Impact of liquid bioconsortia on the composting dynamics and maturity of sugarcane trash

Introduction

Liquid formulations have emerged as an advanced technology in India, characterized by unique physicochemical properties and production processes. Liquid biofertilizers are specialized formulations that contain beneficial microbial strains along with cell protectants and metabolic by-products that enhance the viability, shelf life, and tolerance of the microbes under adverse environmental conditions (Pindi et al., 2012) [11] . Microorganisms such as bacteria, fungi, and actinomycetes play distinct yet complementary roles in the composting process. When applied as a mixed culture, their synergistic interactions accelerate the degradation of lignocellulosic residues by efficiently utilizing intermediate decomposition products. Hence, the use of microbial consortia facilitates the rapid breakdown of complex organic wastes. Burning of crop residues has become a common but detrimental practice, significantly altering the chemical, biological, and physical properties of soil. This practice reduces soil organic matter (Malhi et al., 2011) [8] , disrupts soil aggregation and structure (Turmel et al., 2015), and adversely affects nutrient cycling. Continuous residue burning depletes soil organic carbon, increases soil pH, and diminishes nutrient availability (Butterly et al., 2011) [4] . Moreover, intensive crop harvesting without replenishment of organic inputs has led to a progressive decline in soil organic carbon levels. Traditionally, compost and farmyard manure served as vital amendments for maintaining soil fertility. However, modernization of agriculture and reduced livestock populations have limited their availability, prompting the exploration of alternative organic sources. In this context, agrowastes particularly sugarcane trash represent an abundant and renewable resource for compost production (Roohallah et al., 2024) [13] . The main challenge lies in efficiently and rapidly converting agrowastes into mature compost. Conventional open-air composting often proceeds slowly and inconsistently due to suboptimal microbial and environmental conditions (Mohd Huzairi et al., 2022) [9] . The introduction of liquid bioconsortia offers a promising solution. These formulations, composed of cellulolytic fungi, bacteria, and actinomycetes, enhance the degradation of International Journal of Advanced Biochemistry Research 2025; SP-9(10): 1451-1458 lignocellulosic residues through a diverse enzymatic system. By providing functional microbial diversity and metabolic synergy, liquid bioconsortia accelerate decomposition, improve compost quality, and contribute to sustainable recycling of agricultural residues.

Materials and Methods Experimental Site and Design

A field experiment was conducted at Mahatma Phule Krishi Vidyapeeth (MPKV), Rahuri, Maharashtra, to investigate the impact of liquid bioconsortia on the composting dynamics and maturity of sugarcane trash. The experiment was laid out in a Randomized Block Design (RBD) with four replications and six treatments. The treatments were as follows:  T₁: Cellulolytic liquid bioconsortia @ 0.5 L per metric ton (MT) of sugarcane trash  T₂: Cellulolytic liquid bioconsortia @ 1.0 L per MT  T₃: Cellulolytic liquid bioconsortia @ 1.5 L per MT  T₄: Cellulolytic liquid bioconsortia @ 2.0 L per MT  T₅: MPKV reference decomposing culture @ 1 kg per MT  T₆: Absolute control (without inoculant)

The data were subjected to statistical analysis using analysis of variance (ANOVA) as per Panse and Sukhatme (1985). The standard error (SE) and critical difference (CD) at 5% significance level were computed to compare treatment means.

Composting Procedure

Composting was carried out in pits of 1 × 1 × 1 m³. Chopped sugarcane trash (4-5 cm) weighing 45 kg per pit was used. A 1% urea solution was added to lower the C:N ratio and promote microbial growth. Treatments were applied according to protocol, while uninoculated pits served as control. Moisture was maintained at 60-65% and pits were turned fortnightly. Initial and final C:N ratios were recorded. The initial and final C:N ratios were determined following standard analytical procedures.

Physico-Chemical Analysis

Organic carbon was determined by the ignition method (Bremner et al., 1970) [3] . Compost maturity was evaluated using established parameters (Ranalli et al., 2001; Goyal et al., 2005) [12,6] . Temperature was measured weekly with a digital thermometer. Microbial populations (bacteria, fungi, actinomycetes) were determined using serial dilution techniques.

Determination of Organic Matter and Ash Content

The loss on ignition (LOI) method was used to determine the organic matter and ash content in compost samples. Approximately 5-10 g of air-dried compost (2 mm sieve) was weighed into a pre-weighed silica crucible (W₁). The crucible was then:  Dried at 105°C for 4 hours and reweighed (W₂).  Ignited in a muffle furnace at 550-600°C for 4 hours and reweighed after cooling (W₃).

The ash content (%) and organic matter (%) were calculated as follows:

ii) Organic matter (%) = 100 -Ash content (%)

iii) Organic Carbon (%) = Organic matter (%)

1.724

Where 1.724 is the Van Bemmelen factor, assuming organic matter contains 58% organic carbon. The C:N ratio was computed as: iv) C: N ratio = Organic Carbon (%)

Results and Discussion

The total organic carbon content of the compost varied from 14.11% to 20.67% in 2022-23, from 14.65% to 20.23% in 2023-24, and from 14.38% to 20.45% on a two-year average basis (Table 1 andFig [5] reported that cellulolytic fungal isolates reduced the C:N ratio of sugarcane trash compost to 16.3 and organic carbon to 17.5%, while increasing nitrogen to 1.07%. Similarly, Bambharolia et al. (2024) [1] reported that lignocellulolytic microorganisms enhanced the biodegradation of sugarcane trash, resulting in an organic carbon content of 17.85% and a C:N ratio of 13.02. The effects of liquid bioconsortia on weight loss and percentage decomposition of sugarcane trash compost are presented in [7] similarly reported that the application of a microbial consortium at 2 kg/ton of sugarcane trash accelerated decomposition by 39.45%, achieving a C:N ratio of 18. (2021) [10] , who observed that sugarcane waste decomposed in 128 days, while a mixture of banana, cotton, and sugarcane residues required 144 days. Temperature dynamics during composting followed a typical thermophilic pattern (Table 4 and Table 5). In the 2022-23 cycle, T4 (cellulolytic liquid bioconsortium @ 2 L/MT) reached a maximum temperature of 65.5°C during the ninth week, after which it gradually declined. In 2023-24, T4 recorded a peak temperature of 66.8°C during the ninth week, followed by a decrease. Treatment T3 (1.5 L/MT) exhibited a temperature peak of 63.2°C in the thirteenth week during 2022-23 and 64.4°C during the eighth week in 2023-24. In contrast, the absolute control (T6) showed delayed peaks, reaching 65.8°C in the twenty-second and twenty-first weeks during 2022-23 and 2023-24, respectively. These results agree with the findings of Hemalatha et al. (2024) [7] , who observed temperature variations ranging from 47.8°C to 28°C during sugarcane trash decomposition, indicating a progression from the thermophilic to the maturation phase. Microbial population dynamics of bacteria, fungi, and actinomycetes also showed significant variation among treatments ( [2] , who noted substantial increases in bacterial (2 × 10⁸ cfu g⁻¹) and fungal (1 × 10⁷ propagules g⁻¹) populations following the application of microbial consortia to sugarcane residues. Overall, the findings of the present study demonstrate that the application of cellulolytic liquid bioconsortia significantly enhances the rate of sugarcane trash decomposition, improves compost maturity, and supports the proliferation of beneficial microbial populations. These combined effects contribute to the production of highquality compost and sustainable recycling of agrowaste resources.

References

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