Peer review

A simulation experiment was conducted to evaluate the effects of planting time, nitrogen rate, and crop variety choice on potato productivity and to assess the adaptation role of these practices in a changing climate in the northwestern tropical highlands of Ethiopia. The study used agroecosystem (AES) as the lens for spatial analysis. Thirty years of simulations were performed for the baseline (1981–2010), near-term (2011–2040), and mid-century (2041–2070) climate periods using a calibrated and validated SUBSTOR-Potato (DSSAT) model. The results showed that shifting planting time forward and changing the nitrogen application rate had greater productivity benefits than switching varieties in all climate periods and AESs. Late planting and higher nitrogen rates increased tuber yield during the near-term climate period. However, in the mid-century climate period, early planting of both medium and long maturity varieties with higher nitrogen rates showed potential adaptation benefits despite its negative impact on yield in the current climate. This result highlights the distinction between optimal management under current conditions and practices that are truly adaptive to climate change.

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