scholarly journals Effects of Changing Temperature on Gross N Transformation Rates in Acidic Subtropical Forest Soils

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 894
Author(s):  
Xiaoqian Dan ◽  
Zhaoxiong Chen ◽  
Shenyan Dai ◽  
Xiaoxiang He ◽  
Zucong Cai ◽  
...  
Keyword(s):  
Temperature Change ◽  
N Mineralization ◽  
Organic N ◽  
Mineralization Rate ◽  
Soil N ◽  
Autotrophic Nitrification ◽  
N Transformation ◽  
Gross N Transformation ◽  
Increasing Temperature ◽  
N Pool

Soil temperature change caused by global warming could affect microbial-mediated soil nitrogen (N) transformations. Gross N transformation rates can provide process-based information about abiotic–biotic relationships, but most previous studies have focused on net rates. This study aimed to investigate the responses of gross rates of soil N transformation to temperature change in a subtropical acidic coniferous forest soil. A 15N tracing experiment with a temperature gradient was carried out. The results showed that gross mineralization rate of the labile organic N pool significantly increased with increasing temperature from 5 °C to 45 °C, yet the mineralization rate of the recalcitrant organic N pool showed a smaller response. An exponential response function described well the relationship between the gross rates of total N mineralization and temperature. Compared with N mineralization, the functional relationship between gross NH4+ immobilization and temperature was not so distinct, resulting in an overall significant increase in net N mineralization at higher temperatures. Heterotrophic nitrification rates increased from 5 °C to 25 °C but declined at higher temperatures. By contrast, the rate of autotrophic nitrification was very low, responding only slightly to the range of temperature change in the most temperature treatments, except for that at 35 °C to 45 °C, when autotrophic nitrification rates were found to be significantly increased. Higher rates of NO3− immobilization than gross nitrification rates resulted in negative net nitrification rates that decreased with increasing temperature. Our results suggested that, with higher temperature, the availability of soil N produced from N mineralization would significantly increase, potentially promoting plant growth and stimulating microbial activity, and that the increased NO3− retention capacity may reduce the risk of leaching and denitrification losses in this studied subtropical acidic forest.

Empirical relationships between temperature and nitrogen availability across North American forests

1992 ◽  
Vol 22 (5) ◽  
pp. 707-712 ◽  
Author(s):  
Xiwei Yin
Keyword(s):  
N Mineralization ◽  
Regional Scale ◽  
Mineral Soil ◽  
Published Data ◽  
N Availability ◽  
Net N Mineralization ◽  
Soil N ◽  
Litter Fall ◽  
Available N ◽  
N Pool

Published data were analyzed to examine whether nitrogen (N) availability varies along macroclimatic gradients in North America. Extractable N produced during 8-week aerobic laboratory incubation was used as an index of potential net N mineralization. Mean extractable N during the growing season in the forest floor plus top mineral soil was used as an index of the available N pool. Using multiple regression, potential net N mineralization was shown to increase with available N and with litter-fall N (R2 = 0.722). Available N increased with increasing total soil N and with decreasing mean January and July air temperatures (R2 = 0.770). These relationships appeared to hold also for deciduous and coniferous forests separately across regions. Results suggest that net N mineralization output under uniform temperature and moisture conditions can be generally expressed by variations of N input (litter fall) and the available soil N pool, and that the available soil N pool is predictable along a temperature gradient at a regional scale.

scholarly journals The biodiversity - N cycle relationship: a 15N tracer experiment with soil from plant mixtures of varying diversity to model N pool sizes and transformation rates

2020 ◽  
Vol 56 (7) ◽  
pp. 1047-1061 ◽  
Author(s):  
Soni Lama ◽  
Thomas Kuhn ◽  
Moritz F. Lehmann ◽  
Christoph Müller ◽  
Odette Gonzalez ◽  
...  
Keyword(s):  
N Mineralization ◽  
Tracer Experiment ◽  
Soil Samples ◽  
N Cycling ◽  
Organic N ◽  
Autotrophic Nitrification ◽  
Gross N Mineralization ◽  
Jena Experiment ◽  
N Cycle ◽  
The Jena Experiment

