## 4 Discussion
Despite targeting wheat crop lands, specifically classifying each of the various crop types in the region could have improved the classification results overall. Nonetheless, the lack of this exact information did not jeopardize the classification of only the wheat crop lands too much, which showed relatively high Fscores for all of the zones and was the central aim of this study. Topographic features and rainfall together accounted for an average of 11% to 20% of the observed spatial variation in grain yield in Navarre; this percentage range is consistent with other studies dealing with these factors. Regarding topography effects on wheat at the field level in central Europe, slope and altitude have been estimated to account for an average of 5% to 42.5% variation in grain yield [68], meanwhile in North America those same topographic attributes were estimated to account for an average of 39% to 65% of the variation in grain yield [69]. Moreover, [PERSON] et al. showed that in the Mediterranean context aspect, altitude, and slope are directly linked with wheat grain yield [70] and that rainfall distribution is a major limiting factor for wheat yields [71]. It has been observed that topographic features affect grain yield more dramatically in dry years or in areas with naturally irregular rainfalls (i.e., Mediterranean rain-fed wheat croplands) [72], which explains the relatively wide range of variability of the rainfall and topographic effects on grain yield in this study as well as in the scientific literature. Thus, an increased effect of topographic features might be expected in Spanish wheat agrosystems in a climate change scenario, and these features consequently deserve attention. In this sense, the results of this study demonstrate novelty as the relations between topography and grain yield found in the scientific literature have been, on the one hand, studied in few or single fields [73], presumably due to the difficulty in obtaining precise grain yield predictions for multiple fields from both traditional methods (i.e., time consuming field-work) and from remote sensing techniques (i.e., access restrictions or coarser resolutions to correlate with grain yields and delineate fields). On the other hand, when focusing on regional-scale topographic and climatic data, previous studies have defined suitability zones solely within the agroecological landscape [74; 75; 76], none have completed an estimation of the effects of those factors directly on grain yield. We here took advantage of both topographic and climatic data of Navarre, Spain to explore the potential effects on grain yield in various regions, while estimating precisely the grain yield per field at a regional level using to the best of our advantage all of the Sentinel-2 improved characteristics. We believe that studying climatic and topographic impacts on grain yield at a larger scale can provide new insights that in turn will be of interest for managing croplands systemically while advancing towards improved agroecological landscape assessments. Regarding the previously-mentioned GWR results, approximately 80%, 89%, and 80% of grain yield variability are yet to be explained in each region respectively, as the tested variables cannot explain the whole of the variability. Factors such as soil type, evapotranspiration, radiation, and fertilization or farming practices, among others, could not be evaluated with the remote sensing techniques employed in this study, and might help to explain the remaining variability. Be that as it may, the mean coefficient of regression is positive for rainfall at all three zones. This suggests a relatively strong effect of the rainfall gradient distribution on wheat grain yield in the northern zone. This might be explained with the varying precipitation patterns of the area due to the rugged topography and the numerous valleys that the area includes and that may consequently affect wheat grain yield. Regarding zone VI, the result links the drier features of the southern climate and its positive strong dependence on rainfall.