Cumulative Ammonia Volatilization Research Articles

Biochanin A feed supplementation alters dynamics of trace gas emissions from lamb urine-amended soil.

Sustainable growth in livestock production requires reductions in trace gas emissions on grazing lands. Urine excreta patches are hot spots for accelerated emissions of carbon and nitrogen. Ruminant dietary supplementation with the isoflavone biochanin A (BCA) has been shown to improve cattle weight gain. To determine if BCA supplementation affects urine N excretion and soil trace gas emissions, soil in microcosms was amended with urine from lambs fed 0, 0.45, or 0.90g BCA day-1. Soil gas emissions were measured over 60 days and analyzed with a linear mixed-effects model with repeated measures. On 2 days during the incubation, BCA addition across doses significantly reduced nitrous oxide emissions by 73% and methane by 98% compared to urine from non-dosed lambs. Cumulative ammonia volatilization was significantly reduced by 33% but cumulative nitrous oxide and methane emissions were not. Alterations in trace gas emissions occurred despite no change in urine N content with BCA feed supplementation. A separate laboratory incubation using urine from a non-supplemented lamb that was exogenously spiked with varying BCA concentrations supported these results: BCA significantly altered ammonia and methane emission dynamics and reduced cumulative nitrous oxide emissions by up to 41%. BCA did not change soil microbial community structure, suggesting alterations to other processes, such as soil enzyme activity, were affecting soil trace gas emissions. Overall, lamb BCA supplementation did not affect urine N but reduced ammonia volatilization, which may contribute to greater sustainability in livestock production systems.

Effects of Bio-Organic Fertilizers Substitution on Gaseous Nitrogen Losses in Rice Fields

Traditional practices for managing irrigation and fertilizer in Chinese rice fields have historically consumed large amounts of water resources and caused serious gaseous nitrogen losses (ammonia volatilization and N2O), resulting in low water and fertilizer use efficiency. While both water-saving irrigation and substituting organic fertilizer for chemical fertilizer can impact ammonia volatilization and N2O emissions, the impact of their combined application on gaseous nitrogen loss in rice fields remains unclear. To achieve this goal, we conducted a two-year experiment using two irrigation methods and three bio-organic fertilizer substitution modes. The experiment investigated the effect of different irrigation and fertilizer management techniques on gaseous nitrogen losses in rice fields. The result indicated that controlled irrigation could reduce the peak value of ammonia volatilization by 36.8~75.9% and ammonia volatilization accumulation by 45.8%. However, it also leads to a 71.4% increase in N2O accumulation emissions, resulting in a 43.0% reduction in gaseous nitrogen losses. Compared to full chemical fertilizers, bio-organic fertilizer substitution could effectively reduce the peak of N2O and ammonia volatilization. Cumulative ammonia volatilization and N2O emissions went down by 22.7~60.0% and 38.6~42.6%, respectively. This then led to a 23.4~52.9% drop in total gaseous nitrogen losses. In contrast, the utilization of controlled irrigation and bio-organic fertilizer substitution did not have a significant impact on rice yield. However, it did reduce the intensity of gaseous nitrogen loss from rice fields by 42.7% and 22.5% to 56.5%, respectively. When taken together, the substitution of bio-organic fertilizer in controlled irrigation can effectively reduce gaseous nitrogen losses while maintaining rice yields. This study has significant practical implications for reducing nitrogen loss from paddy fields, improving water and fertilizer utilization, and achieving sustainable agricultural development.

Effect of reed-biochar application on ammonia volatilization from different types of soils

