Spatial variation of root yield within cultivated carrot fields is strongly impacted by plant spacing

The establishment of yield in carrot fields should be determined by diverse factors. In order to identify the main factors involved in carrot growth variability under traditional producing conditions, spatiotemporal variability of yield and yield components was analyzed from raw observations acquired from three fields of carrot in the sandy soil of the western coast of Normandy (France). The three fields were cultivated strictly according to practices of the producers without any other intervention or controlled modalities. The relative position of carrots within harvested samples was investigated before winter mulching. The analysis revealed that total root yield and marketable root yield were both highly variable with coefficient of variations (CV) ranging [17.3%-32.2%] and [33.4%-46.8%] respectively. This showed that the potential for increasing carrots productivity needs to be investigated. Geostatistical analysis revealed that root yield was not spatially correlated, which means there was no effect of sample localization within cultivated fields. Individual root diameter showed high variability (CV ranging [19.1%-25%]) and was strongly related to the distance of the nearest neighbour. The number of carrots in marketable diameters and also total root yield were consequently impacted by the variability of plant spacing. To enhance both the total root yield and the number of carrots in marketable diameters, our results strongly suggest that efforts should be directed towards the control of average plant spacing and the reduction of plant spacing variability.