Abstract We conducted a 15N tracer experiment in laboratory microcosms with field-fresh soil samples from a biodiversity experiment to evaluate the relationship between grassland biodiversity and N cycling. To embrace the complexity of the N cycle, we determined N exchange between five soil N pools (labile and recalcitrant organic N, dissolved NH4+ and NO3− in soil solution, and exchangeable NH4+) and eight N transformations (gross N mineralization from labile and recalcitrant organic N, NH4+ immobilization into labile and recalcitrant organic N, autotrophic nitrification, heterotrophic nitrification, NO3− immobilization, adsorption of NH4+) expected in aerobic soils with the help of the N-cycle model Ntrace. We used grassland soil of the Jena Experiment, which includes plant mixtures with 1 to 60 species and 1 to 4 functional groups (legumes, grasses, tall herbs, small herbs). The 19 soil samples of one block of the Jena Experiment were labeled with either 15NH4+ or 15NO3- or both. In the presence of legumes, gross N mineralization and autotrophic nitrification increased significantly because of higher soil N concentrations in legume-containing plots and high microbial activity. Similarly, the presence of grasses significantly increased the soil NH4+ pool, gross N mineralization, and NH4+ immobilization, likely because of enhanced microbial biomass and activity by providing large amounts of rhizodeposits through their dense root systems. In our experiment, previously reported plant species richness effects on the N cycle, observed in a larger-scale field experiment within the Jena Experiment, were not seen. However, specific plant functional groups had a significant positive impact on the N cycling in the incubated soil samples.

The effects of long-term applications of inorganic nitrogen fertilizer on soil nitrogen in the Broadbalk Wheat Experiment

1996 ◽  
Vol 127 (3) ◽  
pp. 347-363 ◽  
Author(s):  
M. J. Glendining ◽  
D. S. Powlson ◽  
P. R. Poulton ◽  
N. J. Bradbury ◽  
D. Palazzo ◽  
...  
Keyword(s):  
N Mineralization ◽  
Inorganic Nitrogen ◽  
Organic N ◽  
Soil N ◽  
Fertilizer N ◽  
Short Term ◽  
N Content ◽  
Total Soil ◽  
Total Soil N

SUMMARYThe Broadbalk Wheat Experiment at Rothamsted (UK) includes plots given the same annual applications of inorganic nitrogen (N) fertilizer each year since 1852 (48, 96 and 144 kg N/ha, termed N1 N2 and N3 respectively). These very long-term N treatments have increased total soil N content, relative to the plot never receiving fertilizer N (N0), due to the greater return of organic N to the soil in roots, root exudates, stubble, etc (the straw is not incorporated). The application of 144 kg N/ha for 135 years has increased total soil N content by 21%, or 570 kg/ha (0–23 cm). Other plots given smaller applications of N for the same time show smaller increases; these differences were established within 30 years. Increases in total soil N content have been detected after 20 years in the plot given 192 kg N/ha since 1968 (N4).There was a proportionally greater increase in N mineralization. Crop uptake of mineralized N was typically 12–30 kg N/ha greater from the N3 and N4 treatments than the uptake of c. 30 kg N/ha from the N0 treatment. Results from laboratory incubations show the importance of recently added residues (roots, stubble, etc) on N mineralization. In short-term (2–3 week) incubations, with soil sampled at harvest, N mineralization was up to 60% greater from the N3 treatment than from N0. In long-term incubations, or in soil without recently added residues, differences between long-term fertilizer treatments were much less marked. Inputs of organic N to the soil from weeds (principally Equisetum arvense L.) to the N0–N2 plots over the last few years may have partially obscured any underlying differences in mineralization.The long-term fertilizer treatments appeared to have had no effect on soil microbial biomass N or carbon (C) content, but have increased the specific mineralization rate of the biomass (defined as N mineralized per unit of biomass).Greater N mineralization will also increase losses of N from the system, via leaching and gaseous emissions. In December 1988 the N3 and N4 plots contained respectively 14 and 23 kg/ha more inorganic N in the profile (0–100 cm) than the N0 plot, due to greater N mineralization. These small differences are important as it only requires 23 kg N/ha to be leached from Broadbalk to increase the nitrate concentration of percolating water above the 1980 EC Drinking Water Quality Directive limit of 11·3mgN/l.The use of fertilizer N has increased N mineralization due to the build-up of soil organic N. In addition, much of the organic N in Broadbalk topsoil is now derived from fertilizer N. A computer model of N mineralization on Broadbalk estimated that after applying 144 kg N/ha for 140 years, up to half of the N mineralized each year was originally derived from fertilizer N.In the short-term, the amount of fertilizer N applied usually has little direct effect on losses of N over winter. In most years little fertilizer-derived N remains in Broadbalk soil in inorganic form at harvest from applications of up to 192 kg N/ha. However, in two very dry years (1989 and 1990) large inorganic N residues remained at harvest where 144 and 192 kg N/ha had been applied, even though the crop continued to respond to fertilizer N, up to at least 240 kg N/ha.