The application of straw biochar in farmland in Dongting Lake area can realize the resource utilization of straw and reduce environmental risk. In 2020, a rice pot experiment was conducted to investigate the effects of different biochar application levels on ammonia volatilization rate, cumulative ammonia volatilization, pH value, and NH4+-N concentration in surface water. Six levels of reed (Miscanthus lutarioriparius) biochar amount, i.e., 0%, 1%, 2%, 4%, 6% and 8% of soil weight of the 0-20 cm column, were applied in two typical paddy soils in sou-thern China, i.e., reddish clayey soil derived from quaternary red soil and granitic sandy soil derived from granite. Compound fertilizer was applied at a rate of 200 kg N·hm-2. The results showed that biochar application resulted in significant differences in the rate and cumulative amount of ammonia volatilization between the two soils and among different biochar treatments. For the granitic sandy soil, peak ammonia volatilization under different biochar treatments appeared at the second day after fertilization, which was decreased by 23.6%-53.4%. For the reddish clayey soil, peak ammonia volatilization appeared between the 7th to 13th day after fertilization, which increased with biochar addition level. The rate of ammonia volatilization from the granitic sandy soil was generally higher than that from the reddish clayey soil. For the granitic sandy soil, addition of <4% biochar could inhibit the ammonia volatilization and cumulative volatilization amount, with the greatest reduction (46.9%) at the treatment with 2% biochar addition. The addition of biochar did not affect the pH value of surface water at the early stage of rice growth. For the reddish clayey soil, the pH value and NH4+-N concentration in the surface water increased with biochar addition level, resulting in the increases of ammonia volatilization rate and cumulative volatilization amount by 1.3-10.5 times. Biochar addition level was the key factor affecting ammonia volatilization from the two soils. Elovich equation could well fit the variation trend of cumulative ammonia volatilization with time for the two soils, with the correlation reaching extremely significant level for each treatment. Overall, the application of reed biochar could suppress ammonia volatilization from the granitic sandy soil which was nearly neutral in acidity, while would promote ammonia volatilization via increasing pH value and NH4+-N concentration of surface water for the acidic reddish clayey soil. Therefore, appropriate dosages of reed biochar should be selected for different types of soil in order to reduce nitrogen loss.

Impact of Biochar Application on Ammonia Volatilization from Paddy Fields under Controlled Irrigation

Ammonia volatilization is an important nitrogen loss pathway in the paddy field ecosystem which leads to low nitrogen-utilization efficiency and severe atmospheric pollution. To reveal the influence and the mechanism of biochar application on ammonia volatilization from paddy fields under controlled irrigation, field experiments were conducted in the Taihu Lake Basin in China. The experiment consisted of three levels of biochar application (0, 20, and 40 t·ha−1) and two types of irrigation management (controlled irrigation and flood irrigation). Increasing ammonia volatilization occurred after fertilization. Biochar application reduced the cumulative ammonia volatilization from controlled-irrigation paddy fields, compared with non-biochar treatment. The cumulative ammonia volatilization in controlled-irrigation paddy fields with 40 t·ha−1 biochar application was reduced by 12.27%. The decrease in ammonia volatilization was related to the change in soil physical and soil physical–chemical properties and soil microbial activities. The high biochar application (40 t·ha−1) increased the NH4+-N content in soil (p &lt; 0.01) and soil solution (p &lt;0.05), increased by 64.98% and 19.72%, respectively. The application also increased the soil urease activity (p &lt; 0.01), and high biochar application (40 t·ha−1) increased soil urease activity by 33.70%. Ammonia volatilization from paddy fields was significantly correlated with the nitrogen concentration (p &lt; 0.01) in the soil solution and soil urease activity (p &lt; 0.05). Meanwhile, the abundance of ammonia monooxygenase subunit A (AOA) and ammonia-oxidizing bacteria (AOB) with biochar application under controlled irrigation showed an increasing trend with rice growth. The long-term application of biochar may have a relatively strong potential to inhibit ammonia volatilization. In general, the combined application of controlled irrigation and biochar provides an eco-friendly strategy for reducing farmland N loss and improving paddy field productivity.

Effects of fertilizer under different dripline spacings on summer maize in northern China

Maximizing grain yields with effective fertilization technologies and minimizing nitrogen losses is essential in agroecosystems. In this research, we conducted a two-year field experiment to explore whether dripline spacing and fertilization rate would affect maize grain yield. Two dripline spacings (i.e., one drip line per row of maize with a row space of 60 cm and one drip line per two rows of maize) and two fertilization rates (i.e., high fertilization level: N, 180 kg ha−1; P2O5, 90 kg ha−1; and K2O, 90 kg ha−1 and low level: N, 139.5 kg ha−1; P2O5, 76.5 kg ha−1; and K2O, 76.5 kg ha−1) were employed in this research. The results showed that maize yield was significantly affected by both dripline spacing and fertilization rate. The maize yield was 10.2% higher in the treatment with one drip line per two rows than that in the treatment with one drip line per row. Maize yield increased by 10.9% at the high fertilization level compared to that at the low fertilization level. The quantity of cumulative ammonia volatilization was reduced by 15.1% with one drip line per two rows compared to that with one drip line per row, whereas it increased by 26.9% at the high fertilization level compared with that at the low fertilization level. These results indicated that one drip line per two rows with a high fertilization rate increased the yield and could reduce the environmental burden, which may be economically beneficial and environmentally sound for maize fertigation for green agricultural development.

