EC, Acidity and Total Nitrogen of Soil

ABSTRACT

IV. RESULTS AND DISCUSSION

4.2 EC, Acidity and Total Nitrogen of Soil

different treatments (products and control treated soils) varied significantly (P<0.05).

The data showed that the lowest EC value (96.60 µS/dl) was recorded for untreated soil (control) and the highest value (190.10 µS/dl) was observed for product NSP treated soil. The next higher value (175.70µS/dl) was recorded in soil treated with product CNP. The soil EC is related to soil porosity, cations exchange capacity, salinity and the presence of clay amount (Robert et al., 2009). The map of soil EC after product application showed that it enhanced the Soil EC, which might improve the soil porosity or cations exchange capacity as compare to control (Anderson et al., 2002). This might be due to the presence of humic acids in the products and also of certain minerals (Singh et al., 2008).

Acidity of soil showed a range of 0.97x10^-2 to 1.4x10^-2g/L. The variation in acidity values of the treated (products and controls) soils was significant (P<0.05).

The lowest acidity (0.97g/L) was detected in product S treated soil while the highest acidity (1.41g/L) was found in soil treated with product FP followed by product FN and CNS with acidity value of 1.39 g/L each. The acidity values of untreated soil were 1.01x10^-2 g/L, while that of NPK was 0.99 x10^-2 g/L. The data indicated that there seem no significant difference among the product and control treated soil.

Acidity of soil increase with addition of certain elements (Van-Breeman et al., 1983).

The seemingly higher acidity values of products treated soil might be due to the sulfur, aluminum or hydrogen addition by the product in the soil or release of these metals or hydrogen ions from the soil into soluble form (Brady and Weil 2002).

The total nitrogen content of the products and controls treated soil ranged from 2.03 x 10^-3 to 6.58 x 10^-3%. The least total nitrogen (2.03 x 10^-3%) content was observed in product S treated soil, while the highest total nitrogen value (6.58x10^-3%) was recorded in soil treated with product CFNSP followed by product FN with total nitrogen value of 6.40x10^-3%. The difference among the total nitrogen values of the treated soils was statistically significant (P<0.05).The data showed that higher values of total nitrogen were given by the products where nitric acid was present. However, products total nitrogen values were closed to controls ones with minor elevation, which favored the products in their nitrogen provision to the soils. Total nitrogen is readily available form of nitrogen and necessary for plants rapid growth (Mulvaney 1996). Some studies also showed that acidified biochar withhold the total nitrogen

from being leaching down or overhead escaping from the soil (Sarah et al., 2011), which favored the present study .

Table-1: pH and EC (uSdl^-1) of wood coal products

Treatments pH EC

1. C 1.48ⁿ 28.4^a

2. F 1.85^klmn 16.1^f

3. N 1.72^klmn 12.85^h

4. S 10.45^c 3.52^uv

5. P 11.32^b 4.15^s

6. CF 1.82^klmn 17.45^e

7. CN 1.52^mn 27.6^b

8. CS 7.15^ef 4.15^s

9. CP 2.2^jkl 7.77^m

10. FN 1.67^lmn 21.5^d

11. FS 6.65^f 3.53^uv

12. FP 7.37^e 4.09^s

13. NS 2.58^ij 5.59^p

14. NP 2.03^jklmn 9.29^l

15. SP 11.9^a 4.9^r

16. CFN 1.65^lmn 22.8^c

17. CFS 2.28^jk 6.12^o

18. CFP 2.2^jkl 6.82ⁿ

19. FNS 2.05^jklm 10.48^k

20. FNP 1.92^klmn 12.75^h

21. FSP 3.73^h 3.72^t

22. CNS 2.2^jkl 7.77^m

23. CNP 1.9^klmn 11.3^j

24. CSP 9.75^d 3.45^v

25. FSP 9.23^d 3.54^uv

26. NSP 4.35^g 3.68^tu

27. CFNS 1.9^klmn 12.21ⁱ

28. CFNP 1.88^klmn 13.18^g

29. CFSP 1.5^mn 4.06^s

30. CNSP 2.55^ij 5.1^q

31. FNSP 3.1ⁱ 5^qr

32. CFNSP 2.25^jk 7.7^m

Treatment means in the two columns followed by same letters were not significantly different (α=0.05) Key: Hydrochloric acid (C), Sulfuric acid (F), Nitric acid (N), Sodium hydroxide (S), Potassium hydroxide (P)

Table-2: Effect of wood coal products on EC (µS/dl), acidity (g/100ml) and total nitrogen (%) pot soil

Treatment means in vertical columns followed by same letters were not significantly different (α=0.05) Key: Hydrochloric acid (C), Sulfuric acid (F), Nitric acid (N), Sodium hydroxide (S), Potassium hydroxide (P)

Treatments EC Acidity x 10^-2 Total nitrogen 10^-3

1. C 128.80^defghij 1.12^l 2.88^w

2. F 117.90^ghij 1.05^m 2.73^y

3. N 108.60^ij 1.17^ijk 2.97^v

4. S 113.10^ghij 0.97^o 2.03^c

5. P 126.70^defghij 1.01^mno 3.78^o 6. CF 145.00^bcdefghi 1.22^gh 3.15^t 7. CN 126.30^defghij 1.19^hi 2.47^a 8. CS 143.00^bcdefghi 1.13^kl 2.83^wx

