Acceleration of N mineralization by release of enzymes and substrates from soil mineral particles with phosphates

The distribution and dynamics of N following green manuring of full bloom field pea (Pisum sativum ’Sirius’) were investigated in the soil mineral, microbial and non-microbial organic (NMO N) fractions at two contrasting field sites in central Alberta; one on a Chernozemic (Dark Brown) soil near Provost and the other on a Luvisolic (Gray Luvisol) soil near Rimbey. Soils were sampled four times during a 1-yr period. The accumulations of N in the whole soil and in the soil mineral and microbial fractions were similar between sites. Net mineralization rates under controlled environments were strongly influenced by pre-incubation soil conditions. The short-term dynamics of N were distinguished best between the two soils by mineralization rates normalized to selected soil fractions rather than on the basis of N accumulation in these fractions. Net N mineralization rates expressed on the basis of soil N, microbial N or NMO N were greater in the Luvisolic soil indicating a more rapid internal N cycling system and greater activity of microbial biomass. These observations were consistent with the hypothesis that higher rates are associated with soils of lower clay content. Key words: Soil N dynamics, N mineralization rate, legume green manuring, Chernozemic, Luvisolic

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Colloid-bound and dissolved phosphorus species in topsoil water extracts along a grassland transect from Cambisol to Stagnosol

Biogeosciences ◽

10.5194/bg-14-1153-2017 ◽

2017 ◽

Vol 14 (5) ◽

pp. 1153-1164 ◽

Cited By ~ 16

Author(s):

Xiaoqian Jiang ◽

Roland Bol ◽

Barbara J. Cade-Menun ◽

Volker Nischwitz ◽

Sabine Willbold ◽

...

Keyword(s):

31P Nmr ◽

Soil Mineral ◽

Phosphorus Species ◽

Dissolved Phosphorus ◽

Water Extracts ◽

Mineral Particles ◽

Soil Fractions ◽

P Fraction ◽

Total P ◽

Soil Colloids

Abstract. Phosphorus (P) species in colloidal and dissolved soil fractions may have different distributions. To understand which P species are potentially involved, we obtained water extracts from the surface soils of a gradient from Cambisol, Stagnic Cambisol to Stagnosol from temperate grassland in Germany. These were filtered to <  450 nm, and divided into three procedurally defined fractions: small-sized colloids (20–450 nm), nano-sized colloids (1–20 nm), and dissolved P (<  1 nm), using asymmetric flow field-flow fractionation (AF4), as well as filtration for solution 31P-nuclear magnetic resonance (NMR) spectroscopy. The total P of soil water extracts increased in the order Cambisol  <  Stagnic Cambisol  <  Stagnosol due to increasing contributions from the dissolved P fraction. Associations of C–Fe/Al–PO43−/pyrophosphate were absent in nano-sized (1–20 nm) colloids from the Cambisol but not in the Stagnosol. The 31P-NMR results indicated that this was accompanied by elevated portions of organic P in the order Cambisol  >  Stagnic Cambisol  >  Stagnosol. Across all soil types, elevated proportions of inositol hexakisphosphate (IHP) species (e.g., myo-, scyllo- and D-chiro-IHP) were associated with soil mineral particles (i.e., bulk soil and small-sized soil colloids), whereas other orthophosphate monoesters and phosphonates were found in the dissolved P fraction. We conclude that P species composition varies among colloidal and dissolved soil fractions after characterization using advanced techniques, i.e., AF4 and NMR. Furthermore, stagnic properties affect P speciation and availability by potentially releasing dissolved inorganic and ester-bound P forms as well as nano-sized organic matter–Fe/Al–P colloids.

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Nitrogen mineralization dynamics of meat bone meal and cattle manure as affected by the application of softwood chips biochar in soil

Suomen Maataloustieteellisen Seuran Tiedote ◽

10.33354/smst.75646 ◽

2012 ◽

pp. 1-7

Author(s):

Priit Tammeorg ◽

Tero Brandstaka ◽

Asko Simojoki ◽

Juha Helenius

Keyword(s):

