Modelling soil nutrient dynamics under alternative farm management practices in the Northern Highlands of Ethiopia.

摘要: Abstract Agricultural production in the Northern Highlands of Ethiopia is low, stagnant or unsustainable. The objectives this study were to explore long-term dynamics soil organic carbon (C), nitrogen (N) and phosphorus (P) consequences for crop-available N P support design sustainable farm management practices higher yields improved livelihoods Ethiopia. Simplified modules are described. C have been linked via C:N ratio. model has calibrated on basis empirical data from area. OC validated an set fields continuously cultivated 7–53 years smallholder farms applied exploration N, crop available under alternative regimes. simulation results indicate that, terms OC, control 44, 42 38% depletion, respectively, Cambisols, Luvisols Leptosols; current practice (Alt1) 16% reduction 32% Luvisols, but a 22% increase Alt2 (returning all non-economic material soil) 27% whereas Cambisols Leptosols it increases by 1 57%, after 50 cultivation. rates changes similar those management, Alt1 Alt2. In total P, result 46 43% depletion 53 52% over years. On other hand, build-up (69% years), still (8%) Luvisols. All regimes not ‘sustainable’ lead ‘soil mining’. Finally, used estimate required amendments inorganic inputs maintain status as benchmark practices. To composted 5.3, 15.0 2.1 Mg ha−1 annually Leptosols, respectively. P-levels, P-doses (in addition contributions fertilizer 5.3 Cambisols) Luvisols) Mg ha−1 year−1) 8 kg ha−1 year−1 23 kg relatively easy parameterize specific situations reproduces most important aspects nutrient dynamics. modelling approach developed can appropriate that eventually should livelihoods.