Vigna radiata

Cultivation Details

A plant of the drier tropics, where it is found at elevations up to 2,000 metres. It grows best in areas where annual daytime temperatures are within the range 21 - 36°c, but can tolerate 8 - 40°c^[1]. The plant does not tolerate frost. It prefers a mean annual rainfall in the range 650 - 900mm, but tolerates 500 - 1,250mm^[1]. Plants do well when treated as a dry season crop^[2]. Seed set can be adversely affected by rainfall during the flowering period^[2]. Prefers a sunny position, tolerating light shade^[1]. Grows best in a well-drained soil rich in organic matter, succeeding in sandy to clayey soils^{[2, 1]}. Some cultivars are tolerant of moderately saline and alkaline conditions^{[2, 1]}. Prefers a pH in the range 5.5 - 6.2, tolerating 4.3 - 8.3^[1]. Established plants are moderately drought resistant^[2]. Young pods can be harvested in about 2 months from sowing the seed^[2]. A yield of dried seeds can be obtained within 50 - 120 days^[3]. Yields of 400 - 700 kilos of dried seed per hectare can be obtained^[2]. There are many named varieties^[4]. Two main sets of cultivars have been identified:- Golden gram has yellow seeds, the pods often shatter at maturity. Green gram has dark or light green seeds, the pods ripen more uniformly and are less likely to shatter^[2]. Cultivars can be short-day, long-day or daylength-neutral^[2]. The plant has deeply penetrating, vigorous roots^[2]. This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby^[5]. When removing plant remains at the end of the growing season, it is best to only remove the aerial parts of the plant, leaving the roots in the ground to decay and release their nitrogen.