Currently observed expansion of salt-affected areas provokes profound concern by loss of the land productivity. Actually the future of agricultural production will depend on capability to grow plants in saline environment with low quality lands and mineralized water. Salt-tolerant plants like Salsola sclerantha, Climacoptera lanata, Climacoptera brachiata, Suaeda paradoxa, Kochia scoparia, alfalfa, Glycyrrhiza glabra, Atriplex nitens were cultivated in farmer plots with hot slightly mineralized irrigation water from artesian well and sandy low fertile soils with medium sulphate-chloride type of salinity in Central Kyzylkum. Growth and development of the plants were observed. It was shown that it is possible to get high yield of halophytic biomass using hot mineralized water and low-fertile soils. Green biomass yield was about 18.95 t/ha for Salsola sclerantha ; 23.10 t/ha - Climacoptera lanata, 25.45 t/ha - Suaeda paradoxa, 44.10 t/ha - Kochia scoparia, 13.84 t/ha - Glycyrrhiza glabra, and 42.05 t/ha - Atriplex nitens.
Chemical composition of the biomasses was analyzed; mineral and organic matter was evaluated. Highest total salt accumulation among investigated plants was revealed for Salicornia europaea and Climacoptera lanata. Plants grown in farm trial contained less mineral things as compared with the same species from solonchak (for instance, 31.6% ash versus 46.9% for Climacoptera sp.). Suaeda paradoxa, Kochia scoparia and Glycyrrhiza glabra accumulated very small amounts of mineral ions in biomass; ash contents in their biomasses were 5.52; 6.39 and 10.45%DM accordingly.
It was revealed that Na+; Cl-; SO4 2- are mainly accumulated in aboveground biomass of halophytes, not in the roots. It is applied to all real halophytes which accumulate sodium ions selectively to set up certain osmotic pressure in their cells and pump mineralized water; and redundant amounts of Na+ are sequestered in cell vacuoles in leaf tissues. Sodium and chloride ions are mostly accumulated by halophytes. Climacoptera lanata, Karelinia caspia, Salsola sclerantha and Tamarix hispida accumulated biggest amounts of sulfates in their biomasses. At the same time Climacoptera lanata, Salicornia europaea, Tamarix hispida and Halostachys belongeriana contained biggest quantities of chlorides in biomass. Such salt tolerant plants as alfalfa don’t accumulate mineral compounds in the biomass. Carry-over indices of main mineral salts from the soil were calculated for some salt-tolerant plant under the investigation.
To assess fodder value of halophytic plants some nutritional compounds (crude fat, cellulose and protein contents) were measured and hay feeding values were calculated. High nutritional value of salt tolerant plant’s biomass was revealed. Possibility to use salt tolerant plants as forage/fodder or feed additions was verified by the study. Halophytes contain a lot amounts of crude protein – from 5 to 13 mg/gDM; cellulose – from 10.38 to 20.54 mg/gDM; and fats – from 0.5 to 5.06 mg/gDM. Atriplex nitens, Suaeda paradoxa and Kochia scoparia are recognized as the most nutritional valuable plants and promising fodder.
Biogas productions at anaerobic digestion of halophytic biomasses were studied in batch-test and continuous mode experiments. It was revealed that 200-380 mL of biogas can be produced in anaerobic reactors from 1 g of dry matter of halophytic biomasses at 35°C; and 300-480 mL - at 55°C. Taking into consideration current and possible use of different salt-tolerant plants, their yield and value as fodder etc., it is recommended to use Karelinia caspia as the most promising source of biogas.