Effect of the application of alkaline FA in conjunction with NPK fertilizers and FYM on physico chemical properties of acidic soil

Introduction

Fly ash is an obnoxious waste materials produced from coal based thermal power plants. This obnoxious solid waste has been causing environmental problems all over the world. It is produced is huge quantities in our country. It is used in manufacturing of bricks, cements and other civil construction activities. But its utilization is limited. However most of the FA produced in India including in the state of Odisha are alkaline in nature and thus fit well to acid soils as an amending agent. FA has many other physical and chemical characteristics such as porosity, bulk density, water holding capacity and nutrient constituents which can enhance the soil quality which may aid in the uptake of nutrients and hence the quality of grains would be better. Out of the total ice-free land area of the world, approximately 30% or 3950 m.ha comes under acid soil. Asia, as a continent has the second largest area of such soil which is about 1044 m.ha. However, only 4.5% (179 m.ha) of area of the acid soil in the world has been used for arable crops. In India, acid soils comprise about 28% of the total geographical area (TGA), out of which 9.3% are strong to moderately acidic (pH < 5.5) while 18.9% are slightly acidic (pH 5.5 to 6.5). These soils are distributed in the Himalayan region, the eastern and the north -eastern plains, peninsular India and the coastal plains under varying agro -climatic conditions. Such soils occupy about 90Mha of the TGA, out of which 50% is under cultivation and the rest is under forestry and other uses. About 30Mha of cultivated land with pH less than 5.5 is critically degraded with major soil -related constraints leading to poor crop production. The degraded area in Chhattisgarh and Arunachal Pradesh is predominantly under forests. About 21 Mha of acid soils are found in the North -eastern hill (NEH) region including Sikkim. Farmers apply FYM along with various types of fertilizers in soil to grow crops. There is a need to evaluate the effect of the combination of FA and NPK fertilizers with and without FYM on the soil health after the harvest of crop.

Materials and Methods

A field experiment was carried out to study the effect of application of different treatments consisting of alkaline FA in conjunction with NPK fertilizers and FYM on the nutrient uptake by rice cv. Pooja. After harvest the physico -chemical properties of soil were determined. The field of study was Regional Research and Technology Transfer Station (RRTTS), Odisha University of Agriculture and Technology, Bhubaneswar, India taking nine numbers of different treatments in 5m × 3m plots replicated thrice in a randomized block design. Both of those were given nine treatments consisting of various doses of FA, nitrogen, phosphorous, potassium (NPK) fertilizer and FYM with only NPK serving as the control as per Pradhan, 2002. The treatments were: (1) RD of 80,40, 40 kg N, P, K ha -1 (2) 20 t FA ha -1 (3) 40 t FA ha -1 (4) RD + 20 t FA ha -1 (5) RD + 40 t FA ha -1 (6) 50% RD + 20 t FA ha -1 (7) 50% RD+ 20 t FA ha -1 (8) 50% RD + 20 t FA ha -1 + 10 t FYM ha -1 (9) 50% RD + 40 t FA ha -1 + 10 t FYM ha -1 . The RD with neither FA nor FYM served as the control. The physical properties were examined before transplanting and after harvest. The mechanical analysis was done by Bouyoucos Hydrometer method as described by Piper, C.S. (1950). The pH and EC was determined by taking 1: 2 soil: water suspension. The organic carbon (O.C) and available P was determined by Walkley and Black method as described by Jackson M.L. (1967). Available K was extracted by 1N Ammonium Acetate (pH 7.0) abd estimated by flame photometer). N was determined by Alkaline Potassium Permanganate method as described by.

Results and Discussion

The soil of the experimental site at the Regional Research and Technology Transfer Station (R.R.T.T.S), Odisha University of Agriculture and Technology, Bhubaneswar was lateritic silty loam having acidic pH of 5.32, electrical conductivity of 0.31dSm -1 , medium O.C content of 0.53%, available N, P and K content were 370.0, 19.6 and 166.8 kgha -1 respectively. It has cation exchange capacity (CEC) of 8.65 cmol (P + ) kg -1 and available micronutrients were above the critical limit. The available sulphur was however low. The properties of the experimental soil are given in Table -1 The FA used for the experiment collected from ICCL, Chowdwar, Odisha was alkaline in nature (pH = 7.30) and had low bulk density (BD) (0.847 Mgm -3 ) with 89.6% WHC and 41.0% porosity. It also contained 30.0 mgkg -1 P, 180.0 mgkg -1 K and 180.3 mgkg -1 S. Besides, it was also rich in many important micronutrients like Zn, Cu and B which were low in the experimental soil but had beneficial effect on soil health. The properties of the FA are recorded in Table -2 The physical properties of the soil were examined after the harvest of cv. Pooja in 2022 in order to determine the residual effects of FA, FYM and their combinations with N, P, and K on it. The results of the physical properties has been given in Table -3 and shown in Fig - 1.