Effect of Biochar and Chemical Fertilizer Mixture on Ammonia Volatilization and Phosphorus Fixation

In order to explore biochar fertilizer addition, two types of industrial wastes (YM) and lees (JZ) and agricultural waste corn stover (JG) were used as the raw materials to make biochar, and the biochar was modified to make smoke-modified biochar (M-YM). The culture test method was used to study the law of ammonia volatilization and phosphorus fixation over a certain period of time with the different fertilizer ratios of the four biochars. We aimed to provide a scientific basis for the agricultural utilization of biochar. The results show that:① The cumulative volatilization and volatilization rate of ammonia of the four kinds of biochar with different fertilizer ratios were as follows:A1 > A2 > A3 (A1:2.25 g urea; A2:2.25g urea +2.25 g chlorination potassium; A3:2.25 g urea +2.25 g potassium dihydrogen phosphate). The addition of potassium chloride and potassium dihydrogen phosphate in urea reduced ammonia volatilization, and the cumulative ammonia volatilization and volatilization rate of different biochars under all chemical fertilizer ratios was JZ > M-YM > YM > JG; ② The amount of phosphorus by biochars fixation under the B1, B2, and B3 treatments (B1:0.4 g potassium dihydrogen phosphate; B2:0.4 g potassium dihydrogen phosphate +0.3 g urea; B3:0.4 g potassium dihydrogen phosphate +0.3 g potassium chloride) all increased and then decreased. Then, the fixation amount of phosphorus not significantly changed in period from 30th to 60th day. Among four biochar, the fixation rate of phosphorus was the highest under the B1 treatment.With the ratios of B1, B2, and B3 fertilizers, the order of the fixation rate of the four biochars to phosphorus was:M-YM > YM > JG > JZ. Therefore, in order to reduce the volatilization of ammonia in nitrogen fertilizers in agricultural fertilization, potassium chloride and potassium dihydrogen phosphate can be added to urea. At the same time, in the fixation of phosphorus, increasing the particle size of biochar may weaken the phosphorous fixation ability.

Sewage sludge-derived hydrochar that inhibits ammonia volatilization, improves soil nitrogen retention and rice nitrogen utilization.

Hydrothermal carbonization (HTC) is a promising technique for treating sewage sludge. In this study, three sewage sludge-derived hydrochars produced with water (SSHW), 1wt% magnesium citrate (SSHM) solution, and 1wt% magnesium citrate mixed with 1wt% sulfuric acid (SSHMS) solution were applied to columns of packed paddy soil. We evaluated the effects of these differently modified sewage sludge-hydrochars on ammonia volatilization, soil nitrogen (N) retention and rice growth. Results showed that compared to the control, SSHMS reduced the cumulative ammonia volatilization determined after three split application of N-fertilizer. SSHM and SSHMS both reduced the yield-scale ammonia volatilization by 20.3% and 41.2% respectively. Moreover, the addition of three sewage sludge-derived hydrochars increased soil ammonium-N retention after the first supplementary fertilization; however, after the second supplementary fertilization, only SSHMS addition significantly increased soil ammonium-N retention. Of the three hydrochars tested, SSHMS has the strongest effects on soil ammonium-N retention and inhibition of ammonium-N loss in floodwater. This was attributed to increased ammonium sorption driven by SSHMS's lower surface pH and porous diameter, larger adsorption porous volume and higher abundance of carboxyl functional groups. Additionally, the increased soil N retention increased grain N content and yield. Our results provide a novel method to valorize sewage sludge into a valuable fertilizer that if applied to paddy soil it can inhibit ammonia volatilization, N loss in floodwater, and promote N use efficiency by rice, with positive implications for sustainable rice production.

Modeling ammonia volatilization following urea application to winter cereal fields in the United Kingdom by a revised biogeochemical model

