Farm land tends to erode most rapidly when planted with

Potato cultivation typically involves intensive and repeated soil disturbance (hilling, ridging and frequent tillage) that degrades soil structure, reduces infiltration and increases runoff and erosion risk, especially where timing and overworking occur. Practices described as “clean tillage” that leave the field bare exacerbate susceptibility to sheet and rill erosion by removing protective vegetation and residue cover [1]. By contrast, cover and green-manuring crops such as clover actively protect the soil surface and reduce erosion through ground cover and root mats [2]. Therefore, among the listed crops, potato fields are most likely to erode most rapidly due to their common cultivation practices that leave soil exposed and disturbed [2].

Sources

1. [1] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Advantages > p. 356
2. [2] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > iv) Green Manuring > p. 20