Contribution of Root Development and Soil Properties to Soil Loss during Carrot Harvest : Effects of Irrigation Regimes, Growth Stages, Varieties, and Clay Content

Yang, Junjian and Quinton, John and Dodd, Ian (2026) Contribution of Root Development and Soil Properties to Soil Loss during Carrot Harvest : Effects of Irrigation Regimes, Growth Stages, Varieties, and Clay Content. Masters thesis, Lancaster University.

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Abstract

Soil loss due to crop harvest (SLCH) has been studied much less than other types of erosion, such as wind and water erosion. However, SLCH can cause soil loss comparable to, or even greater than, these other forms. SLCH is controlled by soil properties, crop traits, agronomic practices, and harvesting techniques. At present, knowledge of the relationship between crop root systems and SLCH, as well as the underlying mechanisms, remains limited. This study tested how root development and soil properties affect SLCH during carrot harvest under greenhouse conditions. The SLCH rate in this study may be higher than values reported from field and industrial studies, as soil adhering to the carrots was retained as much as possible to better investigate the relationship between SLCH and its controlling factors. Three experiments were carried out: (1) irrigation at different intervals (1, 4, and 8 days) and crop ages (89, 107, and 131 days); (2) comparison of carrot varieties (Chantenay, Early Nantes, Autumn King, and Karotela); and (3) soil with different clay types (kaolinite and montmorillonite) and contents (with additional 11.59%, 23.2%, and 34.8% clay addition). Harvesting at a later crop age (131 days) under appropriate irrigation (4-day interval) reduced SLCH while maintaining root volume, whereas excessive irrigation increased SLCH. Under low-clay conditions, varietal differences in SLCH were not significant despite morphological variation. High clay content increased SLCH, enhanced root-related effects, and reduced the contribution of root volume, although the underlying mechanisms remain unclear. This study highlights the high risk of SLCH in carrot harvesting and provides insights into its underlying mechanisms. The findings contribute to a better understanding of SLCH processes and offer a reference for future field-based research. In addition, the results may help inform management practices for growers and producers aiming to reduce soil and associated economic losses.