Factors controlling N mineralization, nitrification, and nitrogen losses in an Oxisol amended with sewage sludge

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 519 ◽  
Author(s):  
J. Sierra ◽  
S. Fontaine ◽  
L. Desfontaines

Laboratory incubations and a field experiment were carried out to determine the factors controlling N mineralization and nitrification, and to estimate the N losses (leaching and volatilization) in a sewage-sludge-amended Oxisol. Aerobically digested sludge was applied at a rate equivalent to 625 kg N/ha. The incubations were conducted as a factorial experiment of temperature (20˚C, 30˚C, and 40˚C) soil water (–30 kPa and –1500 kPa) sludge type [fresh (FS) water content 6230 g/kg; dry (DS) water content 50 g/kg]. The amount of nitrifiers was determined at the beginning and at the end of the experiment. The incubation lasted 24 weeks. The field study was conducted using bare microplots (4 m) and consisted of a factorial experiment of sludge type (FS and DS) sludge placement (subsurface, I+; surface, I–). Ammonia volatilization and the profile (0–0.90 m) of mineral N concentration were measured during 6 and 29 weeks after sludge application, respectively. After 24 weeks of incubation at 40˚C and –30 kPa, net N mineralization represented 52% (FS) and 71% (DS) of the applied N. The difference between sludges was due to an initial period of N immobilization in FS. Nitrification was more sensitive than N mineralization to changes in water potential and it was fully inhibited at –1500 kPa. The introduction of a large amount of nitrifiers with FS did not modify the rate of nitrification, which was principally limited by soil acidity (pH 4.9). Although N mineralization was greatest at 30˚C, nitrification increased continuously with temperature. Nitrogen mineralization from DS was well described by the double-exponential equation. For FS, the equation was modified to take into account an immobilization-remineralization period. Sludge placement significantly affected the soil NO-3/NH+4 ratio in the field: 16 for I+ and 1.5 for I–, after 11 weeks. In the I– treatment, nitrification of the released NH+4 was limited by soil moisture because of the dry soil mulch formed a few hours after rain. At the end of the field experiment, the estimated losses of N by leaching were 432 kg N/ha for I+ and 356 kg N/ha for I–. Volatilization was not detectable in the I+ microplots and it represented only 0.5% of the applied N in the I– microplots. The results showed that placement of sludge may be a valuable tool to decrease NO-3 leaching by placing the sludge under unfavourable conditions for nitrification.

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1470
Author(s):  
Inmaculada Bautista ◽  
Luis Lado-Monserrat ◽  
Cristina Lull ◽  
Antonio Lidón

In order to assess the sustainability of silvicultural treatments in semiarid forests, it is necessary to know how they affect the nutrient dynamics in the forest. The objective of this paper is to study the effects of silvicultural treatments on the net N mineralization and the available mineral N content in the soil after 13 years following forest clearings. The treatments were carried out following a randomized block design, with four treatments and two blocks. The distance between the two blocks was less than 3 km; they were located in Chelva (CH) and Tuéjar (TU) in Valencia, Spain. Within each block, four experimental clearing treatments were carried out in 1998: T0 control; and T60, T75 and T100 where 60%, 75% and 100 of basal area was eliminated, respectively. Nitrogen dynamics were measured using the resin tube technique, with disturbed samples due to the high stoniness of the plots. Thirteen years after the experimental clearings, T100, T75 and T60 treatments showed a twofold increase in the net mineralization and nitrification rates with respect to T0 in both blocks (TU and CH). Within the plots, the highest mineralization was found in sites with no plant cover followed by those covered by undergrowth. These results can be explained in terms of the different litterfall qualities, which in turn are the result of the proportion of material originating from Pinus halepensis Mill. vs. more decomposable undergrowth residues.


2012 ◽  
Vol 58 (No. 2) ◽  
pp. 76-83 ◽  
Author(s):  
J. Černý ◽  
J. Balík ◽  
M. Kulhánek ◽  
F. Vašák ◽  
L. Peklová ◽  
...  