N Mineralization ◽

Cattle Manure ◽

Soil Conditions ◽

Net N Mineralization ◽

Soil Mineral N ◽

Soil Mineral ◽

Bone Meal ◽

Mineral N ◽

Aerobic Soil ◽

Meat Bone Meal

We studied the impact of added biochar on the N mineralization dynamics of two organic fertilizers by incubating sandy loam soil for 133 days in controlled conditions. Biochar made from softwood chips was added to soil at 0, 4.6, 9.1 and 13.6 g kg-1 soil DM either alone, or in combination with meat bone meal (MBM) and composted cattle manure (CCM) fertilizers. Soil mineral N concentration was determined on days 0, 14, 28, 56, 84 and 133. Net N mineralization in MBM treatment was much larger than in CCM and unfertilized treatments. Constant soil moisture during the incubation provided suitable aerobic soil conditions for nitrification: after day 14, soil mineral N was dominated by nitrate in all treatments. Biochar additions decreased the mineral N concentrations in all treatments, probably because of immobilization by microbes. In unfertilized soil, the immobilisation by biochar increased steadily with application rate and time, but in MBM and CCM it started to decrease or level off after two months, possibly due to the turnover of microbial biomass.

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Uncertainties in simulating N uptake, net N mineralization, soil mineral N and N leaching in European crop rotations using process-based models

Field Crops Research ◽

10.1016/j.fcr.2020.107863 ◽

2020 ◽

Vol 255 ◽

pp. 107863 ◽

Cited By ~ 3

Author(s):

Xiaogang Yin ◽

Kurt-Christian Kersebaum ◽

Nicolas Beaudoin ◽

Julie Constantin ◽

Fu Chen ◽

...

Keyword(s):

N Mineralization ◽

N Uptake ◽

Crop Rotations ◽

N Leaching ◽

Net N Mineralization ◽

Soil Mineral N ◽

Soil Mineral ◽

Mineral N ◽

Process Based Models

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Soil mineral N dynamics beneath mixtures of leaves from legume and fruit trees in Central Amazonian multi-strata agroforests

Acta Amazonica ◽

10.1590/s0044-59672007000300001 ◽

2007 ◽

Vol 37 (3) ◽

pp. 313-320 ◽

Cited By ~ 4

Author(s):

Carol Melanie Schwendener ◽

Johannes Lehmann ◽

Marco Rondon ◽

Elisa Wandelli ◽

Erick Fernandes

Keyword(s):

N Mineralization ◽

Dominant Factor ◽

Soil N ◽

Soil Mineral N ◽

Residue Quality ◽

Soil Mineral ◽

Mineral N ◽

N Dynamics ◽

Soil N Mineralization ◽

N Release

Long term applications of leguminous green mulch could increase mineralizable nitrogen (N) beneath cupuaçu trees produced on the infertile acidic Ultisols and Oxisols of the Amazon Basin. However, low quality standing cupuaçu litter could interfere with green mulch N release and soil N mineralization. This study compared mineral N, total N, and microbial biomass N beneath cupuaçu trees grown in two different agroforestry systems, north of Manaus, Brazil, following seven years of different green mulch application rates. To test for net interactions between green mulch and cupuaçu litter, dried gliricidia and inga leaves were mixed with senescent cupuaçu leaves, surface applied to an Oxisol soil, and incubated in a greenhouse for 162 days. Leaf decomposition, N release and soil N mineralization were periodically measured in the mixed species litter treatments and compared to single species applications. The effect of legume biomass and cupuaçu litter on soil mineral N was additive implying that recommendations for green mulch applications to cupuaçu trees can be based on N dynamics of individual green mulch species. Results demonstrated that residue quality, not quantity, was the dominant factor affecting the rate of N release from leaves and soil N mineralization in a controlled environment. In the field, complex N cycling and other factors, including soil fauna, roots, and microclimatic effects, had a stronger influence on available soil N than residue quality.

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Colloid-bound and dissolved phosphorus species in topsoil water extracts along a grassland

10.5194/bg-2016-434 ◽

2016 ◽

Author(s):

Xiaoqian Jiang ◽

Roland Bol ◽

Barbara J. Cade-Menun ◽

Volker Nischwitz ◽

Sabine Willbold ◽

...

Keyword(s):

Temperate Grassland ◽

Soil Types ◽

Soil Mineral ◽

Stagnant Water ◽

Phosphorus Species ◽

Dissolved Phosphorus ◽

Water Extracts ◽

Mineral Particles ◽

P Fraction ◽

Soil Colloids

Abstract. Stagnant water conditions may release phosphorus (P) in soil solution that was formerly bound to Fe oxides. To understand which P species are potentially involved, we obtained water extracts from the surface soils of a gradient from Cambisol, Stagnic Cambisol to Stagnosol from temperate grassland, Germany. These were filtered to Stagnosol. Across all soil types, elevated proportions of inositol hexakisphosphate species (e.g. myo-, scyllo-, and D-chiro-IHP) were associated with soil mineral particles (i.e. bulk soil and small-sized soil colloids) whereas other orthophosphate monoesters and phosphonates were found in the ‘dissolved’ P fraction. We conclude that stagnic properties affect P speciation and availability by potentially releasing dissolved inorganic and ester-bound P forms as well as nano-sized organic matter-Fe/Al-P colloids.

