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Effect of pyrite on conservation of nitrogen during composting
Biological Wastes 25 (1988) 227-231
Short Communication Effect of Pyrite on Conservation of Nitrogen During Composting
INTRODUCTION Diminishing nonrenewable resources used in the manufacture of inorganic fertilizers, rising fertilizer costs, and the necessity for maintaining environmental quality, encourage return of organic wastes to the land. Compost is a possible source of plant nutrients adding humus and improving soil physical properties (Poincelot, 1975), but poor nutrient contents, especially N and P, are hampering its widespread use. We (Mishra et al., 1982, 1984; Bangar el al., 1985; Mishra & Bangar, 1986) have developed a technology to prepare a P-enriched material called 'Phosphocompost' using organic wastes and low-grade rock phosphate. We, however, observed (unpublished) significant losses of nitrogen during an attempt to enrich this compost with N, using inorganic N. The present communication reports on the effect of addition of iron pyrite, which is easily available in India, on the retention of nitrogen in Phosphocompost.
METHODS Paddy straw and leaves of Delbergia sisso (mixed in equal amounts) were powdered and passed through a 4 mm sieve. The material (10g) was then disbursed into 500 ml Erlenmeyer flasks. Mussoorie rock phosphate (MRP) (2.5 g) was added to all flasks and Amjhore pyrite and nitrogen in the form of urea were added as below with three replicates each. 227 Biological Wastes 0269-7483/88/$03.50 ((? 1988 Elsevier Applied Science Publishers Ltd, England. Printed in Great Britain
228
K. C. Bangar, K. K. Kapoor, M. M. Mishra
T1
Organic material + M R P
T2 T3 T4
Organic material + M R P + Pyrite I g Organic material + M R P + Pyrite 2-5 g Organic material + M R P + N 0 " l g
T5
Organic material + M R P +Pyrite l g
T6 T7 T8
Organic material + M R P + Pyrite 2"5g + N 0.1 g Organic material + M R P + N 0 " 2 g Organic material + M R P +Pyrite I g + N 0 . 2 g
T9
Organic material + M R P + Pyrite 2.5g + N 0-2g
+N0'lg
Well-decomposed compost (5 g) was suspended in 100 mi sterile water and 2 ml of this suspension was added as inoculum to each flask. Water was added to bring the contents to 70% of the water-holding capacity. The flasks were incubated at 30 _+ 2°C. Analyses were done periodically. The M R P used in this experiment contained: total P, 8-1%; water-soluble P, 0"056 mg/g; 0"5M NaHCO3-soluble P, 0.18 mg/g; 2% citric acid-soluble P, 2"3mg/g; free CaCO 3 11"2%, pH 8-7. Phosphorus in M R P is present as carbonate fluorapatite which constitutes about 67% of the total phosl~hate rock. M RP was obtained from Pyrites, Phosphates and Chemicals Ltd, Dehradun, India. Agricultural grade Amjhore Pyrite was obtained from Pyrites, Phosphates and Chemicals Ltd, Dehri-on-Sone, Rohtas, Bihar, India, and contained: total sulphur, 22%; iron 20%; magnesium as MgO, 0.6%; calcium as CaO, 0.1%; alumina, 6-5%; silica 37%; carbon, 2% and traces of Zn, Cu and Mn. During decomposition, carbon was determined by an ignition method. Total N was estimated using selenium dioxide in the catalytic mixture (Bremner & Mulvaney, 1982). Ammoniacal and nitrate-nitrogen were determined by a steam distillation method (Bremner, 1965). Ammonia volatilization was estimated by absorption in boric acid (Rao & Batra, 1983). The pH was determined in a 1:2 suspension of decomposing material and water using an Elico pH meter.
RESULTS A N D DISCUSSION The data in Table 1 show that the nitrogen losses through volatilization in the form of N H 3 - - N during decomposition were negligible in the absence of additional nitrogen, but significant amounts of nitrogen were volatilized when N was added. More than 50% of the ammonia volatilization took place in the first fortnight. The hydrolysis of urea has been found to be very
E]fect of pyrite on conservation o[ nitrogen
229
TABLE I Losses o f Nitrogen as A m m o n i a D u r i n g Decomposition re_
Incubation period {days)
Treat-
Total in 90 days
191ents a
TI T2 T3 T4 T5 T6 T7 T8 T9 LSD (P = 0.05)
0-4
4 14
14 28 28-49 NH3-N (mg.([task)
0.03 0'03 003 648 5.21 3. I I 14.54 10.50 7.00
001 001 001 1280 7.06 3.32 35.73 27.23 10.76
0 0 0 308 301 1.73 19.21 14.62 7.54
0.46
0.72
0.52
49 60
60-90
0 0 0 532 3.62 1.40 15.62 10.32 6.24
0 u 0 3-26 2-29 0.37 10.40 9-10 5.76
0 0 0 232 2.36 0.32 10.20 5.00 3.20
0.61
0.43
0.39
0.04 0.04 0-04 33.26 23.55 10.25 105.70 64.47 40-30
'~ For meaning ot" symbols see "Methods' section.
