Mineralization Of Organic Nitrogen Research Articles

Effect of Media Nitrogen Concentration on Biofilter Performance

ABSTRACT A pilot-scale biofilter was used to determine important design and operational parameters related to biofiltration of volatile organic compounds (VOCs). The importance of nitrogen availability in terms of biofilter performance was determined. Results showed that microbially accessible nitrogen (ammonia and nitrate) in the areas of highest microbial activity were depleted when toluene loading rates were 30 g/m3-h or greater. This depletion led to a marked reduction in performance in terms of the VOC elimination rate of the biofilter. The amount of nitrogen available to microorganisms can be depleted by microbial uptake of soluble nitrogen to make new biomass, stripping of ammonia, denitrification of nitrate, and leaching. Nitrogen is made available by mineralization of biomass, mineralization of organic nitrogen to soluble nitrogen, and addition of nitrogen fertilizers. Mineralization of biomass to ammonia results in the recycle of nitrogen through the system. Even though organic nitrogen in the media was present at a high concentration, its mineralization to ammonia was not fast enough to keep the media from becoming nitrogen limited during extended periods of high toluene loading. Therefore, if biofilters are designed to operate at high VOC loading rates and over long periods of time, care must be taken to assure adequate amounts of microbially available nitrogen. The threshold amount of soluble nitrogen that is needed to avoid nitrogen limitations is discussed.

Changes in water‐soluble and exchangeable ions, cation exchange capacity, and phosphorusmax in soils under alternating waterlogged and drying conditions

The effects of waterlogging and subsequent drying on pH, Eh, dissolved oxygen (DO), water soluble ions, exchangeable cations, cation exchange capacity (CEC), and phosphorus sorption capacity (Pmax) in three soils were studied (krasnozem, sandy loam, and highly organic material from a Melaleuca wetland). Fifty grams of each soil were mixed with 75 mL of distilled water, and left in a waterlogged state for 21 days. After removing a sample of the ponded water and sediment for analysis, the remaining water was discarded and the soils allowed to dry at room temperature for 21 days. All soils demonstrated a decrease in Eh, PO4, NO3 and DO, and an increase in pH, soluble organic carbon (SOC), iron (Fe), manganese (Mn), NH4, calcium (Ca), magnesium (Mg), potassium (K), and sodium (Na), in the solution phase due to waterlogging, but the magnitudes of change were greatest in soils with the higher levels of organic matter. Increases in Fe and Mn were attributed to the dissolution of Fe and Mn oxides under chemically reducing conditions. Increases in Ca, Mg, K, and Na were attributed to increased solubility of organic carbon, and from increased competition for the CEC sites due to elevated Fe and Mn concentrations. Increases in CEC due to the presence of colloids with variable charge were largely balanced by Fe and Mn. Mineralization of organic nitrogen (N) by anaerobic bacteria, and the absence of DO, was considered responsible for the accumulation of water soluble NH4. Decreases in water soluble NO3 and PO4 due to waterlogging were attributed to denitrification and sorption by amorphous Fe(OH)2, respectively. Reoxidation by drying caused increases in Eh and DO, decreases in exchangeable Fe and Mn, but had no significant effect on pH, exchangeable cations or CEC. Waterlogging nearly doubled Pmax in the krasnozem A horizon and wetland soils, and produced only small changes in the other soils. Sorption by freshly precipitated Fe(OH)2 is considered the major mechanism increasing PO4 sorption.

Seasonal trends in soil nitrogen from injected or surface‐incorporated sewage sludge applied to corn

Use of sewage sludge on cropland may contribute to nitrate leaching or runoff from fields if mineralization of organic nitrogen (N) is not in synchrony with crop N uptake. Differences in sludge application method may influence sludge N use efficiency. A two‐year field experiment was conducted to determine how method of applying lime‐stabilized digested sewage sludge in the spring affected seasonal patterns of soil mineral N. Sludge rate was such as to supply 157 kg ha‐1 plant available N as determined by State of Maryland regulations. Corn (Zea mays) yield in year 2 and corn earleaf N at tasseling in both years were significantly lower for surface‐incorporated sludge than for injected sludge, although equivalent N was applied to both. Vertical distribution of soil ammonium‐N and nitrate‐N within the surface 30 cm of soil in year 2 suggested that, compared to injected sludge, surface‐incorporated sludge lost more nitrate by leaching before the period of rapid plant N uptake. Release of nitrate was delayed by at least one month with injected as compared to surface‐incorporated sludge. In both years, soil pH and electrical conductivity measured about one month after sludge application were sufficiently high to inhibit nitrification in the injected sludge band. Residual mineral soil N remaining in the upper 30 cm of soil after plant N uptake ceased in fall was greatest with injected sludge in both years. Delayed nitrification in the injected band should be considered in planning method and timing of sludge applications to cropland.

