Effects of Rice Straw Returning on the Yield and Quality of Common Buckwheat

To clarify the effects of rice straw returning on the yield and quality of common buckwheat.

Common buckwheat cultivar Fengtian 1 was used across two years and treated with no rice straw returning combined with no compound fertilizer (CK), no rice straw returning combined with normal fertilizer (NSNF), full rice straw returning with 20% (FSRF20%), 40%, (FSRF40%) and 80% (FSRF80%) reduction in compound fertilizer application, and full rice straw returning with no compound fertilizer (FSNF).

Compared with the CK treatment, the FSRF20% treatment increased the accumulation and transport rate of non-structural carbohydrate in leaves at full bloom and grain filling stages and the enzyme activity of rhizosphere soil. With decreased compound fertilizer application rate, the grain weight per plant, 100-grain weight, and yield initially increased and then decreased, reaching the maximum at FSRF20% treatment. Compared with that of the CK treatment, the NSNF, FSRF20%, FSRF40%, FSRF80%, and FSNF treatment increased the yield by 172.54%, 181.02%, 104.49%, 69.30%, and 22.33%, respectively. The proportion of essential amino acids was about half that of total amino acids of common buckwheat. The flavonoid and starch content in grains of FSRF40% treatment were the highest. The protein, total amino acids, and essential amino acids content in grains of CK treatment were the highest.

For the sustainable development of farmland and improve the economic benefits of cultivating common buckwheat, 20% reduction in compound fertilizer can be considered when the total amount of rice straw was returned to the field.