Porosity

Porosity is the air space between soil particles, which is occupied by water when available. Perusal of the data from table -3 revealed that the porosity of the soil varied between the lowest of 46.06% in T1 receiving 100% RD of N, P and K fertilizer (control) and the highest of 53.58% in T9 receiving 50% RD of NPK integrated with FA @ 40tha -1 and FYM @ 10tha -1 . When FA @ 20tha -1 was added, there was an increase by 7.05% and when the dose of FA was doubled there was further increment of 4.78%. On an average, treatments receiving FA recorded an increase in porosity by 9.61% over control. It might be due to the presence of Ca present in FA (900ppm) that readily replaces Na at clay exchange sites and thereby enhances flocculation of soil clay particles, keeps the soils friable, enhances water penetration and allows roots to penetrate compact soil layers [1] . Treatments receiving 100% RD of NPK fertilizer integrated with FA recorded a significant increase by 4.40% over FA and 14.43% over 100% RD of NPK. However, when the dose of fertilizer was reduced to 50% there was a fall by 0.13%. But, when FYM was included in the doses (T8 and T9) there was an increment by 1.42% over the treatments receiving same dose of other nutrients except FYM. On an average, treatments receiving FA @ 40tha -1 registered 1.85% more porosity of soil than the treatments receiving FA @ 20tha - 1 . The higher porosity was however, recorded in the treatments receiving FYM which 15.91% higher than control. Except T2 receiving FA @ 20tha -1 , all other treatments recorded a significant increase over control. Higher porosity in FYM amended treatments might be due to the increased microbial activity. The application of organic manures resulted in the increased organic matter in soil and hence the porosity of soil [2] .

Bulk Density

The BD of soil varied between the lowest of 1.23 Mgm -3 in T9 receiving 50% RD of NPK fertilizer integrated with FA @ 40tha -1 and FYM @ 10tha -1 and the highest of 1.43Mgm -3 in T1 (control) receiving only 100% RD of NPK fertilizer. It decreased significantly by 6.29% to 1.34Mgm -3 with FA @ 20tha -1 and by 10.49% to 1.28Mgm -3 when the dose of FA was doubled over control. It might be due to the fact that the particle size of FA is similar to silt having low specific gravity that decreased the BD of soil. Application of FA @ 0%, 5%, 10% and 15% by weight in soil significantly reduced the BD of soil [3] . T3 receiving FA @ 40tha -1 was at par with the treatments receiving 100% RD of NPK fertilizer integrated with FA. When the RD of fertilizer was reduced to 50% there was no significant decrease in BD of soil. It further reduced by 1.59% when FYM was added. It is because of the combined effect of inorganic fertilizer and FA with FYM since FYM is also low in BD [4] . FYM treated plots registered lower values among all the treatments. On an average, there was an increment by 1.95% when the dose of FA was increased from 50% to 100%. Water Holding Capacity (WHC) WHC of soil varied between the lowest of 31.2% in T1 (control) receiving 100% RD of fertilizer and the highest of 41.54% in T9 receiving 50% RD of NPK fertilizer integrated with FA @ 40tha -1 and FYM @ 10tha -1 (Figure 4.3.1.3). On application of FA @ 20tha -1 and 40tha -1 respectively, WHC registered an increase by 8.43% and 23.40% respectively over control receiving only 100% RD of FA. On an average, application of FA registered an increase in WHC by 15.91% over control. Amendment with FA up to 40% increased WHC of soil from 39% to 55% [5] . It might be due to the fact that FA application to soil increases microporosity, decreases bulk density and thereby improves the WHC. When FA was blended with 100% RD of NPK fertilizer there was a further increase by 5.97% over FA and significant increase by 22.83% over control. However, when there was a reduction of RD of fertilizer by 50%, there was a fall by 2.99%. But when FYM was incorporated in the treatments, there was an increase by 8.95% over the treatments receiving no FYM. There was an increase by 29.83% in FYM treated plots over control receiving no FA and fertilizer. On an average there was an increase by 7.18% when the dose of FA increased. The chemical properties and macro nutrients of the soil were examined after the harvest of cv. Pooja in order to determine the residual effects of FA, FYM and their combinations with N, P, and K on it. The result has been given in Table - RD of fertilizer integrated with FA @ 40tha -1 and FYM @ 10tha -1 . With FA @ 20tha -1 and 40tha -1 there was an increase of 1.46% and 9.0% respectively over control. This might be due to the presence of alkaline hydroxide and carbonate salts of Ca, Na and Al present in FA which helps in neutralizing the acidity in soil 6 [15]. But when full dose of NPK fertilizer was integrated with FA, there was a fall in pH by 3.31% over FA but registered an increase by 1.74% over 100% RD of fertilizer (control). It might be because combined effect of fertilizer and FA could not lime the soil effectively as compared to FA. However, when the RD of fertilizer was reduced to half, there was an increment by 5.05%. On an average, when FYM was included in the treatments, there was an increase by 3.43% over its exclusion. It might be due to the addition of basic cations through application of organic materials [7] . On an average, there was an increase of 3.61% in treatments receiving 40tha -1 FA over its lower dose.

