Modelling the long-term productivity and soil fertility of maize/millet cropping systems in the mid-hills of Nepal

摘要: Abstract Finding ways of maintaining or increasing crop yields without degrading soil fertility is an important goal in sustaining livelihoods many parts the world. In mid-hills Nepal, problem particular importance due to fragility mountain ecosystems. Previously reported field experiments have investigated influence different combinations inorganic fertilisers and farmyard manure (FYM) on maize/millet cropping systems at two sites this region, Pakhribas Dordor Gaun, but short-time period involved (three years), long-term trends could not be determined, neither changes carbon nitrogen levels measured. paper, we describe use PALM simulation model address these questions, its parameterisation validation based data from experiments. Using weather generated for 100 years each site, was then used investigate effect nutrient management treatments dynamics. Overall, were higher than both lower temperatures causing slower development hence a longer biomass accumulation, inherent status faster growth rates. At sites, highest obtained treatment receiving only fertiliser rate 90 kg N ha−1. Declines organic C N predicted all FYM treatments, with severest rates loss no inputs slowest 7 t ha−1 manure. Economic analysis showed that, current prices, by far most rational option farmers terms net returns, regardless despite associated decline levels. It estimated that if greater promoted as way sequestration soil, Nepal will need compensated least US$9.90 (t C)−1 they obtain.