Your search found 3 records
1 Hartmann, C.; Poss, R.; Noble, Andrew D.; Jongskul, A.; Bourdon, E.; Brunet, D.; Lesturgez, G. 2008. Subsoil improvement in a tropical coarse textured soil: effect of deep-ripping and slotting. Soil and Tillage Research, 99(2):245-253.
(Location: IWMI HQ Call no: IWMI 633.15 G750 HAR Record No: H041505)
2 Jouquet, Pascal; Zangerle, A.; Rumpel, C.; Brunet, D.; Bottinelli, N.; Toan, Tran Duc. 2009. Relevance of the biogenic and physicogenic classification: a comparison of approaches to discriminate the origin of soil aggregates. European Journal of Soil Science, 60:1117-1125. [doi: https://doi.org/ 10.1111/j.1365-2389.2009.01168.x]
Soil analysis ; Biogenic amines ; Earthworms ; Soil structural units ; Soil organic matter ; Nutrient cycling in ecosystems ; Soil structure
(Location: IWMI HQ Call no: e-copy only Record No: H042643)
(0.84 MB)
Although freshly formed or unaltered biogenic aggregates are easily recognized, identifying the origin of aggregates altered by physical and biological processes remains empirical and prone to error. The aim of this study was to distinguish between biogenic (BIO) and physicogenic (PHYS) aggregates in various states of fragmentation or size classes using visual, physical and chemical characteristics. Casts produced by Amynthas khami (BIO) and surrounding soil aggregates without visible biological activity (PHYS) were left to disaggregate by natural rainfall events and then separated into five size classes of >10, 10–5, 5–2, 2–0.5 and <0.5 mm. We then analysed aggregate morphology, elemental and stable isotope composition and soil stability, and used near-infrared spectroscopy (NIRS) to determine their chemical characteristics. Although visual assessment is the method most commonly used in the field to distinguish between BIO and PHYS, our study found that the results obtained were always prone to error and that the classification was arbitrary for BIO and PHYS aggregates smaller than 5 and 2 mm in size, respectively. Soil structural stability was only useful for identifying BIO aggregates larger than 2 mm. While C content and d13C in BIO were always different from PHYS, regardless of soil aggregate size, N content and d15N were similar. NIRS was the most effective method because it clearly discriminated soil aggregates on the basis of size and origin. The NIRS characteristics of BIO were also more uniform than those of PHYS, suggesting that BIO aggregates have a simpler organization and as a consequence more homogeneous ecological functions. Thus, our findings suggest that information may be lost when only the physical aspect of aggregates is used to quantify the activity of ecosystem engineers in soil. After fragmentation, BIO aggregates become hidden and although it may be impossible to distinguish them visually from PHYS aggregates they retain some of their specific chemical characteristics.
3 Jouquet, Pascal; Hartmann, C.; Choosai, C.; Hanboonsong, Y.; Brunet, D.; Montoroi, J. P. 2008. Different effects of earthworms and ants on soil properties of paddy fields in North-East Thailand. Paddy and Water Environment, 6(4):381-386. [doi: https://doi.org/10.1007/s10333-008-0134-x]
(Location: IWMI HQ Call no: e-copy only Record No: H042766)
(0.36 MB)
As soil engineers, earthworms and ants play major roles in soil functioning, especially in modifying soil physical and chemical properties. This study was conducted in a very constraining environment, i.e., paddy fields which have anoxic conditions (approximately four months per year), and which are affected by soil salinisation during the dry period (approximately eight months per year). This study points out that despite those very adverse conditions, soil invertebrates must be taken into account in the dynamic of soil organic and mineral properties in paddy fields. The effects of one earthworm species, Glyphodrillus sp., and an ant species, Epelysidris sp., on soil physical and chemical properties were determined through elemental soil physical and chemical properties (texture, pH, conductivity, C and N contents) and near infrared reflectance spectroscopy (NIRS) in order to evaluate their ability to influence soil organic matter quality. PCA processed with NIRS data clearly showed that biogenic structures (ant sheetings and earthworm casts) were separated from the control surrounding soil. Earthworms and ants affected differently soil properties. Glyphodrillus sp. increased the SOM content and decreased the pH on the surface of the soil. These effects were attributed to an increase in fine particle content (clay). Conversely, Epelysidris sp. only increased the content of coarse particles (sand) and did not influence either soil pH or SOM content. Soil conductivity was found to be very variable but was not significantly affected by soil invertebrates. These results show the potential of soil macro-fauna to create heterogeneity at small spatial scale and to modify the quality of surface soils even under adverse conditions like saline paddy fields.
Powered by DB/Text WebPublisher, from
