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Effect of flyash incorporation on soil properties of texturally variant soils
Bioresource Technology 75 (2000) 91±93
Short communication
Eect of ¯yash incorporation on soil properties of texturally variant soils Naveen Kalra *, R.C. Harit, S.K. Sharma Division of Environmental Sciences, Indian Agricultural Research Institute, Nuclear Research Laboratory Building, New Delhi 110 012, India Received 28 September 1998; received in revised form 5 February 2000; accepted 14 February 2000
Abstract Modi®cations in soil properties caused by ¯yash incorporation in clayey, sandy-clay-loam, sandy and sandy-loam soils were evaluated. Flyash was collected from the National Capital Power Project, Dadri, Ghaziabad, UP. Ash incorporation treatments were 10%, 20%, 30% and 40% ash by weight in the soil±ash mixtures. Moisture retained at ®eld capacity increased with ash content in sandy-clay-loam, sandy and sandy-loam soils, whereas the reverse trend was noted for clayey soil. Moisture retained at wilting point increased with ash content for all the soils. The changes in moisture retention constants associated with ash incorporation were due to macro- and micro-particle size modi®cations. The pH of soil±ash mixtures decreased with ash content for clayey, sandy and sandy-loam soils, whereas the reverse trend was noted for sandy-clay-loam soil. Electrical conductivity of the mixtures increased with the ash content for all the soils. Organic carbon values increased with ash content for sandy and sandy-loam soils, whereas they decreased for clayey and sandy-clay-loam soils. Modi®cations to the soil environment with incorporation of ¯yash need to be investigated on a long-term basis. Ó 2000 Elsevier Science Ltd. All rights reserved. Keywords: Flyash; Texturally variant soils; Field capacity; Wilting point; pH; Electrical conductivity; Organic carbon
1. Introduction Disposal of the huge amount of burnt coal ash produced from thermal power stations can cause air and water pollution if proper management controls are not taken in time. Flyash is used as land®ll material and for reclaiming of acid and alkaline soils. Ash incorporation modi®es the physical and chemical characteristics of the soil and the extent of change depends on soil and ash properties. Flyash amended soils tend to have lower bulk density, higher water holding capacity, lower hydraulic conductivity, increased organic carbon (OC) content and increased soil strength (Chang et al., 1977; Aitken and Bell, 1985; Eisenberg et al., 1986; Garg et al., 1996; Kalra et al., 1998). The changes in soil properties with ash incorporation in¯uence crop yields (Kalra et al., 1997, 1998). Addition of ¯yash (at 10 t/ha) at the time of maize sowing showed reduced bulk density and increased moisture retention and release characteristics in the sandy-loam soil of the IARI farm, New Delhi, and dierences persisted even during the subsequent growth of a wheat crop (Garg et al., 1996). The fa*
Corresponding author. Tel.: +91-578-6367.
vourable soil physical environment induced by using ¯yash resulted in a greater root growth, which ensured enhanced water use by the crop and higher grain yields for maize as well as wheat. An incubation study conducted with sandy-loam and sandy soils amended with 0%, 5% and 10% acidic ¯yash (weight basis) decreased bulk density and pH but increased salt content of the mixtures. The plant available water content increased by 52% and 124% over the control for sandy-loam and sandy soils, respectively, with the addition of 10% ¯yash (Singh and Kansal, 1994). The eects of ¯yash on the chemical properties of soil are greatly in¯uenced by the characteristics of ash, mainly pH. Application of alkaline ¯yash has invariably been associated with corresponding increases in soil pH (Adriano et al., 1982). Application of ¯yash to soil at a rate of 8% on weight basis increased the pH of calcareous soil from 5.4 to 9.9 (Page et al., 1979). A study carried out at Kanpur, UP, indicated that pH of a sandy-loam soil was signi®cantly in¯uenced with ¯yash application, the values being minimum under 30% ¯yash application and maximum under control (no ¯yash) (Singh and Singh, 1986). The changes in the soil physical and chemical environment with the ash addition at varying levels needs to
0960-8524/00/$ - see front matter Ó 2000 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 0 - 8 5 2 4 ( 0 0 ) 0 0 0 3 6 - 5
92
N. Kalra et al. / Bioresource Technology 75 (2000) 91±93
be investigated in texturally variant soils, for suggestion of its use as land®ll material or as a soil amendment for reclaiming acid and alkaline soils.
