Nutrient Management Practices in Coffee (Coffea Arabica L.) Influences: Nitrogen Uses Efficiency, Carbon Footprint and Soil Health

Nitrogen (N) is the most applied nutrient by the coffee farmers, followed by potassium (K), and phosphorous (P), without application of other important macronutrients like calcium (Ca), boron (B) and zinc (Zn). The study conducted in Colombia, in the Central-west coffee region during 2018 to 2024, evaluated the response of coffee (cv. Castillo®) with two different nutritional management practices (NPs) on productivity, nitrogen use efficiency (NUE), carbon footprint (CFP) and soil health. The NPs evaluated were NP1: Ammonium-nitrate based NPK with 15% less nitrogen containing the most important nutrients to produce coffee in acid soils (181 kg N, 53 kg P2O5, 171 kg K2O, 78 kg CaO, 18 kg MgO, 27 kg S-1.6 kg B,0.4 kg Zn, 0.1 kg Mn), and NP 2: Urea based NPK blend, representing common farmer practice (210 kg N, 70 kg P2O5, 204 kg K2O; 22 kg MgO and 22 kg S, without CaO). Both treatments were amended with dolomitic lime to increase base saturation (˃60%) and soil pH (˃5.0). After six years trial no significant differences on coffee yield were observed (2.55 and 2.50 t ha-1 of green coffee beans for NP 1 and 2, respectively), but significant differences occurred on NUE with 45% and 35% for NP 1 and 2, respectively, as well as for CFP, with significant differences during 2019, 2020 and 2023. Soil health indicators estimated by Solvita ® test including soil respiration and microbial biomass were significantly influenced by NP, soil depth and sampling time (wet season- May and dry season- September ), but other soil fertility parameters were less affected by soil moisture variation, with higher contents of Ca, Mg, S, B in the soil profile and lower soil acidity for NP 1 as compared to NP 2.