TABI,E 2 A m m o n i a c a l , Nitrate and Total Nitrogen C o n t e n t s D u r i n g Dccomposition
Treat-
Incubation period (days)
tHents
0
TI T2 T3 T4 T5 T6 T7 T8 T9 LSD (P=0.05)
I0
3O
60
90
A
B
C
A
B
("
A
B
C
A
B
C
A
B
C
71 65 60 495 457 382 653 527 429
32 37 46 144 149 168 219 266 275
0.87 0.75 0.63 1.86 1.75 1.69 2'87 2.63 2.42
72 65 68 1416 2541 2698 2985 4184 5246
35 38 40 273 560 650 709 842 847
0.89 0.77 0.66 1-82 1.82 1.87 2'46 2.48 254
71 68 71 1842 3199 3581 3460 4709 6287
28 30 30 160 212 231 210 246 298
0.92 0-88 0.77 1.28 1.57 1.79 1.33 1.83 2.12
70 62 68 2013 2241 3272 3735 5086 6844
18 28 28 138 189 235 249 247 290
0'98 0.89 0-78 1-14 1.53 1.78 1.28 1.75 2.05
68 62 65 1264 1622 2816 2615 3485 4720
30 28 28 115 169 192 232 248 262
1.06 0.98 0.86 1.25 1-63 1-85 1.34 1.84 2.26
12 0.09
20
8 0.10
28
9 0.08
25
11
8 fill
26
A = A m m o n i a c a l N (pg/g); B = nitrate N (~ug/g); a n d C = total N (%}.
I1 0-10
230
K. C. Bangar, K. K. Kapoor, M. M. Mishra TABLE 3
Carbon-Nitrogen (C/N) Ratio and pH During Decomposition Treatments
Incubation period (days) 0
30
60
90
0
10
C/N ratio
30
60
90
pH
T1 T2 T3 T4 T5 T6 T7 T8 T9
528 49'1 46.6 21.3 19.9 17.1 16.1 14-0 12.2
41.3 36'2 35.2 29.8 20.4 16.1 28.7 18.5 14.8
34"6 30'8 27.1 25-7 18-7 15-1 24.2 17-2 13-2
29'2 27.3 24.2 22.1 17.2 14.5 20.2 16.7 12-8
8'4 7-6 7.2 8.6 7-8 7.2 8-6 7-8 7-2
8"3 7-6 7-2 9.4 8.0 7.0 9.6 8.2 7.4
8-4 7-5 7.0 9-2 7.8 7.2 9.4 8.0 7.2
83 7.4 7.0 9.0 7.6 7.0 9.4 8.0 7.2
8-2 7.2 6.8 8.8 7.6 7.2 9.0 8.0 7.2
LSD (P = 0.05)
I-2
1.8
1.6
2-0
0-2
0.1
0.2
0.2
0-I
rapid and all urea N is converted to N H ~ - N within 15 days. The gaseous loss was reduced on addition of pyrite along with urea N. In treatments containing pyrite, less NH4T-N was present initially than in treatments without pyrite, but as the decomposition progressed, more N H ~ - N was found in the treatments containing pyrite and the N H ~ - N increased with increase in pyrite concentration (Table 2). The action of pyrite in retaining N H 2 - N could be attributed to pH reduction (Table 3), a high pH promoting volatilization losses. In treatments containing pyrite, the lower N H ~ - N observed at zero time was due to the fact that pyrite diluted the N content. The N O 3 - N content (Table 2) was lower in all treatments than the NH,~-N, and it increased initially, for 10 days, and then decreased slowly. Incubation caused a decrease in N, but this decrease was relatively lower with pyrite than without, so the decomposed compost containing pyrite has significantly more N than the non-pyrite-containing compost. The organic N values after 90 days obtained after deducting (NH~ + N O 3 ) - N values from total N indicated that more urea N was converted into an organic form in the presence of pyrite than in its absence. The assimilation of added nitrogen was less in treatments without pyrite owing to the high pH which reduced the rate of decomposition. The C / N ratio decreased gradually in treatments containing no nitrogen. In the presence of 1 and 2% N, the C / N ratio first increased due to loss of nitrogen, but gradually decreased later due to decomposition. The changes in C/N ratio were smaller with the addition of pyrite since there was less loss of nitrogen (Table 3).
