scholarly journals Root Traits and Architecture Affect Standard Litter Decomposition: A Comparative Study on Five Plant Species

2020 ◽  
Author(s):  
Adriano Sofo ◽  
Hazem S. Elshafie ◽  
Ippolito Camele
Keyword(s):  
Plant Species ◽  
Net Primary Production ◽  
Early Stage ◽  
Root Traits ◽  
Soil C ◽  
Soil Microbial ◽  
Decomposition Reactions ◽  
Soil C And N ◽  
C And N ◽  
C And N Cycling

Plants are affected by soil environments to the same extent they affect soil functioning through interactions between environmental and genetic factors. Here, five plant species (broad bean, pea, cabbage, fennel, and olive) grown under controlled pot conditions were tested for their ability to differently stimulate the degradation of standard litter. Litter, soil C and N contents and soil microbial abundance were measured. The architecture and morphological traits of roots systems were also evaluated by using specific open-source software (SmartRoot). Soil chemical and microbiological characteristics were significantly influenced by the plant species. Variations in soil C/N dynamics were correlated with the diversity of root traits among species. Early-stage decomposition of the standard litter changed on the basis of the plant species. The results indicated that key soil processes are governed by interactions between plant roots, soil C and N, and the microbial metabolism that stimulate decomposition reactions. This, in turn, can have marked effects on soil chemical and microbiological fertility, both fundamental for sustaining crops, and can promote the development of new approaches for optimizing soil C and N cycling, managing nutrient transport, and sustaining and improving net primary production.

scholarly journals Structural and Functional Organization of the Root System: A Comparative Study on Five Plant Species

Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1338 ◽  
Author(s):  
Adriano Sofo ◽  
Hazem S. Elshafie ◽  
Ippolito Camele
Keyword(s):  
Plant Species ◽  
Functional Organization ◽  
Net Primary Production ◽  
Early Stage ◽  
Root Traits ◽  
Soil C ◽  
Soil Microbial ◽  
Soil C And N ◽  
C And N ◽  
C And N Cycling

Plants are affected by soil environments to the same extent that they affect soil functioning through interactions between environmental and genetic factors. Here, five plant species (broad bean, pea, cabbage, fennel, and olive) grown under controlled pot conditions were tested for their ability to differently stimulate the degradation of standard litter. Litter, soil C and N contents were measured for evaluating chemical changes due to plant presence, while soil microbial abundance was evaluated to assess if it had a positive or negative catalyzing influence on litter decomposition. The architecture and morphological traits of roots systems were also evaluated by using specific open-source software (SmartRoot). Soil chemical and microbiological characteristics were significantly influenced by the plant species. Variations in soil C/N dynamics were correlated with the diversity of root traits among species. Early stage decomposition of the standard litter changed on the basis of the plant species. The results indicated that key soil processes are governed by interactions between plant roots, soil C and N, and the microbial metabolism that stimulate decomposition reactions. This, in turn, can have marked effects on soil chemical and microbiological fertility, both fundamental for sustaining crops, and can promote the development of new approaches for optimizing soil C and N cycling, managing nutrient transport, and sustaining and improving net primary production.

The magnitude of temperature increase matters: how will soil organic mineralization respond to future climate warming?

2020 ◽  
Author(s):  
Jie Zhou ◽  
Yuan Wen ◽  
Lingling Shi ◽  
Michaela Dippold ◽  
Yakov Kuzyakov ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Climate Warming ◽  
Temperature Increase ◽  
Microbial Growth ◽  
N Cycling ◽  
Soil C ◽  
Soil Microbial ◽  
Soil C And N ◽  
C And N ◽  
C And N Cycling

