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Impact of flyash incorporation in soil on germination of crops
Bioresource Technology 61 (1997) 39-41 0 1997 Elsevier Science Limited All rights reserved. Printed in Great Britain 0960-8524197 $17.00 ELSEVIER
PII:SO960-8524(96)00050-3
IMPACT OF FLYASH INCORPORATION IN SOIL ON GERMINATION OF CROPS Naveen Kalra,* H. C. Joshi, A. Chaudhary, Division of Environmental
R. Choudhary
& S.
K. Sharma
Sciences, IARI, New Delhi 110012, India
(Received 22 January 1997; revised version received 15 March 1997; accepted 25 March 1997)
ing material and for other constructional purposes, but in India its utilization is less than 5% (Mandal and Sinha, 1988). It can also be used as a landfill material, or for reclaiming acidic or sodic soils (Plank and Martens, 1974; Taylor and Schuman, 1988). Because of the restricted use of ash in such activities, thermal power stations have to provide adequate storage space and check associated environmental pollution problems (Pathak et al., 1996). In view of ash incorporation in soil from ash mounds and chimneys by climatic actions, or while using ash as a soil amendment, it becomes necessary to evaluate its effects on soil and crop productivity. Germination and crop stand establishment are prime plant-growth processes, which play a major role in deciding subsequent growth and yield, and so need to be evaluated under varying levels of ash incorporation within the soil. The present study evaluated ash incorporation effects on germination of several crops to work out the optimum level of ash addition and relate germination effects with changes in soil characteristics caused by mixing ash with the soil.
Abstract Pot-culture experiments were conducted to evaluate the effect of ash incorporation in soil on germination and stand establishment of wheat (Triticum aestivum L.), chickpea (Cicer arietinum L.), mustard (Brassica juntea L.) and lentil (Lens esculenta Moench.) during the winter season of 1995, and rice (Oryza sativa L.) and maize (Zea mays L.) during the summer season of 1996. Ash levels tested were 0, lo%, 20%, 30% and 40% for winter-season crops, and 0, 5%, lo%, 15% and 20% for summer-season crops. Changes in soil physical and chemical characteristics due to ash addition were analyzed. Germination time, defined as the time taken for 75% germination (60% in case of mustard), and delay index, a normalized parametel; were introduced to evaluate ash-incorporation effects on germination of crops. Ash addition in soil delayed germination of crops due to the increased impedance offered by the soil matrix to germinating seeds. Rice and maize were relatively less sensitive to ash for germination than winter-season crops. Mustard was most affected for germination and stand establishment. The delay index showed variations between crops as well as for ash levels within a crop. 0 1997 Elsevier Science Ltd. Key words: Flyash, germination soil mechanical-impedance.
METHODS
time, delay index, Pot culture experiments were conducted. The test crops were wheat (Ttiticum aestivum L.), chickpea (Cicer arietinum L.), mustard (Brassica juncea L.) and lentil (Lens esculenta Moench.) during the winter season of 1995 (study period; 1-15 November), and rice (Oryza sativa L.) and maize (Zea mays L.) during the summer season of 1996 (study period; 15-30 June). Coal-ash from the National Capital Power Project, Dadri, Ghaziabad, Uttar Pradesh and surface soil (O-15 cm layer) from the Indian Agricultural Research Institute Farm, New Delhi were collected and analyzed. Treatments were 0, lo%, 20%, 30% and 40% of ash on dry weight basis in a soil-ash mixture for winter season crops, and 0, 5%, lo%, 15% and 20% for summer season crops and were replicated thrice in a complete randomized block design. Two days prior to sowing of each crop,
INTRODUCTION Disposal of the huge amount of ash produced by burning of coal for energy purpose is a major concern. By 2000 A.D., the projected annual consumption of coal and lignite in the world is more than 4350 million tonnes with ash production of about 300 million tonnes (Shanmugasundaram, 1988). Coal-ash, though, finds a use in the manufacture of cement, bricks and other construction materials, but this is not so popular in India on cost considerations. Countries like USA, Germany and The Netherlands utilize 70% of waste ash as build*Author to whom correspondence should be addressed. 39
