Effect of levels of biochar and FYM on physico-chemical properties, nutrients release and carbon dioxide evolution from the soil

Abstract

To know the dissolution and release of nutrients from biochar and FYM, an incubation study was conducted during 2018 in College of Agriculture, using sandy loam with acidic pH (5.88) soil collected from Zonal Agricultural and Horticultural Research Station, Navile, Shivamogga. Two kilo gram of soil was filled in separate plastic boxes (2 kg capacity) and treatments imposed as per the treatments details (T1: Control (without biochar and FYM), T2: FYM @ 5 t ha-1, T3: FYM @ 10 t ha-1, T4: Biochar @ 2 t ha-1, T5: Biochar @ 4 t ha-1, T6: Biochar @ 6 t ha-1, T7: Biochar @ 8 t ha-1) and replicated thrice and was laid out in a completely randomized block design (CRBD). results revealed that, application of different levels of biochar increased the pH and EC of soil over control and FYM levels applied treatments, the greater increase of pH (6.20) and EC (0.25 dS m-1) was noticed with the application of CS-biochar @ 8 t ha-1 at 120 DAI. Available nitrogen and potassium showed a gradual increase throughout incubation. Significantly, higher available nitrogen (330.26 kg ha-1) and available potassium (229.95 kg ha-1) were registered in the treatment T7 (CS-biochar @ 8 t ha-1) at 120 DAI. However, available phosphorus content in the soil gradually increased up to 60 days of incubation and slightly decreased afterward. Secondary nutrients gradually increased over an increasing incubation period. Significantly, higher exchangeable Ca (3.64 cmol (p+) kg-1) and Mg (2.57 cmol (p+) kg-1) was recorded in the treatment T7 (CS-biochar @ 8 t ha-1). However, significantly higher available S (12.5 mg kg-1) was registered in the treatment T3 (FYM @ 10 t ha-1) at 120 DAI. Similarly, DTPA extractable micronutrients significantly, higher Fe (31.69 mg kg-1), Mn (1.24 mg kg-1), Zn (0.58 mg kg-1) and Cu (0.52 mg kg-1) was recorded in the treatment T7 (CS-biochar @ 8 t ha-1). Application of biochar and FYM levels significantly influenced the CO2 evolution as compared to control. At 60, 90 and 120 DAI, significantly maximum CO2 evolution was noticed in the biochar @ 8 t ha-1 treatment. In general, the maximum CO2 evolution increased with the increasing incubation period and levels of biochar.