A field experiment was conducted on a chernozem soil to estimate fertiliser N efficiency of silage maize (Zea mays L.) by the difference method as influenced by the type of N fertiliser (mineral-MF vs. sewage sludge-SS), and N rate. Eight N treatments were included (0, 60, 120, 180, and 240 kg N/ha prior to maize sowing, 60 kg N/ha at planting in MF; 120, and 240 kg N/ha in SS. The average dry mater (DM) yields were 11.2&ndash;14.8 t/ha. Average nitrogen uptakes were 88&ndash;185 kg N/ha, when the average N contents in DM were 0.8&ndash;1.25%. Nitrogen utilization efficiency (NUE) was a relatively stable value for treatments with MF. The best use of nitrogen from MF was reached by 60 and 120 kg/ha N doses. The average values of recovery efficiency of applied N (RE<sub>N</sub>) were calculated as 41&ndash;57%. The use of SS increased the yield of silage maize by 19&ndash;25% compared to control, above all first and second year after their application. Mineral-fertilizer-N equivalents (MFE) for SS were calculated as 55 and 64%. &nbsp;


Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 444 ◽  
Author(s):  
Chen-Chi Tsai ◽  
Yu-Fang Chang

Adding biochar to excessive compost amendments may affect compost mineralization rate and nitrogen (N) availability. The objective of this 371-day incubation study was to evaluate the effects of four proportions of woody biochar (0%, 0.5%, 1.0%, and 2.0%) from lead tree (Leucaena leucocephala (Lam.) de. Wit) biochar produced at 750 °C through dynamic mineral N and N mineralization rates in three rural soils (one Oxisol and two Inceptisols). In each treatment, 5% poultry–livestock manure compost was added to serve as an excessive application. The results indicated that the biochar decreased available total inorganic nitrogen (TIN) (NO3−-N+NH4+-N) by on average 6%, 9% and 19% for 0.5%, 1.0% and 2.0% treatments, respectively. The soil type strongly influenced the impact of the biochar addition on the soil nitrogen mineralization potential, especially the soil pH and clay content. This study showed that the co-application of biochar and excessive compost benefited the agricultural soils by improving NO3−-N retention in agroecosystems. The application of biochar to these soils to combine it with excessive compost appeared to be an effective method of utilizing these soil amendments, as it diminished the net N mineralization potential and reduced the nitrate loss of the excessive added compost.


1992 ◽  
Vol 72 (1) ◽  
pp. 31-42 ◽  
Author(s):  
D. L. Burton ◽  
W. B. McGill

We compared changes in components of the N-mineralization cascade ranging from the very specific, such as a deaminase, to the highly integrated, such as biomass in a Black Chernozemic seeded to barley (Hordeum vulgare L.) under field conditions at Edmonton. Changes in enzyme content were related to soil [Formula: see text] to determine if the microbial environment changed sufficiently to exert feedback control on N mineralizing reactions and thereby to be detected. Histidase and protease were chosen as model systems for depolymerization and deamination respectively because information exists on their control in pure culture studies, on histidine content and control of histidase in soil, and assay procedures are available for soils. We observed an inverse relationship of labile histidase activity with [Formula: see text] in soils with high [Formula: see text] content and low [Formula: see text] ratio. This relationship provides indirect evidence for [Formula: see text] control of histidase content, but emphasizes that it is only one element of a complex control mechanism. Conversely, enzyme content was not rate limiting to net N mineralization, or sensitive to common control mechanisms. Biomass-C, an integrative measure of substrate supply, potential biological activity and enzymatic activity, describes net mineral-N production better than do indices of any single step. Regular spatial variability is exhibited by [Formula: see text] (and [Formula: see text]). [Formula: see text] is a product of mineralization; a substrate for immobilization, nitrification, plant uptake, and other reactions; and may also be a regulator of activity, or synthesis, of some enzymes. It is intriguing that none of the variables that influence mineral N, such as enzyme activity, biomass, or respiration, varied spatially in a statistically identifiable manner, yet [Formula: see text] did. Key words: Nitrogen mineralization, enzyme content, biomass, protease, histidase, ammonium regulation


1990 ◽  
Vol 20 (9) ◽  
pp. 1490-1497 ◽  
Author(s):  
P. J. Smethurst ◽  
E. K. S. Nambiar

The effects of clear-felling and slash removal on the distribution of organic matter and nutrients, fluxes of mineral N, and soil water and temperature were studied in a 37-year-old Pinusradiata D. Don plantation, on a sandy Podzol in southeastern Australia. Slash, litter, and the top 30 cm of soil combined contained 1957 kg N•ha−1, of which slash and litter contained 12 and 25%, respectively. Therefore, loss of slash and litter due to burning or other intensive site preparation practices would substantially reduce the N capital at the site. During the first 18 months after clear-felling, soil water content in the clear-felled area was up to 50% higher than in the uncut plantation, but there were only minor differences in soil temperature. Slash removal decreased the water content of litter, but had little effect on the water content or temperature of the soil. In the uncut plantation, N mineralized in litter and soil was completely taken up by the trees. Following clear-felling, rates of N mineralization increased in litter after 4 months, and in soil after 12 months, but changes were less pronounced with slash removal. After clear-felling, increased mineralization and the absence of trees (no uptake) led to increased concentrations of mineral N in both litter and soil, 64–76% of which was leached below the 30 cm soil depth prior to replanting. Despite leaching, concentrations of mineral N after clear-felling remained higher than those in the uncut plantation for at least 3 years.


