Fluxes of nutrient stocks and limiting nutrients in a a coffee field in Kabanyolo

Abstract

Agricultural practices have contributed to widespread soil degradation by contributing to nutrient loss, erosion, salinity and compaction and by reducing carbon storage. Perennial systems are expected to increase carbon and nutrient stocks in the soil and this could improve soil fertility. A study was conducted in a coffee field at Kabanyolo to assess fluxes of soil carbon and nutrient stocks during the period 2013 to 2023 and establish if there are currently nutrients limiting coffee productivity. The mean stocks and standard errors (t ha-1) of Carbon, N, and P were 2.8±0.32, 0.16±0.07 and 1.68±0.29 respectively in the coffee field as of 2023. The fluxes of nutrient stocks were -0.94 t C ha-1yr-1 , 0.002 t N ha-1yr-1 and -0.04 t P ha- 1yr-1 between 2013 and 2023. Nitrogen was the most limiting nutrient to productivity in MUARIK coffee field with a level of 1.3±0.05% N among the coffee plants which is below the critical value of Nitrogen in Robusta coffee. The coffee field sequestered more carbon compared to the adjacent grass strips implying that more carbon can be stored in perennial system. Nutrient additions are needed to improve the productivity of coffee field following a comprehensive evaluation of all nutrient interactions