Decomposition of plant material in Australian soils. I. The effect of quantity added on decomposition and on residual microbial biomass

Soil Research ◽  
1983 ◽  
Vol 21 (4) ◽  
pp. 563 ◽  
Author(s):  
JN Ladd ◽  
RB Jackson ◽  
M Amato ◽  
JHA Butler
Keyword(s):  
Microbial Biomass ◽  
Plant Material ◽  
Sandy Loam ◽  
Plant Residue ◽  
Organic Residues ◽  
Percentage Decrease ◽  
Residue Decomposition ◽  
Medicago Littoralis ◽  
Percentage Retention ◽  
C And N

14C and 15N-labelled legume (Medicago littoralis) material was added in amounts ranging from 23.0 to 92.1 kg nitrogen ha-1 to a calcareous, sandy-loam topsoil and allowed to decompose under field conditions for up to four years. Characteristic curves for decomposition were obtained; residual organic 14C accounted for about 65% and 18% of input after four weeks and four years respectively. About one-half of the 15N in the added plant material remained in organic residues after four years. However, the amounts of residual organic 14C and 15N were only approximately proportional to the amounts originally added. The proportions of plant material 14C and 15N mineralized calculated from recovery data differed significantly with the amount of substrate added; the greater the amount of plant material added, the more extensive its decomposition. Carbonate in soil became labelled during plant residue decomposition. Levels of carbonate 14C were low, however, and were directly related to the total residual 14C levels, whether in soils sampled four weeks or four years after substrate addition. Carbonate 14C accounted for only 1.1% of total residual 14C. Biomass 14C and 15N in soil decreased significantly with time within a 2-4 year decomposition period, the percentage decrease being greater than for 14C and 15N in the corresponding non-biomass organic pool. Further, the proportions of substrate 14C and 15N retained as biomass 14C and 15N in soils decreased significantly with increasing amounts of added substrate. From a consideration of the turnover of biomass C and N during plant residue decomposition in soils, we concluded that stabilization of extracellular substrates and metabolites alone does not account for the greater percentage retention of organic residues when lower amounts of substrate are added, but that factors leading to the accumulation of higher proportions of substrate carbon and nitrogen in microbial biomass are important.

scholarly journals Short-Term Effect of Nitrogen Fertilization on Carbon Mineralization during Corn Residue Decomposition in Soil

Nitrogen ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 444-460
Author(s):  
Tanjila Jesmin ◽  
Dakota T. Mitchell ◽  
Richard L. Mulvaney
Keyword(s):  
Microbial Biomass ◽  
C:N Ratio ◽  
Carbon Mineralization ◽  
N Fertilization ◽  
Co2 Production ◽  
Microbial Biomass C ◽  
N Availability ◽  
Soil C ◽  
Residue Decomposition ◽  
C And N

The effect of N fertilization on residue decomposition has been studied extensively; however, contrasting results reflect differences in residue quality, the form of N applied, and the type of soil studied. A 60 d laboratory incubation experiment was conducted to ascertain the effect of synthetic N addition on the decomposition of two corn (Zea mays L.) stover mixtures differing in C:N ratio by continuous monitoring of CO2 emissions and periodic measurement of microbial biomass and enzyme activities involved in C and N cycling. Cumulative CO2 production was greater for the high than low N residue treatment, and was significantly increased by the addition of exogenous N. The latter effect was prominent during the first month of incubation, whereas N-treated soils produced less CO2 in the second month, as would be expected due to more rapid substrate depletion from microbial C utilization previously enhanced by greater N availability. The stimulatory effect of exogenous N was verified with respect to active biomass, microbial biomass C and N, and cellulase and protease activities, all of which were significantly correlated with cumulative CO2 production. Intensive N fertilization in modern corn production increases the input of residues but is not conducive to soil C sequestration.

scholarly journals Fate of carbon and nitrogen from plant residue decomposition in a calcareous soil

2011 ◽  
Vol 52 (No. 3) ◽  
pp. 137-140 ◽  
Author(s):  
F. Nourbakhsh
Keyword(s):  
Biochemical Properties ◽  
Plant Residue ◽  
Plant Residues ◽  
Order Kinetic ◽  
Nitrogen Transformations ◽  
Plant Materials ◽  
Carbon And Nitrogen ◽  
Residue Decomposition ◽  
N Concentration ◽  
Order Kinetic Model