Urea accounts for over half of the global ammonia volatilization from synthetic nitrogen fertilization. Process-oriented models, such as the widely applied DeNitrification DeComposition 9.5 version (DNDC95), are expected to predict ammonia volatilization from agricultural urea applications under various conditions. However, compared to the wind-tunnel ammonia observations of a nationwide, seven-site/ten-case network in the United Kingdom, the DNDC95 greatly underestimated the ammonia volatilization from winter cereal fields applied with urea at a constant dose. The model was revised in this study mainly through (i) newly parameterizing the effects of clay fraction, plant standings and canopy wetting on ammonia release from the soil solution, and (ii) re-calibrating the parameters of the urea hydrolysis function and the original parameterizations of wind, soil temperature and moisture effects on ammonia volatilization using the observations in one case of the network. Next, the performances of the revised model (DNDC95_NH3) in simulating grain yield, full crop nitrogen uptake, cumulative ammonia volatilization (CAV) and daily ammonia fluxes were evaluated using the observations of these variables in the other nine network cases. The DNDC95_NH3 performed considerably better than the DNDC95. Particularly, the slopes of the zero-intercept regression for the observations versus simulations decreased from 1.97 to 0.86 and 1.65 to 0.75 for the CAV and daily ammonia fluxes, respectively. In addition, the number of the cases with significant discrepancies between simulated and observed CAV was reduced from six of the nine network cases to only two. The simulations by the revised model for these two cases showed a significant underestimation and an extremely large overestimation, respectively. However, reasons especially for the significant overestimation still remain unclear. Future studies still need to diagnose and solve the other existing problems so as to further improve the model's performance.

Ammonia Volatilization in Acidic Mine Soils Applied with Livestock Manure Compost and Liming Materials

To investigate the possibility of ammonia volatilization in mine lands limed, we conducted an incubation experiment with treating livestock manure compost as an organic fertilizer and dolomite and oyster shell as a liming material. For trapping ammonia volatilized, installing boric acid in a closed system was efficient, with a recovery of 101.2±3.7%. Treating compost and liming material increased soil pH to a range of 5.75-5.88 for a metal-mine soil and 6.02-6.06 for a coal-mine soil. Ammonium-N in soils decreased rapidly with time during early stage of incubation, but nitrate-N changed little. Accumulated ammonia volatilization during incubation was negligible, less than 0.3 mg N kg-1, and only 0.4-0.5% of ammonium-N was volatilized during incubation. Ammonium fixation by clay minerals and immobilization by soil microbes possibly account for the decrease in concentration of ammonium-N. From these results, we concluded that nitrogen loss by ammonium volatilization would be significantly low when acidic mine soils treated with livestock manure compost and liming materials were neutralized to slightly acidic condition. Cumulative ammonia volatilization in (a) metal and (b) coal mine soils after treating compost (Com), compost and dolomite (Com+Dol), and compost and oyster shell (Com+Oys).

Prolonged sampling time increases correlation between wind tunnel and integrated horizontal flux method

Agriculture is still the main source of NH3 emissions. Consequently, ammonia reduction and monitoring are included in the strict EU targets. Unfortunately, the main issue with the quantification of NH3 emissions is that some uncertainties are still related to NH3 volatilization measurements, mainly because of the absence of a standard measurement technique.This study compares two different methods for measuring NH3 fluxes: the Integrated Horizontal Flux (IHF) method used with glass tubes and the wind tunnels (WT) with acid traps, in order to provide further insights into quantification of NH3 emissions. Specifically, three field trials were carried out, using different fertilizers on bare soil: urea, raw manure and liquid separated digestate from Mediterranean buffalo cows (Bubalus bubalis L.).Results show that the same diurnal flux variations for both methods was observed, except for those in urea trials, mainly because of the dynamics of urea volatilization. Generally, WT underestimated ammonia emissions, especially during the first six hours of experimentation, since the fixed air speed inside the tunnel is lower than the outside wind speed at the same height. Cumulative ammonia volatilization measured with WT differs from those measured with IHF by 32% (urea), 43% (raw manure) and 46% (liquid separated digestate), respectively. Moreover, WT estimations seemed to be affected by a short exposition time of the acid traps, demonstrating a poor correlation of IHF and WT method within 2–3 h. Indeed, linear correlation between two methods was improved to R2 = 0.92, by increasing the minimum samplers exposition time up to 3 h.

Control Effect of Side Deep Fertilization with Slow-release Fertilizer on Ammonia Volatilization from Paddy Fields