40
N. Kalra et al.
the pots were filled with water to field capacity. Twenty good-quality seeds were put at 5 cm depth in every pot. The germination count was recorded at regular intervals till termination of the experiment (200 h for winter crops and 120 h for summer crops). At this stage, above ground, biomass values were recorded after keeping the samples at 65°C for about 48 h. Soil-ash mixtures were analyzed for physical (bulk density, hydraulic conductivity, soil strength, moisture retention at field capacity and permanent wilting point) and physico-chemical (pH, electrical conductivity and organic carbon) properties by the following standard techniques. Germination time, defined as the time taken for 75% germination (60% in case of mustard due to relatively poor germination), was worked out for crops under different ash application treatments. Delay index (DI), a normalized parameter, was introduced to compare performance of crops under different ash application levels, and is defined as below: DI =X/Y, where X = delay in germination time over Control (no ash) and Y= germination time for Control. RESULTS AND DISCUSSION Soil and flyash characteristics About 45% of the coal used at NCPP, Dadri, consisted of ash, while volatile material and fixed carbon were 15.2% and 28.6%, respectively. Analysis showed that the flyash was an amorphous ferroalumino silicate, which contained about 93% of silica, A1203 and FezO,. In the remaining portion, Ca was the dominant cation followed by Mg, Na and K. Approximately 69% of flyash was made up of silt and clay fractions, silt loam in texture (Table l), whereas the soil used in the study was sandy loam. The bulk density of flyash was 1.01 Mg/m3, which was very low compared to 1.43 Mg/m3 for soil. Water movement was slower in ash, as shown by the saturated hydraulic conductivity value of 3.57 cm/d versus 10.7 cm/d for soil. Organic carbon values for ash and soil were 0.36% and 0.28%, respectively. Water holding capacity of flyash was 56.9% (on weight basis), which was very high compared to 30.8% for soil, due to silt dominancy in the ash. The pH value of 6.9 for ash was relatively lower than for soil (8.3), while the electrical conductivity of ash was higher (0.65 mmhos/cm) than that of soil (0.47 mmhos/cm). Table 1. Particle size of the soil and flyash
Particle size 2.0-0.02 mm (sand) 0.02-0.002 mm (silt) < 0.002 mm (clay)
Soil
Flyash (% at each particle size)
52.3 32.5 15.2
30.5 57.6 11.9
Physical and chemical characteristics of soil-ash mixture The pH decreased from 8.31 for the Control (no ash) to 7.98 for 40% ash, whereas the respective electrical conductivity (mmhos/cm) and organic carbon (%) values increased from 0.467 to 0.746, and 0.28 to 0.313. Bulk density decreased from 1.43 ~g/ m3 (Control) to 1.27 Mg/m’ at 40% ash. Percent moisture retained at saturation, field capacity and wilting point, expressed on weight basis, increased with flyash addition and the results were in agreement with the studies conducted by Ghodrati et al., 1995. Available water (mm of water/cm of soil), though, showed an increasing trend with flyash amount, but the differences were only in a narrow range of 1.45 (Control) to 1.54 at 40% ash. The results suggested the use of ash for improving moisture retention in soils having poor water holding capacity. Water movement in light- and mediumtextured soils could be reduced by ash incorporation, shown by the decrease in saturated hydraulic conductivity with ash content. Addition of ash increased soil mechanical impedance, as shown by the higher penetration resistance value of 2.23 kg/cm2 at 40% ash compared to 1.57 kg/cm2 for the Control. This character appeared to play a dominant role in germination and subsequent establishment of crops. Crop-stand establishment Wheat The germination