Mineralisation of soil organic nitrogen and microbial respiration after simulated summer rainfall events in an agricultural soil

Simulated rainfall events were applied during the summer fallow period to a Western Australian agricultural soil, a loamy sand, under continuous wheat and after the second pasture phase of a 2 pasture : 1 wheat (2P : 1W) rotation. The aims of this study were to determine the change in microbial activity, amount of net and gross nitrogen (N) mineralised, and inorganic N produced after dry soil was re-wet during summer rainfall. Three irrigation treatments were applied: (i) control soils received no water, (ii) the single wet treatment received 45 mm of water on day 0 and was allowed to dry, and (iii) the multiple wet treatment received 45 mm of water on day 0 plus further applications of 5 mm on days 3 and 8. The CO2 production and N mineralisation were measured in the surface 10 cm of soil for a period of 14 days after initial irrigation. Net N mineralisation was measured from in situ incubation of soil cores and gross N mineralisation by 15N isotopic dilution. The CO2 production was measured by infrared gas analysis of air samples taken from a closed headspace above the soil. A large flush in CO2 production and gross N mineralisation occurred immediately after rewetting the dry soil. This response was short-lived and rates of CO2 production and gross N mineralisation declined rapidly after 2 days. After irrigation on day 0, CO2 production was twice as large and gross N mineralisation was slightly larger in the 2P : 1W soil than continuous wheat. Gross N mineralisation and CO2 production were not significantly different in the multiple and single wet treatments after the re-wet on day 3, but an additional flush in activity occurred in the multiple wet treatment after the re-wet on day 8. The patterns of gross N mineralisation and CO2 production corresponded to changes in the soil water content, especially in the surface 2·5 cm of soil. Net and gross N mineralised and gross N immobilised over the 14-day period after the initial re-wet were greater in the multiple wet compared with the single wet treatments under both wheat and 2P : 1W. However, gross N mineralisation was approximately 4-fold greater than net N mineralisation under wheat and 15-fold greater under 2P : 1W. The majority of gross N mineralised after simulated summer rainfall was immobilised which resulted in an increase in inorganic N within the soil profile (0-50 cm) during opening winter rains.

Sedimentation and mineralisation of organic carbon, nitrogen and phosphorus in a large humic lake, northern Sweden

Lake Ortrasket is a large (7.3 km2) and deep (64 m) humic (DOC 10 mg-L-1) lake in northern Sweden. Sediment trap data (gross sedimentation) and sediment core data (net sedimentation) has been used ...

Quantification par méthode isotopique de l'effet de la rhizosphère sur la minéralisation de l'azote (cas d'un sol ferrugineux tropical)

The rhizospheric effect on mineralization of soil organic nitrogen was quantified by comparing nitrogen mineralization in rhizospheric soil (cultivation of ryegrass, high root density plant) and in non-rhizospheric soil (soil without plant). Three different approaches showed that the plant enhances net mineralization, gross mineralization (at least 35%) and available nitrogen pool (50%). This rhizospheric effect may contribute highly to crop nitrogen supply in tropical regions.