Effect of pyrite on conservation of nitrogen
231
The study indicates the possibility of both N and P enrichment of compost with the addition of pyrite.
REFERENCES Bangar, K. C., Yadav, K. S. & Mishra, M. M. (1985). Transformation of rock phosphate during composting and the effect of humic acid. Plant and Soil., 85, 259-66. Bremner, J. M. (! 965). Inorganic forms of nitrogen. In: Methods of Soil Analysis Part 2, Chemical and Microbiological Properties. (Black, C. A. (Ed.)). American Society of Agronomy, Madison, Wisconsin, 1179-237. Bremner, J. M. & Mulvaney, C. S. (1982). Nitrogen-Total. In: Methods" of Soil Analysis Part 2, Chemical and Microbiological Properties, Second Edition (Page, A. L. (Ed)). American Society of Agronomy, Madison, Wisconsin, 595 624. o Mishra, M. M. & Bangar, K. C, (1986). Rock phosphate composting: Transformation of phosphorus forms and mechanisms of solubilization. Biological Agriculture and Horticulture, 3,331-40. Mishra, M. M., Kapoor, K. K. & Yadav, K. S. (1982). Effect of compost enriched with Mussoorie rock phosphate on crop yield. Indian Journal of Agricultural Sciences, 52, 674 8. Mishra, M. M., Khurana, A. L., Dudeja, S. S. & Kapoor, K. K. (1984). The effect of phosphocompost on the yield and P uptake by red gram. Tropical Agriculture, 23, 136-8. Poincelot, R. P. (1975). Biochemistry and Methodology of Composting. Connecticut Agricultural Experiment Station Bulletin No. 754, New Haven, 1-18. Rao, D. L. N. & Batra, Lalita (1983). Ammonia volatilization from applied nitrogen in alkali soils. Plant and Soil, 70, 219-28.
K. C. Bangar, K. K. Kapoor & M. M. Mishra Department o f Microbiology, Harvana Agricultural University, Hisar- 125004, India (Received 9 June 1987; revised version received 20 November 1987; accepted 1 December 1987)
Short Communication Effect of Pyrite on Conservation of Nitrogen During Composting
INTRODUCTION Diminishing nonrenewable resources used in the manufacture of inorganic fertilizers, rising fertilizer costs, and the necessity for maintaining environmental quality, encourage return of organic wastes to the land. Compost is a possible source of plant nutrients adding humus and improving soil physical properties (Poincelot, 1975), but poor nutrient contents, especially N and P, are hampering its widespread use. We (Mishra et al., 1982, 1984; Bangar el al., 1985; Mishra & Bangar, 1986) have developed a technology to prepare a P-enriched material called 'Phosphocompost' using organic wastes and low-grade rock phosphate. We, however, observed (unpublished) significant losses of nitrogen during an attempt to enrich this compost with N, using inorganic N. The present communication reports on the effect of addition of iron pyrite, which is easily available in India, on the retention of nitrogen in Phosphocompost.