count decreased with increase in ash content and differences persisted till 100 h, but thereafter the counts were similar for the various treatments, except for 40% ash where germination remained poor throughout the study period. The Control germination time was 87 h, and delays of 7, 11, 13 and 58 h were found under lo%, 20%, 30% and 40% ash, respectively. Corresponding DI values for ash application treatments were 0.081, 0.126, 0.149 and 0.667. Above-ground biomasses (mg/plant) of 200-h-old seedlings ranged from 7.4 at 40% ash to 12.0 for the Control, and also significantly differed among treatments, which might be the consequence of delayed germination. Chickpea
The germination count differed significantly among ash application treatments till 140 h after seeding, but thereafter differences were confined to a narrow range, except for 30% and 40% ash treatments which showed considerable reduction in germination. Germination time was 109 h for the Control with delays of 15, 16, 22 and 29 h, and corresponding DI values of 0.138, 0.146, 0.202 and 0.266 for lo%, 20%, 30% and 40% ash treatments, respectively. Increasing the amount of ash in the soil had a relatively lower effect on germination time and DI with this crop than with wheat. Above-ground biomasses (mg/plant) at the termination of the experiment ranged from 7.4 under 40% ash to 11.6
Flyash and crop germination
for the Control, and were significantly different among treatments, showing a response similar to wheat. Mustard
The germination was adversely affected by application of ash in soil. For computation of germination time, 60% was taken as the criterion, since germination in this crop was in general poor, even under no flyash treatment. This mark could be attained only at 10% ash, but with a delay of 23 h compared to the Control which had a germination time of 97.h. After a delay of 68 h over the Control, germination was only 55%, 35% and 20% under 20%, 30% and 40% ash treatments, respectively. The DI value for 10% ash treatment was 0.237, which was relatively high compared to wheat and chickpea crops. This crop is highly sensitive to ash application in soil. Above-ground biomass (mg/plant) of 200-h-old seedlings ranged from 3.8 under 40% ash to 5.8 under no flyash treatment. The reduced germination under ash application may lead to reduced growth when expressed on a per unit area of soil basis. Lentil
The germination was poor under ash-application treatments till 78 h after seeding, and thereafter germination picked up but remained significantly lower than the no-ash treatment. At 170 h, germinations under lo-30% ash treatments were similar, but significantly lower than the Control, while 40% ash treatment showed highly reduced germination. The germination time of the Control was 78 h, and delays of 16, 17, 30 and 92 h were noted under lo%, 20%, 30% and 40% ash treatments, respectively. Corresponding DI values for ash treatments were 0.205, 0.218, 0.385 and 1,179, and were higher than for wheat and chickpea crops. Seedling mass (mg/ plant) at the 200 h stage ranged from 3.4, 3.7, 4.2 and 5.7 under 40%, 30%, 20% and 10% ash, respectively with the Control 5.9. Rice
Flyash addition gave reduced germination counts in the beginning, but these then picked up even under higher flyash levels in the later stages of the growth and became similar to the Control at the 115 h stage. Germination time for the Control averaged 62 h, with little delays of 0.4, 1.0, 1.2 and 2.8 h under 5%, lo%, 15% and 20% ash treatments, respectively. Corresponding DI values for ash-addition treatments were 0.0064, 0.0162, 0.0194 and 0.045, which were very low compared to winter-season crops. The results showed that rice is less sensitive than other crops to ash application for germination and initial crop stand establishment. Above ground, biomasses (mg/plant) at the termination of the experiment (120 h) were 8.21, 8.44, 8.56 and 8.76 under 20%, 15%, 10% and 5% ash treatments, respectively, with the Control 8.93.