The nitrification inhibitor dicyandiamide increases mineralization–immobilization turnover in slurry-amended grassland soil

2014 ◽  
Vol 152 (S1) ◽  
pp. 137-149 ◽  
Author(s):  
M. ERNFORS ◽  
F. P. BRENNAN ◽  
K. G. RICHARDS ◽  
K. L. MCGEOUGH ◽  
B. S. GRIFFITHS ◽  
...  
Keyword(s):  
Nitrification Inhibitor ◽  
Organic N ◽  
Nitrification Inhibitors ◽  
N Losses ◽  
N Transformations ◽  
Autotrophic Nitrification ◽  
Gross Mineralization ◽  
Soil N Mineralization ◽  
Inhibition Of Nitrification ◽  
Gross N Transformation

SUMMARYNitrification inhibitors are used in agriculture for the purpose of decreasing nitrogen (N) losses, by limiting the microbially mediated oxidation of ammonium (NH4+) to nitrate (NO3−). Successful inhibition of nitrification has been shown in numerous studies, but the extent to which inhibitors affect other N transformations in soil is largely unknown. In the present study, cattle slurry was applied to microcosms of three different grassland soils, with or without the nitrification inhibitor dicyandiamide (DCD). A solution containing NH4+and NO3−, labelled with15N either on the NH4+or the NO3−part, was mixed with the slurry before application. Gross N transformation rates were estimated using a15N tracing model. In all three soils, DCD significantly inhibited gross autotrophic nitrification, by 79–90%. Gross mineralization of recalcitrant organic N increased significantly with DCD addition in two soils, whereas gross heterotrophic nitrification from the same pool decreased with DCD addition in two soils. Fungal to bacterial ratios were not significantly affected by DCD addition. Total gross mineralization and immobilization increased significantly across the three soils when DCD was used, which suggests that DCD can cause non-target effects on soil N mineralization–immobilization turnover.

scholarly journals Subcritical water extraction to isolate kinetically different soil nitrogen fractions

2013 ◽  
Vol 10 (6) ◽  
pp. 9765-9795
Author(s):  
S. Sleutel ◽  
M. A. Kader ◽  
K. Demeestere ◽  
C. Walgraeve ◽  
J. Dewulf ◽  
...  
Keyword(s):  
N Mineralization ◽  
Subcritical Water ◽  
Abiotic Factors ◽  
Clay Mineralogy ◽  
Water Extraction ◽  
Organic N ◽  
Soil N ◽  
Subcritical Water Extraction ◽  
Mineralization Process ◽  
N Fractions