2. Methods Flyash was collected from National Capital Power Project, Dadri, Ghaziabad, UP. Four texturally variant soils (clayey, sandy-clay-loam, sandy and sandy-loam) were collected from dierent agro-ecological zones of India. The ash incorporation treatments were T0 (control, no ash), T1 (10% ash in soil±ash mixtures on dry weight basis), T2 (20% ash), T3 (30% ash) and T4 (40% ash). The treatments were replicated thrice in a completely randomized design. Flyash was analyzed for sand, silt and clay-size fractions, pH, electrical conductivity (EC) and OC. The soil±ash mixtures were recharged to ®eld capacity (FC) and kept under natural conditions for a month. Thereafter the mixtures under various treatments were analyzed for moisture retention constants, i.e., FC and wilting point (WP), using a pressure plate and membrane apparatus, soil strength using a pocket penetrometer, pH, EC and OC. The methods used for soil analysis were reported earlier (Kalra et al., 1998).
3. Results and discussion The physical and physico-chemical characteristics of various soils and ¯yash used in the study are reported in Table 1. Moisture retained at FC in the mixtures increased with ash for sandy-clay-loam, sandy and sandyloam soils, whereas the reverse trend was noticed for clayey soil. Under T4 treatment, FC value increased over T0 by 16.2%, 38.5% and 295.7% for sandy-loam, sandy-clay-loam and sandy soils, respectively, whereas it decreased by 10.8% for clayey soil. Moisture retained at WP increased with ash content for all the soils, but the response was texturally dierent. Increase in WP, with per cent increase of ash content in the mixtures over T0, ranged from 0.21% (for sandy-loam soil) to 6.81% (for
sandy soil), with intermediate values of 0.35% (for clayey soil) and 0.58% (for sandy-clay-loam soil). Available water (expressed as mm water/cm soil) increased with ash content for all soils, except for clayey soil. Increase in available water per unit % increase in ash content in the mixtures over the T0 treatment was 0.49%, 1.26% and 7.93% for sandy-loam, sandy-clayloam and sandy soils, respectively, and decreased by 0.65% for clayey soil. The results indicated an appreciable increase in moisture availability caused by ash incorporation in the case of light- and medium-textured soils, which could thereby cause reduced water losses as drainage, enhanced water use eciency for crops and increased crop yields. The soil strength in various mixtures increased with ash content. The slope values for % ash content when plotted against soil strength were signi®cantly dierent for soils, thereby showing textural dependence. Increase in soil strength for per cent increase of ash content in the mixtures over the T0 treatment ranged from 0.56% (for sandy-clay-loam soil) to 4.15% (for sandy soil), with intermediate values of 1.03% and 1.42% for sandy-loam and clayey soils, respectively. The pH of soil±ash mixtures decreased with ash content for clayey, sandy and sandy-loam soils, whereas the reverse trend was noted for sandy-clay-loam soil. There are reports indicating a high buering capacity of the soil for pH restoration (Kalra et al., 1996). Therefore, the changes noted in pH of mixtures need to be evaluated on a long-term basis. The EC of the mixtures increased with the ash content for all the soils. The increase for T4 over T0 treatment ranged from 40% (for sandy soil) to 122% (for clayey soil), with intermediate values of 60% and 88% for sandy-loam and sandy-clayloam soils, respectively. The OC values of soil±ash mixtures increased with ash content for sandy and sandy-loam soils, whereas the reverse trend was noted for clayey and sandy-clay-loam soils. In T4 treatment, OC values increased over T0 treatment by 71% and 11% for sandy and sandy-loam soils, respectively, whereas they decreased by 42% and 22% for clayey and sandy-clay-loam soils. From the present investigation, it can be concluded that ¯yash incorporation in texturally variant soils
Table 1 Characteristics of dierent soils and ¯yash used in the study Place
Texture
Clay (%)
pH
EC (mmhos/cm)
OC (%)
Soil Amravati, Maharastra Kharagpur, West Bengal Jaipur, Rajasthan IARI farm, Delhi
Clayey Sandy-clay-loam Sandy Sandy-loam
55.9 25.9 87.0 48.4
8.5 5.9 8.8 8.3
0.261 0.251 0.502 0.467
0.65 0.23 0.09 0.28
Flyash NCPP, Dadri
Silt-loam
11.9
7.0
0.650
0.36
N. Kalra et al. / Bioresource Technology 75 (2000) 91±93
