Microbial valorization and fortification of agricultural wastes through composting process
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Date
2022-12
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Chaudhary Charan Singh Haryana Agricultural University
Abstract
Worldwide, agricultural residue burning has become a serious environmental issue that has a very bad effect on human and animal health. Burning of agri-residues not only disturbs the soil structure but causes of huge loss of plant nutrients, effects microflora and causes greenhouse gas emissions (Sarkar et al., 2020). Paddy straw, Sugarcane bagasse, and saw dust are agricultural waste and are composed of lignocellulose compounds that cannot be degraded easily (Perez et al., 2002). Their direct use causes the immobilization of nutrients, so composting arises as a safe option, resulting in the reusability of nutrients contained in these residues. So, the present investigation was planned with the objectives of managing paddy straw, sugarcane bagasse, and sawdust along with cattle dung and microbial consortia in different ratios using pits with an initial C/N ratio of these wastes (Raj and Antil, 2011). In log (CFU/ml), the treatment with paddy straw + sugarcane bagasse + sawdust + cattle dung + Microbial consortia (4:1:1:1) (T6) had the highest bacterial and fungal counts, while the treatment with sugarcane bagasse + sawdust + cattle dung + Microbial consortia (4:1:1:1) (T9) had the highest actinomycetes count. Alkaline phosphatase, cellulase, dehydrogenase (DHA), and protease were maximum at 30 days of composting in T6 followed by T9. The pH value is also neutral in the mature compost after 90 days. EC values are minimum with T9 followed by T6. Total organic carbon of the compostable material in different treatments decreased more in T6 followed by T9 due to losses of C and total N increased due to accumulation of nitrogen up to 90 days. The maximum reduction in C/N ratio was in T6 - 26.50 followed by T9. Total nitrogen (%) increased from 0.65 to 1.48. The same pattern was observed in total phosphorus, potassium in T6 was followed by T9. The temperature of compostable material increased from 300C to 55°C after 40 to 45 days of composting and then decreased. The quality of compost was tested by C: N ratio, CO2 evolution, humic substances, and germination index. The C/N ratio of compostable materials ranged from 78.20 to 80.05 initially and dropped down to 23.25 to 31.97 after 90 days of composting. The amount of humic substances was highest in treatment T6 compared to all other treatments. The germination index of wheat and mung bean at different treatments are as follows: T1-71-74%, T2-72-75%, T3-70-71%, T4-80-82, T5- 57-65, T6- 90-91, T7- 83-81, T8-83-85, T9-87-89, T10-83-85, T11-84-85 and T12-88-89% and germination index of mustard is less. Among all treatments, the germination index was highest in T6 followed by T9. These two treatments (T6 and T9) were selected for further fortification with poultry and vegetable waste. Among the fortified treatments, T6 + Poultry showed Organic carbon -30.40%, C/N ratio-18.54, humic acid of 142 mg/gm, CO2 evolution -101 mg per 100 gram of compost and germination index - 90 to 100% leachate of compost extract, which indicates it doesn’t have any phytotoxic effect on seed