其中,大约20％的C2N2转化为NH4+和NO3-,13％的C2N2转化为HCN.熏蒸48 h未检测到NO2-.HCN在土壤中不稳定,可进一步转化为其他含氮化合物.     

Extraction of nitrogen from soils

Summary A roller bed and rotary end-over-end shaker were compared for the extraction of mineral N from a variety of soil types; both were equally efficient with an optimum extraction time of 30 min. However, the roller bed permitted a greater operational capacity, a faster throughput of samples, and easier identification of sample bottles compared with the end-over-end shaker. More NH₄ ⁺-N and NO₃ ^–-N (P<0.001) was recovered from soil by 2 M KCl than by any other extractant, in a soil: extractant ratio of 1 to 5 (w:v), except water, which was equally efficient at removing NO₃ ^–-N from soils.     

Sulphur and nitrogen nutrition and misting effects on the response of bluegrass to ozone,sulphur dioxide,nitrogen dioxide or their mixture

Kentucky bluegrass (Poa pratensis L.) plants, cultivars Cheri, Merion and Touchdown were grown at complete nutrition or with low S or low N. Plants were exposed to 10 ppm (v/v) O₃ for 6 h d^?i, 15 pphm SO₂ continuously, 15 pphm NO₂ continuously, or their mixture at these concentrations for 10 days. The severity of injury was much increased by misting with deionized water for 5 min twice daily, especially with SO₂ and NO₂ single gas exposures. The misting did not have consistent effects on total S, total N, leaf area or fresh weight. Exposure to O₃ decreased leaf area without affecting S or N content, while SO₂ usually increased total S and, in some cases, increased total N. Exposure to NO₂ increased total N without affecting total S, and the mixture increased both total S and total N. Low S or low N usually enhanced the effect of SO₂ or NO₂, respectively. Leaf area and fresh weight were not as responsive to the treatments as total S and total N. Rainfall outdoors may be a major meteorological factor affecting plant injury response to gaseous pollutants.     

Factors Affecting Stability and Efficiency of Ion Exchange Resins in Studies of Soil Nitrogen Transformation

Abstract

Mixtures of cation and anion exchange resins are used as part of the resin core technique to determine nitrogen transformation in forest soils as they adsorb the NH₄‐N and NO₃‐N from soil solution percolating through the incubated soil cores. In the field, the exchange resins may be subjected to a variety of conditions, involving drying, rehydration, freezing, and thawing. This paper examines how these processes affect adsorption of NH₄‐N and NO₃‐N and the stability of the resins. Lab tests were performed on the anion resin Amberlite IRA‐93, the cation resin Amberlite IR‐120, a mixture of IRA‐93 and IR‐120, and the commercially‐mixed bed resin Amberlite MB1. The background content of NO₃‐N and NH₄‐N on the resins was large and highly variable between different batches of resins in spite of a 2 M NaCl pre‐rinse. The IR‐120 cation resin that was subjected to 48 hours air‐drying contained significantly less NH₄‐N than the moist resins, while the drying of the IRA‐93 anion resin caused a significant release of NO₃‐N from resins with no N addition. Although the variation was large, the mixed bed resin MB1 indicated a release of NH₄‐N, which supports results from long term in situ deployments. A reduced adsorption of NO₃‐N was found on the IRA‐93 anion resins and the MB1 mixed bed resins that were dried prior to N addition while the dry IR‐120 cation resins adsorbec significantly less NH₄‐N than the control resin. No effect of freezing and thawing efficiency was observed on resin stability or N adsorption efficiency. Sufficient blanks that have been subjected to similar moisture changes are necessary in N limited systems with low levels of available NH₄‐N and NO₃‐N.     

