Evaluating compost tea recipes for enhanced nutrient cycling: An innovative management practice for sustainable soil health

Compost tea is one of the organic amendments that contributes significantly to enhancing soil quality. Compost tea, an alternative to synthetic fertilizer, is incredibly important for sustainable plant growth and soil health; however, many of its biochemical characteristics remain poorly understood. In this study, eight compost tea recipes with two compost sources (WSU bedding compost and vermicompost) and four additive-based formulations (A, B, C, and D) were evaluated under varying aeration and brewing conditions. Recipes A and B, with whey powder and sugar, exposed higher microbial populations 36.3 ± 2.15 (Mean ± SE) and 53.7 ± 3.82 nmol ml −1 , than the microbial population 3.5 ± 0.25 and 1.9 ± 0.18 nmol ml −1 in recipes C and D respectively. Recipes A, B, and C revealed distinct microbial communities, dominated by bacteria, fungi, and protozoa, respectively. Brewing time influenced the properties of compost tea. Compost teas showed the highest bacterial populations on day 1 (3.1 ± 0.75 nmol ml −1 ) compared to days 3, 6, and 10 (2.2 ± 0.56, 1.4 ± 0.18, and 0.87 ± 0.09 nmol ml −1 , respectively). There was an increase in protozoa and fungal populations on day 3, while relatively fewer populations were observed on other days. NH 4 -N levels were higher in additive-rich recipes (A and B) than in recipes (C and D), reflecting ammonification. In contrast, NO 3 -N levels were higher under the control recipes, indicating greater aerobic microbial activity than under the other recipes. Nutrient concentrations varied significantly, underscoring the importance of recipe composition. Phospholipid fatty acid analysis and fungal-to-bacterial biomarker ratios indicated that nutrient-rich additives B and A favor fungi and overall microbial activity. Overall, compost teas with varying additive compositions, brewing times, and aeration times differed significantly from the compost source. Optimizing compost tea recipes and brewing conditions can improve the efficacy of compost teas for sustainable soil and plant health.