Espresso coffee residues as a nitrogen amendment for small-scale vegetable production

Area of Science:

• Agricultural Science
• Soil Science
• Plant Nutrition

Background:

• Espresso coffee grounds (ECG) are a substantial daily residue with potential agricultural applications.
• ECG is often considered for its nutrient contributions to plant nutrition.
• This study investigates the impact of ECG on key crop species.

Purpose of the Study:

• To evaluate the nitrogen (N) and phosphorus (P) supply potential of ECG for plant nutrition.
• To assess the effects of ECG on the germination and yield of carrot, spinach, and lettuce.
• To understand the underlying mechanisms of ECG's impact on plant growth.

Main Methods:

• Two experimental approaches were employed: laboratory incubations and field trials.
• Incubation experiments monitored N and P immobilization.
• Field experiments assessed crop germination and yield in the presence of ECG.

Main Results:

• Nitrogen and phosphorus immobilization was observed in all incubation experiments.
• The presence of ECG significantly decreased germination and yield for all studied plant species.
• These negative effects were consistent across carrot, spinach, and lettuce.

Conclusions:

• ECG application inhibits nitrogen and phosphorus mineralization, reducing nutrient availability.
• A significant reduction in plant germination and growth was observed.
• Further research is needed to determine if caffeine or the residue's immobilizing capacity causes these effects.