41
Maize
The germination count differed significantly from the Control in ash-applied plots till 105 h after seeding, but in the later stages the ash-addition effect diminished, with similar count values among all treatments at 115 h. Germination time averaged 83.9 h for the Control, with delays of 3.0, 5.3, 6.6 and 10.1 h, and DI values of 0.036, 0.063, 0.079 and 0.120 for 5%, lo%, 15% and 20% ash level treatments, respectively. The results were in agreement with studies conducted on maize by Sims et al., 1995. Above-ground biomasses (mg/plant) at the termination of the experiment were 9.56 for the Control, with significantly different values of 8.23, 8.57, 8.73 and 9.14 under 20%, 15%, 10% and 5% ash treatments, respectively. CONCLUSION Flyash incorporation in soil delays germination of crops, most likely because of increased impedance offered by the soil/ash matrix to germinating seeds. This causes reduced growth of crops in the earlier stages, which subsequently may lead to reduced yield under unfavorable environments. Differential responses of crops to ash mixing in soil were noted: rice and maize were less sensitive than winter-season crops. Mustard was most affected by ash addition for germination and stand establishment. The delay index showed variations for crops as well as for ash levels within a crop. Flyash effects on germination need to be linked with subsequent plant-growth activities for understanding of differences in final growth and yield. REFERENCES Ghodrati, M., Sims, J. T. & Vasilas, B. L. (1995). Evaluation of flyash as a soil amendment for the Atlantic Coastal Plain: I. Soil hydraulic properties and elemental leaching Wateq Air and Soil Pollution, 81, 349-361. Mandal, P. K. and Sinha, A. K. (1988) Potential of utilization of flyash from thermal power stations - Magnitude of problems and remedies thereof. National Workshop on Coal Ash Utilization in India sponsored by DST, New Delhi on 28 June, pp. 1-18. Pathak, H., Kalra, N., Sharma, S. & Joshi, H. C. (1996). Use of flyash in agriculture: Potentialities and constraints. Yojana, 40, 6 24-25. Plank, C. 0. & Martens, D. C. (1974). Boron availability as influenced by application of fly ash to soil. Proc. Soil Sci. Sot. Am., 38, 974-977.
Sims, J. T., Vasilas, B. L. & Ghodrati, M. (1995). Evaluation of flyash as a soil amendment for the Atlantic Coastal Plains: II. Soil chemical properties and crop growth Watec Air and Soil Pollution, 81, 363-372. Shanmugasundaram, M. (1988) Flyash waste to wealth. An overview with special reference to Neyveli. National Workshop on Coal Ash Utilization in India sponsored by DST, New Delhi on 28 June, pp. 1-18. Taylor, E. M. & Schuman, G. E. (1988). Flyash and lime amendment of acidic coal spoil to aid revegetation. J. Environ. Qual., 17, 120-124.
PII:SO960-8524(96)00050-3
IMPACT OF FLYASH INCORPORATION IN SOIL ON GERMINATION OF CROPS Naveen Kalra,* H. C. Joshi, A. Chaudhary, Division of Environmental
R. Choudhary
& S.
K. Sharma
Sciences, IARI, New Delhi 110012, India
(Received 22 January 1997; revised version received 15 March 1997; accepted 25 March 1997)
ing material and for other constructional purposes, but in India its utilization is less than 5% (Mandal and Sinha, 1988). It can also be used as a landfill material, or for reclaiming acidic or sodic soils (Plank and Martens, 1974; Taylor and Schuman, 1988). Because of the restricted use of ash in such activities, thermal power stations have to provide adequate storage space and check associated environmental pollution problems (Pathak et al., 1996). In view of ash incorporation in soil from ash mounds and chimneys by climatic actions, or while using ash as a soil amendment, it becomes necessary to evaluate its effects on soil and crop productivity. Germination and crop stand establishment are prime plant-growth processes, which play a major role in deciding subsequent growth and yield, and so need to be evaluated under varying levels of ash incorporation within the soil. The present study evaluated ash incorporation effects on germination of several crops to work out the optimum level of ash addition and relate germination effects with changes in soil characteristics caused by mixing ash with the soil.
Abstract Pot-culture experiments were conducted to evaluate the effect of ash incorporation in soil on germination and stand establishment of wheat (Triticum aestivum L.), chickpea (Cicer arietinum L.), mustard (Brassica juntea L.) and lentil (Lens esculenta Moench.) during the winter season of 1995, and rice (Oryza sativa L.) and maize (Zea mays L.) during the summer season of 1996. Ash levels tested were 0, lo%, 20%, 30% and 40% for winter-season crops, and 0, 5%, lo%, 15% and 20% for summer-season crops. Changes in soil physical and chemical characteristics due to ash addition were analyzed. Germination time, defined as the time taken for 75% germination (60% in case of mustard), and delay index, a normalized parametel; were introduced to evaluate ash-incorporation effects on germination of crops. Ash addition in soil delayed germination of crops due to the increased impedance offered by the soil matrix to germinating seeds. Rice and maize were relatively less sensitive to ash for germination than winter-season crops. Mustard was most affected for germination and stand establishment. The delay index showed variations between crops as well as for ash levels within a crop. 0 1997 Elsevier Science Ltd. Key words: Flyash, germination soil mechanical-impedance.