Carbon and nitrogen transformations in soil are microbially mediated processes that are functionally related. The fate of C and N was monitored in a clay-textured soil (Typic Haplocambid) which was either unamended (control) or amended with various plant materials at the rate of 10 g residue C/kg soil. To evaluate C mineralization, soils were incubated for 46 days under aerobic conditions. Nitrogen mineralization/immobilization was evaluated at the end of eight-week incubation experiment. All CO<sub>2</sub> evolution data conformed well to a first-order kinetic model, C<sub>m&nbsp;</sub>= C<sub>0</sub> (1 &ndash; e<sup>&ndash;Kt</sup>). The product of K and C<sub>0 </sub>(KC<sub>0</sub>) was significantly correlated with some chemical and biochemical properties of the plant residues, including N concentration (r = 0.83, P &lt; 0.001), C:N (r = &ndash;0.64, P &lt; 0.05) and lignin:N (r = &ndash;0.81, P &lt; 0.001). Among the plant residue composition characteristics, N concentration (r = 0.96, P &lt; 0.001), C:N (r = &ndash;0.69, P &lt; 0.01) and lignin:N (r = &ndash;0.68, P &lt; 0.01) were significantly correlated with the net rates of N mineralization/immobilization (N<sub>m/i</sub>).

Warming affects seasonal dynamics of microorganisms and reduces the N storage capacity of soil microbes in winter

2021 ◽  
Author(s):  
Philipp Gündler ◽  
Alberto Canarini ◽  
Sara Marañón Jiménez ◽  
Gunnhildur Gunnarsdóttir ◽  
Páll Sigurðsson ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Growth Rates ◽  
Seasonal Dynamics ◽  
Soil Microbes ◽  
Storage Capacity ◽  
Ambient Conditions ◽  
Soil Warming ◽  
Carbon Use Efficiency ◽  
Use Efficiency ◽  
C And N

&lt;p&gt;Seasonality of soil microorganisms plays a critical role in terrestrial carbon (C) and nitrogen (N) cycling. The asynchrony of immobilization by microbes and uptake by plants may be important for N retention during winter, when plants are inactive. Meanwhile, the known warming effects on soil microbes (decreasing biomass and increasing growth rates) may affect microbial seasonal dynamics and nutrient retention during winter.&lt;/p&gt;&lt;p&gt;We sampled soils from a geothermal warming site in Iceland (www.forhot.is) which includes three in situ warming levels (ambient, +3 &amp;#176;C, +6 &amp;#176;C). We harvested soil samples at 9 time points over one year and measured the seasonal variation in microbial biomass carbon (Cmic) and nitrogen (Nmic) and microbial physiology (growth and carbon use efficiency) by an &lt;sup&gt;18&lt;/sup&gt;O-labelling technique.&lt;/p&gt;&lt;p&gt;We observed that Cmic and Nmic peaked in winter, followed by a decline in spring and summer. In contrast growth and respiration rates were higher in summer than winter. The observed biomass peak at lower growth rates, suggests that microbial death rates must have declined even more than growth rates. Soil warming increased biomass-specific microbial activity (i.e., growth, respiration, and turnover rates per unit of microbial biomass), prolonging the period of higher microbial activity found in summer into autumn and winter. Microbial carbon use efficiency was unaltered by soil warming. Throughout the seasons, warming reduced Cmic and Nmic, albeit with a stronger effect in winter than summer and restrained winter biomass accumulation by up to 78% compared to ambient conditions. We estimated a reduced microbial winter N storage capacity by 45.5 and 94.6 kg ha&lt;sup&gt;-1&lt;/sup&gt; at +3 &amp;#176;C and +6 &amp;#176;C warming respectively compared to ambient conditions. This reduction represents 1.57% and 3.26% of total soil N stocks, that could potentially be lost per year from these soils.&lt;/p&gt;&lt;p&gt;Our results clearly demonstrate that soil warming strongly decreases microbial C and N immobilization when plants are inactive, potentially leading to higher losses of C and N from warmed soils over winter. These results have important implications as increased N losses may restrict increased plant growth in a future climate.&lt;/p&gt;

scholarly journals Perennial herbaceous legumes as live soil mulches and their effects on C, N and P of the microbial biomass

2003 ◽  
Vol 60 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Gustavo Pereira Duda ◽  
José Guilherme Marinho Guerra ◽  
Marcela Teixeira Monteiro ◽  
Helvécio De-Polli ◽  
Marcelo Grandi Teixeira
Keyword(s):  
Microbial Biomass ◽  
Soil Depth ◽  
Vegetation Management ◽  
Pueraria Phaseoloides ◽  
Organic C ◽  
Arachis Pintoi ◽  
Factorial Combination ◽  
C And N ◽  
Microbial C ◽  
Macroptilium Atropurpureum