Effects of irradiation on sludge organic carbon and nitrogen mineralization

Irradiation used to eliminate pathogens in sewage sludge may deleteriously affect properties of sludge organic matter. Three anaerobically digested, dewatered sewage sludges were irradiated with gamma-irradiation at absorption doses of 0, 6 and 12 kGy, respectively, then mixed with a soil and incubated for 16 wk. Evolved CO 2 and concentrations of NH 4 +N and NO 3 −N in the sludge-soil mixture were measured. The effects of irradiation were not consistent in the three sludges tested. Irradiation did not significantly affect sludge organic C nor N mineralization in Guelph sludge (GS). However, in sludges from Ottawa (OS) and Toronto (TS), C mineralized in irradiated treatments was less than from the non-irradiated treatments. In response to slower organic matter decomposition caused by irradiation in the OS and TS, the inorganic N concentrations were higher with irradiated than with non-irradiated in the OS, but the converse was true for the TS. This was probably related to the difference in C-to-N ratio of the organic matter (19.5 in OS and 9.5 in TS). Increasing the irradiation doses did not significantly affect inorganic N concentrations with the OS, but with the TS, the high dose (12 kGy) treatment resulted in higher C and N mineralization than did the low dose (6 kGy).

Organic carbon and nitrogen mineralization under Mediterranean climatic conditions: The effects of incubation depth

In a soil profile, temperature and humidity regimes change with depth. Under Mediterranean conditions, upper horizons are more affected by water deficits and drying-rewetting cycles than deep horizons. Our aim was to study how carbon and nitrogen mineralization are affected by depth, and special attention is paid to separating the effects of pedoclimate fromthe effects of other constraints like amount and quality of organic matter. To this end, mixtures of plant + soil material were exposed by incorporation in the field, at depths of 5, 20 and 40 cm, in nylon mesh bags. Mineralization of C and N was studied for 2 y. For all types of plant material studied ( Eucalyptus globulus, Quercus ilex and Pinus halepensis), mineralization of both carbon and nitrogen was lower at 5 cm. No differences were between 20 and 40 cm. This result, probably as a result of the higher drying of the upper-most horizons, contrasts with the usual findings on this topic. The amounts of both C and N mineralized were lower than expected, probably because plant materials were finely ground, allowing stabilization in the mineral matrix of soil. With the possible exception of Pinus, depth affected the rate of mineralization, not the relation between C and N. It is concluded that, at least under Mediterranean conditions, the pedoclimate in deep layers is more favourable to microbial activity than in upper layers, in which drought is a strong limiting factor. Reduced oxygen availability in the subsoil layers did not inhibit decomposition and mineralization to the same extent as did desiccation in the surface layer. The higher mineralization of C and N usually found in upper horizons may be attributed to the higher amount and quality of organic matter in these horizons, rather than to pedoclimatic constraints.

Mineralização do nitrogênio incorporado como material vegetal em três solos da Amazônia Central

A mineralização do N proveniente do resíduo de feijão-caupi marcado com 15N foi estudada em condições de laboratório de setembro a dezembro de 1992. O material vegetal foi incorporado em amostras dos três principais solos da Amazônia Central: dois de terra firme, classificados como latossolo amarelo e podzólico vermelho-amarelo, e um de várzea, classificado como glei pouco húmico (GP). As variações nos teores e na forma de N mineral provenientes do resíduo de caupi foram relacionadas com as características químicas dos solos estudados. No latossolo e no podzólico, a incorporação do resíduo de caupi aumentou significativamente a mineralização do N, sendo a forma amoniacal predominante, enquanto, no GP, a forma nítrica preponderou. Nos solos de terra firme, a incorporação do resíduo de caupi aumentou a mineralização do N orgânico do solo, indicando a ocorrência do efeito "priming". Após 60 dias de incubação, cerca de 30 (podzólico) a 40% (latossolo) do N proveniente do caupi foi mineralizado nos solos de terra firme, enquanto no de várzea somente 18% foi mineralizado nesse período. Tais resultados mostram o potencial que essa leguminosa apresenta como fornecedora de N para as plantas nos solos de terra firme da Amazônia Central.