METHODS Paddy straw and leaves of Delbergia sisso (mixed in equal amounts) were powdered and passed through a 4 mm sieve. The material (10g) was then disbursed into 500 ml Erlenmeyer flasks. Mussoorie rock phosphate (MRP) (2.5 g) was added to all flasks and Amjhore pyrite and nitrogen in the form of urea were added as below with three replicates each. 227 Biological Wastes 0269-7483/88/$03.50 ((? 1988 Elsevier Applied Science Publishers Ltd, England. Printed in Great Britain
228
K. C. Bangar, K. K. Kapoor, M. M. Mishra
T1
Organic material + M R P
T2 T3 T4
Organic material + M R P + Pyrite I g Organic material + M R P + Pyrite 2-5 g Organic material + M R P + N 0 " l g
T5
Organic material + M R P +Pyrite l g
T6 T7 T8
Organic material + M R P + Pyrite 2"5g + N 0.1 g Organic material + M R P + N 0 " 2 g Organic material + M R P +Pyrite I g + N 0 . 2 g
T9
Organic material + M R P + Pyrite 2.5g + N 0-2g
+N0'lg
Well-decomposed compost (5 g) was suspended in 100 mi sterile water and 2 ml of this suspension was added as inoculum to each flask. Water was added to bring the contents to 70% of the water-holding capacity. The flasks were incubated at 30 _+ 2°C. Analyses were done periodically. The M R P used in this experiment contained: total P, 8-1%; water-soluble P, 0"056 mg/g; 0"5M NaHCO3-soluble P, 0.18 mg/g; 2% citric acid-soluble P, 2"3mg/g; free CaCO 3 11"2%, pH 8-7. Phosphorus in M R P is present as carbonate fluorapatite which constitutes about 67% of the total phosl~hate rock. M RP was obtained from Pyrites, Phosphates and Chemicals Ltd, Dehradun, India. Agricultural grade Amjhore Pyrite was obtained from Pyrites, Phosphates and Chemicals Ltd, Dehri-on-Sone, Rohtas, Bihar, India, and contained: total sulphur, 22%; iron 20%; magnesium as MgO, 0.6%; calcium as CaO, 0.1%; alumina, 6-5%; silica 37%; carbon, 2% and traces of Zn, Cu and Mn. During decomposition, carbon was determined by an ignition method. Total N was estimated using selenium dioxide in the catalytic mixture (Bremner & Mulvaney, 1982). Ammoniacal and nitrate-nitrogen were determined by a steam distillation method (Bremner, 1965). Ammonia volatilization was estimated by absorption in boric acid (Rao & Batra, 1983). The pH was determined in a 1:2 suspension of decomposing material and water using an Elico pH meter.
RESULTS A N D DISCUSSION The data in Table 1 show that the nitrogen losses through volatilization in the form of N H 3 - - N during decomposition were negligible in the absence of additional nitrogen, but significant amounts of nitrogen were volatilized when N was added. More than 50% of the ammonia volatilization took place in the first fortnight. The hydrolysis of urea has been found to be very
E]fect of pyrite on conservation o[ nitrogen
229
TABLE I Losses o f Nitrogen as A m m o n i a D u r i n g Decomposition re_
Incubation period {days)
Treat-
Total in 90 days
191ents a
TI T2 T3 T4 T5 T6 T7 T8 T9 LSD (P = 0.05)
0-4
4 14
14 28 28-49 NH3-N (mg.([task)
0.03 0'03 003 648 5.21 3. I I 14.54 10.50 7.00
001 001 001 1280 7.06 3.32 35.73 27.23 10.76
0 0 0 308 301 1.73 19.21 14.62 7.54
0.46
0.72
0.52
49 60
60-90
0 0 0 532 3.62 1.40 15.62 10.32 6.24
0 u 0 3-26 2-29 0.37 10.40 9-10 5.76
0 0 0 232 2.36 0.32 10.20 5.00 3.20
0.61
0.43
0.39
0.04 0.04 0-04 33.26 23.55 10.25 105.70 64.47 40-30
'~ For meaning ot" symbols see "Methods' section.
TABI,E 2 A m m o n i a c a l , Nitrate and Total Nitrogen C o n t e n t s D u r i n g Dccomposition
Treat-
Incubation period (days)
tHents
0
TI T2 T3 T4 T5 T6 T7 T8 T9 LSD (P=0.05)
I0
3O
60
90
A
B
C
A
B
("
A
B
C
A
B
C
A
B
C
71 65 60 495 457 382 653 527 429
32 37 46 144 149 168 219 266 275
0.87 0.75 0.63 1.86 1.75 1.69 2'87 2.63 2.42
72 65 68 1416 2541 2698 2985 4184 5246
35 38 40 273 560 650 709 842 847
0.89 0.77 0.66 1-82 1.82 1.87 2'46 2.48 254
71 68 71 1842 3199 3581 3460 4709 6287
28 30 30 160 212 231 210 246 298
0.92 0-88 0.77 1.28 1.57 1.79 1.33 1.83 2.12
70 62 68 2013 2241 3272 3735 5086 6844
18 28 28 138 189 235 249 247 290
0'98 0.89 0-78 1-14 1.53 1.78 1.28 1.75 2.05
68 62 65 1264 1622 2816 2615 3485 4720
30 28 28 115 169 192 232 248 262
1.06 0.98 0.86 1.25 1-63 1-85 1.34 1.84 2.26
12 0.09
20
8 0.10
28
9 0.08
25
11
8 fill
26
A = A m m o n i a c a l N (pg/g); B = nitrate N (~ug/g); a n d C = total N (%}.