Abstract. Soil organic N is largely composed of inherently biologically labile proteinaceous N and its persistence in soil is mainly explained by stabilization through binding to minerals and other soil organic matter (SOM) components at varying strengths. In order to separate kinetically different soil N fractions we hypothesize that an approach, which isolates soil N fractions on the basis of bonding strength is required, rather than employing chemical agents or physical methods. We developed a sequential subcritical water extraction (SCWE) procedure at 100 °C, 150 °C and 200°C to isolate SOM fractions. We assessed these SCWE N fractions as predictors for aerobic and anaerobic N mineralization measured from 25 paddy soil cores in incubations. SCWE organic carbon (SCWE OC) and N (SCWE N) increased exponentially with the increase of temperature and N was extracted preferentially over OC. The efficiency of SCWE and the selectivity towards N were both lower in soils with increasingly reactive clay mineralogy. The 100–150 °C SCWE N and the 100 °C + 100–150 °C SCWE N correlated slightly better with the aerobic N mineralization than soil N content. The resulting explained percentages (46–49%) are, however, too small to allow accurate fertilizer recommendations. No correlations were found between the SCWE fractions and anaerobic N mineralization rate and consequently alternative driving factors should be looked for. Nonetheless, perhaps SCWE does, still hold potential to separate kinetically different SOM pools from upland soils, in which the bio-availability of N is more likely to be a key constraint in the N mineralization process. This in contrast to the studied paddy soils, in which N mineralization appeared to be largely decoupled from SOM quantity and quality or its availability, perhaps due to an overriding control of abiotic factors on the anaerobic N mineralization process.

scholarly journals Optimization of Nitrogen Demand in Vegetables by Different Impacts on Autotrophic and Heterotrophic Nitrification

2022 ◽  
Author(s):  
Xiaoqian Dan ◽  
Lei Meng ◽  
Mengqiu He ◽  
Xiaoxiang He ◽  
Chang Zhao ◽  
...  
Keyword(s):  
N Uptake ◽  
Heterotrophic Nitrification ◽  
Organic N ◽  
Nitrification Rate ◽  
N Accumulation ◽  
N Transformations ◽  
N Transformation ◽  
Uptake Rates ◽  
Greenhouse Soils ◽  
Gross N Transformation

Abstract Aims The understanding of the interactions between N transformations and N uptake by plants in greenhouse soils with large N accumulation is still not clear. The aim is to understand the plant- soil interactions (vegetables) on N transformations with respect to N supply. Methods 15N tracing studies were conducted in two greenhouse soils to simultaneously quantify soil gross N transformation and plant N uptake rates using the Ntraceplant tool. Results There were significant feedbacks between vegetable N uptake and soil gross N transformation rates, whether soil N accumulation occurred or not. Plant NO3– uptake rates (UNO3) were higher than the NH4+ uptake rates (UNH4), which is consistent with the NO3–-preference of the vegetable plants studied. While UNH4 was still responsible for 6-49% of total N uptake rates, significantly negative relationships between UNH4 and NH4+ immobilization rate and autotrophic nitrification rate (ONH4) were observed. ONH4 was significantly inhibited in the presence of plants and decreased with time. ONH4 (1.11 mg N kg-1 d-1) was much lower than UNO3 (8.29 mg N kg-1 d-1) in the presence of plants. However, heterotrophic nitrification rate (ONrec), which ranged from 0.10 to 8.11 mg N kg-1 d-1 was significantly stimulated and was responsible for 5-97% of NO3– production in all plant treatments, providing additional NO3– to meet N requirements of plants and microorganisms.Conclusions The management of organic N fertilizers should be improved to stimulate inorganic N production via heterotrophic nitrification in greenhouse cultivation.

