Prosopis cineraria (L.) Druce
Khejri, jandi, ghaf
|Author: Le Houérou
Small tree 3-5 m high with a rounded canopy, often lopped to feed stock. Life expectancy is about 200 years or more, branches and twigs bear short (3-6 mm) thorns all along the internodes, by contrast with the new-world species where thorns are axillary. Leaves are bipinnate 1.2-5 cm long bearing 1-3 pairs of pinnae having 7-14 pairs of sub-sessil leaflets 4-15 mm long x 2-4 mm wide, each. Flowers are small, cream-yellow clustered in acute spikes 5-23 cm long with a 1-2.5 mm long peduncle. Pods are pale yellow, 8-25 cm long x 4-8 mm wide, cylindrical and hanging, containing 10-25 seeds ovoid in shape and dark brown in color, packed in a brown pulp. Flowering in India occurs in February-March in the mid-dry season, pods are mature in May-June before the onset of the rains.
The tree occurs in areas with MAR as low as 150 mm and extends to the sub-humid zones with up to 800 mm MAR. In the lower rainfall areas tree density is of the order of 5 per ha but may raise to 250 trees / ha in higher rainfall zones.
Found under desert conditions but on deep alluvial soils provided with a water table (often saline). This species is very flexible in terms of soils, accepting highly alkaline soils with pH's up to 9.5 and to salinity accepting salt concentrations up to 1 / 2 of sea water strength i.e. 18,000 ppm or 25 mS / cm EC, the presence of a more or less deep water table is, however, mandatory ; the tap roots have been observed to reach a depth of 60 m in Oman (Brown, 1992) ; but the species concerned in the latter case could actually be the relative P. koelziana Burkart., rather than P. cineraria, as both have been confused for decades.
This species originates from NorthWest India and East Pakistan where it is the basis of an agroforestry production system very similar to the one established in Africa with Acacia albida. It was introduced to the Sahel in the early 1980's and was found well adpated to the local conditions of northern Senegal. A closely related species is present in the South Arabian Peninsula, SouthEast Saudi Arabia, United Arab Emirates, Oman : Prosopis koelziana Burkart which also extends to South Iraq and South Iran, along the Arabo-Persian Gulf shores and the Oman Sea
Propagation is usually made by seeds, but the trees coppice easily and may be managed that way. The trees stand lopping and pruning. Propagation by cuttings is difficult, as often occurs with Prosopis spp.
The wood is a good fuel rating 5,000 kcal / kg. Leaves are good forage with 12-18 % CP while the pods contain 10-13 % CP ; they are consumed by all livestock species. P. cineraria is much appreciated as a sand binder and a wind-break.
In Rajasthan an agoforestry system based on millet and Prosopis cineraria, locally known as "khejri", has developed over the centuries which is an almost exact replicate of the Acacia albida-millet system of Africa and bringing about the same benefits. This has been carefully analysed (Mann & Saxena,1980 ; Mann & Shankarnarayan, 1980) in terms of geobiogene elements and water turnovers, in relation to soil fertility upkeep by the tree.