Spatial and temporal patterns of water-extractable organic carbon (WEOC) of surface mineral soil in a cool temperate forest ecosystem

Labile organic carbon (LOC) fractions are considered as sensitive indicators of change in soil quality and can serve as proxies for soil organic carbon (SOC). Although the impact of tillage, crop rotation and crop residue management on soil quality is well known, less is known about LOC and SOC dynamics in the sweet sorghum production systems in South Africa. This short-term study tested two tillage levels: no-till and conventional-tillage, two crop rotations: sweet-sorghum/winter grazing vetch/sweet sorghum and sweet-sorghum/winter fallow/sweet sorghum rotations and three crop residue retention levels: 30%, 15% and 0%. Tillage was the main factor to influence SOC and LOC fractions under the sweet sorghum cropping system in South Africa. NT increased SOC and all LOC fractions compared to CT, which concurs with previous findings. Cold water extractable organic carbon (CWEOC) and hot water extractable organic carbon (HWEOC) were found to be more sensitive to tillage and strongly positively correlated to SOC. An increase in residue retention led to an increase in microbial biomass carbon (MBC). This study concludes that CWEOC and HWEOC can serve as sensitive early indicators of change in soil quality and are an ideal proxy for SOC in the sweet-sorghum cropping system in South Africa.

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Timing of bud burst of smaller individuals is not always earlier than that of larger trees in a cool-temperate forest with heavy snow

Journal of Forest Research ◽

10.1080/13416979.2020.1753279 ◽

2020 ◽

Vol 25 (4) ◽

pp. 285-290

Author(s):

Erika Marumo ◽

Kentaro Takagi ◽

Kobayashi Makoto

Keyword(s):

Temperate Forest ◽

Bud Burst ◽

Cool Temperate ◽

Cool Temperate Forest ◽

Heavy Snow

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Change in water extractable organic carbon and microbial PLFAs of biochar during incubation with an acidic paddy soil

Soil Research ◽

10.1071/sr14259 ◽

2015 ◽

Vol 53 (7) ◽

pp. 763 ◽

Cited By ~ 1

Author(s):

Ming Li ◽

Ming Liu ◽

Stephen Joseph ◽

Chun-Yu Jiang ◽

Meng Wu ◽

...

Keyword(s):

Organic Carbon ◽

Paddy Soil ◽

Reduction Rate ◽

Chemical Properties ◽

Nutrient Status ◽

Biological Properties ◽

Uv Absorbance ◽

Water Extractable Organic Carbon ◽

Microbial Plfas ◽

Water Extractable

Biochar has been considered to affect the transformation of soil organic carbon, soil microbial activity and diversity when applied to soil. However, the changes in chemical and biological properties of biochar itself in soil have not been fully determined. In this study, various biochar samples were obtained from three crop straws (rice, peanut and corn) and two wood chips (bamboo and pine), and incubated with an acidic paddy soil. We examined the changes of biochar water extractable organic carbon (WEOC) content and its ultraviolet (UV) absorbance at 280 nm during incubation period, and also investigated the microbial phospholipid fatty acids (PLFAs) profile of biochar after 75 days of incubation. The WEOC content of biochars decreased at the end of incubation, except for the biochar pyrolysed from bamboo chips at 400°C. An average reduction rate of 61.2% in WEOC concentration for straw biochars occurred within the first 15 days, while no significant change was observed for all biochars between day 15 and 45, and a slight increase in WEOC occurred for all biochars in the last 30 days. There was a positive relationship between biochar WEOC content and its UV absorbance properties. The microbial PLFAs concentrations of biochars varied from 15.56 to 60.35 nmol g–1, and there was a greater abundance in content and species for corn straw biochars than for the other types of biochars. General bacteria were the dominant microbial group that colonised biochar sample, while gram-positive bacterial and fungi were less in abundance. The chemical properties of fresh biochar were well correlated with total PLFAs concentrations, and significantly related to the composition of microbial community. We concluded that the WEOC component of most biochars change within such short-term application to soil, and the WEOC in combined with the pH and nutrient status of biochar, can alter the type and abundance of microorganisms that colonised biochar.

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