Soil resources and the growth and nutrition of tree seedlings near harvest gap – forest edges in interior cedar–hemlock forests of British Columbia

2006 ◽  
Vol 36 (1) ◽  
pp. 62-76 ◽  
Author(s):  
Michael B Walters ◽  
Cleo C Lajzerowicz ◽  
K David Coates
Keyword(s):  
Soil Water ◽  
Seedling Growth ◽  
N Mineralization ◽  
Forest Edge ◽  
Organic N ◽  
Tree Seedlings ◽  
Net N Mineralization ◽  
Soil N ◽  
Forest Edges ◽  
Mineral N

Observations of tree seedlings with chlorotic foliage and stunted growth near harvest gap – forest edges in interior cedar–hemlock forests inspired a study addressing the following questions: (1) Do seedling foliar chemistry, foliar nitrogen (N) versus growth relationships, and fertilizer responses suggest N-limited seedling growth? (2) Are patterns in soil characteristics consistent with N limitation, and can interrelationships among these characteristics infer causality? Our results suggest that seedling growth near gap–forest edges was colimited by N and light availability. Soil mineral N and dissolved organic N (DON) concentrations, in situ net N mineralization, and water generally increased from forest to gap, whereas N mineralization from a laboratory incubation and total N and carbon did not vary with gap–forest position. Interrelations among variables and path analysis suggest that soil water and total soil N positively affect DON concentration and N mineralization, and proximity to mature gap–forest edge trees negatively impacts mineral N concentration and water. Collectively, our results suggest that soil N levels which limit seedling growth near gap edges can be partially explained by the direct negative impacts of gap–forest edge trees on mineral N concentrations and their indirect impacts on N cycling via soil water, and not via effects on substrate chemistry.

EFFECTS OF SOIL ACIDITY AND LIMING ON MINERALIZATION OF SOIL NITROGEN

1978 ◽  
Vol 58 (3) ◽  
pp. 331-338 ◽  
Author(s):  
M. NYBORG ◽  
P. B. HOYT
Keyword(s):  
Soil Ph ◽  
Soil Nitrogen ◽  
N Mineralization ◽  
Soil Acidity ◽  
Field Experiments ◽  
Base Saturation ◽  
Organic N ◽  
Soil N ◽  
Mineral N ◽  
Cultivated Soils

Forty acid surface soils of pH 4.0–5.6 were incubated with and without lime, and the amounts of N that were mineralized or nitrified were statistically compared with several soil acidity characteristics. In addition, three field experiments were used to find the effect of liming on N mineralization. There was no relation between the amounts of mineral N released per unit of organic N in 120 days of incubation and soil pH, base saturation or soluble Fe, Al or Mn. Despite this, liming the soils to about pH 6.7 approximately doubled the amounts of N mineralized during incubation. In the field experiments, lime increased uptake of soil N by 15–42 kg/ha in the 1st yr but only 7–10 kg/ha in the 3rd yr. Thus these laboratory and field experiments indicate that soil acidity does not restrict mineralization of organic N and although liming increases mineralization of N, it is generally a temporary effect. Nitrification in the 40 incubated soils occurred much more rapidly in cultivated soils than in virgin soils. For both the virgin and cultivated soils, nitrification decreased with decreasing soil pH. However, nitrification was not statistically related to base saturation or soluble Fe, Al or Mn. Liming established good nitrification in most of the soils and this effect did not diminish with time.

Modelling the impact of soil processes on the N and O isotope signatures of nitrate in groundwater

2021 ◽  
Author(s):  
Neus Otero ◽  
Mathieu Sebilo ◽  
Bernhard Mayer ◽  
Daren Gooddy ◽  
Dan Lapworth ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Isotope Composition ◽  
Organic N ◽  
Soil Biology ◽  
Soil N ◽  
Plant System ◽  
Soil Microbial ◽  
The Impact ◽  
Loire Valley ◽  
N Pool