METHODS
time, delay index, Pot culture experiments were conducted. The test crops were wheat (Ttiticum aestivum L.), chickpea (Cicer arietinum L.), mustard (Brassica juncea L.) and lentil (Lens esculenta Moench.) during the winter season of 1995 (study period; 1-15 November), and rice (Oryza sativa L.) and maize (Zea mays L.) during the summer season of 1996 (study period; 15-30 June). Coal-ash from the National Capital Power Project, Dadri, Ghaziabad, Uttar Pradesh and surface soil (O-15 cm layer) from the Indian Agricultural Research Institute Farm, New Delhi were collected and analyzed. Treatments were 0, lo%, 20%, 30% and 40% of ash on dry weight basis in a soil-ash mixture for winter season crops, and 0, 5%, lo%, 15% and 20% for summer season crops and were replicated thrice in a complete randomized block design. Two days prior to sowing of each crop,
INTRODUCTION Disposal of the huge amount of ash produced by burning of coal for energy purpose is a major concern. By 2000 A.D., the projected annual consumption of coal and lignite in the world is more than 4350 million tonnes with ash production of about 300 million tonnes (Shanmugasundaram, 1988). Coal-ash, though, finds a use in the manufacture of cement, bricks and other construction materials, but this is not so popular in India on cost considerations. Countries like USA, Germany and The Netherlands utilize 70% of waste ash as build*Author to whom correspondence should be addressed. 39
40
N. Kalra et al.
the pots were filled with water to field capacity. Twenty good-quality seeds were put at 5 cm depth in every pot. The germination count was recorded at regular intervals till termination of the experiment (200 h for winter crops and 120 h for summer crops). At this stage, above ground, biomass values were recorded after keeping the samples at 65°C for about 48 h. Soil-ash mixtures were analyzed for physical (bulk density, hydraulic conductivity, soil strength, moisture retention at field capacity and permanent wilting point) and physico-chemical (pH, electrical conductivity and organic carbon) properties by the following standard techniques. Germination time, defined as the time taken for 75% germination (60% in case of mustard due to relatively poor germination), was worked out for crops under different ash application treatments. Delay index (DI), a normalized parameter, was introduced to compare performance of crops under different ash application levels, and is defined as below: DI =X/Y, where X = delay in germination time over Control (no ash) and Y= germination time for Control. RESULTS AND DISCUSSION Soil and flyash characteristics About 45% of the coal used at NCPP, Dadri, consisted of ash, while volatile material and fixed carbon were 15.2% and 28.6%, respectively. Analysis showed that the flyash was an amorphous ferroalumino silicate, which contained about 93% of silica, A1203 and FezO,. In the remaining portion, Ca was the dominant cation followed by Mg, Na and K. Approximately 69% of flyash was made up of silt and clay fractions, silt loam in texture (Table l), whereas the soil used in the study was sandy loam. The bulk density of flyash was 1.01 Mg/m3, which was very low compared to 1.43 Mg/m3 for soil. Water movement was slower in ash, as shown by the saturated hydraulic conductivity value of 3.57 cm/d versus 10.7 cm/d for soil. Organic carbon values for ash and soil were 0.36% and 0.28%, respectively. Water holding capacity of flyash was 56.9% (on weight basis), which was very high compared to 30.8% for soil, due to silt dominancy in the ash. The pH value of 6.9 for ash was relatively lower than for soil (8.3), while the electrical conductivity of ash was higher (0.65 mmhos/cm) than that of soil (0.47 mmhos/cm). Table 1. Particle size of the soil and flyash
Particle size 2.0-0.02 mm (sand) 0.02-0.002 mm (silt) < 0.002 mm (clay)
Soil
Flyash (% at each particle size)
52.3 32.5 15.2
30.5 57.6 11.9
Physical and chemical characteristics of soil-ash mixture The pH decreased from 8.31 for the Control (no ash) to 7.98 for 40% ash, whereas the respective electrical conductivity (mmhos/cm) and organic carbon (%) values increased from 0.467 to 0.746, and 0.28 to 0.313. Bulk density decreased from 1.43 ~g/ m3 (Control) to 1.27 Mg/m’ at 40% ash. Percent moisture retained at saturation, field capacity and wilting point, expressed on weight basis, increased with flyash addition and the results were in agreement with the studies conducted by Ghodrati et al., 1995. Available water (mm of water/cm of soil), though, showed an increasing trend with flyash amount, but the differences were only in a narrow range of 1.45 (Control) to 1.54 at 40% ash. The results suggested the use of ash for improving moisture retention in soils having poor water holding capacity. Water movement in light- and mediumtextured soils could be reduced by ash incorporation, shown by the decrease in saturated hydraulic conductivity with ash content. Addition of ash increased soil mechanical impedance, as shown by the higher penetration resistance value of 2.23 kg/cm2 at 40% ash compared to 1.57 kg/cm2 for the Control. This character appeared to play a dominant role in germination and subsequent establishment of crops. Crop-stand establishment Wheat The germination
