15 January 2016, Vol.262:45–51, doi:10.1016/j.geoderma.2015.08.020
Title
Influence of soil pedological properties on termite mound stability
Author
P. Jouquet a,b,,
N. Guilleux a,b
L. Caner c
S. Chintakunta b
M. Ameline b
R.R. Shanbhag d
aInstitute of Ecology and Environmental Sciences (UMR 242 iEES Paris), Institute of Research for Development (IRD), 32 av. H. Varagnat, 93143 Bondy, France
bIndo-French Cell for Water Science (IFCWS), Civil engineering Department, Indian Institute of Science, 560 012 Bangalore, Karnataka, India
cUniversité de Poitiers, IC2MP-HydrASA UMR 7285, B35, 5 rue Albert Turpain, TSA51106, 86073 Poitiers, France
dInstitute of Wood Science and Technology, Malleswaram, 560 003 Bangalore, Karnataka, India
Received 7 April 2015. Revised 13 July 2015. Accepted 12 August 2015. Available online 25 August 2015.
Highlights
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Termite mound density is similar in ferralsol and in vertisol.
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Stability of termite mound aggregates is reduced compared to control.
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Degradation of termite nests by rain is more important in vertisol than ferralsol.
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Termites impact differently soil dynamics depending on the environment.
Abstract
This study investigated the influence of soil properties on the density and shape of epigeous fungus-growing termite nests in a dry deciduous forest in Karnataka, India. In this environment, Odontotermes obesus produces cathedral shaped mounds. Their density, shape (height and volume) and soil physicochemical properties were analyzed in ferralsol and vertisol environments. No significant difference was observed in O. obesus mound density (n = 2.7 mound ha− 1 on average in the vertisol and ferralsol areas). This study also showed that O. obesus has a limited effect on soil physical properties. No differences in soil particle size, pH, or the C:N ratio and base saturation were measured whereas the C and N contents were reduced and CEC was higher in termite nest soils in both environments. Clay mineralogical composition was also measured, and showed the presence of higher amounts of smectite clays in termite nest soils, which thus explained the increasing CEC despite the reduced C and N content. However, the main difference was the shape of the termite mounds. The degradation of the nests created a hillock of eroded soil at the base of termite mounds in the vertisol while only a thin layer of eroded soil was observed in the ferralsol. The increased degradation of termite mounds in the vertisol is explained by the presence of smectites (2:1 swelling clays), which confer macroscopic swelling and shrinking characteristics to the soil. Soil shrinkage during the dry season leads to the formation of deep cracks in the termite mounds that allow rain to rapidly penetrate inside the mound wall and then breakdown unstable aggregates. In conclusion, it appears that despite a similar abundance, termite mound properties depend to a large extent on the soil properties of their environments.
October 2014, Vol.169:731–741, doi:10.1016/j.biortech.2014.06.110
Title
Composting of cow dung and crop residues using termite mounds as bulking agent
Author
Tanmoy Karak a,b,,,
Indira Sonar b
Ranjit K. Paul c
Sampa Das d
R.K. Boruah b
Amrit K. Dutta b
Dilip K. Das a
aDepartment of Agricultural Chemistry and Soil Science, Faculty of Agriculture, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur-741252, Nadia, West Bengal, India
bUpper Assam Advisory Centre, Tea Research Association, Dikom-786101, Assam, India
cIndian Agricultural Statistics Research Institute, New Delhi 110012, India
dDibrugarh Polytechnic, Lahowal, Dibrugarh-786010, Assam, India
Received 6 June 2014. Revised 28 June 2014. Accepted 30 June 2014. Available online 23 July 2014.
Highlights
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Composting of crop residues with termite mound is composed and low cost technology.
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Addition of termite mound as composting materials decrease composting time.
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Termite mound addition improves the quality of finished compost.
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Incorporation of termite mound significantly improved NPK in prepared compost.