<p>Stable isotope fingerprinting is widely applied to plant-soil-groundwater systems in an aim to identify and even quantify the sources of nitrates found in groundwater. Frequently, in such studies, the <em>δ</em><sup>15</sup>N and <em>δ</em><sup>18</sup>O values of nitrogen sources, such as inorganic fertilizers and manure, are directly compared to the isotope signatures of nitrate encountered in groundwater bodies below agricultural watersheds. We submit that the underlying assumptions (conservative behavior of isotope composition, rapid transfer from surface to groundwater) may only be realistic under very specific conditions whereas, in most cases, significant isotope effects exerted by the soil-microbial-plant system on the <em>δ</em><sup>15</sup>N and <em>δ</em><sup>18</sup>O values of nitrate need to be taken into account when attempting a quantitative apportionment of sources of groundwater nitrate.</p><p>We hypothesise that the isotopic signature of nitrate exported from below the root zone and migrating towards the groundwater will reflect the nitrogen isotope composition of the soil organic N pool, rather than the isotope composition of source fertilizer or organic amendments, due to processes that reset source isotope compositions within soil N pools. We test this hypothesis using empirical observations from a diversity of settings, in France, Spain and Canada with a relatively constant historic anthropogenic N source or a simple and well constrained landuse history. Furthermore, through the use of a process-based model (SIMSONIC, Billy et al., 2010) we estimate to what extent the isotopic composition of the predominant N input to the soil-microbial-plant system and the soil N pool has been modified in an attempt to consider these changes in source apportionment studies elucidating the sources of groundwater nitrate.</p><p>This research was supported through the Consortium award MUTUAL, by the LE STUDIUM® Loire Valley Institute for Advanced Studies via its SMART LOIRE VALLEY (SLV) fellowship programme, co-funded by the H2020 Marie Sklodowska-Curie programme, Contract No. 665790.</p><p> </p><p>Billy C., Billen G., Sebilo M., Birgand F., Tournebize J. (2010) Nitrogen isotopic composition of leached nitrate and soil organic matter as an indicator of denitrification in a sloping drained agricultural plot and adjacent uncultivated riparian buffer strips. Soil Biology and Biochemistry, 42, 108-117.</p>

scholarly journals Nitrogen Sources for Organic Vegetable Crops

2007 ◽  
Vol 17 (4) ◽  
pp. 431-441 ◽  
Author(s):  
Mark Gaskell ◽  
Richard Smith
Keyword(s):  
Cover Crops ◽  
N Mineralization ◽  
Cultural Practice ◽  
Organic N ◽  
Mineralization Rate ◽  
Vegetable Crops ◽  
Feather Meal ◽  
N Content ◽  
N Sources ◽  
Seabird Guano

Fertilization is the most expensive cultural practice for the increasing numbers of organic vegetable growers in the United States. Nitrogen (N) is the most important and costly nutrient to manage, and cost-effective N management practices are needed for efficient organic vegetable production. There is a wide array of organic N sources available, but they vary in cost, N content, and N availability. Compost and cover crops are commonly used sources of N for vegetables because they are relatively inexpensive and offer additional nutrients or soil improvement qualities in addition to N. Studies have shown that compost quality factors that affect N mineralization vary by source and among different batches from the same source. Compost carbon to N ratio should be equal to or less than 20:1 to assure net short-term mineralization. Cover crops also vary in N content and mineralization rate after incorporation. Leguminous cover crops decompose and release N more rapidly than grass or cereal cover crops at the preheading stage typically incorporated. Even the most efficient N-supplying composts, cover crops, or other organic N sources do not release appreciable N to a subsequent crop beyond 6 to 8 weeks from incorporation, and this burst of early N may not synchronize with N requirements for many vegetable crops. Other potential organic fertilizer N sources have been evaluated for vegetables, and they vary in N cost and N mineralization rate. Materials evaluated include seabird guano, liquid fish, feather meal, corn meal (Zea mays), blood meal, and liquid soybean meal (Glycine max) among others. Of those evaluated, feather meal, seabird guano, and liquid fish stand out as more economical organic sources of available N. Organic sources generally lack uniformity and are bulky, unstable, and inconsistent as a group, and this contributes to additional hidden management costs for organic growers. Liquid organic N sources for use in microirrigation systems may have additional disadvantages caused by loss of valuable nutrient N that is removed by filters.

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