9. CP 98.70^j 1.25^g 2.64^z

10. FN 154.70^abcdef 1.39^ab 6.40^b

11. FS 149.00^bcdefg 1.26^fg 4.21^m

12. FP 118.60^fghij 1.41^a 3.82^o

13. NS 125.90^defghij 1.13^kl 3.08^u 14. NP 130.80^cdefghij 1.24^g 5.13^h 15. SP 124.20^efghij 1.33^cde 5.41^g

16. CFN 111.70^hij 1.18^hij 4.85ⁱ

17. CFS 143.30^bcdefghi 1.03^mn 6.19^c

18. CFP 99.00^j 1.25^g 3.27^s

19. FNS 120.00^fghij 1.32^cde 2.81^x 20. FNP 133.40^cdefghij 1.13^kl 3.53^p

21. FSP 102.60^j 1.26^fg 4.41^k

22. CNS 145.20^bcdefgh 1.39^ab 3.35^r

23. CNP 175.70^ab 1.14^jkl 3.99ⁿ

24. CSP 161.70^abcd 1.35^bcd 2.34^b 25. FSP 132.60^cdefghij 1.24^g 4.31^l

26. NSP 190.10^a 1.36^bc 5.75^f

27. CFNS 140.30^bcdefghi 1.22^gh 3.93ⁿ 28. CFNP 118.90^fghij 1.14^jkl 6.02^e

29. CFSP 166.80^abc 0.99^no 5.17^h

30. CNSP 146.70^bcdefgh 1.36^bc 5.81^f 31. FNSP 146.00^bcdfegh 1.24^g 4.67^j 32. CFNSP 159.20^abcde 1.30^ef 6.58^a 33. N.P.K 129.90^cdefghij 0.99^no 3.42^q 34. H.ACID 153.00^bcdefg 1.03^mn 6.12^d 35. F.Y.M 122.00^fghij 1.31^de 5.99^e 36. W.COAL 143.40^bcdefgh 1.18^hij 3.43^q 37. U. SOIL 96.60^j 1.01^mno 2.53^a

Table-3: Soil pH pot^-1 treated with wood coal products at two different intervals

Treatment means followed by same letters were not significantly different (α=0.05) A: Pot soil pH after initial product application

B: Pot soil pH after last product application

Key: Hydrochloric acid (C), Sulfuric acid (F), Nitric acid (N), Sodium hydroxide (S), Potassium hydroxide (P)

Treatments A B Mean

1. C 7.74 8.61 8.26^cdefgh

2. F 7.86 8.43 8.15^fgh

3. N 7.84 8.43 8.14 ^gh

4. S 7.85 8.51 8.18^cdefgh

5. P 7.77 8.73 8.25^abcde

6. CF 7.92 8.39 8.15^efgh

7. CN 8.06 8.44 8.25^abcde

8. CS 7.93 8.66 8.30^ab

9. CP 7.83 8.65 8.24^abcdef

10. FN 7.84 8.46 8.15^fgh

11. FS 7.86 8.43 8.15^fgh

12. FP 7.89 8.53 8.21^bcdefg

13. NS 7.76 8.45 8.10 ^h

14. NP 7.82 8.50 8.16^defgh

15. SP 7.83 8.47 8.15^fgh

16. CFN 7.87 8.59 8.23^abcdefg

17. CFS 7.82 8.66 8.24^abcdef

18. CFP 7.92 8.72 8.32 ^a

19. FNS 7.82 8.66 8.24^abcdef

20. FNP 7.77 8.69 8.23^abcdefg

21. FSP 7.84 8.73 8.28^ab

22. CNS 7.86 8.77 8.32 ^a

23. CNP 7.85 8.77 8.31 ^a

24. CSP 7.86 8.69 8.27^abc

25. FSP 7.75 8.77 8.26^abc

26. NSP 7.83 8.75 8.29^ab

27. CFNS 7.86 8.59 8.23^abcdefg

28. CFNP 7.87 8.63 8.25^abcd

29. CFSP 7.84 8.72 8.28^ab

30. CNSP 7.77 8.66 8.22^bcdefg

31. FNSP 7.85 8.71 8.28^ab

32. CFNSP 7.85 8.65 8.25^abcd

Mean 7.85^b 8.61^a

The average value of soil pH noted at the start of product application was 7.85 and it was 8.61 at the last time of product application (Table–3). The difference was statistically significant (P<0.05) showing a trend from basic to more basic. The tendency towards basic pH favors absorption of certain elements by the plants (Yuan et al., 2011). The variation in the average values of soil pH applied with different products and controls was also significant (P<0.05). The pH of products and control applied soils, ranged from 8.10 to 8.32. The lower value (8.10) of pH was recorded in soil applied with NS product while the highest value of 8.32 was found in the soils applied with CFP and CNS products. pH refers to hydrogen ion concentration in the soil solution. The increase in soil pH might be due to the release of some basic metals like Ca, K, C etc. (Zwieten et al., 2010), which cause elevation in soil pH. Christopher et al., (2014) also reported that biochar application, due to its high particle surface area, favors the growth of micro-flora in soil and tends to increase soil pH, EC and cations exchange capacity. These physical changes in soil, in turn increase the availability of macronutrients such as nitrogen and phosphorus.