Response of nine forage grasses to saline irrigation and its schedules in a semi-arid climate of north-west India

Abstract Traditionally, the degraded lands in arid and semi-arid regions are left for pastures but their forage productivity is low, unstable and unremunerative. Often this results in acute shortages of fodder during the post-monsoon period that can perhaps be partly overcome if the limited saline ground-water resources are effectively utilized to supplement water supplies. Thus, a field experiment was conducted during 1993–1997 on a calcareous soil in a semi-arid part of north-west India (average rainfall 350 mm/annum) to evaluate the suitability of forage grasses to saline irrigation (ECiw 8.5–10.0 dS/m) and optimize its schedule. Grass species included in this experiment were Brachiaria mutica Stapf. Cenchrus setigerus Vahl. Chloris gayana Kunth, Cymbopogon flexuosus , Cynodon dactylon Pers. Echinochloa colonum Link. Panicum antidotale Retz., P. coloratum Linn., P. laevifolium Hack., P. maximum Jacq. (Local wild), P. maximum Jacq. (Cultivated) and P. virgatum . Species those were identified to be the most promising included Panicum laevifolium and P. maximum (both local wild and cultivated) with an annual forage production of 3.43–4.23 Mg/ha. The overall reduction in forage yield with saline irrigation equalled 29 per cent when compared with canal water (ECiw 0.4 dS/m). Scheduling saline irrigation based on climatological approach, i.e. when the ratio of depth of irrigation water (Diw) and cumulative open pan evaporation (CPE) equalled 0.4, was observed to be optimal whereas increased salt accumulation nullified the benefits of enhanced water supplies (Diw/CPE=0.8). Two of the definite advantages of irrigated forages were about three–four-fold increase in productivity as compared with natural/seeded pastures and extension of production period to those of conventional shortages, i.e. during summer months (April–June) when the most nomad populations are forced to migrate to traditionally irrigated areas. Thus, it was concluded that saline water use strategies for rehabilitating arid lands with above grass species would not only render these degraded lands be more productive but also ensure conservation and improvement for long-range ecological security of these lands.