Effects of continuous cropping on soil, senescence, and yield of Tartary buckwheat

The yield of Tartary buckwheat (Fagopyrum tataricum Gaertn) is significantly affected by continuous cropping. This study aimed to clarify the effects of continuous cropping on the growth and yield formation of Tartary buckwheat. Tartary buckwheat cultivar Jinqiao was used as the experimental material to study the effects of different continuous cropping years on the rhizosphere soil, root morphology and physiology, senescence, and yield of Tartary buckwheat. Available nutrients, number of actinomycetes, soil enzyme activities, and contents of total chlorophyll and soluble protein in the leaves of Tartary buckwheat continuously decreased with an increase in continuous cropping years. However, the pH and number of fungi showed a continuous increasing trend. The number of bacteria in rhizosphere soil, root morphological indexes and root activity, and oxidase activity of the leaves initially increased and then decreased. Compared with that of the control, the yield of Tartary buckwheat significantly reduced by 6.36, 24.85, 78.62, and 83.10% with 1, 2, 3, and 4 yr of continuous cropping, respectively. Therefore, continuous cropping reduces the yield of Tartary buckwheat by destroying the microenvironment system of rhizosphere soil, inhibiting the growth and development of the root and shoot systems, and accelerating senescence.