Electrical conductivity (EC)

The electrical conductivity of the soil varied from the lowest of 0.41 dSm -1 in control plot 100% receiving RD of fertilizer to the highest of 0.53dSm -1 in T9 receiving 50% RD of fertilizer integrated with FA @ 40tha -1 and FYM @ 10tha -1 . With FA@ 20tha -1 and 40tha -1 , there was an increase by 9.75% and 2.22% respectively over control. Increase in the EC value of soil due to the addition of FA may be attributed to the fact that the soluble salts from FA might have dissolved in soil moisture and there by increased the ionic concentration of the soil solution 8 [39]. When 100% RD of fertilizer was integrated with FA, there was a further increase by 5.62% over FA and 14.63% over control. But, when the dose of fertilizer was reduced to 50%, there was a reduction by 3.19%. However, when FYM was included in the doses, there was a significant increase by 14.28% over the treatments receiving same doses of fertilizers except FYM. On an average, treatments receiving FA @ 40tha -1 increased the EC of soil by 2.13% over 20tha -1 .

Fig 2: Chemical properties after harvest

Organic Carbon (OC):

The OC content of the soil varied from the lowest of 0.50% in T2 receiving FA @ 20tha -1 to the highest of 0.64% in T9 receiving 50% RD of fertilizer integrated with FA @ 40tha -1 and FYM. When 100% RD of fertilizer was replaced by FA @ 20tha -1 and 40tha -1 , there was a decrease by 7.40% and 3.70% respectively. Increase in the dose of FA resulted in the increase of the organic matter content in acid soil [8] . When 100% RD of fertilizer was integrated with FA, there was an increase by 7.84% over FA and 1.85% over control. However, when the dose of fertilizer was reduced to 50%, there was a fall by 4.54%. With integrated use of 50% RD of NPK with FA and FYM, there was significant increase by 20% and recorded higher values among all the treatments. This proved that the integrated use of FYM and FA with reduced dose of fertilizer built up more organic carbon. It might be due to the fact that FYM contains considerable amount of organic matter [8] . On an average, there was a hike in carbon content by 3.12% in treatments receiving 40tha -1 FA over 20tha -1 FA.

Available Nitrogen (N):

The residual available nitrogen content of the soil varied from the lowest value of 458.11 kgha -1 in T2 receiving FA @ 20tha -1 and 499.81kgha -1 in T9 receiving 50% RD integrated with FYM and FA @ 40tha -1 . It was observed that on an average there was a significant fall in the available nitrogen status by 1.82% over control by the application of FA.

