Vigna umbellata, previously Phaseolus calcaratus, is a warm-season annual vine legume with yellow flowers and small edible beans. It is commonly called ricebean. A multipurpose crop, Vigna umbellata is also a viable fodder species (provided as fresh or dried forage) and green manure cover crop. In the vegetative stage the rice bean plant (moisture content 84%) contains on a dry matter basis: 18.0% crude protein, 1.1% fat, 31.5% crude fibre, 39.9% N-free extract, 9.5% ash, 1.4% Ca and 0.35% P.

Origin And Distribution:

The presumed center of domestication is Indo-Burma (Vavilov, 1951) and Indo-China.  It is thought to be derived from the wild form V. umbellata var gracilis, with which it is cross-fertile, and which is distributed from Southern China through the north of Vietnam, Laos, and Thailand into Burma and India.

Varieties:

RBL 1, RBL 6 , RBL 35 , RBL 50 , BRS1 , Bidhan-1(BC15/K1) , Bidhan-2

Climate and Soil Requirements:

Vigna umbellata is a versatile warm-season crop that can grow in humid subtropical to warm and cool temperate climates with annual rainfall ranging from 1000 to 1500 mm but it is also fairly tolerant of drought. It does better in areas where average temperatures range from 18 to 30°C, tolerates 10-40°C but does not withstand frost. Ricebean requires a short day length but full sunlight for growth and development. Most cultivars are photoperiod-sensitive, tend to be late in flowering and produce vigorous vegetative growth when grown under ample water and warm temperature in the subtropics.

It is grown in a variety of soil ranging from loamy to sandy loam soil having a good drainage system. It grows moderately on poor or lightly fertile soil. The optimum pH is 6.8-7.5. Well-drained loamy soil with pH 5.5-8 is best suited. Ricebean is also known to be tolerant to acid soils. Avoid cultivation in the saline-alkaline soil, sandy or having waterlogged soils. Do not grow rice beans in light soils as it causes root-knot nematode problems to the crop.

Land Preparation:

Land should be well leveled, friable and free from weeds. There should not be water logging conditions. As the seeds of ricebean are very small, one deep plowing with 1-2 cross harrows will be good for preparing the soil.

Seed Treatment:

Treat the seeds with Carbendazim 50%WP or Thiram 75%WP @2 g/kg of seed 24 hours before sowing (or) with talc formulation of Trichoderma viride @ 4g/kg of seed (or) Pseudomonas fluorescens @ 10 g/kg seed.

Rhizobium culture (Rhizobium phaseoli) for better nodulation, good growth, and higher fodder yields. For treating the seed it should be first soaked into freshwater for about 8-12 hours. Jiggery 10% sugar solution- About 1.5 liter of water is mixed with 150 g of sugar and boiled. After cooling the jaggery liquid about two cigarette tins of culture is mixed with it and then the seed is well mixed and dried in a cool shady place.

Sowing Time:

In India and Nepal, rice beans are sown in February and March for harvest during summer and in July but sown in Mid June-Mid July in the hills before the onset of monsoon.

Irrigation:

Irrigate immediately after sowing followed by life irrigation on the third day. Irrigate at intervals of 7 to 10 days depending upon soil and climatic conditions. Pre-sowing, Flower initiation, and pod formation stages are critical periods where irrigation is a must. Avoid water stagnation at all stages.

Weed control:

Frequent weeding and hoeing are required for keeping the field weed-free. 2 hand hoeing is required after 20 and 40 days of sowing for controlling the weeds. Use of glyphosate @1kg ai/ha pre-plant, pendimethalin@1.5 kg ai/ha as pre-emergence at 3 days of sowing, and isoproturon @1.5 kg ai/ha as post-emergence at 25-30 days of sowing is recommended.

Pest and Disease Management:

In the ricebean, reports on serious disease problems have not so far been identified. But if required, one spray of systemic fungicide like Carbendazim @ 1g/l of water may be sprayed. For controlling pests like aphids, flea beetles, etc. spraying of Malathion 50 EC @ 1-1.5 l/ha in 500l may be applied. But, in forage crops use of resistant varieties and cultural practices like early planting, destruction of crop residues, crop rotation are to be adopted avoiding the use of chemicals.

Harvesting:

Rice beans are normally ready to harvest in 4-5 months after sowing in October-November. Harvesting is done in pickings. It can be harvested when approximately 75% of the pods turn brown. Harvesting is generally done by hand. The whole plant is to be harvested when the majority of the pods are dry and then the plants should be sun-dried on the threshing floor for 3-4 days. After this, the pods along with the whole plant are beaten with sticks to collect the seeds. Rice bean should be harvested when the pods are immature and before the leaves drop for fodder purpose while the crop is to be plowed at about 30 days after sowing for green manuring purpose

Yield:

Average seed yield of 200-300 kg and fodder yield of about 35 t can be obtained from a 1-ha crop. Fodder yields were reported to range from 5-7 t DM/ha in May and June, to 8-9 t DM/ha in November and December.

Cultivated ricebean varieties