In order to reduce the ammonia volatilization in paddy fields, seven treatments were evaluated. These included three slow-release nitrogen fertilizers[sulfur-coated urea (SCU); resin-coated urea (RCU); release bulk blending fertilizer (RBB)], two fertilization modes[single base fertilization (B) and combined with panicle fertilizer (BF)], and conventional split fertilization (CN). The effects of side deep fertilization for slow-release nitrogen fertilizers on ammonia volatilization and surface water nitrogen dynamics were examined using a rice transplanter with a fertilizer sowing mechanism in the Taihu Lake region. The results showed that total nitrogen and ammonium nitrogen concentration in the surface water of the SCU treatment in the base period were higher, and those for RCU and RBB were lower than in the CN treatment. The cumulative ammonia volatilization during the whole rice season varied among different types of slow-release nitrogen fertilizers from 3.84% to 28.17% of the total N applied. The nitrogen loss from ammonia volatilization using the three slow-release nitrogen fertilizers was decreased when compared with conventional split fertilization. The ammonia volatilization loss exhibited the following relationship for the treatments:CN, B-SCU > BF-SCU, BF-RBB, BF-RCU, B-RBB, and B-RCU. When the slow-release nitrogen fertilizers were applied in single base fertilization, the total ammonia volatilization for the SCU was significantly higher than those for the RCU and RBB, while no significant differences were detected when these three slow-release fertilizers were combined with panicle fertilizer. Moreover, although the ammonia volatilization of BF-SCU was lower than that of B-SCU, those of BF-RCU and BF-RBB were higher than those with the B-RCU and B-RBB treatments, respectively. There are no significant differences for nitrogen volatilization when any of these three different fertilizers are applied as B or BF. The results for the emissions during ammonia volatilization during different stages indicated that the ammonia volatilization of SCU at the basal-tillering fertilization stage (7.54%) and the tillering-panicle fertilization stage (16.04%) were higher than those of the panicle fertilization-mature stage. The N loss from ammonia volatilization for RBB in the base-tillering fertilization stage (2.91%) increased more than in the tillering-panicle fertilization stage and panicle fertilization-mature stage. For RCU treatment, the highest rate for ammonia volatilization was detected at the panicle fertilization-mature stage (2.75%). Compared with the single base fertilization mode, ammonia volatilization during the panicle fertilization-mature stage was increased when combined with panicle fertilizer (BF) for the slow-release fertilizer. There was no obvious correlation between the N loss with ammonia volatilization for the three slow-release nitrogen fertilizers and the concentration of ammonium nitrogen in surface water during the panicle fertilization-mature stage.

Ammonia Volatilization of Zinc Sulfate‐Coated and NBPT‐Treated Urea Fertilizers

Core Ideas Combining Zn sulfate‐coated urea with low percent NBPT improved ammonia volatilization control in low pH soil when compared to the recommended NBPT application rate. Combining Zn sulfate‐coated urea with boron compounds provided ammonia volatility control. The inhibitory effect of urea coated with Zn sulfate alone on ammonia volatilization is influenced by soil properties. A study was conducted to determine ammonia loss from surface‐broadcast urea, urea treated with three rates of N‐(n‐butyl) thiophosphoric triamide (NBPT), and experimental zinc sulfate (ZnSO4)‐coated urea (ZSCU) fertilizers with or without urease inhibitors. Four trials were conducted in environmentally regulated boxes over a 14‐d period. Cumulative ammonia loss from urea was 13.98, 15.57, 23.07, and 27.74% of applied N for the Mowata, Crowley H, Crowley L, and Kinder soils, respectively. Cumulative ammonia loss from urea was greater than all rates of NBPT‐treated urea (5.57–13.35%) and ZSCU fertilizer containing urease inhibitors (2.63–11.50%) across soil types. The number of days after fertilization when the maximum rate of ammonia loss occurred increased with each incremental increase in NBPT rate for the Mowata and Crowley L soils, increased between the 0.3 and 0.6 g kg−1 NBPT rates for the Crowley H soil, and increased between the 0.6 and 0.9 g kg−1 NBPT rates for the Kinder soil. Only one of the experimental ZSCU fertilizers (zinc sulfate‐coated urea with boron and NBPT [ZUN]; Crowley H soil only) increased the number of days after fertilization when the maximum rate of ammonia loss occurred; however, the volatilization rate was lower than urea for all ZSCU fertilizers across soils. The ZUN and ZUC were the most effective ZSCU fertilizer in minimizing cumulative ammonia volatilization by 58 to 81%. The ZSCU fertilizers have the potential to reduce ammonia losses as compared to urea; however, ZSCU fertilizers with B and NBPT were the most effective.

Effect of Straw Incorporation and Domestic Sewage Irrigation on Ammonia Volatilization from Paddy Fields