<p>The Paris climate agreement is pursuing efforts to limit the increase in global temperature to below 2 °C above pre-industrial level. The overall consequence of relatively slight warming (~2 °C), on soil C and N stocks will be dependent on microorganisms decomposing organic matter through release of extracellular enzymes. Therefore, the capacity of soil microbial community to buffer climate warming in long-term and the self-regulatory mechanisms mediating soil C and N cycling through enzyme activity and microbial growth require a detailed comparative study. Here, microbial growth and the dynamics of enzyme activity (involved in C and N cycling) in response to 8 years warming (ambient, +1.6 °C, +3.2 °C) were investigated to identify shifts in soil and microbial functioning. A slight temperature increase (+1.6 °C) only altered microbial properties, but had no effect on either hydrolytic enzyme activity or basic soil properties. Stronger warming (+3.2 °C) increased the specific growth rate (μ<sub>m</sub>) of the microbial community, indicating an alteration in their ecological strategy, i.e. a shift towards fast-growing microorganisms and accelerated microbial turnover. Warming strongly changed microbial physiological state, as indicated by a 1.4-fold increase in the fraction of growing microorganisms (GMB) and 2 times decrease in lag-time with warming. This reduced total microbial biomass but increased specific enzyme activity to be ready to decompose increased rhizodeposition, as supported by the higher potential activitiy (V<sub>max</sub>) and lower affinity to substrates (higher K<sub>m</sub>) of enzymes hydrolyzing cellobiose and proteins cleavage in warmed soil. In other words, stronger warming magnitude (+3.2 °C) changed microbial communities, and was sufficient to benefit fast-growing microbial populations with enzyme functions that specific to degrade labile SOM. Combining with 48 literature observations, we confirmed that the slight magnitude of temperature increase (< 2 °C) only altered microbial properties, but further temperature increases (2-4 °C) was sufficient to change almost all soil, microbial, and enzyme properties and related processes. As a consequence, the revealed microbial regulatory mechanism of stability of soil C storage is strongly depended on the magnitude of future climate warming.</p>

Mineralisation of organic matter in intact versus sieved/refilled soil cores

Soil Research ◽  
2002 ◽  
Vol 40 (1) ◽  
pp. 149 ◽  
Author(s):  
R. Stenger ◽  
G. F. Barkle ◽  
C. P. Burgess
Keyword(s):  
Organic Matter ◽  
N Mineralisation ◽  
Soil Cores ◽  
Nitrogen Mineralisation ◽  
Soil C ◽  
Soil Microbial ◽  
Conditioning Period ◽  
Incubation Study ◽  
Soil C And N ◽  
C And N

In a 6-month laboratory incubation study, we compared the net C and N mineralisation of the soil organic matter (SOM) of 3 pasture soils and the mineralisation of glucose-C in intact versus sieved/refilled soil cores. The main questions were whether the net C and N mineralisation differed between intact and sieved/refilled soil cores after a conditioning period of 4 weeks, and how much the C and N mineralisation of SOM differed among the similarly managed pasture soils. Apart from the net nitrogen mineralisation in one soil, there were no significant differences in cumulated mineralisation of C or N from SOM between the core types. In a fine-textured soil, net mineralisation of glucose-C differed significantly between core types, which was attributed to the different distribution of the amended glucose in intact and sieved/refilled cores. Net C and N mineralisation of SOM were closely correlated in the sieved/refilled cores, whereas no significant correlation was found in the intact cores. Expressing net C and N mineralisation as percentages of total soil C and N showed a more than 2-fold maximum difference between the soils in spite of similar long-term organic matter input. Subsequent studies should be done using more replicates and wider diameter, better controllable cores on ceramic plates. CO2, net nitrogen mineralisation (NNM), soil microbial biomass.

Long-term effects of afforestation with Pinus radiata on soil carbon, nitrogen, and pH: a case study

Soil Research ◽  
2011 ◽  
Vol 49 (6) ◽  
pp. 494 ◽  
Author(s):  
R. L. Parfitt ◽  
D. J. Ross
Keyword(s):  
Pinus Radiata ◽  
Mineral Soil ◽  
Early Spring ◽  
Early Years ◽  
Long Term Effects ◽  
Soil C ◽  
Soil Microbial ◽  
Soil C And N ◽  
C And N ◽  
Microbial C

Planting of Pinus radiata D. Don in previously grazed pastures is a common land-use change in New Zealand. Although carbon (C) accumulates relatively rapidly in the trees, there have been no studies of the annual effect on soil C content during the early years of establishment. Here, we study soil properties under P. radiata and pasture each year over 11 years after P. radiata was planted into pasture that had been grazed by sheep. Under the growing trees, grass was gradually shaded out by the unpruned trees, and completely disappeared after 6 years; needle litterfall had then increased appreciably. By year 9, soil microbial C and nitrogen (N), and net N mineralisation, were significantly lower under pine than under pasture. Soil pH, sampled at 0–100 mm in early spring each year, decreased by ~0.3 units under pine and increased by ~0.3 units under pasture. Close to the pine stems, total C and N decreased significantly for 3 years, while ~100 kg N/ha accumulated in the trees. Soil C and N increased in subsequent years, when litterfall increased. Overall, the mineral soil under pine lost ~500 kg N/ha over 11 years, consistent with uptake by the trees. Leaching losses (estimated using lysimeters) in year 9 were 4.5 kg N/ha.year. These data indicate that ~6 Mg C/ha may have been lost from the mineral soil at this site. The difficulties associated with measuring losses of C are discussed.

