Intercropping of Echinochloa frumentacea with Leguminous Forages Improves Hay Yields, Arbuscular Mycorrhizal Fungi Diversity, and Soil Enzyme Activities in Saline–Alkali Soil

Abstract

Soil salinization is detrimental to crop growth, agricultural yields, and environmental protection. Echinochloa frumentacea (Roxb.) Link is a pioneer species for the alteration of saline–alkali lands. In this paper, we examined the effects of intercropping between E. frumentacea and leguminous forages on saline land improvement in the saline–alkali soil of the Hetao-Ningxia Plain, China. We found that intercropping increased the diversity and richness of the arbuscular mycorrhizal fungi (AMF) community in the rhizosphere soil of E. frumentacea. Glomus was the dominant genus in the saline–alkali soil of the Hetao-Ningxia Plain, where Glomeraceae, VTX00067, VTX000193, and VTX000165 were the dominant species. Intercropping improved the activities of soil urease, sucrase, alkaline phosphatase, and catalase. The hay yields of E. frumentacea were correlated positively with soil enzyme activities, Chao1 index, and ACE index, and negatively with total water-soluble salt content. Together, intercropping between E. frumentacea and leguminous forages enhances AMF diversity and soil enzyme activities, which provides an agricultural practice for improving sustainability of the agro-ecosystem in saline–alkali areas.