I1 0-10
230
K. C. Bangar, K. K. Kapoor, M. M. Mishra TABLE 3
Carbon-Nitrogen (C/N) Ratio and pH During Decomposition Treatments
Incubation period (days) 0
30
60
90
0
10
C/N ratio
30
60
90
pH
T1 T2 T3 T4 T5 T6 T7 T8 T9
528 49'1 46.6 21.3 19.9 17.1 16.1 14-0 12.2
41.3 36'2 35.2 29.8 20.4 16.1 28.7 18.5 14.8
34"6 30'8 27.1 25-7 18-7 15-1 24.2 17-2 13-2
29'2 27.3 24.2 22.1 17.2 14.5 20.2 16.7 12-8
8'4 7-6 7.2 8.6 7-8 7.2 8-6 7-8 7-2
8"3 7-6 7-2 9.4 8.0 7.0 9.6 8.2 7.4
8-4 7-5 7.0 9-2 7.8 7.2 9.4 8.0 7.2
83 7.4 7.0 9.0 7.6 7.0 9.4 8.0 7.2
8-2 7.2 6.8 8.8 7.6 7.2 9.0 8.0 7.2
LSD (P = 0.05)
I-2
1.8
1.6
2-0
0-2
0.1
0.2
0.2
0-I
rapid and all urea N is converted to N H ~ - N within 15 days. The gaseous loss was reduced on addition of pyrite along with urea N. In treatments containing pyrite, less NH4T-N was present initially than in treatments without pyrite, but as the decomposition progressed, more N H ~ - N was found in the treatments containing pyrite and the N H ~ - N increased with increase in pyrite concentration (Table 2). The action of pyrite in retaining N H 2 - N could be attributed to pH reduction (Table 3), a high pH promoting volatilization losses. In treatments containing pyrite, the lower N H ~ - N observed at zero time was due to the fact that pyrite diluted the N content. The N O 3 - N content (Table 2) was lower in all treatments than the NH,~-N, and it increased initially, for 10 days, and then decreased slowly. Incubation caused a decrease in N, but this decrease was relatively lower with pyrite than without, so the decomposed compost containing pyrite has significantly more N than the non-pyrite-containing compost. The organic N values after 90 days obtained after deducting (NH~ + N O 3 ) - N values from total N indicated that more urea N was converted into an organic form in the presence of pyrite than in its absence. The assimilation of added nitrogen was less in treatments without pyrite owing to the high pH which reduced the rate of decomposition. The C / N ratio decreased gradually in treatments containing no nitrogen. In the presence of 1 and 2% N, the C / N ratio first increased due to loss of nitrogen, but gradually decreased later due to decomposition. The changes in C/N ratio were smaller with the addition of pyrite since there was less loss of nitrogen (Table 3).
Effect of pyrite on conservation of nitrogen
231
The study indicates the possibility of both N and P enrichment of compost with the addition of pyrite.
REFERENCES Bangar, K. C., Yadav, K. S. & Mishra, M. M. (1985). Transformation of rock phosphate during composting and the effect of humic acid. Plant and Soil., 85, 259-66. Bremner, J. M. (! 965). Inorganic forms of nitrogen. In: Methods of Soil Analysis Part 2, Chemical and Microbiological Properties. (Black, C. A. (Ed.)). American Society of Agronomy, Madison, Wisconsin, 1179-237. Bremner, J. M. & Mulvaney, C. S. (1982). Nitrogen-Total. In: Methods" of Soil Analysis Part 2, Chemical and Microbiological Properties, Second Edition (Page, A. L. (Ed)). American Society of Agronomy, Madison, Wisconsin, 595 624. o Mishra, M. M. & Bangar, K. C, (1986). Rock phosphate composting: Transformation of phosphorus forms and mechanisms of solubilization. Biological Agriculture and Horticulture, 3,331-40. Mishra, M. M., Kapoor, K. K. & Yadav, K. S. (1982). Effect of compost enriched with Mussoorie rock phosphate on crop yield. Indian Journal of Agricultural Sciences, 52, 674 8. Mishra, M. M., Khurana, A. L., Dudeja, S. S. & Kapoor, K. K. (1984). The effect of phosphocompost on the yield and P uptake by red gram. Tropical Agriculture, 23, 136-8. Poincelot, R. P. (1975). Biochemistry and Methodology of Composting. Connecticut Agricultural Experiment Station Bulletin No. 754, New Haven, 1-18. Rao, D. L. N. & Batra, Lalita (1983). Ammonia volatilization from applied nitrogen in alkali soils. Plant and Soil, 70, 219-28.
K. C. Bangar, K. K. Kapoor & M. M. Mishra Department o f Microbiology, Harvana Agricultural University, Hisar- 125004, India (Received 9 June 1987; revised version received 20 November 1987; accepted 1 December 1987)