A pot experiment was conducted to study the effect of straw returning and domestic sewage irrigation on the dynamics of NH4+-N concentration and pH in the flood water, and ammonia volatilization of paddy fields. The results showed that the NH4+-N concentration in flood water was significantly increased by wheat straw returning while significantly decreased by domestic sewage irrigation. The cumulative ammonia volatilization in the whole rice season under tap water irrigation and straw removal treatment was 58.29 kg·hm-2, accounting for 24.29% of the total N applied. The N loss ratio of ammonia volatilization was significantly increased to 45.66% by wheat straw returning, while significantly decreased to 17.26% under straw removal and 32.72% under straw returning by domestic sewage irrigation. Significant positive interaction was observed between straw incorporation and domestic sewage irrigation on ammonia volatilization loss. The average N loss from ammonia volatilization during the tillering stage was the highest among the three fertilization stages, accounting for 7.38%-24.44% of the total N applied. In addition, ammonia volatilization fluxes showed a significant positive correlation with the flood water NH4+-N concentration, irrespective of the irrigation water, but had no significant correlation with pH. These results indicated that straw returning increased ammonia volatilization losses, whereas domestic sewage irrigation could effectively reduce ammonia volatilization losses and simultaneously replace 44.41% of chemical nitrogen fertilizer by the N contained in the domestic sewage. The combination of domestic sewage irrigation and straw returning would be an ecological and environmental-friendly measure for rice nitrogen management in Taihu Lake region.

Lysimeter study of nitrogen losses and nitrogen use efficiency of Northern Chinese wheat

A study was conducted in the lysimeters and rain-out shelter facility at Shandong Agricultural University to investigate the impact of nitrogen (N) fertilization management practices and irrigation on the losses of N and N use efficiencies of winter wheat in the Huang Huai Hai Plains of northern China. 4 factors, each with two levels, including wheat varieties (SM15 and JM19), irrigation level (well water and deficit water), N fertilizer type (manure fertilizer and urea), N fertilizer rates (90 and 180kg Nha−1) were applied in duplicate over three wheat growing seasons from 2009 to 2012. Ammonia volatilization rates (AVR) were highest immediately following fertilizer application and declined over 20 days after fertilization, AVR following urea is significantly greater than following manure application and is largely affected by soil NH4+-N concentrations. Cumulative ammonia volatilization (CAV) from urea was approximately three times that from manure. AV accounts for most of N losses and may account for 25% or more of applied N. Leaching losses increased with N fertilization concentration. Pre-winter leaching losses accounted for 69.6–100% of total leaching loss. Total N losses through AV and leaching during the whole wheat growing season were estimated to range from 30 to 60% of applied N. Nitrogen use efficiency (NUE), and N uptake efficiency (NUpE) of the cultivar SM15 is 10.1 and 19.8% greater than JM19 by average under well watered conditions, respectively, but NUE and N utilization efficiency (NUtE) of JM19 were 17.5% and 21.8% higher than SM15 under water stress condition, respectively. In addition, the difference of crop N use efficiency (NUEc) and crop N uptake efficiency (NUpEc) between two varieties was inconsistent to NUE and NUpE. The following results were implicated from this study: (1) ammonia volatilization could be reduced by 66.6% through manure application instead of urea application; (2) reducing fertilizer and irrigation supply during pre-winter stage could be a effective method to reduce N loss in the region; (3) all treatments in this study lead to progressively lower soil fertility except for the 180kg Nha−1 manure which is able to maintain soil fertility; (4) wheat variety, N fertilizer level, irrigation amount and their interactions have obviously impact on NUE parameters.

Bioleached sludge composting drastically reducing ammonia volatilization as well as decreasing bulking agent dosage and improving compost quality: A case study

Sludge bioleaching technology with Acidithiobacillus species has been commercially adopted for improving advanced dewatering of sludge in China since 2010. However, up to now, little information on bioleached dewatered sludge (BS) composting is available. Here, we report the changes of physicochemical and biological properties in BS composting and evaluate compost product quality compared to conventional dewatered sludge (CS) composting in an engineering scale composting facility. The results showed that the amount of bulking agents required in BS composting was only about 10% of CS composting to obtain optimum moisture content, reducing about 700kg bulking agents per ton fresh sludge. pH of BS composting mixture was slightly lower consistently by about 0.2–0.3 pH units than that in CS mixture in the first 30days. Organic matter biodegradation in BS system mainly occurred in the first 9days of composting. In spite of higher content of NH4+-N was found in BS mixture in related to CS mixture; unexpectedly the cumulative ammonia volatilization in the former was only 51% of the latter, indicating that BS composting drastically reduced nitrogen loss. Compared to CS composting system, the relative lower pH, the higher intensity of microbial assimilation, and the presence of water soluble Fe in BS system might jointly reduce ammonia volatilization. Consequently, BS compost product exhibited higher fertilizer values (N+P2O5+K2O=8.38%) as well as lower heavy metal levels due to the solubilization of sludge-borne heavy metals during bioleaching process. Therefore, composting of BS possesses more advantages over the CS composting process.