Effects of nitrogen dioxide on selected soil processes

Nitrogen dioxide gas was rapidly absorbed by soil. After a 15 min incubation at 25°C, soil at a moisture content of 16% absorbed 99% of the NO₂ introduced into the gas-phase volume of a closed system. The presence of microorganisms hatl no influence on the rate of absorption of the gas by soil. The absorption of NO₂ by sandy clay loam soil was not an oxygen- or temperature-dependent process nor did it depend upon the moisture content of the soil. These physical factors acquired significance only in determining the initial rate of absorption of the gas and the rate at which NO₂ diffused through the soil. Exposure of soil to NO₂ resulted in substantial increases in the levels of NO _inf2 ^sup? N in the soil. Chemical oxidation of the NO _inf2 ^sup? N resulted in an increase in NO _inf3 ^sup? N levels. During a 14-day incubation, NO _inf2 ^sup? N concentrations in sterile soil exposed to an atmosphere containing 100 μg ml^?1 of NO₂ decreased from 190 μg g^?1 of soil to 105 μg g^?1 with an accompanying increase in NO _inf3 ^sup? N from 2 μg g^? ₁ to 63 μg g^?1 of soil. Nitrogen dioxide severely inhibited the growth of both aerobic and anaerobic asymbiotic N₂-fixing bacteria in soil. After a 48 h incubation at 25°C, soil aggregates exposed to an atmosphere containing 100 μg ml^?1 of NO₂ contained 88% and 98% fewer aerobic and anaerobic N₂-fixing bacteria, respectively. C₂H₂-reduction measurements showed that nitrogenase synthesis and activity in artificial soil aggregates amended with 2% glucose were inhibited by 20% and 48%, respectively, when exposed to atmospheric concentrations of 35 and 3.5 μg ml^?1 of NO₂, respectively.     

Residual Organic Compound Removal from Aqueous Solution Using Commercial Coconut Shell Activated Carbon Modified by a Mixture of Seven Metal Salts

The modified activated carbon (MAC) derived from commercial coconut shell activated carbon (AC) with mixture of seven metal salts was used as an adsorbent to remove target residual organic compound (sucrose) from aqueous solutions in batch modes. The results indicated that the highest adsorption capacity of sucrose onto MAC reached when the AC was modified at the ratio of impregnation of AC with mixture of seven metal salts, including nitrate silver (AgNO₃), manganese nitrate (Mn (NO₃)₂), potassium bichromate (K₂Cr₂O₇), nitrate cobalt (Co (NO₃)₂·6H₂O), nitrate copper (Cu (NO₃)₂·3H₂O), nitrate nickel (Ni (NO₃)₂·6H₂O) and nitrate iron (Fe (NO₃)₂·9H₂O) of 3% (w/w). The most appropriate conditions for sucrose adsorption onto MAC in batch experiments obtained at pH 7, contact time of 120 min, 800 mg MAC/50 mL of sucrose solution with initial concentration of 1500 mg/L. At this condition, the highest adsorption capacity of sucrose onto MAC reached 28.28 mg/g. The Langmuir, Freundlich, and Sips adsorption isothermal equilibrium models can adequately describe the adsorption properties of sucrose on MAC. The adsorption kinetic of sucrose onto MAC obeyed pseudo-first-order and pseudo-second-order models with the chemical sorption process. The saturated MAC was recovered by heat from an oven. The highest recovery efficiency of saturated MAC obtained at 180 °C in 120 min. The highest adsorption capacity of sucrose onto recovered MAC was 24.31 mg/g, appropriately adsorption capacity of initial MAC.     

Uptake and assimilation of atmospheric NO2 — N by spruce needles (Picea abies): A field study

NO₂ enters spruce needles by gas exchange through the slomata. Nitrate formed from NO₂ is reduced in the cytosol by nitrate reductase (NR), the rate limiting enzyme of the nitrogen assimilatory pathway. A linear relationship was found between the nitrate reductase activity (NRA), NO₂ concentration and the amount of N incorporated into amino acids and proteins, so that NRA was suggested as an estimate of NO₂-uptake. In the present field study, 50 spruce trees (Picea abies) have been selected, which grow in a natural habitat in a NO₂ concentration gradient in a forest crossed by a highway which is a major NO source. At part of the sites, the microclimatic conditions have been recorded, so that common models of local gas exchange of the needles could be used to estimate stomatal uptake of NO₂. NRA was investigated as a function of radiation and stomatal uptake on the day before needle sampling. Close to the highway NRA was permanently elevated with a maximum in summer. As with the laboratory results, a linear relationship between stomatal uptake and NRA was found. Total N — content of current year shoots was not affected by the additional N-source provided by airborne NO₂. The present study shows that the gas exchange models are consistent with the physiological reactions of spruce needles on a local level and therefore contribute to the validation of calculations of NO₂ dry deposition to spruce forests.     