modi®es the soil physical and physico-chemical environment, which in turn may in¯uence the crop yields. However, the changes in the soil environment caused by ash incorporation need to be investigated on a long-term basis. References Adriano, D.C., Page, A.L., Chang, A.C., Elseewi, A.A., 1982. Cadmium availability to sudangrass grown on soils amended with sewage sludge and ¯y ash. J. Environ. Qual. 11, 197±203. Aitken, R.L., Bell, L.C., 1985. Plant uptake and phytotoxicity of boron in Australian ¯y ashes. Plant Soil 84, 245±257. Chang, A.C., Lund, L.J., Page, A.L., Warneke, J.E., 1977. Physical properties of ¯yash-amended soils. J. Environ. Qual. 6 (3), 267±270. Eisenberg, S.H., Tittlebaun, M.E., Eaton, H.C., Soroczak, M.M., 1986. Chemical characteristics of selected ¯y ash leachates. J. Environ. Sci. Health 21, 383±402. Garg, R.N., Singh, G., Kalra, N., Das, D.K., Singh, S., 1996. Eect of soil amendments on soil physical properties, root growth and grain
93
yields of maize and wheat. Asian Paci®c J. Environ. Develop. 3 (1), 54±55. Kalra, N., Joshi, H.C., Chaudhary, A., Choudhary, R., Sharma, S.K., 1997. Impact of ¯yash incorporation in soil on germination of crops. Bioresource Technol. 61, 39±41. Kalra, N., Jain, M.C., Joshi, H.C., Choudhary, R., Harit, R.C., Vatsa, B.K., Sharma, S.K., Kumar, V., 1998. Flyash as a soil conditioner and fertilizer. Bioresource Technol. 64, 163±167. Kalra, N., Joshi, H.C., Kishor, B., Sharma, S.K., Jain, N., Harit, R.C., 1996. Impact of coal-burnt ash on environment and crop productivity. Asia Paci®c J. Environ. Develop. 3 (2), 65±87. Page, A.L., Elseewi, A.A., Straughan, I.R., 1979. Physical and chemical properties of ¯yash from coal ®red power plants with reference to environmental impacts. Residue Rev. 71, 83±120. Singh, D., Kansal, B.D., 1994. Changes in physico-chemical properties of soils on addition of ¯yash. In: Extended Summaries, National Seminar on Developments in Soil Science Organized by Indian Society of Soil Science, 28 November±1 December, pp. 202±203. Singh, N.B., Singh, M., 1986. Eect of ¯yash application on saline soil and on yield components, yield and uptake of NPK of rice and wheat at varying fertility levels. Ann. Agric. Res. 7 (2), 245±257.
Short communication
Eect of ¯yash incorporation on soil properties of texturally variant soils Naveen Kalra *, R.C. Harit, S.K. Sharma Division of Environmental Sciences, Indian Agricultural Research Institute, Nuclear Research Laboratory Building, New Delhi 110 012, India Received 28 September 1998; received in revised form 5 February 2000; accepted 14 February 2000
Abstract Modi®cations in soil properties caused by ¯yash incorporation in clayey, sandy-clay-loam, sandy and sandy-loam soils were evaluated. Flyash was collected from the National Capital Power Project, Dadri, Ghaziabad, UP. Ash incorporation treatments were 10%, 20%, 30% and 40% ash by weight in the soil±ash mixtures. Moisture retained at ®eld capacity increased with ash content in sandy-clay-loam, sandy and sandy-loam soils, whereas the reverse trend was noted for clayey soil. Moisture retained at wilting point increased with ash content for all the soils. The changes in moisture retention constants associated with ash incorporation were due to macro- and micro-particle size modi®cations. The pH of soil±ash mixtures decreased with ash content for clayey, sandy and sandy-loam soils, whereas the reverse trend was noted for sandy-clay-loam soil. Electrical conductivity of the mixtures increased with the ash content for all the soils. Organic carbon values increased with ash content for sandy and sandy-loam soils, whereas they decreased for clayey and sandy-clay-loam soils. Modi®cations to the soil environment with incorporation of ¯yash need to be investigated on a long-term basis. Ó 2000 Elsevier Science Ltd. All rights reserved. Keywords: Flyash; Texturally variant soils; Field capacity; Wilting point; pH; Electrical conductivity; Organic carbon
1. Introduction Disposal of the huge amount of burnt coal ash produced from thermal power stations can cause air and water pollution if proper management controls are not taken in time. Flyash is used as land®ll material and for reclaiming of acid and alkaline soils. Ash incorporation modi®es the physical and chemical characteristics of the soil and the extent of change depends on soil and ash properties. Flyash amended soils tend to have lower bulk density, higher water holding capacity, lower hydraulic conductivity, increased organic carbon (OC) content and increased soil strength (Chang et al., 1977; Aitken and Bell, 1985; Eisenberg et al., 1986; Garg et al., 1996; Kalra et al., 1998). The changes in soil properties with ash incorporation in¯uence crop yields (Kalra et al., 1997, 1998). Addition of ¯yash (at 10 t/ha) at the time of maize sowing showed reduced bulk density and increased moisture retention and release characteristics in the sandy-loam soil of the IARI farm, New Delhi, and dierences persisted even during the subsequent growth of a wheat crop (Garg et al., 1996). The fa*
Corresponding author. Tel.: +91-578-6367.
