Carbon mineralization and microbial activity in agricultural topsoil and subsoil as regulated by root nitrogen and recalcitrant carbon concentrations

Digestates are commonly used as organic inputs in agriculture. This study aimed to answer four questions: (1) What are the immediate and longer-term impacts of digestates on soil microbial activity?; (2) How much of the digestates’ carbon is mineralized within the first months? (3) How do the nitrogen, lignin, cellulose, and hemicellulose contents of digestates influence microbial activity and carbon mineralization? (4) How does the soil type influence mineralization? To investigate this, dehydrogenase activity (DHA) was measured in a field trial and in laboratory experiments with five digestates (DGs), cattle slurry, and cattle manure. DHA measurements were supplemented with soil respiration experiments using two different soils. DHA was significantly increased by all organic inputs, but decreased back to the control level within seven months under field conditions. Twenty percent to 44% of the organic carbon (Corg) in the digestates was converted to CO2 after 178 days. Soil respiration was significantly negatively correlated to lignin content (r = −0.82, p < 0.01) and not correlated to nitrogen, cellulose, or hemicellulose content. On the basis of equal carbon application, slurry promoted soil respiration and DHA more strongly than digestates in the short term.

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Organic acid adsorption and mineralization in oxisols with different textures

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832013000400015 ◽

2013 ◽

Vol 37 (4) ◽

pp. 976-985 ◽

Cited By ~ 9

Author(s):

Felipe Vaz Andrade ◽

Eduardo de Sá Mendonça ◽

Ivo Ribeiro da Silva

Keyword(s):

Organic Acids ◽

Organic Acid ◽

Factorial Design ◽

Microbial Activity ◽

Carbon Mineralization ◽

Co2 Production ◽

Co2 Efflux ◽

Adsorption Sites ◽

Nutritional Conditions ◽

Soil Adsorption

Organic acids play an important role in the nutritional conditions of plants. Their relevance is related to their formation dynamics, mineralization rate and adsorption by soil colloids. This study was carried out to evaluate the dynamics of mineralization and adsorption of organic acid (acetic acid - AA, citric acid - CA and humic acid - HA) applied to the soil. Samples of two Oxisols were used: Rhodic Haplustox (LV) and Typic Haplustox (LVA). The mineralization experiment was arranged in a 2 x 3 x 5 factorial design, based on the factors: two soils (LV and LVA) x three organic acid (OA) types (AA, CA and HA) x five OA rates (0, 1, 2, 4, and 8 mmol dm-3). Organic carbon mineralization in samples was measured by the C-CO2 efflux, produced by the microbial activity, in a 30-day (measurements after 4, 8, 12, 21, and 30 days) and in a 4-day experiment (measured after 24, 48, 72 and 96 h). Organic acid adsorption was tested in a 2 x 2 x 5 x 4 factorial design, with the factors and levels: two Oxisols; two organic acids (AA and CA); five OA rates (0, 1, 2, 4, and 8 mmol dm-3) and four adsorption periods (6, 24, 48, and 72 h). The C-CO2 production of soil treated with CA was highest. In the adsorption experiment, the affinity of CA to soil adsorption sites was greatest. The adsorption of organic acids to soils may be an important mechanism by which bioavailability and thus mineralization capacity by microbial activity are reduced.

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Carbon mineralization and microbial activity in a field site trial used for 14 C turnover experiments over a period of 30 years

Biology and Fertility of Soils ◽

10.1007/s003740050659 ◽

2000 ◽

Vol 31 (3-4) ◽

pp. 294-302 ◽

Cited By ~ 18

Author(s):

M. Stemmer ◽

K. Roth ◽

E. Kandeler

Keyword(s):

Microbial Activity ◽

Carbon Mineralization ◽

Field Site

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Arbuscular mycorrhiza fungi and related soil microbial activity drive carbon mineralization in the maize rhizosphere

Ecotoxicology and Environmental Safety ◽

10.1016/j.ecoenv.2019.109476 ◽

2019 ◽

Vol 182 ◽

pp. 109476 ◽

Cited By ~ 4

Author(s):

Hongwen Xu ◽

Hongbo Shao ◽

Yan Lu

Keyword(s):

Arbuscular Mycorrhiza ◽

Microbial Activity ◽

Carbon Mineralization ◽

Soil Microbial Activity ◽

Maize Rhizosphere ◽

Soil Microbial ◽

Arbuscular Mycorrhiza Fungi

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Biochar-Compost Interactions as Affected by Weathering: Effects on Biological Stability and Plant Growth

Agronomy ◽

10.3390/agronomy11020336 ◽

2021 ◽

Vol 11 (2) ◽

pp. 336 ◽

Cited By ~ 1

Author(s):

Marie-Liesse Aubertin ◽

Cyril Girardin ◽

Sabine Houot ◽

Cécile Nobile ◽

David Houben ◽

...

Keyword(s):

Plant Growth ◽

Microbial Activity ◽

Carbon Mineralization ◽

Soil Microbial Activity ◽

Biological Stability ◽

Physical Weathering ◽

Soil Microbial ◽

Positive Effects ◽

Carbon Retention ◽

Ryegrass Growth

Biochar addition to compost is of growing interest as soil amendment. However, little is known about the evolution of material properties of biochar-compost mixtures and their effect on plants after exposure to physical weathering. This study aimed to investigate the physico-chemical characteristics of fresh and weathered biochar-compost mixtures, their biological stability and their effect on ryegrass growth. To this end, we used the contrasting stable isotope signatures of biochar and compost to follow their behavior in biochar-compost mixtures subjected to artificial weathering during 1-year of incubation. We assessed their impact on ryegrass growth during a 4-week greenhouse pot experiment. Weathering treatment resulted in strong leaching of labile compounds. However, biochar-compost interactions led to reduced mass loss and fixed carbon retention during weathering of mixtures. Moreover, weathering increased carbon mineralization of biochar-compost mixtures, probably due to the protection of labile compounds from compost within biochar structure, as well as leaching of labile biochar compounds inhibiting microbial activity. After soil application, weathered mixtures could have positive effects on biomass production. We conclude that biochar-compost interactions on soil microbial activity and plant growth are evolving after physical weathering depending on biochar production conditions.

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