count decreased with increase in ash content and differences persisted till 100 h, but thereafter the counts were similar for the various treatments, except for 40% ash where germination remained poor throughout the study period. The Control germination time was 87 h, and delays of 7, 11, 13 and 58 h were found under lo%, 20%, 30% and 40% ash, respectively. Corresponding DI values for ash application treatments were 0.081, 0.126, 0.149 and 0.667. Above-ground biomasses (mg/plant) of 200-h-old seedlings ranged from 7.4 at 40% ash to 12.0 for the Control, and also significantly differed among treatments, which might be the consequence of delayed germination. Chickpea
The germination count differed significantly among ash application treatments till 140 h after seeding, but thereafter differences were confined to a narrow range, except for 30% and 40% ash treatments which showed considerable reduction in germination. Germination time was 109 h for the Control with delays of 15, 16, 22 and 29 h, and corresponding DI values of 0.138, 0.146, 0.202 and 0.266 for lo%, 20%, 30% and 40% ash treatments, respectively. Increasing the amount of ash in the soil had a relatively lower effect on germination time and DI with this crop than with wheat. Above-ground biomasses (mg/plant) at the termination of the experiment ranged from 7.4 under 40% ash to 11.6
Flyash and crop germination
for the Control, and were significantly different among treatments, showing a response similar to wheat. Mustard
The germination was adversely affected by application of ash in soil. For computation of germination time, 60% was taken as the criterion, since germination in this crop was in general poor, even under no flyash treatment. This mark could be attained only at 10% ash, but with a delay of 23 h compared to the Control which had a germination time of 97.h. After a delay of 68 h over the Control, germination was only 55%, 35% and 20% under 20%, 30% and 40% ash treatments, respectively. The DI value for 10% ash treatment was 0.237, which was relatively high compared to wheat and chickpea crops. This crop is highly sensitive to ash application in soil. Above-ground biomass (mg/plant) of 200-h-old seedlings ranged from 3.8 under 40% ash to 5.8 under no flyash treatment. The reduced germination under ash application may lead to reduced growth when expressed on a per unit area of soil basis. Lentil
The germination was poor under ash-application treatments till 78 h after seeding, and thereafter germination picked up but remained significantly lower than the no-ash treatment. At 170 h, germinations under lo-30% ash treatments were similar, but significantly lower than the Control, while 40% ash treatment showed highly reduced germination. The germination time of the Control was 78 h, and delays of 16, 17, 30 and 92 h were noted under lo%, 20%, 30% and 40% ash treatments, respectively. Corresponding DI values for ash treatments were 0.205, 0.218, 0.385 and 1,179, and were higher than for wheat and chickpea crops. Seedling mass (mg/ plant) at the 200 h stage ranged from 3.4, 3.7, 4.2 and 5.7 under 40%, 30%, 20% and 10% ash, respectively with the Control 5.9. Rice
Flyash addition gave reduced germination counts in the beginning, but these then picked up even under higher flyash levels in the later stages of the growth and became similar to the Control at the 115 h stage. Germination time for the Control averaged 62 h, with little delays of 0.4, 1.0, 1.2 and 2.8 h under 5%, lo%, 15% and 20% ash treatments, respectively. Corresponding DI values for ash-addition treatments were 0.0064, 0.0162, 0.0194 and 0.045, which were very low compared to winter-season crops. The results showed that rice is less sensitive than other crops to ash application for germination and initial crop stand establishment. Above ground, biomasses (mg/plant) at the termination of the experiment (120 h) were 8.21, 8.44, 8.56 and 8.76 under 20%, 15%, 10% and 5% ash treatments, respectively, with the Control 8.93.
