• Energy Research

Espresso coffee grounds constitute a residue which is produced daily in considerable amounts, and is often pointed out as being potentially interesting for plant nutrition. Two experiments (incubations and field experiments) were carried out to evaluate the potential nitrogen (N) and phosphorus (P) supply for carrot (Daucus carota L.), spinach (Spinacea oleracea L.) and lettuce (Lactuca sativa L.) nutrition.Immobilisation of nitrogen and phosphorus was detected in all the incubations and, in the field experiments, germination and yield growth were decreased by the presence of espresso coffee grounds, in general for all the species studied.The study showed an inhibition of N and P mineralisation and a reduction of plant germination and growth. Further research is required to determine whether this is related to the immobilising capacity of the residue or possibly due to the presence of caffeine.

Good soil quality implies the maintenance of properties at levels capable of ensuring an equilibrated and healthy ecosystem, with sustained agricultural production to supply the world population. Climate change, land-use change, and agriculture intensification are causing a decline in soil quality, which in most parts of the world is becoming severe (desertification). Land-use changes, the associated loss of soil organic matter (SOM), and beneficial microbial diversity are major reasons for deteriorating soil fertility and declining agricultural productivity, as well as affecting water, air, and biodiversity. Adaptation towards climate-resilient and climate-smart agriculture is necessary to cope with climate change and extreme events. This requires the following measures: (1) sustainable production (integrated livestock and cropping systems, including agroforestry); (2) increased soil organic matter (SOM) (bio-based and organic fertilizers, crop rotations, crop associations, no-till, conservation agriculture, C sequestration, and microbial processes); (3) reduced greenhouse gas emissions, less nutrient losses from agriculture, and increased nutrient use efficiency (NUE) (precision agriculture).