Saline agriculture is defined as the use of genetic resources (plants, animals, fish, insects and micro-organisms) and improved agricultural practices to obtain profitable use from saline land and irrigation water on a sustainable basis.

It is a rich collection of possible systems for the use of saline resources.

The components of these systems vary according to the needs of farmers and the capabilities of land and water.

Pakistan has some major advantages in the development of saline agricultural systems. Its greatest advantage is a rich heritage of research that commenced in the 1970s and continues today. Over the last three decades, there has been outstanding work on the selection of salt tolerant trees, shrubs, grasses and crops that enable increased production from salt-affected land.

However, it remains clear that despite these achievements, there has been little change in the farmers’ fields. Adaptation varies with location, but is mostly negligible.

Modern research has identified more than 1,500 plant species that have high level of tolerance to saline soils. Some are able to withstand salt concentrations in excess of those found in seawater. These plants (trees, shrubs and salt tolerant grasses, crops and herbs) are a major resource that can be used in the development of agricultural systems for salt affected soils.

Furthermore, some of these plants are able to lower local water tables, improving the condition of the land, and acting as a form of effective “biological drainage”. In addition, there are opportunities to increase salt tolerance of the existing crops using conventional plant breeding and molecular biological approaches.

Crops vary widely in their tolerance to salts. Sugar-beet, cotton and barley can tolerate up to 10 times as much salt as most clover, beans and fruit trees.

Scientists have successfully grown a number of crops on marginal saline lands.

It is pointed out that if the average electrical conductivity (EC) of a plot is 0-15 decisiemens (dSm-1) (9600 ppm), which is fairly high and may have serious effects on the growth and development of plants, but the soil is loamy in texture, underground water-table is at a depth of 8-10ft and some good quality irrigation water is also available, the conditions become less hostile for plant sustenance.

There are a number of species which may be grown in such conditions as given below. Good quality irrigation water should be used during the initial establishment phase and for periodical leaching of salts from soil surface. Under proper management, this can be a positive and cost-effective venture.

Cereals: certain cultivars of paddy rice (oryza sativa), sugarcane, oat, wheat, aegilops, triticale, sorghum, barley, pearl millet, rye; Oilseeds: rape, canola, mustard; vegetables: spinach, sugarbeet, redbeet; fodders and forages: guar, dhancha (Sesbania sesban L.), berseem (trifolium alexandrinum), lucerne (medicago sativa L.); fibre: cotton, sunhemp, kenaf; fruits: fig, grape, pomegranate, zizyphus (Zizyphus jujuba).

However, the salinity of a plot ranges between 15-20 dSm-1 (9600-12800 ppm), with coarse textured soil and the only source of irrigation is bad quality underground water (EC 10-15 dSm-1) present at a shallow depth, the growth of majority of the plants will be restricted under such highly adverse conditions and only some salt tolerant plants can be grown.

Suitable plants under these scenarios are given below. Economic benefits of many of these plants are well established.

Fruits: date palm, wild date palm and coconut; Grasses: karnal or kallar grass (Leptochloa fusca), orchard grass, bermuda grass, rhodes grass (Chloris guyana), para grass, tall wheat grass (Agropyron elongatum), rye grass, sudan grass; Woody species: jojoba (Simmondsia chinensis L.), guava (Psidium guajava L.), jujube (Zizyphus mauritiana L), mesquite (Prosopis species), mangroves, acacias (nilotica, ampliceps, stenophylla, machonochieana), atriplex species, mustard tree (Salvadora persica); Miscellaneous Plants: life plant (Bryophyllum pinnatum), aloe (Aloe perfolia), dodonaea (Dodonaea viscosa), periwinkle (Vinca rosea), purslane (Portulacea oleraceae), reed plant (Saccharum arundinacea), bottle palm, cactus, China rose, drumstick tree, wild banana (Agave americana), wild cherry (Withania somnifera), senna (Cassia angustifolia).

These plants are also effective in reclamation of salt-affected soils. The biological approaches to reclaim the salt-affected soils by growing plants are proved to be beneficial effects.

Proper choice of crops and appropriate crop rotations are also helpful in the utilization of salt-affected soils. Drainage and leaching are the principal elements of maintaining soil productivity in irrigated agriculture.