41
Maize
The germination count differed significantly from the Control in ash-applied plots till 105 h after seeding, but in the later stages the ash-addition effect diminished, with similar count values among all treatments at 115 h. Germination time averaged 83.9 h for the Control, with delays of 3.0, 5.3, 6.6 and 10.1 h, and DI values of 0.036, 0.063, 0.079 and 0.120 for 5%, lo%, 15% and 20% ash level treatments, respectively. The results were in agreement with studies conducted on maize by Sims et al., 1995. Above-ground biomasses (mg/plant) at the termination of the experiment were 9.56 for the Control, with significantly different values of 8.23, 8.57, 8.73 and 9.14 under 20%, 15%, 10% and 5% ash treatments, respectively. CONCLUSION Flyash incorporation in soil delays germination of crops, most likely because of increased impedance offered by the soil/ash matrix to germinating seeds. This causes reduced growth of crops in the earlier stages, which subsequently may lead to reduced yield under unfavorable environments. Differential responses of crops to ash mixing in soil were noted: rice and maize were less sensitive than winter-season crops. Mustard was most affected by ash addition for germination and stand establishment. The delay index showed variations for crops as well as for ash levels within a crop. Flyash effects on germination need to be linked with subsequent plant-growth activities for understanding of differences in final growth and yield. REFERENCES Ghodrati, M., Sims, J. T. & Vasilas, B. L. (1995). Evaluation of flyash as a soil amendment for the Atlantic Coastal Plain: I. Soil hydraulic properties and elemental leaching Wateq Air and Soil Pollution, 81, 349-361. Mandal, P. K. and Sinha, A. K. (1988) Potential of utilization of flyash from thermal power stations - Magnitude of problems and remedies thereof. National Workshop on Coal Ash Utilization in India sponsored by DST, New Delhi on 28 June, pp. 1-18. Pathak, H., Kalra, N., Sharma, S. & Joshi, H. C. (1996). Use of flyash in agriculture: Potentialities and constraints. Yojana, 40, 6 24-25. Plank, C. 0. & Martens, D. C. (1974). Boron availability as influenced by application of fly ash to soil. Proc. Soil Sci. Sot. Am., 38, 974-977.
Sims, J. T., Vasilas, B. L. & Ghodrati, M. (1995). Evaluation of flyash as a soil amendment for the Atlantic Coastal Plains: II. Soil chemical properties and crop growth Watec Air and Soil Pollution, 81, 363-372. Shanmugasundaram, M. (1988) Flyash waste to wealth. An overview with special reference to Neyveli. National Workshop on Coal Ash Utilization in India sponsored by DST, New Delhi on 28 June, pp. 1-18. Taylor, E. M. & Schuman, G. E. (1988). Flyash and lime amendment of acidic coal spoil to aid revegetation. J. Environ. Qual., 17, 120-124.