Nutrient Behaviour During Post-flood Recovery of the Richmond River Estuary, Northern NSW, Australia

Dissolved and particulate inorganic and organic forms of phosphorus and nitrogen, suspended sediments, dissolved silica and physico-chemical parameters were examined in the Richmond River Estuary following a small flood event. Under flood conditions, nutrient concentrations were elevated, estuarine processes were bypassed and freshwater, sediments and nutrients were discharged directly onto the continental shelf. The Estuary recovered by way of a salt wedge penetrating landward along the channel bottom, and progressed from a small highly stratified, through a moderately stratified, to a large vertically homogeneous system. Flushing times were the dominant control on the degree to which nutrients were internally processed, with most of the river-supplied nutrients transformed under normal conditions due to very long flushing times. Dissolved inorganic phosphorus is apparently removed at low salinities by adsorption to iron and aluminium colloidal oxyhydroxides which aggregate and undergo sedimentation. At higher salinities, dissolved inorganic phosphorus is apparently desorbed due to a sharp rise in pH. Dissolved nitrate and silica were probably depleted by phytoplankton, and some nitrate may also have been removed through denitrification. As the riverine supply of nutrients is potentially nitrogen limited (i.e. low dissolved inorganic nitrogen: dissolved inorganic phosphorus), primary production for much of the year appears to be supported by the benthic flux of ammonium produced by the mineralization of particulate organic nitrogen deposited during the recovery stage. When this benthic supply of ammonium is exhausted, riverine nitrate becomes an important source of nitrogen. There also appears to be continuous wind-driven resuspension and deposition of bottom materials under the shallow well-mixed conditions that prevail during normal conditions. A three-stage (flood, recovery, normal) conceptual model is presented, which may be more applicable to highly variable Australian estuaries than the typical North American and West European estuarine models found in the literature.

Effects of Legume Live-Mulch on Crop Performance, Soil Available Nitrogen and Crop N Status in Intensive Tropical Vegetable Production

ABSTRACT In an attempt to introduce legume green manure to intensive tropical vegetable production, we studied the effects of live-mulch. Soil nitrogen, crop-N status, and yields were closely monitored in a continuous, year-round vegetable sequence from 1992 to 1995 in the rice-based lowland environment of southern Taiwan. When live-mulch was newly established at high density, vegetable yields were negatively affected. With change in proportion and spatial arrangement, inter-specific competition was reduced. Besides direct competition between live-mulch and vegetable intercrops, incorporating legume biomass into the soil resulted in immobilization of available soil nitrogen. This effect was presumably conditioned by seasonal cool temperature. Short-term negative effects of live-mulch on vegetable production were offset in the longer term by a positive influence of previous year's biomass of legume clippings on vegetable yields in 1994/95. No differences were found in mineralized soil nitrogen between no-mulch and live-mulch treatments, but there was indication that crop-N status was better in live-mulch plots. This might have resulted from a slow but sustained mineralization of soil organic nitrogen which was presumably improved by live-mulch application and was readily absorbed by vegetables. From a practical viewpoint, a live-mulch-vegetable system is probably too expensive and labour-intensive to implement for the minimal positive longer-term effects.

Influence of spatial root distribution, organic nitrogen mineralization and fertilizer application on soil interlayer ammonium

Influence of spatial root distribution, organic nitrogen mineralization and fertilizer application on soil interlayer ammonium

Organic Matter and Nitrogen Cycles in a Pine Afforested Catchment with a Shrub Layer of Adenocarpus decorticansand Cistus laurifoliusin South-eastern Spain

Organic matter and nitrogen cycles in two mediterranean woody shrubs ( Adenocarpus decorticansBoiss. and Cistus laurifoliusL.) and two pine species were investigated during 1987–1989 in a small, recently pine-afforested catchment in Sierra de los Filabres (Almerı́a Province, south-eastern Spain). Pine cover was sparse because canopy closure was not yet completed, allowing strong shrub colonization in the clearings. The aim of this study was to compare the contribution of different annual fluxes and the distribution of organic matter and nitrogen in both shrub and pine components for the entire catchment. Special emphasis was placed on the N use strategy shown by the two shrub species, a symbiotic N 2fixing species ( A. decorticans) and a non-fixing species ( C. laurifolius). Our results showed that the characteristics of C and N cycling in the Nacimiento catchment are mainly determined by the early stage of pine layer development and the significant contribution of the two shrub species differing with respect to C acquisition and N use. The pine layer was characterized by a low standing biomass, substantial percentages of needle biomass and high (net production/biomass) and (needle production/total net production) ratios. N uptake was mainly diverted to biomass increment, as shown by the substantial allocation found in this study. Overall, these results are consistent with the patterns described for even-aged stands during the early-growth phase. Retranslocation supplied 21% of the annual N requirements for pine above-ground biomass production. C. laurifoliusshowed low litter-fall return, strong retranslocation, efficient utilization of N in bulk deposition and slow decomposition, suggesting a closer, self-regulated organic matter and N-conserving behaviour than A. decorticans. On the contrary, A. decorticansshowed high leaf turnover, strong litter-fall return, low retranslocation and fast mineralization of organic matter and nitrogen, indicating that internal organic matter and N cycling is less efficient, and thus, that this species is more dependent on the soil to meet its N requirements.

