Purpose: Agricultural chemicals either used as nutrient inputs for soil fertility or pesticides are creating physicochemical and biological deterioration of the soils and disturbing the agro-ecosystems worldwide. Alarming concerns towards integrated agroecology demand for renewed interest in low-external input-based farming practices. These practices comprise strengthening of soil biological properties, recycling of inherent soil minerals and reuse of agricultural residual wastes. Methods: We described approaches for the bioconversion of agricultural residual wastes into value-added compost. The process involves conversion of residual waste into raw compost followed by its fortification with beneficial decomposer microorganisms to produce quality fortified compost product. Finally, incubation of fortified compost with single or consortia of beneficial microorganisms like N-fixers, P-solubilizers or K-mobilizers and biocontrol agents further enriches compost to produce bioorganic products. Results: Bioconversion of agricultural wastes into compost using potential decomposer microorganisms and fortification of decomposed organic matter with beneficial bacterial and fungal species is of immense importance. Additional enrichment of compost with botanicals, humic acid, amino acids, mineral nutrients, phytohormones etc. may also add value to the bioinput products. Conclusion: In an integrated way, on-farm production of raw compost using different agricultural residual wastes and its further fortification with bioorganic farm inputs can help farmers produce value-added compost products for direct application in the crop production. Adoption of microbial bioconversion technologies and their field applications may become eco-enterprising for the rural resource-poor farming communities for enhancing their livelihood along with improving farm productivity and soil health.

Background: While the increase in the number of coconut-based industries in Malaysia supports economic growth positively, it affects the environment negatively by generating large amounts of coconut wastes. This study has endeavored to assess the possibility of vermicomposting different types of coconut wastes and, in doing so, evaluated the potential of using the African nightcrawler (Eudrilus eugeniae) to decompose coconut wastes. The study was conducted over a 50-day duration using two different types of coconut wastes: coconut husk (CH) and spent coconut flakes (SCF). The nutrient content of the vermicompost at various stages of treatments was determined. Three different percentage ratios were used: {C1-W or B1-W (100% waste), C2-W or B2-W (70% waste+30% goat manure), and C3-W or B3-W (50% waste+50% goat manure)}. Twenty healthy adult E. eugeniae (each 0.02 to 0.03 kg) were introduced to each treatment.Results: Results showed that the degradation process was very fast in the spent coconut flakes which needed only 16 days for complete decomposition, while that in the coconut husk needed 2 months. Available phosphorous (P) and total potassium (TK) values declined in CH. The available P and TK in C3-W (50% waste+50% goat manure) were less than the initial values by 26.6% and 53.69%, respectively. Moreover, P and TK values increased in SCF at the final stage as in B2-W (70% waste+30% goat manure) which was 69.3% more than the initial level. The weights of the worms were recorded throughout the experimental period.Conclusions: The study showed that vermicomposting could be an efficient method to convert coconut wastes into a valuable by-product.

Adsorption capacity of Cr (VI) onto sawdust of aspen tree and activated sawdust, was investigated in a batch system by considering the effects of various parameters like contact time, initial concentration, pH, temperature, agitation speed, absorbent dose and particle size. Cr (VI) removal is pH dependent and caused to be maximum at pH 2.0. The amounts of Cr (VI) adsorbed increased with increase in dose of both adsorbents and their contact time. Experimental results show that the low cost biosorbent was effective for the removal of pollutants from aqueous solution. The Langmuir, Freundlich and Temkin isotherm were used to describe the adsorption equilibrium studies of agrowaste. Freundlich isotherm shows better fit than Langmuir and Temkin isotherm in the temperature range studied.

Adsorption capacity of Cr (VI) onto cousinia eryngioides boiss, activated carbon was investigated in a batch system by considering the effects of various parameters like contact time, initial concentration, pH, temperature, agitation speed, absorbent dose and particle size. Cr (VI) removal is pH dependent and found to be maximum at pH 2.0. The amounts of Cr (VI) adsorbed increased with increase in dose of both adsorbents and their contact time. A contact time of 30 min was found to be optimum.Experimental results show low cost biosorbent were effective for the removal of pollutants from aqueous solution. The Langmuir, Freundlich and Temkin isotherm were used to describe the adsorption equilibrium studies of agrowaste.Freundlich isotherm shows better fit than Langmuir and Temkin isotherm in the temperature range studied.

Unfertilizable fruiting buds of mango plant Mangifera Indica L, an agrowaste, is used as a biomass in this study. The efficacy of the biosorbent was tested for the removal of lead, copper, zinc and nickel metal ions using batch experiments in single and binary metal solution under controlled experimental conditions. It is found that metal sorption increases when the equilibrium metal concentration rises. At highest experimental solution concentration used (150 mg/L), the removal of metal ions were 82.76 % for lead, 76.60 % for copper, 63.35 % for zinc and 59.35 % for nickel while at lowest experimental solution concentration (25 mg/L), the removal of metal ions were 92.00% for lead, 86.84 % for copper, 83.96 % for zinc and 82.29 % for nickel. Biosorption equilibrium isotherms were plotted for metal uptake capacity (q) against residual metal concentrations (Cf) in solution. The q versus Cf sorption isotherm relationship was mathematically expressed by Langmuir and Freundlich models. The values of separation factor were between zero and one indicating favourable sorption for four tested metals on the biosorbent. The surface coverage values were approaching unity with increasing solution concentration indicating effectiveness of biosorbent under investigation. The non-living biomass of Mangifera indica L present comparable biosorption capacity for lead, copper, zinc and nickel metal ions with other types of biosorbent materials found in literature and is effective to remove metal ions from single metal solutions as well as in the presence of other co-ions with the main metal of solution.