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Experimental Study on the Effect of Freeze—Thaw Cycles on the Mineral Particle Fragmentation and Aggregation with Different Soil Types

Minerals ◽

10.3390/min11090913 ◽

2021 ◽

Vol 11 (9) ◽

pp. 913

Author(s):

Jinbang Zhai ◽

Ze Zhang ◽

Andrey Melnikov ◽

Mingyi Zhang ◽

Linzhen Yang ◽

...

Keyword(s):

Grain Size ◽

Size Distribution ◽

Soil Types ◽

Silty Clay ◽

Soil Mineral ◽

Freeze Thaw ◽

Fine Grained ◽

Mineral Particles ◽

Thaw Cycle ◽

Freeze Thaw Cycle

The freeze–thaw cycle can change the size and shape of soil particles, that is, cause fragmentation and aggregation of soil mineral particles, thereby affecting the soil structure, which, in turn, affects the soil properties. In addition, the process of soil mineral fragmentation and aggregation, as an event closely related to the cold climate, plays an irreplaceable role in reconstructing the climatic conditions of a certain area and a certain period of time and has important referential significance for the restoration of historical permafrost boundaries and the study of climate change. Therefore, in order to better study the effect of freeze–thaw cycles on the fragmentation and aggregation of soil mineral particles, four soil specimens were selected for this study; the freeze–thaw cycle tests were carried out 0, 3, 6, 9, 50, and 100 times, respectively, and the test results were analyzed. The results of these experiments indicate that (1) after freeze–thaw cycles, the changes in grain-size distribution are different in various soil types, and the changes are mainly concentrated in 0.001–0.1 mm; (2) the coarse particle size particles (sand, silt) can be fragmented into relatively fine-grained particles (silt, clay). The fine-grained particles (clay) cannot undergo fragmentation, and the decrease in clay is due to its aggregation; (3) with the increase in freeze–thaw cycles, the fraction change trend of four specimens is parallel to the x-axis, which means the fragmentation and aggregation of soil mineral particles are in a state of equilibrium or balance; (4) the increase in the Kvar value indicates the change in grain-size distribution, which means aggregation and fragmentation of soil mineral particles. After the 100th cycle, the Kvar value of four specimens is <0.1, which belongs to a low-intensity area; (5) the freeze–thaw cycle will change the type of soil, and after 100 freeze–thaw cycles, the soil type of specimen (H) changes from silty clay loam to silty clay; (6) during the freeze–thaw process, different types of soil have different situations of aggregation and fragmentation.

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The analysis of “Gels” in polymer films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153786 ◽

1989 ◽

Vol 47 ◽

pp. 362-363

Author(s):

G. M. Brown ◽

D. F. Brown ◽

J. H. Butler

Keyword(s):

Molecular Weight ◽

Film Industry ◽

Local Stress ◽

Melt Index ◽

Polyethylene Films ◽

Crosslinked Polymer ◽

Polymeric Gels ◽

Mineral Particles ◽

Polymeric Species ◽

Special Concern

The term “gel”, in the jargon of the plastics film industry, may refer to any inclusion that produces a visible artifact in a polymeric film. Although they can occur in any plastic product, gels are a principle concern in films where they detract from the cosmetic appearance of the product and may compromise its mechanical strength by acting as local stress concentrators. Many film gels are small spheres or ellipsoids less than one millimeter in diameter whereas other gels are fusiform-shaped and may reach several centimeters in length. The actual composition of gel inclusions may vary from miscellaneous inorganics (i.e. glass and mineral particles) and processing additives to heavily oxidized, charred or crosslinked polymer. The most commonly observed gels contain polymer differing from the bulk of the sample in its melt viscosity, density or molecular weight.Polymeric gels are a special concern in polyethylene films. Over the years and with the examination of a variety of these samples three predominant polymeric species have been observed: density gels which have different crystallinity than the film; melt-index gels in which the molecular weight is different than the film and crosslinked gels which are comprised of crosslinked polyethylene.

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