Results of Twenty-Four Years of Crop Rotation Research at ‘De Schreef’ Experimental Site

Summary

Crop rotation research carried out at ‘De Schreef’ experimental farm for 24 years shows that ware potatoes (cv. Bintje) are poorly self-compatible on a clay loam soil. When potatoes were grown once every three years, every four years and every six years, the tuber yields were respectively 21, 16 and 7% lower than those of plots where potatoes were grown for the first time. Although the yield depression can partly be explained by differences in soil structure, it was mainly caused by pathogens: Verticillium dahliae, Streptomyces spp. (netted scab) and possibly by growth inhibiting bacteria. Potato cyst nematodes were not involved.

An additional decrease in tuber yield was observed when potatoes were grown after sugar beet in short rotations and after peas in long rotations.