Boron toxicity in kiwifruit plants (Actinidia deliciosa), treated with nitrate,ammonium, and a mixture of both

The objective of this research was to study the effects of nitrogen (N) forms (NO₃^–, 2.6 mM; NH₄⁺, 2.6 mM; NO₃^–, 1 mM + NH₄⁺, 1.6 mM) on the growth and mineral composition of kiwifruit plants exposed to three boron (B) levels (0.025, 0.1, 0.3 mM). The kiwifruit plants were grown in a 1:1 sand : perlite mixture and irrigated daily with nutrient solutions. Shoot height, mean shoot dry weight, the number of leaves, mean leaf dry weight, and N concentration of NH₄‐treated plants were significantly higher compared to the NO₃^– treatment at all B levels. The concentration of 0.3 mM B significantly reduced shoot height for all N treatments. Boron toxicity symptoms appeared 14 days after starting the experiment, when plants were treated with 0.1 and/or 0.3 mM B. The nitrate supply reduced the B concentration of roots, but B levels of different leaf parts were hardly affected by the N form. Furthermore, the NH₄‐N form significantly reduced the Mg concentration of the leaves.     

Casuarina and Eucalyptus response to single and multiple gaseous air pollutants

Casuarina cunninghamiana and Eucalyptus camadulensis (Egyptian var.) plants were exposed to 0.20 and 0.40 μL L^?1 O₃, SO₂ or NO₂ for 6 hr daily for 10 days. Eucalyptus plants were very sensitive to SO₂ and NO₂ and less sensitive to O₃. Casuarina plants were insensitive to the 3 gases. The rate of sorption of the 3 gases was estimated over a 10 day exposure to 0.20 μL L^?1 pollutant concentration singly and in a 3-gas mixture. Casuarina plants removed air pollutants more efficiently than Eucalyptus plants. Leaves of both species generally sorbed about the same volume of a given gas from the mixture and from the same single gas. The sorption rate over the 10 day exposure was almost constant after a higher sorption rate during the first day for both species.     

Nitrate reductase activity of soils

Dissimilatory nitrate reductase in soils is the enzyme that catalyzes the reduction of NO₃3⁻ to NO₂⁻ under anaerobic conditions. The detection of this enzyme in soils is reported, and a simple, sensitive and precise method to assay its activity is described. The method involves determination of the NO₂⁻-N produced when soil. 2,4-dinitrophenol (DNP), and KNO₃ are incubated under waterlogged conditions at 25°C for 24 h. At a certain concentration, depending on the soil type, DNP inhibits nitrite reductase but not nitrate reductase. The DNP concentration required for optimum NO₂⁻ production in five soils ranged from 5 to 300 μg DNP g⁻¹ soil. The nitrate reductase activity of six soils studied ranged from 18 to 80 μg NO₂⁻-N produced g⁻¹ soil 24 h⁻¹. Optimum activity was found at 5 mM KNO₃ and nitrate reductase was inhibited at >5 mM KNO₃. Nitrate reductase activity in soils is inactivated at temperatures above 40°C and is completely destroyed by steam sterilization. The relationship between duration of incubation and the amount of NO₂⁻-N produced showed a lag of about 10 h, but in general, thereafter, this relationship was linear for a certain period of incubation, which varied among the soils studied. The duration of the lag was reduced, but not completely eliminated, either by previous incubation for 10 h or by bubbling N₂ gas in the soil-water mixture for 3 min to remove the dissolved O₂ in the soil-water mixture before addition of NO₃⁻. The relationship between the amount of soil used and the NO₂⁻-N produced was linear unless the substrate concentration was limiting the reaction rate. Application of the Lineweaver-Burk transformation of the Michaelis-Menten equation indicated that the K_m values for nitrate reductase in Ames and Okoboji soils were 3.7 and 2.9, respectively, and the V_max values were 122 and 126μg NO₂⁻-N produced g⁻ soil 24 h⁻.     

