Use of spent mushroom substrate as an ingredient in new high efficiency biofertilizers, with the inclusion of beneficial microorganisms in the grains and horticultural crops (chickpeas and lettuce).

Abstract

In response to demographic growth and changes in consumer spending, sustainable management of organic waste becomes crucial. New techniques aligned with the principles of the circular economy, promoting reduction, reuse, and recycling, are solutions to these global problems. Therefore, this project aims to assess the effectiveness of spent mushroom substrate as an ingredient for new biofertilizers in the cultivation of chickpeas and lettuce, considering the application of beneficial bacteria (nitrogen-fixing and phosphorus-solubilizing). The research during the proposed period is summarized in two phases: one under controlled conditions and another in a commercial field. Under controlled conditions, different treatments will be applied, including spent mushroom substrate and biofertilizers derived from this compost as an enhanced product, with the addition or not of beneficial bacteria, to the target crops (chickpeas and lettuce). Agronomic assessments, analyses of soil and crop chemical composition, and isolation of microorganisms, along with estimation of microbial community diversity indices through soil DNA extraction and sequencing, will be conducted. The field phase will focus on the commercial cultivation of lettuce, based on the best results obtained in the previous phase. Productivity, chemical composition, and greenhouse gas emissions such as CO2, CH4, and N2O will be evaluated. All data will be collected in triplicates. Statistical tests (ANOVA, normality, homoscedasticity, Tukey 5%) will be applied to assess agronomic, microbial, and chemical composition analyses. Microorganism sequencing will use alpha diversity indices. For gas flows, a generalized linear mixed model will be employed. Expected outcomes of the project include obtaining 1-3 new biofertilizers optimized for target crops, including a comprehensive approach to the agronomic, economic, and environmental capabilities of this solution compared to other conventional fertilizers.