Characteristics of soil ammonia volatilization and the absorption and utilization of nitrogen, phosphorus and potassium of pepper under slow-release fertilizer application

采用室内扩散模拟试验研究了施用大颗粒尿素(PUR)、辣椒专用复混肥(LCCF)、辣椒专用缓释复混肥(LSRF)土壤的氨挥发特性, 并采用土培试验研究了LSRF、LCCF、普通复合肥(OCCF)、市场非包膜缓释复合肥(MSRF)对'渝椒五号'和'改良早丰'辣椒产量、氮磷钾养分吸收利用、土壤有机质及酶活性的影响, 探讨LSRF的应用效果。结果显示, 室内扩散模拟试验中, 前28 d氨释放速率总体表现为PUR>LCCF>LSRF>不施肥(CK), 28 d以后LSRF的氨释放速率略高于PUR和LCCF处理。培养70 d时, PUR、LSRF和LCCF的氨挥发量分别为71.87 mg·kg^-1、54.29 mg·kg^-1和63.49 mg·kg^-1, LSRF比PUR和LCCF分别降低了24.5%和11.7%。土培试验中, LSRF处理显著提高了2个辣椒品种的果实重量, '渝椒五号'和'改良早丰'分别较OCCF处理增产64.7%和33.8%。与OCCF处理相比较, LSRF处理增加了土壤有机质含量、土壤脲酶、蔗糖酶和过氧化氢酶活性, 提高了辣椒对氮磷钾养分的吸收利用。'渝椒五号'和'改良早丰'LSRF处理的氮素表观利用率较OCCF处理分别增加62.5%和123.1%, '改良早丰'和'渝椒五号'LSRF处理的磷素表观利用率分别较OCCF处理提高了14.0倍和3.2倍, 钾素表观利用率分别较OCCF处理提高了28.7% 和120.9%。

Effects of irrigation and nitrogen application on ammonia volatilization in solar greenhouse soils in winter-spring cucumber cultivation

Ammonia volatilization characteristics in fertilized and non-fertilized belts of greenhouse soils were investigated under different irrigation and nitrogen application treatments during winter-spring cucumber cultivation via the venting method.Also differences in ammonia volatilization among water-saving irrigation,reduced nitrogen treatment and traditional water/nitrogen treatments were analyzed and discussed.From the study,peak ammonia volatilization rate was on 7 days after basal fertilization in the solar greenhouse soil.Compared with traditional nitrogen treatment,the peak value for 25%-reduction in nitrogen fertilization dropped by 18.2%~34.3%.While peak ammonia volatilization rate was on the first day in the fertilization belt,it was on the fifth day in the non-fertilization belt after topdressing.Also compared with traditional treatments,the peak value for 25%-reduction in nitrogen fertilization also dropped by 12.3%~37.2% and that for water-saving irrigation treatment increased by 3.9%~47.0%.Ammonia volatilization and loss in the fertilization belt of greenhouse soils mainly occurred during cucumber blooming and initial fruiting periods,which were respectively 1.07~1.50 and 1.06~1.27 times those of the non-fertilization belt.No significant differences in ammonia volatilization and loss existed between fertilization and non-fertilization belts of greenhouse soils during cucumber full-fruit period and end-fruit periods.Ammonia volatilization rate increased with(0~10 cm) soil ammonium nitrogen content and improvement in(5 cm) soil temperature.However,a negative correlation existed between(0~10 cm) soil water content and ammonia volatilization rate.Cumulative ammonia volatilization was 11.4~26.6 kg.hm 2 during the entire cucumber growth season.Compared with traditional nitrogen and irrigation treatments,cumulative ammonia volatilization in the 25%-reduction in nitrogen fertilization dropped by 20.8%~22.2%.Also water-saving irrigation treatments concurrently improved cumulative ammonia volatilization by 0~4.51%.The analysis showed that appropriate reductions in nitrogen fertilization significantly limited ammonia volatilization and enhanced irrigation/nitrogen fertilizer efficiency in solar greenhouse soils in Hebei Province.While water-saving also significantly improved irrigation/nitrogen fertilizer efficiency,it failed to significantly reduce ammonia volatilization.Irrigation water-use efficiency of the 25%-reduction in nitrogen fertilization improved by 2.6%~5.9% over traditional nitrogen treatment.Compared with traditional irrigation,agronomic efficiency of nitrogen in water-saving irrigation increased by 13.9%~75.0%.