Rapid and sensitive determination of nitrate in plant tissue using flow injection analysis

Abstract

The determination of nitrate in waters and soil extracts by the reduction of nitrate to nitrite by metallic or liquid reductants followed by the colorimetric determination of NO₂ ^‐using the Griess‐Ilosvay reaction has been automated for use with air‐segmented auto‐analyzers or flow injection techniques. However, this technique is not applicable to plant extracts as organic species in the extracts inactivate the reduction columns. The objective of this study was to develop an automated procedure that would allow the determination of NO₃ ^‐in plant extracts without the necessity of prior manual treatment. A flow injection technique was developed that successively traps and releases NO₃in an anion exchange column thereby removing pigments and other non‐ionic and cationic species that otherwise interfere with conversion of NO₃ ^‐ to NO₂ ^‐on a copperized cadmium column. This reduction step is subsequently followed by standard Griess‐Ilosvay colorimetric detection of this ion at a wavelength of 530 nm. The technique uses relatively simple and inexpensive equipment, principally a spectrophotometer equipped with a flow‐through cell and a pen recorder output, a 6‐channel peristaltic pump with accompanying tubing and a Perspex injector/commutator valve made in a laboratory workshop. The technique was found to avoid any significant interference of pigments or other organic compounds in the plant extracts, and the results compared favorably with those obtained using the manual transnitration technique. Analysis time was approximately 1.5 min per sample and could detect NO₃’ concentration as low as 0.1 ug NO₃’‐N ml/¹ in plant extracts (10 ug NO₃’‐N g‘¹of plant material).     

Optimization of Culture Conditions for the Biodegradation of Lindane by the Polypore Fungus Ganoderma australe

The performance of a lab-scale model biofilter system was investigated to treat CH₄ gas emitted from modern sanitary landfills using landfill cover soil as the filter bed medium. From the batch experiment to measure the influence of moisture content and temperature of the filter medium on CH₄ removal capacity of a biofilter system, the optimum moisture content and temperature were found to be 10–15% by weight and 25–35°C, respectively. From the model biofilter experiment to measure the influence of inlet CH₄ concentration and landfill gas inflow rate on CH₄ removal capacity of a biofilter system, it was found that the removal percentage of CH₄ increased as the inlet CH₄ concentration decreased. Up to a landfill gas inflow rate of 1,000 mL min^?1 (empty bed retention time?=?7.7 min), the CH₄ removal efficiency of the biofilter was able to reach 100%. Up to CH₄ loading rate of 278.5 g CH₄ m^?3 h^?1, the ratio of elimination capacity to CH₄ loading rate was 1 while they were 0.68 and 0.34 at CH₄ loading rate of 417.8 and 557.1 g CH₄ m^?3 h^?1, respectively. The CH₄ removal by biofilter was also confirmed by measuring the change of temperature and moisture content of the filter medium in the model biofilter. The results demonstrated that the installation of a properly managed biofilter system should be effective to reduce atmospheric CH₄ emissions from modern sanitary landfills at the low CH₄ generation stage.     

Effect of biuret on the transformation of urea in two egyptian soils

In model experiments (60 % water holding capacity and 30°C) with a loamy clay (pH 8.3) and a calcareous sand (pH 7.9) the effect of biuret upon the breakdown of urea was studied. Ammonification and nitrification occured very quickly, in case of the calcareous sand at the beginning more NH₄ was evolved. Biuret in concentration from 0.4 to 8 % maximum did not influence urea hydrolysis, however it resulted in higher NO₂-figures at the beginning of the experiments demonstrating an initial marked inhibition of the process NO₂ → NO₃ especially in the calcareous sand. The total nitrification seemed to be a little retarded but did not differ very much finally.     