scholarly journals Soil Microbial Responses to 28 Years of Nutrient Fertilization in a Subarctic Heath

Ecosystems ◽  
2019 ◽  
Vol 23 (5) ◽  
pp. 1107-1119 ◽  
Author(s):  
Lettice C. Hicks ◽  
Kathrin Rousk ◽  
Riikka Rinnan ◽  
Johannes Rousk
Keyword(s):  
Community Structure ◽  
Soil Microorganisms ◽  
N Availability ◽  
Soil C ◽  
Soil Microbial ◽  
C And N Mineralization ◽  
Microbial Responses ◽  
Soil C And N ◽  
C And N

AbstractArctic and subarctic soils are typically characterized by low nitrogen (N) availability, suggesting N-limitation of plants and soil microorganisms. Climate warming will stimulate the decomposition of organic matter, resulting in an increase in soil nutrient availability. However, it remains unclear how soil microorganisms in N-limited soils will respond, as the direct effect of inorganic N addition is often shown to inhibit microbial activity, while elevated N availability may have a positive effect on microorganisms indirectly, due to a stimulation of plant productivity. Here we used soils from a long-term fertilization experiment in the Subarctic (28 years at the time of sampling) to investigate the net effects of chronic N-fertilization (100 kg N ha−1 y−1, added together with 26 kg P and 90 kg K ha−1 y−1, as expected secondary limiting nutrients for plants) on microbial growth, soil C and N mineralization, microbial biomass, and community structure. Despite high levels of long-term fertilization, which significantly increased primary production, we observed relatively minor effects on soil microbial activity. Bacterial growth exhibited the most pronounced response to long-term fertilization, with higher rates of growth in fertilized soils, whereas fungal growth remained unaffected. Rates of basal soil C and N mineralization were only marginally higher in fertilized soils, whereas fertilization had no significant effect on microbial biomass or microbial community structure. Overall, these findings suggest that microbial responses to long-term fertilization in these subarctic tundra soils were driven by an increased flow of labile plant-derived C due to stimulated plant productivity, rather than by direct fertilization effects on the microbial community or changes in soil physiochemistry.

Nitrogen and calcium additions increase forest growth in northeastern USA spruce–fir forests

2007 ◽  
Vol 37 (9) ◽  
pp. 1574-1585 ◽  
Author(s):  
Andrew Kulmatiski ◽  
Kristiina A. Vogt ◽  
Daniel J. Vogt ◽  
Phillip M. Wargo ◽  
Joel P. Tilley ◽  
...  
Keyword(s):  
New York ◽  
Net Primary Production ◽  
Abies Balsamea ◽  
Forest Growth ◽  
Red Spruce ◽  
Soil C ◽  
Soil C And N ◽  
C And N ◽  
Nitrogen Treatments ◽  
Forest Species Composition

We determined responses of red spruce ( Picea rubens Sarg.) – balsam fir ( Abies balsamea (L.) Mill.) forests to 6 years of nitrogen (N), calcium (Ca), and N + Ca treatments (100, 160, and 260 kg·ha–1·year–1 of N, Ca, and N + Ca, respectively) in New York (NY) and New Hampshire (NH). Forest responses to Ca treatments were also determined in Vermont (VT). Nitrogen treatments increased aboveground net primary production (ANPP) by 33% and 25% above controls in NY and NH, respectively. Similarly, N + Ca treatments increased ANPP by 27% and 28% in NY and NH, respectively. Calcium treatments increased ANPP by 25% and 21% above controls in NY and VT. Calcium treatment did not increase ANPP in NH, suggesting N, but not Ca limitation. Leaf-litter quantity and quality, and soil C and N storage were greater in treated than in control plots. Fine-root mass and production did not differ among treatments. Trees, therefore, assimilated more soil nutrients without increasing root growth in treated plots. Red spruce ANPP, however, declined or remained unchanged in response to N and Ca additions. The equivalent of 68–102 years of anthropogenic N addition to soils changed forest species composition without decreasing ANPP, and Ca additions did not prevent this change.

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