Nitrogen Sources and Timing Effects on Nitrogen Loss and Uptake in Delayed Flood Rice

Field experiments were conducted in 2009 and 2010 in Louisiana and Mississippi to evaluate ammonia volatilization loss and subsequent effects on apparent nitrogen recovery efficiency (ANRE) and grain yield for rice (Oryza sativa L.). A semi‐open static chamber approach was used to measure ammonia volatilization loss from multiple N sources applied 10 days before flood (dbf) at the rate of 168 kg N ha−1. Cumulative ammonia volatilization losses for urea for Louisiana environments were 19 and 33% compared to 7% for both Mississippi environments. Urea + [N‐(n‐butyl) thiophosphoric triamide] (NBPT), urea + NBPT + dicyandiamide (DCD), and ammonium sulfate (AS) all minimized volatilization losses over all environments (range of 1.9–4.9%). Additionally, ammonia volatilization data fitted to the Gompertz model demonstrated that urea + NBPT and urea + NBPT + DCD had longer lag phases (7.2–7.7 d) relative to urea, AS, and urea + ammonium sulfate (UAS) blend (3.6 d). The same N sources and rate of N was applied 10, 7, 4, and 1 dbf to determine the effects on ANRE and yield. Apparent N recovery efficiency ranged from 43 to 71%. Grain yield was influenced by application time for two environments. Nitrogen application 10 dbf resulted in the least grain yield and yields tended to increase with fewer days between application and permanent flood. In Louisiana, urea + NBPT and urea + NBPT + DCD resulted in yields greater than urea alone. Where volatilization potential is substantial, NBPT should be included with the urea application to protect yield potential.

Ammonia volatilization from crop residues and frozen green manure crops

Agricultural systems can lose substantial amounts of nitrogen (N). To protect the environment, the European Union (EU) has adopted several directives that set goals to limit N losses. National Emission Ceilings (NEC) are prescribed in the NEC directive for nitrogen oxides and ammonia. Crop residues may contribute to ammonia volatilization, but sufficient information on their contribution to the national ammonia volatilization is lacking. Experiments were carried out with the aim to assess the ammonia volatilization of crop residues left on the soil surface or incorporated into the soil under the conditions met in practice in the Netherlands during late autumn and winter. Ammonia emission from residues of broccoli, leek, sugar beet, cut grass, fodder radish (fresh and frozen) and yellow mustard (frozen) was studied during two winter seasons using volatilization chambers. Residues were either placed on top of soil or mixed with soil. Mixing residues with soil gave insignificant ammonia volatilization, whereas volatilization was 5–16 percent of the N content of residues when placed on top of soil. Ammonia volatilization started after at least 4 days. Total ammonia volatilization was related to C/N-ratio and N concentration of the plant material. After 37 days, cumulative ammonia volatilization was negligible from plant material with N concentration below 2 percent, and was 10 percent of the N content of plant material with 4 percent N. These observations can be explained by decomposition of plant material by micro-organisms. After an initial built up of the microbial population, NH 4 + that is not needed for their own growth is released and can easily emit as NH 3 at the soil surface. The results of the experiments were used to estimate the contribution of crop residues to ammonia volatilization in the Netherlands. Crop residues of arable crops and residues of pasture topping may contribute more than 3 million kg NH 3–N to the national ammonia volatilization of the Netherlands, being more than 3 percent of the national emissions in 2005. This contribution should therefore be considered when focusing on the national ceilings for ammonia emissions.

Environmental Losses of Soil-applied Nitrogen Sources in Lowbush Blueberry Production

Environmental losses of soil-applied nitrogen fertilizers were examined during 2004 in commercial wild blueberry fields in the vegetative phase of production in Nova Scotia (NS) and Prince Edward Island (PE). A randomized complete-block experimental design with five treatments, five replications, a plot size of 8 × 6 m, and 2-m buffers between plots was used. Treatments consisted of a control (no fertilizer application) and nitrogen applications (N at 35 kg·ha-1) of ammonium sulphate (AS), urea (U), diammonium phosphate (DAP), and sulfur-coated urea (SCU). Nitrogen applications occurred on 19 May and 9 June at the Kemptown (NS) and Mount Vernon (PE) sites, respectively. Cumulative ammonia volatilization was determined through the use of open top chambers with volatilization samples collected on 1, 2, 5, 8, and 12 days after treatment application. In addition, leaf tissue and yield component data were collected. A significant volatilization treatment effect was present at the Kemptown site with the U and SCU treatments having volatilization rates that were 321% and 207% greater than the control, respectively. Therefore, results from this study indicate that volatilization losses are significant and site specific and can negatively influence blueberry growth.