Abstract
The present study reports the suitability of termite mounds as a bulking agent for composting with crop residues and cow dung in pit method. Use of 50 kg termite mound with the crop residues (stover of ground nut: 361.65 kg; soybean: 354.59 kg; potato: 357.67 kg and mustard: 373.19 kg) and cow dung (84.90 kg) formed a good quality compost within 70 days of composting having nitrogen, phosphorus and potassium as 20.19, 3.78 and 32.77 g kg−1 respectively with a bulk density of 0.85 g cm−3. Other physico-chemical and germination parameters of the compost were within Indian standard, which had been confirmed by the application of multivariate analysis of variance and multivariate contrast analysis. Principal component analysis was applied in order to gain insight into the characteristic variables. Four composting treatments formed two different groups when hierarchical cluster analysis was applied.
15 October 2009, Vol.153(1):217–230, doi:10.1016/j.geoderma.2009.08.011
Title
Rare earth and trace element geochemistry of termite mounds in central and northeastern Namibia: Mechanisms for micro-nutrient accumulation
Author
Aboubakar Sako a,,
Anthony J. Mills b
Alakendra N. Roychoudhury c
aDepartment of Geological Sciences, University of Cape Town, Rondebosch 7700, South Africa
bDepartment of Soil Science, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa
cDepartment of Geology, Geography and Environmental Studies, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa
Received 10 November 2008. Revised 28 July 2009. Accepted 19 August 2009. Available online 8 September 2009.
Abstract
Rare earth element (REE) and trace element concentrations of ten termite mounds and adjacent topsoil from central and northeastern Namibia were used to investigate the processes underlying the alteration of soil chemical and physical properties by termites (Macrotermesspp.). Accumulation of micro-nutrients in the mounds was of particular interest because of the ecological implications of the enhanced availability of these scarce elements. The absolute concentrations of REE and trace elements, including nine micro-nutrients (B, Fe, Mn, Ni, Cu, Zn, Se, Mo and Cd), were greater in termite mounds compared to topsoil, suggesting a possible external supply of enriched materials or accumulation ofin situweathering products of the underlying bedrock. Similarities between the chondrite normalized REE patterns of the samples and those of the average upper continental crust (UCC) and Post-Archaean Average Australian Shale compositions indicated that the mounds and topsoil at each site originated from the same host bedrock. Coherent behavior between two incompatible elements (Th and La) in both topsoil and mound samples suggested that the two sets of samples were exposed to two different weathering processes. The relatively low Zr/Sc ratios, fine particle sizes and the persistence of positive Eu anomalies of the mounds relative to UCC were interpreted as reflecting (1) a lack of grain sorting effects and (2) active transport of materials rich in primary clay minerals and trace elements from the deeper regolith to the surface by termites. Lower permeability of mound materials may also prevent leaching of primary minerals and trace elements. Titanium and Zr enrichment in most mound samples (8 samples) was attributed to the decomposition of biotite byMacrotermeswith the concomitant release of Ti and Zr into the mounds, suggesting the termites' ability to transform soil minerals and enhance chemical weathering. This was further corroborated by a substantial increase in Th/U ratios in most mounds relative to topsoil. Because of the oxidizing conditions of the mounds, Ti and Zr are likely to be adsorbed onto Fe-oxides. Positive Ce anomalies relative to UCC and the high pH values in the mounds indicate calcrete aggradation or mound aeration as a result of burrowing activities of the termites and evaporation from mounds. The impacts of the changes in environmental conditions and the termite activities on the mound geochemistry are highlighted by heavy REE (HREE) as well as Fe and Mn retentions in the mounds. Heavy REE and light REE (LREE) are likely to coprecipitate with carbonate complexes and Fe- and Mn-oxyhydroxides, and in the process, scavenge a series of micro-nutrients such as Zn, Cu, Cd and Co. A substantial enrichment of Se in mounds, despite the oxidizing conditions of the mounds, could be attributed to active transport of Se-enriched materials from deep soil horizons. The study demonstrated the suitability of REE and trace element geochemistry for assessing the influence ofMacrotermeson the physico-chemical properties of semi-arid soils.
