Effects of the Salt-Tolerant Gramineous Forage Echinochloa frumentacea on Biological Improvement and Crop Productivity in Saline–Alkali Land on the Hetao Ningxia Plain in China

Abstract

Biological improvement is a sustainable approach for saline–alkali land amelioration and utilization. Echinochloa frumentacea (Roxb.) link is a salt-tolerant gramineous forage, which plays an important role in improving saline–alkali land. The Hetao Ningxia Plain is located in the upper–middle reaches of the Yellow River with a large area of saline–alkali soil, where E. frumentacea has potential applications for improving saline–alkali land. Three experiments were conducted on saline–alkali land in Pingluo County, Ningxia, including soil-leaching experiments in pots as well as monoculture or intercropping experiments involving E. frumentacea in fields. The results showed that: (1) E. frumentacea had a strong leaching ability of Na+ and SO42− in saline–alkali soil. (2) The planting of E. frumentacea decreased soil pH and total salt; enhanced the available N, P and K; and increased plant height, stem thickness and yields compared with the control. (3) The diversity of soil bacteria and land use efficiency could be improved by the intercropping of E. frumentacea with legume forages. Overall, E. frumentacea is an important pioneer species of biological improvement for the sustainable utilization of secondary saline–alkali land produced by irrigation around the world.