The possibility of forage production in two kochia (Kochia scoparia L.) ecotypes by application of low amounts of water in saline conditions

Background and objectives:
In all areas where irrigation is necessary for crop production, salinization of soil is also unavoidable. Therefore, to guarantee the continuation of crop production in such areas, growing crop species with threshold of yield reduction well above the salinity of the irrigation water is needed. Agriculture and animal husbandry in arid and semi-arid regions always have been together. Therefore, provide forage for livestock in these areas is one of the main concerns of farmers. Kochia (Kochia scoparia L.) is an annual salt- drought tolerant plant. It is capable to rapid established in salinity soils, and is a ground cover plant that can introduced as an alternative fodder, in arid and semi-arid areas. Therefore, the aim of this study was to evaluate the drought tolerance of kochia in irrigation with saline water at different growth stages with emphasis on the forage characteristics.
Materials and methods:
Experiment was conducted as split-plot based on Complete Randomized Block Design with three replications to evaluate some photosynthetic characteristics of halophyte plant, Kochia scoparia, in different salinity levels at the Salinity Research Station of Ferdowsi University of Mashhad, Iran in 2008. Three levels of drought stress (control, no irrigation in vegetative stage (recovery treatment) and no irrigation at reproductive stage for one month (stress treatment)), and two kochia local cultivars (Birjand and Borujerd) were allocated as main and sub plots, respectively. Plants were irrigated with underground water having electrical conductivity (EC) of 5.2dS.m-1. Forage harvesting was carried out after the third-stress treatment, in full flowering stage.
Results:
The results showed that plant height in vegetative growth stage was more sensitive to water stress than the reproductive stage in kochia. In all irrigation treatments at different growth stages, Boroujerd local cultivar produced taller plants than Birjand local cultivar and the greatest reduction plant height in both local cultivars occurred in drought stress at vegetative growth stage. Branch number and forage yield in kochia were not affected by Irrigation treatments. Total dry matter percent of drought stress treatment at both vegetative and reproductive stages were significantly higher than control full irrigation. Stems and leaves yield of Boroujerd and Birjand local cultivars were not significantly affected by irrigation treatments. The highest and lowest leaf to stem ratio were obtained in drought stress at vegetative and reproductive growth stage, respectively.
Conclusion:
Four weeks irrigation cuts at vegetative and reproductive stages did not affect forage yield of kochia, and this plant showed the high capability to recover the adverse effects of drought stress in the vegetative growth stage. Generally, kochia has morphological features for introduction as a forage crop and arid and saline areas. In addition, the physiological mechanisms of drought and salt tolerance of kochia may introduce it as a candidate forage species for cultivation and to help feed the livestock in areas where salinity and drought stress is dominant.