It is because FA contains very less quantity of the element as most of it is lost during the combustion of coal. However, when the dose of FA was doubled as in T3 there was significant increase by 0.66%. When 100% RD of fertilizer was integrated with FA, on an average there was an increment by 2.73% over FA and 0.86% over control plot. It is because 100% RD of fertilizer contains more nitrogen. However, when the dose of fertilizer was reduced to half, there was a fall by 0.94%. When FYM was included in the treatments, there was an increase by 6.27% over the treatments receiving same dose of nutrients except FYM and 6.17% over control. They had even significantly higher values than integrated use of 100% RD of NPK and FA (T4 and T5). This proved that the reduction of the dose of fertilizer had been compensated by the application of FYM. This might be because FYM augmented the mobilization of soil nitrogen [9] .

Available Phosphorous (P)

The amount of available P varied between the lowest of 21.00kgha -1 in T2 receiving FA @ 20tha -1 to the highest of 30.11kgha -1 in T9 receiving 50% RD integrated with FYM and FA @ 40tha -1 . Application of FA @ 20tha -1 registered a fall by 9.71%. This is because FA contains less quantity of phosphorous. However, when the dose of FA was doubled there was an elevation by 0.71%. This might be due to the desorption of some native soil P by anions such as silicate, citrate and tartarate from colloidal surfaces by the high addition of FA [10] . When 100% RD of NPK fertilizer along with FA was applied, there was an increase by 13.77% over FA and 4.03% over 100% RD of NPK. This is due to the supply of more P through NPK fertilizer. But when the dose of NPK fertilizer was reduced by 50%, there was a fall by 3.55%. However, when FYM was included in the treatments there was a significant increase by 28.16%. This is due to the increase in soil pH in those plots that reduced the fixation of available P [11] . This proved that the reduction of the dose of fertilizer by 50% had been counter balanced by the inclusion of FYM since FYM mobilized the availability of P in acid soil. There was an increase by 28.60% in FYM treated plots over control. On an average, there was an increase by 3.07% with the application of higher dose of FA over its lower dose.

References

1. Jala S, Goyal D. Fly ash as a soil ameliorant for improving crop production: a review. Bioresour Technol. 2006;97:1136-1147.
2. Haynes RJ, Naidu R. Influence of lime, fertilizer and manure applications on soil organic matter content and soil physical conditions: a review. Nutr Cycl Agroecosyst. 1998;51:123-137.
3. Garg RN, Pathak H, Das DK. Use of fly ash and biogas slurry for improving wheat yield and physical properties of soil. Environ Monit Assess. 2005;107:1-9.
4. Mittra BN, Karmakar S, Swain DK, Ghosh BC. Fly ash: a potential source of soil amendment and a component of an integrated plant nutrient system. Fuel. 2005;84:1447-1451.
5. Singh LP, Siddiqui ZA. Effects of fly ash and Helminthosporium oryzae on growth and yield of three cultivars of rice. Bioresour Technol. 2003;86(1):73-78.
6. Basu M, Pande M, Bhadoria PBS, Mahapatra SC. Potential fly ash utilization in agriculture: a global review. Prog Nat Sci. 2009;19:1173-1186.
7. Rautray SK, Ghosh BC, Mittra BN. Effect of fly ash, organic wastes and chemical fertilizers on yield, nutrient uptake, heavy metal content and residual fertility in a ricemustard cropping sequence under acid lateritic soils. Bioresour Technol. 2003;90:275-283.
8. Das BK, Choudhury BH, Das KN. Effect of integration of fly ash with fertilizers and FYM on nutrient availability, yield and nutrient uptake of rice in Inceptisols of Assam, India. Int J Adv Res Technol. 2013;2(11):190-208.
9. Singh JS, Pandey VC, Singh DP. Coal fly ash and farmyard manure amendments in dry-land paddy agriculture field: effect on N-dynamics and paddy productivity. Appl Soil Ecol. 2011;47:133-140.
10. Lee H, Ha HO, Lee CH, Lee YB, Kim PL. Fly ash effect on improving soil properties and rice productivity in Korean paddy soils. Bioresour Technol. 2006;97:1490-1497.
11. Swain DK, Rautray SK, Ghosh BC. Alkaline coal fly ash amendments are recommended for improving rice-peanut crops. Acta Agric Scand B Soil Plant Sci. 2007;57:201-211.
12. Bhople BS, Bhoyan SM, Nimje AM. Impact of fly ash on physical and chemical properties of black cotton soil and yield of sunflower crop. J Soils Crops. 2011;21(2):234-238.