Influence of spatial root distribution, organic nitrogen mineralization and fertilizer application on soil interlayer ammonium

The amount of interlayer NH 4 + -N and net mineralization of organic N were measured at periodic intervals, over a period of 10 months, in soil samples collected from a peach orchard which had been subjected to different rates of N fertilizer application. Two different groups of soil samples, designated sampling 1 and sampling 2 were collected. Soils of sampling 1 were collected from sites where the soil was heavily penetrated by tree roots and those of sampling 2 were collected from sites where the soil remained free from tree roots. In sampling 1, during the 10-month period, the concentration of interlayer NH 4 + -N showed significant variations, while in sampling 2 no significant variation was found. In sampling 1 the amount of NH 4 + -N released from the interlayers of the clay minerals were not influenced by the N fertilizer application rate. Changes in the interlayer NH 4 + -N concentrations were related to variation in net N mineralization and immobilization rates as well as to plant uptake N. It is concluded that, in our experiment, the dynamics of interlayer NH 4 + -N in soil were influenced by the spatial distribution of the tree roots and organic N mineralization, while N application influenced seasonal variation but not the total interlayer NH 4 + -N released during the experiment.

Variations in mineral nitrogen levels: the River Adour

A section of the River Adour (SW France) has been investigated to determine the role of the riparian vegetative strips (rvs) in the retention of mineral nitrogen. Entering and exiting fluxes have been measured along this segment throughout a hydrological season. The study indicates gains in mineral nitrogen (∼ 28%) during periods of low flow in the summer months, with riparian vegetation utilising 2.3 to 3.7% of the entering flux. Significant losses (∼ 50%) of nitrogen are observed in autumn, whereas minor losses are observed during the two flood events of November 1991 and June 1992 (4.6 – 4.9% of the entering flux). In winter losses of mineral nitrogen due to denitrification are small varying from 0.07% in winter, to 7% in summer, of the entering flux. The input of dissolved nitrogen through rainfall is estimated to be negligible within the zone studied. Additions of fertiliser for maize cultivation in February, May, June and July of 1992 have a significant impact on the fluxes exiting, the study zone. In May, the added nitrogen is used largely in the growth of the maize, what remains is is retained in the riparian vegetation. By contrast, in June, 27.2% of the available nitrogen added as fertiliser is found in the river. Finally, during the course of the hydrological year an increase in mineral nitrogen of 519 tonnes is observed in the area studied between Pontonx and Dax, of which only 224.8 tonnes can be ascribed to the addition of fertiliser. The remainder of this enrichment is explained by mineralisation of organic nitrogen stored in the riparian vegetative strips.

Mineralization of soil organic nitrogen solubilized by aqua ammonia fertilizer

Mineralization of soil organic nitrogen solubilized by aqua ammonia fertilizer

Dynamic transformation of sewage sludge and farmyard manure components. 1. Content of humic substances and mineralisation of organic carbon and nitrogen in incubated soils

An incubation experiment was conducted with farmyard manure (FYM) and two municipal sewage sludges (SS): one from Russia (SSR) and one from Sweden (SSS) using a sandy loam soil at 25°C for 6 weeks. The objectives were to investigate mineralisation of organic C and N and transformations of humic substances (HS). Cumulative C mineralisation was about 0.8–1% of total C and cumulative N mineralised was about 3–7% of the pre-incubation total N contents in the treatments. The organic materials contained 1.2–1.5% humic acids (HA) and 0.8–1.4% fulvic acids (FA). Incubating the soils with manures did not markedly influence soil humus composition, indicating that SS-borne organic C was not converted into HS during the short-term incubation. SSR was more resistant to decomposition than SSS, although both SS were less susceptible than FYM to changes in all parameters.