一种直接测定硝化—反硝化气体的15N示踪—质谱法

本文对¹⁵N示踪—质谱法的可靠性进行了检验。结果表明,在不同的¹⁵N丰度气体样品的测定中,用两种方法(反硝化作用源的¹⁵N丰度法和气样的¹⁵N丰度法)计得的反硝化损失量基本一致,故建立起来的¹⁵N示踪—质谱法是可靠的。该方法的测定偏差随气样¹⁵N丰度的降低而增大。此外,回收率结果表明,(N₂+N₂O+NO_x)-¹⁵N累积释放量占加入NO₃-¹⁵N量的94.1％。因此,这一方法可用于直接测定氮肥的硝化—反硝化损失的研究中。     

Mercury accumulation and resistance to mercury stress in Rumex induratus and Marrubium vulgare grown in perlite

Plants of Rumex induratus and Marrubium vulgare, collected in the mining area of Almadén, were transferred to pots and grown for 2 months using perlite as substrate and treated with soluble mercury (Hg) in the applied nutrient solution. Mercury resistance, Hg bioaccumulation, and some stress biomarkers were investigated in both plant species. Mercury concentration increased in both plant species in response to Hg supply, but R. induratus was more effective in Hg accumulation. Rumex induratus and M. vulgare showed higher [Hg]_shoot‐to‐[Hg]_root ratios than other plant species. Mercury in the growth medium perlite was also investigated, distinguishing soluble, available, and total amounts of Hg in the medium. At the lower doses, one half of the applied Hg was retained by perlite. Rumex induratus decreased the available Hg fraction in perlite more than M. vulgare. The bioaccumulation factor ([Hg]_plant/[Hg]_available) was similar in both species and similar as found in previous field studies. Plant growth, water content, and chlorophyll concentration, and nutrient translocation were reduced in both plant species by the Hg. Rumex induratus showed higher resistance and Hg‐accumulation capacity than M. vulgare, due to the accumulation of thiols in roots and the absence of a lipid oxidative response.     

Effects of hardwood sawdust in potting media containing biosolids compost on plant growth,fertilizer needs,and nitrogen leaching

Abstract

Biosolids compost is used in media to grow potted plants. Nitrogen (N) in media leachate may contribute to nitrate (NO₃‐N) contamination of surface or ground water. Addition of sawdust to potting media containing biosolids compost will increase the carbon (C) to nitrogen ratio and could prevent N leaching without adversely affecting plant growth. A control medium containing 0% sawdust (v/v), 30% perlite, 50% municipal biosolids compost, and 20% sand was modified to contain either 10, 20, or 30% (v/v) fresh hardwood sawdust. The sawdust replaced either 1/3, 2/3, or all of the perlite in the control medium. Slow release fertilizer, slow plus quick release fertilizer, or no fertilizer was added to each of the four media to determine how the sawdust affected fertilizer needs. Coreopsis (Coreopsis grandiflora L.) and Rudbeckia (Rudbeckia hirta L. ’Goldstrum') were grown in pots for five months. Leachate was tested for NO₃‐N and ammonium N (NH₄‐N). Increasing amounts of sawdust produced no differences in growth of Coreopsis and few differences in the growth of Rudbeckia. The addition of slow or slow plus quick release fertilizer had little effect on the growth of Coreopsis and a greater effect on the growth of Rudbeckia. Sawdust and fertilizer had no effect on the leaching of N. Nitrogen leached primarily as NH₄‐N during the first four weeks of the experiment.     

Abstracts of Nippon Dojohiryogaku Zassui

The effects of NO₂ and O₃ exposure alone or in combination were investigated with respect to the amino acid content and composition in kidney bean. The short-term exposure (up to 8 h) to NO₂ at a concentration of 4.0 ppm alone or in combination with O₃ at a concentration of 0.4 ppm induced a rapid increase in the total amino acid content among which glutamine accounted for most of the part. Total amino acid content was also increased by O₃ exposure at 0.4 ppm after 2 hours’ lag period. Ammonium level became higher in the case of combined exposure to NO₂ and O₃, while it remained constant in the case of exposure to NO₂ and O₃ alone.

