Agronomic performance of growing media by co-utilization of mineral and organic matrices: influence of green compost maturity

E. Grilli, R.C. Vigliotti
An experiment was carried out with the aim of creating substrates by co-utilizing a differently aged green amendment (0, 40, and 90 days) mixed with tuffaceous zeolitized-rock debris (0, 10 and 25% wt.), either with or without mineral NKP fertilizer. The rationale of our experiment was based on the capability of zeolites-bearing rocks to act as sorbents of organic matter and as high-performance catalysts increasing the reaction rate of both chemical and biochemical processes. Our investigation firstly considered whether: i) the compost maturation was accelerated by tuffaceous debris, and, ii) the substrates satisfied the legislative requirements according to UNI EN methods. The agronomic performance of the different formulations was tested in terms of both chemical fertility and crop production, evaluated by monitoring the growth and the dry matter production of Lactuca sativa L. The possible use of zeolitized-rocks debris, as catalysts for compost maturation, was the innovative trait of our research with the aim of optimizing the waste management. However, the co-utilization of tuffaceous debris and green amendments did not provide appreciable benefits and only the degree of maturity influenced substrates success. An acceptable plant response was observed only with substrates with 90 days-aged compost, independently from tuff percentage, whereas NPK fertilization had no significant effect on plant response. The bad performance of substrates with immature compost (0 and 40 days) could be due to the establishment of very quick degradation processes by microbes that lead to loss of nutrients and immobilization of plant available N, a pathology known as nitrogen hunger. In addition, possible phytotoxic effects due to the nature of pruning materials (pine sawdust) could have occurred. Finally, the used tuff percentages in substrates seem to be too low to retain and hence protect the humic substances present in the systems.
Grilli, E. and Vigliotti, R.C. (2021). Agronomic performance of growing media by co-utilization of mineral and organic matrices: influence of green compost maturity. Acta Hortic. 1305, 309-316
DOI: 10.17660/ActaHortic.2021.1305.42
green pruning compost, pine sawdust, zeolitized tuff, maturation time, plant response

Acta Horticulturae