ABSTRACT
Summary In searching for plants that can both increase the protein production and improve the sandy-soil conservation of the grassland in the arid, windy regions of North China, so far, from among many native plants, we have identified Hedysarum mongolicum Turcz. as the best species to fulfill our dual purposes. We investigated its distribution, planted its native seeds in the Maowusu desert, and studied it under its native and cultivated growing conditions from 1957 to 1964. Chinese farmers call this perennial subbrush legume of the sweetvetch genus “Yang Cai,” meaning “sheep like to eat.” It can thrive in the stable or substable sand-dune areas between lat 38° and 48° N with annual rainfall less than 300 mm. Under favorable growing conditions, its main green stems may be 100 to 150 cm tall and form a canopy 100 to 150 cm in diameter. Its taproot goes 2 m deep into sandy soil. Below its crown, 5 to 6 m long, strong rhizomes creep out in all directions from which new branches shoot up as high as 1 m, and new roots grow down 20 to 30 cm below sandy soils. We found a single native Yang Cai plant on a sand dune with creeping roots spreading over an area 30 m2 and total root length of 108 m. The roots had also formed 81 vegetative clumps above the ground. Because the seed coat of Yang Cai is impermeable to water, the seeds should be properly scarified before seeding. Early-spring seedings usually are more successful than late-summer seedings. In the year of establishment, very few flowers bloom, because most stems are vegetative. In the second year, branches begin to flower. Beautiful purple-red flowers and green bushes cover the yellow sand in July and August. The annual yield of hay can reach 4,500 kg/ha and that of seeds can reach 100 kg/ha under cultivation. Yang Cai is a high-protein forage with a crude-protein content of more than 20% of total dry matter in the flowering phase. Its several amino acids compare favorably with those of alfalfa. Its high protein content and fine stems lead most animals to devour it green or dry. It has improved the nutritive value of the vegetation of China's sandy soil. Many seed-production regions have been established in Neimenggu Autonomous Region (Inner Mongolia) where many natives in the dry steppes have expanded the acreage of its plantation.
