Effects of planting quinoa on soil properties and microbial community in saline soil

Abstract

Quinoa (Chenopodium quinoa), a herbaceous annual, has been widely cultivated in recent years because of its high nutritional value and strong tolerance to abiotic stresses. The study was conducted at two planting densities (LD, 10 plants/m2; HD, 65 plants/m2) on ameliorated coastal mudflats in Jiangsu Province, China (118° 46′ E, 32° 03′ N). The results showed soil salinity and organic matter were higher in the HD than LD treatment, and salinity of the rhizosphere soil was higher than that of the non-rhizosphere soil. Quinoa grown in HD was taller, with thicker stalks and lower yields per plant, but higher yield per unit area. Amplicon sequencing showed that Proteobacteria, Bacteroidota and Acidobacteria were the dominant bacterial phyla. Regarding the rhizosphere soil, the Shannon index was higher in the HD than LD, and Proteobacteria and Bacteroidota were more abundant in the HD treatment. Fifty-one differential metabolites were identified by metabolomic assays, belonging to 14 annotated metabolic pathways. S-adenosylmethionine was the most abundant and up-regulated metabolite (fold change >1.67), and was more abundant in the roots from the LD than HD treatment. Docosahexaenoic acid was more abundant in the HD than LD treatment, and was down-regulated metabolite. In conclusion, planting density was an important factor affecting quinoa yield; compared with unplanted soil, planting quinoa at low density increased the content of the important metabolite S-adenosylmethionine in the root system of quinoa, and high density cultivation of quinoa increased soil salinity and microbial abundance and diversity.

Changes in Bulk and Rhizosphere Soil Microbial Diversity Communities of Native Quinoa Due to the Monocropping in the Peruvian Central Andes

“…The soil bacterial community was dominated by Actinobacteria and Proteobacteria ( Figure 2 a). This profile is similar to the report in Jiangsu Province, China [ 24 ], with the exception of Chloroflexi, which was reported in the top three of the phylum for our study. The presence of a high number of bacteria from the phyla Proteobacteria and Actinobacteria in the soil is regarded as a dependable parameter for the surveillance of soil wellbeing [ 25 ].…”