Plants annual or short-lived perennial, sparsely covered with appressed white hairs 0.1-0.6 mm. Stems intricately branched, ascending to nearly erect or prostrate to creeping, with long internodes, up to 30 cm, sparsely hairy to subglabrous, rooting at nodes. Leaves 2.5-10 cm; stipules 2-3 mm, free, ciliate; petiole much shorter than to as long as rest of leaf, like rachis sparsely hairy; leaflets in 3-5 pairs, obovate to obcordate, 5-17 × 3-13 mm, abaxially sparsely appressed hairy, adaxially glabrous or with a few scattered hairs, apex widely rounded to distinctly emarginate. Racemes umbellate, 4-10-flowered; peduncle erect, 2.5-25 cm, sparsely hairy; bracts 0.3-1 mm, ciliate. Calyx 3-5 mm, loosely to rather densely or more rarely scarcely covered with appressed, wide and flattened, white hairs 0.1-0.3 mm; teeth 1-2(-3) mm. Petals white, pink, light red, or purple, rarely creamy yellow or yellow; standard ovate, 9-14 × 5-8 mm, apex incised; wings 7-11 mm; keel 9-14 mm. Legumes with a stipe 2-3 mm, 12-20 mm, 2.5-3.5 mm high and wide, with a slender beak up to 5 mm; valves thin, blackish, loosely hairy.
Wet places, riversides, as a weed in rice fields, widespread in E Asia; 100-3000 m. Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Hunan, Jiangsu, Jiangxi, Shaanxi, Sichuan, Taiwan, Yunnan, Zhejiang.
Chinese Milkvetch, Renge.
A. sinicus is very widely grown as a green-manure-cum-forage in central and southern China, usually on rice land too poorly drained to carry a winter crop of wheat.
A. sinicus is a herbaceous, scandent perennial with pinnate leaves and pink-purple flowers, usually grown as a winter annual; it is a native of China and introduced to Japan.
For cultivation as a green manure, climates with only light frost are required. It is fairly tolerant of waterlogging but will not thrive if permanently flooded; the soils where it is grown are usually acid to neutral.
Cultivation and management
Astragalus sinicus is widely used on rice land as a winter crop. It is broadcast into standing rice in August, and the field drained; a phosphate application of 30 kg P/ha at sowing is advised. Fields which are liable to flooding may be set out as cambered beds. Plants, at the full-flowering stage, are usually heavily nodulated with pink-fleshed, apparently active nodules. The condition and yield of the crops seen by the author in China varied widely due to the degree of drainage of the field and soil fertility. A well-grown crop is said to yield fifteen tons per hectare of green material at the early flowering stage.
Seed crops are grown in a similar way, but on better land, receive phosphate and, of course, are left to maturity. The crop is cut manually and dried off the field before threshing and winnowing; 600 kg/ha is a reasonable seed yield.
Crop use and grazing management
It grows slowly throughout the winter but the main flush of growth is in spring when it is grazed by, or fed to, swine and buffaloes. In its main areas ruminants are only kept for draught so there is little information on its use as forage or its conservation. Flowering is in April and in late spring it is usually ploughed in so that the land can be prepared for the rice crop.