2017 ◽  
Vol 9 (2) ◽  
pp. 1123-1128
Author(s):  
Manpreet S. Mavi ◽  
B. S. Sekhon ◽  
Jagdeep Singh ◽  
O. P. Choudhary

An understanding of the mineralization process of organic amendments in soil is required to synchronize N release with crop demand and protect the environment from excess N accumulation. Therefore, we conducted a laboratory incubation experiment to assess nitrogen mineralization potential of crop residues (rice and wheat straw) and organic manures (poultry manure, farmyard manure, cowpea and sesbania) in two benchmark soils (Typic Haplustept and Typic Ustifluvents) of semi-arid region of Punjab, India, varying in textureat field capacity moisture level at a constant temperature of 331°C. Mineralization was faster during first 7 days of incubation in Typic Haplustept and upto 14 days in Typic Ustifluvents which subsequently declined over time. In both soils, net N mineralization continued to increase with increasing period of incubation (expect with crop residues) and was significantly higher in Typic Ustifluvents (54-231µg g-1) than Typic Haplustept (33-203 µg g-1). Compared to unamended soils, percent N mineralized was highest is sesbania (35-40 %) followed by cowpea (32-37 %) and least in wheat (10-11 %) after 42 days of incubation. Thus, sesbania and cowpea may preferably be used to meetthe large N demand during early period of plant growth. Further, mineralization rate constants (k) also indicated that availability of mineral N was significantly higher with application of organic amendments than unamended control treatments in both soils. Therefore, it may be concluded that considerable economy in the use of inorganic N fertilizer can be employed if N mineralization potential of organic inputs is taken into consideration.


2021 ◽  
Vol 12 ◽  
Author(s):  
Petra Bukovská ◽  
Martin Rozmoš ◽  
Michala Kotianová ◽  
Kateřina Gančarčíková ◽  
Martin Dudáš ◽  
...  

Symbiosis between plants and arbuscular mycorrhizal (AM) fungi, involving great majority of extant plant species including most crops, is heavily implicated in plant mineral nutrition, abiotic and biotic stress tolerance, soil aggregate stabilization, as well as shaping soil microbiomes. The latter is particularly important for efficient recycling from soil to plants of nutrients such as phosphorus and nitrogen (N) bound in organic forms. Chitin is one of the most widespread polysaccharides on Earth, and contains substantial amounts of N (&gt;6% by weight). Chitin is present in insect exoskeletons and cell walls of many fungi, and can be degraded by many prokaryotic as well as eukaryotic microbes normally present in soil. However, the AM fungi seem not to have the ability to directly access N bound in chitin molecules, thus relying on microbes in their hyphosphere to gain access to this nutrient-rich resource in the process referred to as organic N mineralization. Here we show, using data from two pot experiments, both including root-free compartments amended with 15N-labeled chitin, that AM fungi can channel substantial proportions (more than 20%) of N supplied as chitin into their plants hosts within as short as 5 weeks. Further, we show that overall N losses (leaching and/or volatilization), sometimes exceeding 50% of the N supplied to the soil as chitin within several weeks, were significantly lower in mycorrhizal as compared to non-mycorrhizal pots. Surprisingly, the rate of chitin mineralization and its N utilization by the AM fungi was at least as fast as that of green manure (clover biomass), based on direct 15N labeling and tracing. This efficient N recycling from soil to plant, observed in mycorrhizal pots, was not strongly affected by the composition of AM fungal communities or environmental context (glasshouse or outdoors, additional mineral N supply to the plants or not). These results indicate that AM fungi in general can be regarded as a critical and robust soil resource with respect to complex soil processes such as organic N mineralization and recycling. More specific research is warranted into the exact molecular mechanisms and microbial players behind the observed patterns.