Mineralization of soil organic nitrogen solubilized by aqua ammonia fertilizer

Organic N solubilized by NH3(aq) was extracted from 15N-labelled or unlabelled soil, concentrated and added to non-extracted soil, which was incubated under aerobic conditions at 27±1°C. Gross N mineralization, gross N immobilization, and nitrification in soils with or without addition of unlabelled soluble organic N were estimated by models based on the dilution of the NH 4 + or NO inf3 sup- pools, which were labelled with 15N at the beginning of incubation. Mineralization of labelled organic N was measured by the appearance of label in the mineral N pool. Although gross N mineralization and gross N immobilization were increased in two soils between day 0 and day 7 following addition of unlabelled organic N solubilized by NH3(aq), there was no increase in net N mineralization. Solubilization of 15N-labelled organic N increased and the 15N enrichment of the soluble organic N decereased as the concentration of NH3(aq) added increased. A constant proportion of approximately one-quarter of the labelled organic N added at different rates to non-extracted soil was recovered in the mineral N pool after an incubation period of 14 days, and the availability ratios calculated from net N mineralization data were 1.1:1 and 2.1:1 for 111 and 186 mg added organic-N kg-1 soil, respectively, indicating that the mineralization of organic N was increased by solubilization.

The influence of organic nitrogen mineralization on the management of agricultural systems in the UK

Abstract. The understanding of nitrogen mineralization is central to providing good advice to ensure that nitrogen (N), from whatever source, is utilized by crops as efficiently as possible to minimize pollution. We have reviewed how mineralization is accounted for in current advice. It is clear that there is at least a qualitative understanding of the effects of soil and crop management on N mineralization and N supply, which has enabled the development of Codes of Good Agricultural Practice and fertilizer recommendations systems, based on sound scientific principles. However, to refine advice there is a need for a better quantitative understanding.Although soil organic matter (SOM) is a major source of N for crops, we are unable adequately to predict fertilizer requirement as affected by mineralization of SOM. Nitrogen returns from crop residues can vary considerably between fields; the provision of better field specific advice is restricted by our inability accurately to quantify this variability. The qualitative controls on the amount and timing of N release from ploughed grass are known, but better quantification of mineralization/immobilization over both the short‐ and long‐term and better understanding of the relationship with sward age, inputs and management are essential. Much N can also be released from pasture and lost to the environment, especially where long‐term leys have been grazed and there is a need to quantify the changing balance of mineralization and immobilization with the age of sward and N input. Whilst the overall principle of cultivation affecting mineralization is well known and appreciated, little is known about the mechanisms and quantification is only possible for a comparison of such extremes as ploughing and direct drilling.

Soil nitrogen availability in the cereal zone of South Australia .1. Soil organic carbon, total nitrogen, and nitrogen mineralisation rates

Assessments of soil nitrogen (N) availability were undertaken using soils sampled at 0-10 and 10-20 cm depths from 123 experimental sites where the responses of cereal crops to N fertilisers were tested, throughout the cereal zone of South Australia. Rates of N mineralisation and percentage N mineralisation, as determined by a laboratory aerobic incubation method, were related to soil properties. Mineralisable N (N mineralised during a Li-week incubation) of 0-10 cm soil varied from 14 to 121 kg N/ha with a median of 50 kg N/ha, and that of 10-20 cm soil, from 5 to 42 kg N/ha (median 19 kg N/ha). Mineralisable N in 0-10 cm soil accounted for 90% of total mineralisable N in 0-20 cm soil. The percentages of N mineralised were generally higher in 0-10 cm soil (0.8-12.5%, median 3.4%) than in 10-20 cm soil (0.4-8.3%, median 2.3%). Soil organic carbon (OC) and total N could be well estimated from each other, and fron! soil pH, bulk density, and held capacity, with coefficients of determination (R2) ranging from 0.64 to 0.78. Overall, either mineralisable N or percentage N mineralisation rate in the surface soils could be well estimated from soil OC, total N, C to N ratio, bulk density, field capacity, and pH (R2, 0.78-0.86 for mineralisable N, and 0.67-0.91 for percentage N mineralisation rate).