vourable soil physical environment induced by using ¯yash resulted in a greater root growth, which ensured enhanced water use by the crop and higher grain yields for maize as well as wheat. An incubation study conducted with sandy-loam and sandy soils amended with 0%, 5% and 10% acidic ¯yash (weight basis) decreased bulk density and pH but increased salt content of the mixtures. The plant available water content increased by 52% and 124% over the control for sandy-loam and sandy soils, respectively, with the addition of 10% ¯yash (Singh and Kansal, 1994). The eects of ¯yash on the chemical properties of soil are greatly in¯uenced by the characteristics of ash, mainly pH. Application of alkaline ¯yash has invariably been associated with corresponding increases in soil pH (Adriano et al., 1982). Application of ¯yash to soil at a rate of 8% on weight basis increased the pH of calcareous soil from 5.4 to 9.9 (Page et al., 1979). A study carried out at Kanpur, UP, indicated that pH of a sandy-loam soil was signi®cantly in¯uenced with ¯yash application, the values being minimum under 30% ¯yash application and maximum under control (no ¯yash) (Singh and Singh, 1986). The changes in the soil physical and chemical environment with the ash addition at varying levels needs to
0960-8524/00/$ - see front matter Ó 2000 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 0 - 8 5 2 4 ( 0 0 ) 0 0 0 3 6 - 5
92
N. Kalra et al. / Bioresource Technology 75 (2000) 91±93
be investigated in texturally variant soils, for suggestion of its use as land®ll material or as a soil amendment for reclaiming acid and alkaline soils.
2. Methods Flyash was collected from National Capital Power Project, Dadri, Ghaziabad, UP. Four texturally variant soils (clayey, sandy-clay-loam, sandy and sandy-loam) were collected from dierent agro-ecological zones of India. The ash incorporation treatments were T0 (control, no ash), T1 (10% ash in soil±ash mixtures on dry weight basis), T2 (20% ash), T3 (30% ash) and T4 (40% ash). The treatments were replicated thrice in a completely randomized design. Flyash was analyzed for sand, silt and clay-size fractions, pH, electrical conductivity (EC) and OC. The soil±ash mixtures were recharged to ®eld capacity (FC) and kept under natural conditions for a month. Thereafter the mixtures under various treatments were analyzed for moisture retention constants, i.e., FC and wilting point (WP), using a pressure plate and membrane apparatus, soil strength using a pocket penetrometer, pH, EC and OC. The methods used for soil analysis were reported earlier (Kalra et al., 1998).
3. Results and discussion The physical and physico-chemical characteristics of various soils and ¯yash used in the study are reported in Table 1. Moisture retained at FC in the mixtures increased with ash for sandy-clay-loam, sandy and sandyloam soils, whereas the reverse trend was noticed for clayey soil. Under T4 treatment, FC value increased over T0 by 16.2%, 38.5% and 295.7% for sandy-loam, sandy-clay-loam and sandy soils, respectively, whereas it decreased by 10.8% for clayey soil. Moisture retained at WP increased with ash content for all the soils, but the response was texturally dierent. Increase in WP, with per cent increase of ash content in the mixtures over T0, ranged from 0.21% (for sandy-loam soil) to 6.81% (for
sandy soil), with intermediate values of 0.35% (for clayey soil) and 0.58% (for sandy-clay-loam soil). Available water (expressed as mm water/cm soil) increased with ash content for all soils, except for clayey soil. Increase in available water per unit % increase in ash content in the mixtures over the T0 treatment was 0.49%, 1.26% and 7.93% for sandy-loam, sandy-clayloam and sandy soils, respectively, and decreased by 0.65% for clayey soil. The results indicated an appreciable increase in moisture availability caused by ash incorporation in the case of light- and medium-textured soils, which could thereby cause reduced water losses as drainage, enhanced water use eciency for crops and increased crop yields. The soil strength in various mixtures increased with ash content. The slope