The use of living mulch with legumes is increasing but the impact of this management technique on the soil microbial pool is not well known. In this work, the effect of different live mulches was evaluated in relation to the C, N and P pools of the microbial biomass, in a Typic Alfisol of Seropédica, RJ, Brazil. The field experiment was divided in two parts: the first, consisted of treatments set in a 2 x 2 x 4 factorial combination of the following factors: live mulch species (Arachis pintoi and Macroptilium atropurpureum), vegetation management after cutting (leaving residue as a mulch or residue remotion from the plots) and four soil depths. The second part had treatments set in a 4 x 2 x 2 factorial combination of the following factors: absence of live mulch, A. pintoi, Pueraria phaseoloides, and M. atropurpureum, P levels (0 and 88 kg ha-1) and vegetation management after cutting. Variation of microbial C was not observed in relation to soil depth. However, the amount of microbial P and N, water soluble C, available C, and mineralizable C decreased with soil depth. Among the tested legumes, Arachis pintoi promoted an increase of microbial C and available C content of the soil, when compared to the other legume species (Pueraria phaseoloides and Macroptilium atropurpureum). Keeping the shoot as a mulch promoted an increase on soil content of microbial C and N, total organic C and N, and organic C fractions, indicating the importance of this practice to improve soil fertility.

Influence of wheel traffic and tillage on microbial biomass, residue decomposition and extractable nutrients in a Coastal Plain Soil

1996 ◽  
Vol 180 (1) ◽  
pp. 129-137 ◽  
Author(s):  
James A. Entry ◽  
D. Wayne Reeves ◽  
Carole B. Backman ◽  
Randy L. Raper
Keyword(s):  
Microbial Biomass ◽  
Coastal Plain ◽  
Residue Decomposition ◽  
Extractable Nutrients ◽  
Coastal Plain Soil

Microbial biomass and activity in the humus layer following burning: short-term effects of two different fires

1993 ◽  
Vol 23 (7) ◽  
pp. 1275-1285 ◽  
Author(s):  
Janna Pietikäinen ◽  
Hannu Fritze
Keyword(s):  
Microbial Community ◽  
Microbial Biomass ◽  
Soil Respiration ◽  
Mass Loss ◽  
Forest Fire ◽  
Prescribed Burning ◽  
Microbial Biomass C ◽  
Soil Microbial ◽  
Fungal Hyphae ◽  
C And N

During a 3-year study, soil microbial biomass C and N, length of the fungal hyphae, soil respiration, and the percent mass loss of needle litter were recorded in coniferous forest soil humus layers following a prescribed burning (PB) treatment or a forest fire simulation (FF) treatment (five plots per treatment). Unburned humus from adjacent plots served as controls (PC and FC, respectively). Prescribed burning was more intensive than the forest fire, and this was reflected in all the measurements taken. The amounts of microbial biomass C and N, length of fungal hyphae, and soil respiration in the PB area did not recover to their controls levels, whereas unchanged microbial biomass N and recovery of the length of the fungal hyphae to control levels were observed in the FF area. The mean microbial C/N ratio was approximately 7 in all the areas, which reflected the C/N ratio of the soil microbial community. Deviation from this mean value, as observed during the first three samplings from the PB area (3, 18, and 35 days after fire treatment), suggested a change in the composition of the microbial community. Of the two treated areas, the decrease in soil respiration (laboratory measurements) was much more pronounced in the PB area. However, when the humus samples from both areas were adjusted to 60% water holding capacity, no differences in respiration capacity were observed. The drier humus, due to higher soil temperatures, of the PB area is a likely explanation for the low soil respiration. Lower soil respiration was not reflected in lower litter decomposition rates of the PB area, since there was a significantly higher needle litter mass loss during the first year in the PB area followed by a decline to the control level during the second year. Consistently higher mass losses were recorded in the FC area than in the FF area.

Relationships between C and N availability, substrate age, and natural abundance 13C and 15N signatures of soil microbial biomass in a semiarid climate

2009 ◽  
Vol 41 (8) ◽  
pp. 1605-1611 ◽  
Author(s):  
Jeff S. Coyle ◽  
Paul Dijkstra ◽  
Richard R. Doucett ◽  
Egbert Schwartz ◽  
Stephen C. Hart ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Natural Abundance ◽  
N Availability ◽  
Soil Microbial ◽  
Semiarid Climate ◽  
C And N ◽  
Substrate Age
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