【作物管理与气候变化】Niklaus Lehmann Robert Finger Tommy Klein Pierluigi Calanca Achim Walter. Adapting crop management practices to climate change: Modeling optimal solutions at the field scale. Agricultural Systems Volume 117 May 2013 Pages 55–65

Abstract

Climate change will alter the environmental conditions for crop growth and require adjustments in management practices at the field scale. In this paper we analyzed the impacts of two different climate change scenarios on optimal field management practices in winterwheat and grain maize production with case studies from Switzerland. Management options included nitrogen fertilization (amount timing and allocation) as well as irrigation. Optimal solutions that maximize the farmer’s utility were sought with the help of a bioeconomic modeling system that integrated the process-based crop growth model CropSyst into an economic decision model. The latter accounted not only for the crop specific average profit margins but also for production risks reflecting the utility (expressed as the certainty equivalent) of a risk-averse farmer’s management decisions at field scale. In view of the non-linearity and complexity of the problem we used a genetic algorithm as optimization technique. For grain maize our results showed that climate change will foster the use of irrigation not only at sites prone to water limitation already under current climatic conditions but more in general for climate change scenarios projecting a substantial decrease in summer precipitation. For winterwheat irrigation was never identified as an optimal management option. For both crops and sites climate change reduced the optimum nitrogen fertilization amount and decreased for winterwheat the number of fertilization applications. In all cases the farmer’s certainty equivalent decreased between 7% and 25% under climate change implying negative impacts on winterwheat and grain maize production even under the assumption of an adjustment of the optimum management practices.

【流域尺度氮动力学】Pierre Moreau Laurent Ruiz Françoise Vertès Christine Baratte Luc Delaby Philippe Faverdin Chantal Gascuel-Odoux Benoit Piquemal Eric Ramat Jordy Salmon-Monviola Patrick Durand. CASIMOD’N: An agro-hydrological distributed model of catchment-scale nitrogen dynamics integrating farming system decisions. Agricultural Systems Volume 118 June 2013 Pages 41–51

Abstract

This work presents the new integrative model CASIMOD’N (Catchment and Agricultural Systems Integrated MODel for Nitrogen) which assesses effects of farming systems on nitrogen (N) dynamics at the catchment level. Its main innovation is the consideration of the level of the farming system through production strategies farmer decisions and the expression of decisions as management practices along with the link between these farming systems their practices and water pollution. CASIMOD’N integrates farming systems at the farm level and N transfers and transformations at the field farm and catchment levels. It was built by adapting and combining three models: the catchment-scale biophysical model TNT2 and two farm-scale models TOURNESOL and FUMIGENE for the allocation of land use and manure respectively. The intrinsic logic behind farming system design and function was represented by ensuring agreement between livestock-feeding and manure-management strategies under specific farm constraints (land fragmentation distance between fields and farmyards) and agronomic rules. The model is able to simulate management practices (crop manure and mineral fertiliser allocation).

An assessment of the farming system modelling was performed by comparing the management practices simulated with CASIMOD’N with (i) observed data from a livestock-oriente