Tropical terrestrial model ecosystems for evaluation of soil fauna and leaf litter quality effects on litter consumption, soil microbial biomass and plant growth

The aim of this work was to evaluate whether terrestrial model ecosystems (TMEs) are a useful tool for the study of the effects of litter quality, soil invertebrates and mineral fertilizer on litter decomposition and plant growth under controlled conditions in the tropics. Forty-eight intact soil cores (17.5-cm diameter, 30-cm length) were taken out from an abandoned rubber plantation on Ferralsol soil (Latossolo Amarelo) in Central Amazonia, Brazil, and kept at 28ºC in the laboratory during four months. Leaf litter of either Hevea pauciflora (rubber tree), Flemingia macrophylla (a shrubby legume) or Brachiaria decumbens (a pasture grass) was put on top of each TME. Five specimens of either Pontoscolex corethrurus or Eisenia fetida (earthworms), Porcellionides pruinosus or Circoniscus ornatus (woodlice), and Trigoniulus corallinus (millipedes) were then added to the TMEs. Leaf litter type significantly affected litter consumption, soil microbial biomass and nitrate concentration in the leachate of all TMEs, but had no measurable effect on the shoot biomass of rice seedlings planted in top soil taken from the TMEs. Feeding rates measured with bait lamina were significantly higher in TMEs with the earthworm P. corethrurus and the woodlouse C. ornatus. TMEs are an appropriate tool to assess trophic interactions in tropical soil ecossistems under controlled laboratory conditions.

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Interpretation of microbial biomass measurements for soil quality assessment in humid temperate regions

Canadian Journal of Soil Science ◽

10.4141/s99-012 ◽

1999 ◽

Vol 79 (4) ◽

pp. 507-520 ◽

Cited By ~ 55

Author(s):

M. R. Carter ◽

E. G. Gregorich ◽

D. A. Angers ◽

M. H. Beare ◽

G. P. Sparling ◽

...

Keyword(s):

Microbial Biomass ◽

Plant Growth ◽

Soil Quality ◽

Soil Microbial Biomass ◽

Spatial And Temporal Variation ◽

Data Set ◽

K Value ◽

Organic C ◽

Soil Microbial ◽

Temperate Soils

Soil microbial biomass (SMB) measurements are often used in soil biological analysis; however, their interpretation can be problematic. In this review, both the limitations and benefits of indirect (both CHCl3 fumigation incubation and fumigation extraction, and substrate-induced respiration) SMB measurements are outlined, along with their value and interpretation as attributes or indicators to assess some soil quality (SQ) functions (e.g., enhance plant growth, maintain aggregation, regulate energy) for mainly humid, temperate soils, with specific emphasis on research conducted in eastern Canada and New Zealand. Indirect SMB methods are subject to limitations analogous to "soil test" procedures (e.g., soil sampling and handling, water content, storage prior to treatment), and also the difficulties with establishing an acceptable "control" and fraction (i.e., k value) of SMB mineralized or extracted. In many cases, such limitations present a need for some degree of standardization (e.g., pre-conditions of 7- to 10-d incubation at 25°C and −0.001 MPa water potential) prior to SMB measurement. However, for SQ assessment, where "comparative" rather than "absolute" values of SMB are often of interest, use of commonly derived k values seem appropriate for surface soils.Soil ecological factors govern SMB and often underlie much of the spatial and temporal variation in SMB. Plant species composition, mainly through net primary productivity and litter quality, can affect SMB measurements along with trophic cascades in soil, where interactions among soil organisms can influence microbial activity. Benefits of SMB measurements relate mainly to the assessment of both soil C turnover and management induced changes in organic matter. The combination of SMB and δ13C to elucidate the transformations and fate of organic C in cropping and soil management systems has also shown that both temporal and spatial redistribution of C inputs, and soil type (i.e., particle size distribution) are dominant factors in turnover and nutrient flow through the SMB.For SQ assessment, SMB is not a useful indicator for the function of soil as a "medium for plant growth" in regard to plant productivity for intensively farmed temperate soils. For the function of soil to "maintain aggregation", where SMB is one agent only of a multi-faceted process, the relationship between SMB and soil aggregation is not always present and tends to be site-specific. In regard to the "regulate energy" soil function, SMB is related to some degree with decomposition and mineralization processes. The main role of SMB for SQ assessment is to serve within a minimum data set of other indicators (e.g., macroorganic C) to monitor soil organic C storage and change. Key words: Soil microbial biomass, humid climate, soil quality

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Relationships between bacterial diversity, microbial biomass, and litter quality in soils under different plant covers in northern Rio de Janeiro State, Brazil

Canadian Journal of Microbiology ◽

10.1139/w09-066 ◽

2009 ◽

Vol 55 (9) ◽

pp. 1089-1095 ◽

Cited By ~ 27

Author(s):

S. M. Ndaw ◽

A. C. Gama-Rodrigues ◽

E. F. Gama-Rodrigues ◽

K. R.N. Sales ◽

A. S. Rosado

Keyword(s):