2011 ◽  
Vol 35 (4) ◽  
pp. 1141-1149 ◽  
Author(s):  
Sérgio Ricardo Silva ◽  
Ivo Ribeiro da Silva ◽  
Nairam Félix de Barros ◽  
Eduardo de Sá Mendonça

The use of machinery in agricultural and forest management activities frequently increases soil compaction, resulting in greater soil density and microporosity, which in turn reduces hydraulic conductivity and O2 and CO2 diffusion rates, among other negative effects. Thus, soil compaction has the potential to affect soil microbial activity and the processes involved in organic matter decomposition and nutrient cycling. This study was carried out under controlled conditions to evaluate the effect of soil compaction on microbial activity and carbon (C) and nitrogen (N) mineralization. Two Oxisols with different mineralogy were utilized: a clayey oxidic-gibbsitic Typic Acrustox and a clayey kaolinitic Xantic Haplustox (Latossolo Vermelho-Amarelo ácrico - LVA, and Latossolo Amarelo distrófico - LA, respectively, in the Brazil Soil Classification System). Eight treatments (compaction levels) were assessed for each soil type in a complete block design, with six repetitions. The experimental unit consisted of PVC rings (height 6 cm, internal diameter 4.55 cm, volume 97.6 cm³). The PVC rings were filled with enough soil mass to reach a final density of 1.05 and 1.10 kg dm-3, respectively, in the LVA and LA. Then the soil samples were wetted (0.20 kg kg-1 = 80 % of field capacity) and compacted by a hydraulic press at pressures of 0, 60, 120, 240, 360, 540, 720 and 900 kPa. After soil compression the new bulk density was calculated according to the new volume occupied by the soil. Subsequently each PVC ring was placed within a 1 L plastic pot which was then tightly closed. The soils were incubated under aerobic conditions for 35 days and the basal respiration rate (CO2-C production) was estimated in the last two weeks. After the incubation period, the following soil chemical and microbiological properties were detremined: soil microbial biomass C (C MIC), total soil organic C (TOC), total N, and mineral N (NH4+-N and NO3--N). After that, mineral N, organic N and the rate of net N mineralization was calculated. Soil compaction increased NH4+-N and net N mineralization in both, LVA and LA, and NO3--N in the LVA; diminished the rate of TOC loss in both soils and the concentration of NO3--N in the LA and CO2-C in the LVA. It also decreased the C MIC at higher compaction levels in the LA. Thus, soil compaction decreases the TOC turnover probably due to increased physical protection of soil organic matter and lower aerobic microbial activity. Therefore, it is possible to conclude that under controlled conditions, the oxidic-gibbsitic Oxisol (LVA) was more susceptible to the effects of high compaction than the kaolinitic (LA) as far as organic matter cycling is concerned; and compaction pressures above 540 kPa reduced the total and organic nitrogen in the kaolinitic soil (LA), which was attributed to gaseous N losses.


2006 ◽  
Vol 36 (1) ◽  
pp. 62-76 ◽  
Author(s):  
Michael B Walters ◽  
Cleo C Lajzerowicz ◽  
K David Coates

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.


2020 ◽  
Vol 18 (1) ◽  
pp. e1101
Author(s):  
Miguel Oliveira ◽  
Dragan Rebac ◽  
João Coutinho ◽  
Luís Ferreira ◽  
Henrique Trindade

Aim of study: To assess the interactive effects of legume species, residue placement and temperature on the net nitrogen (N) mineralization dynamics in a sandy loam soil.Area of study: Northern PortugalMaterial and methods: Cowpea (Vigna unguiculata L. Walp), faba bean (Vicia faba L.) and pea (Pisum sativum L.) residues were incorporated or applied to the soil surface at typical field yields in Europe and incubated in aerobic conditions for up to 240 days, either at 10ºC or 20ºC. Initial chemical characteristics of the soil and residues were determined. Net N mineralization was estimated at eight time intervals.Main results: Cowpea residues caused no negative changes in soil mineral N contents and were able to release the equivalent of 21-45 kg N ha-1 in 240 days. Net N immobilization (up to 17 kg N ha-1) was observed throughout most of the trial in soil with faba bean and pea residues. Differences in mineralization patterns could be attributed to the higher quality (lower carbon to nitrogen (C:N) ratios) of cowpea. Surface placement increased net N mineralized by as much as 18 kg N ha-1. The sensitivity of N mineralization to changes in temperature and residue placement varied with legume species, likely due to effects associated with differences in C:N ratios.Research highlights: Adding cowpea residues to soil is suitable when high N availability is immediately required. Faba bean or pea residues are better suited for conservation of soil N for later release.


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