values for % ash content when plotted against soil strength were signi®cantly dierent for soils, thereby showing textural dependence. Increase in soil strength for per cent increase of ash content in the mixtures over the T0 treatment ranged from 0.56% (for sandy-clay-loam soil) to 4.15% (for sandy soil), with intermediate values of 1.03% and 1.42% for sandy-loam and clayey soils, respectively. The pH of soil±ash mixtures decreased with ash content for clayey, sandy and sandy-loam soils, whereas the reverse trend was noted for sandy-clay-loam soil. There are reports indicating a high buering capacity of the soil for pH restoration (Kalra et al., 1996). Therefore, the changes noted in pH of mixtures need to be evaluated on a long-term basis. The EC of the mixtures increased with the ash content for all the soils. The increase for T4 over T0 treatment ranged from 40% (for sandy soil) to 122% (for clayey soil), with intermediate values of 60% and 88% for sandy-loam and sandy-clayloam soils, respectively. The OC values of soil±ash mixtures increased with ash content for sandy and sandy-loam soils, whereas the reverse trend was noted for clayey and sandy-clay-loam soils. In T4 treatment, OC values increased over T0 treatment by 71% and 11% for sandy and sandy-loam soils, respectively, whereas they decreased by 42% and 22% for clayey and sandy-clay-loam soils. From the present investigation, it can be concluded that ¯yash incorporation in texturally variant soils
Table 1 Characteristics of dierent soils and ¯yash used in the study Place
Texture
Clay (%)
pH
EC (mmhos/cm)
OC (%)
Soil Amravati, Maharastra Kharagpur, West Bengal Jaipur, Rajasthan IARI farm, Delhi
Clayey Sandy-clay-loam Sandy Sandy-loam
55.9 25.9 87.0 48.4
8.5 5.9 8.8 8.3
0.261 0.251 0.502 0.467
0.65 0.23 0.09 0.28
Flyash NCPP, Dadri
Silt-loam
11.9
7.0
0.650
0.36
N. Kalra et al. / Bioresource Technology 75 (2000) 91±93
modi®es the soil physical and physico-chemical environment, which in turn may in¯uence the crop yields. However, the changes in the soil environment caused by ash incorporation need to be investigated on a long-term basis. References Adriano, D.C., Page, A.L., Chang, A.C., Elseewi, A.A., 1982. Cadmium availability to sudangrass grown on soils amended with sewage sludge and ¯y ash. J. Environ. Qual. 11, 197±203. Aitken, R.L., Bell, L.C., 1985. Plant uptake and phytotoxicity of boron in Australian ¯y ashes. Plant Soil 84, 245±257. Chang, A.C., Lund, L.J., Page, A.L., Warneke, J.E., 1977. Physical properties of ¯yash-amended soils. J. Environ. Qual. 6 (3), 267±270. Eisenberg, S.H., Tittlebaun, M.E., Eaton, H.C., Soroczak, M.M., 1986. Chemical characteristics of selected ¯y ash leachates. J. Environ. Sci. Health 21, 383±402. Garg, R.N., Singh, G., Kalra, N., Das, D.K., Singh, S., 1996. Eect of soil amendments on soil physical properties, root growth and grain
93
yields of maize and wheat. Asian Paci®c J. Environ. Develop. 3 (1), 54±55. Kalra, N., Joshi, H.C., Chaudhary, A., Choudhary, R., Sharma, S.K., 1997. Impact of ¯yash incorporation in soil on germination of crops. Bioresource Technol. 61, 39±41. Kalra, N., Jain, M.C., Joshi, H.C., Choudhary, R., Harit, R.C., Vatsa, B.K., Sharma, S.K., Kumar, V., 1998. Flyash as a soil conditioner and fertilizer. Bioresource Technol. 64, 163±167. Kalra, N., Joshi, H.C., Kishor, B., Sharma, S.K., Jain, N., Harit, R.C., 1996. Impact of coal-burnt ash on environment and crop productivity. Asia Paci®c J. Environ. Develop. 3 (2), 65±87. Page, A.L., Elseewi, A.A., Straughan, I.R., 1979. Physical and chemical properties of ¯yash from coal ®red power plants with reference to environmental impacts. Residue Rev. 71, 83±120. Singh, D., Kansal, B.D., 1994. Changes in physico-chemical properties of soils on addition of ¯yash. In: Extended Summaries, National Seminar on Developments in Soil Science Organized by Indian Society of Soil Science, 28 November±1 December, pp. 202±203. Singh, N.B., Singh, M., 1986. Eect of ¯yash application on saline soil and on yield components, yield and uptake of NPK of rice and wheat at varying fertility levels. Ann. Agric. Res. 7 (2), 245±257.