Land Use ◽

Microbial Biomass ◽

Bacterial Diversity ◽

Litter Quality ◽

Soil Microbial Biomass ◽

Stand Age ◽

N Availability ◽

Eucalyptus Plantation ◽

Soil Microbial ◽

C And N

Microbial populations are primarily responsible for the decomposition of organic residues, the nutrients cycle, and the flow of energy inside of soil. The present study was undertaken to link soil microbiological and soil biochemical parameters with soil- and litter-quality conditions in the surface layer from 5 sites differing in plant cover, in stand age, and in land-use history. The aim was to see how strongly these differences affect the soil microbial attributes and to identify how microbiological processes and structures can be influenced by soil and litter quality. Soil and litter samples were collected from 5 sites according to different land use: preserved forest, nonpreserved forest, secondary forest, pasture, and eucalyptus plantation. Soil and litter microbial biomass and activity were analysed and DNA was extracted from soil. The DNA concentrations and soil microbial C and N correlated positively and significantly, suggesting that these are decisive nutrients for microbial growth and time required for microbial biomass renewal. The litter microbial biomass represented a source of C and N higher than soil microbial biomass and can be an important layer to contribute to tropical soil with low C and N availability. The litter quality influenced the litter and soil microbial biomass and activity and the soil bacterial diversity. The chemical and nutritional quality of the litter influenced the structure and microbial community composition in the eucalyptus plantation.

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The relationships between microbiological attributes and soil and litter quality in pure and mixed stands of native tree species in southeastern Bahia, Brazil

Canadian Journal of Microbiology ◽

10.1139/w11-082 ◽

2011 ◽

Vol 57 (11) ◽

pp. 887-895

Author(s):

Emanuela F. Gama-Rodrigues ◽

Antonio Carlos Gama-Rodrigues ◽

Nairam F. Barros ◽

Maria Kellen S. Moço

Keyword(s):

Microbial Biomass ◽

Tree Species ◽

Litter Quality ◽

Soil Microbial Biomass ◽

Mixed Stands ◽

Soil Microbial ◽

Native Tree ◽

C And N ◽

Native Tree Species

This study was conducted to link soil and litter microbial biomass and activity with soil and litter quality in the surface layer for different pure and mixed stands of native tree species in southeastern Bahia, Brazil. The purpose of the study was to see how strongly the differences among species and stands affect the microbiological attributes of the soil and to identify how microbial processes can be influenced by soil and litter quality. Soil and litter samples were collected from six pure and mixed stands of six hardwood species ( Peltogyne angustifolia , Centrolobium robustum , Arapatiella psilophylla , Sclerolobium chrysophyllum , Cordia trichotoma , Macrolobium latifolium ) native to the southeastern region of Bahia, Brazil. In plantations of native tree species in humid tropical regions, the immobilization efficiency of C and N by soil microbial biomass was strongly related to the chemical quality of the litter and to the organic matter quality of the soil. According to the variables analyzed, the mixed stand was similar to the natural forest and dissimilar to the pure stands. Litter microbial biomass represented a greater sink of C and N than soil microbial biomass and is an important contributor of resources to tropical soils having low C and N availability.

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Changes of Soil Microbiological Properties during Grass Litter Decomposition in Loess Hilly Region, China

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph15091797 ◽

2018 ◽

Vol 15 (9) ◽

pp. 1797

Author(s):

Yun Xiang ◽

Shaoshan An ◽

Man Cheng ◽

Lijun Liu ◽

Ying Xie

Keyword(s):

Enzyme Activity ◽

Microbial Biomass ◽

Leaf Litter ◽

Litter Decomposition ◽

Soil Microbial Biomass ◽

Change Rate ◽

Carbon And Nitrogen ◽

Soil Microbial ◽

Microbial Carbon ◽

Microbiological Properties

Litter, the link between soil and plant, is an important part of nutrient return to soil. Deeply understanding the effect of litter decomposition on soil microbiological properties is important for the sustainable development of grasslands. Three plants (Thymus quinquecostatus Celak., Stipa bungeana Trin. and Artemisia sacrorum ledeb.) leaf litter were selected. A simulation experiment using the nylon bag method was conducted to measure the soil microbial biomass carbon and nitrogen, and soil enzyme activity during litter decomposition. The results showed that the decomposition of three leaf litter enhanced soil microbial carbon and nitrogen. The change rate of soil microbial carbon and nitrogen decreased as Ar.S > St.B > Th.Q. The activities of soil invertase, soil urease, and soil nitrate reductase were significantly improved by the coverage of leaf litter. After 741-day litter decomposition, the change rate of soil invertase was from 16.7% to 33.2%. The change rate of soil urease was highest in the Th.Q treatment; St.B treatment and Ar.S treatment followed, and lowest in the control. The change rates of soil nitrate reductase in the St.B and Ar.S treatment were >1000% higher than those of other treatments. The response of soil enzyme activity to litter decomposition “lagged” behind the change of soil microbial biomass. The significant increase of soil microbial biomass and enzyme activity demonstrated that litter decomposition played an important role in maintaining soil ecological function.

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