When the exposure period was extended to 2 to 7 days (long-term exposure), the increase in the content of the total amino acids was observed in most of treatments. Roots of the plants exposed to various concentrations of NO₂ and O₃ showed the most remarkable increase in the content of total amino acids. Asparagine, in place of glutamine, became a major amino acid. The percentage of asparagine was especially increased by the mixed exposure to NO₂ and O₃ These results indicate that glutamine which accumulates considerably in the early phase of the gas exposure (short-term exposure) seems to be gradually converted into other amino acids, mainly asparagine.

The correlation between the content of each amino acid, ammonium and total amino acids was calculated using data from the above experiment. Most of the amino acids in the primary and trifoliate leaves showed a high correlation with the total amino acids, suggesting that the changes in the amount of total amino acids caused by the air pollutants may be reflected not only by a particular amino acid, but also by an individual amino acid composing soluble metabolite pool. A high correlation was obtained among amino acids belonging to the serine family such as glYCine, serine, and cysteine.     

水稻幼苗根系吸收NO3-对细胞膜电位的影响

利用玻璃微电极技术测定了扬稻6号(籼稻)幼苗根尖细胞在吸收不同NO3-浓度(0.01、0.02、0.1、0.2、0.5、1.0和2.0.mmol/L)过程中膜电位的变化。结果表明,1)水稻根系吸收NO3-引起膜的去极化,去极化到一定程度后出现复极化;有小部分水稻根表现为超极化。在0.01～1.0.mmol/L范围内,去极化大小随外界NO3-浓度的增加而增加,且差异显著(P0.05)。0.01.mmol/L.NO3-产生较小的去极化,平均为3.8.mV;0.5.mmol/L.NO3-产生了最大去极化,平均为40.2.mV;当外界NO3-浓度大于1.0.mmol/L时膜电位去极化大小呈下降趋势。根系吸收不同浓度的NO3-而使膜电位去极化的进程符合Michaelis-Menten动力学。2)复极化有部分复极化和完全复极化两种。超极化也有两种:一种是膜电位先超极化,后缓慢复极化;另一种是先出现一个小的去极化,然后是较大幅度的超极化。3)运输蛋白抑制剂PGO抑制了根系吸收NO3-而产生的膜电位的响应。4)对于经CaSO4溶液预培养的水稻来说,C2+主要引起膜电位超极化。     

Effect of Adding Flue Gas Desulphurization Gypsum on the Transformation and Fate of Nitrogen during Composting

The objective of this study was to investigate the effect of adding flue gas desulphurization gypsum (FGDG) on the transformation and fate of nitrogen during co-composting of dairy manure and pressmud of a sugar refinery. The ammonia absorption of FGDG was investigated. The changes in compost temperature, pH, electrical conductivity (EC), moisture, organic matter, the C/N ratio, Kjeldahl N, NH₄⁺-N, NO₂^?-N, NO₃^?-N were assessed. The addition of FGDG did not significantly affect compost temperature, pH, EC, moisture, and organic matter degradation. However, the addition of FGDG significantly increased the NH₄⁺-N content in the compost during the thermophilic phase, and the NH₄⁺-N maximal content in the compost with FGDG (CP+G) was 59.9% more than that in the compost without FGDG (CP–G). FGDG was thought to create the formation of (NH₄)₂SO₄ and the cation exchange between NH₄⁺ and Ca²⁺. The NO₂^?-N content in the CP+G peaked on day 15, and was not observed in the CP–G. In the final compost products, the NO₃^?-N concentration in the CP–G was more than that in the CP+G, which was 1451 (CP–G) and 1109 mg·kg^?1 (CP+G) dry material. This might be due to the NO₂^? accumulation in the CP+G, which accelerated N loss in the form of N₂O. There is a strong correlation between N₂O emission and NO₂^?-N accumulation in the composting process. Compared with the original N content in the compost mixture, the N loss in CP–G and CP+G were 15.0 and 10.8%, respectively. These results revealed that NH₄⁺-N conservation effect was improved during the thermophilic phase and the total N loss was mitigated by adding FGDG into composting materials. FGDG could be utilized as a potential amendment to conserve nitrogen during composting.