Growth characteristics of kochia (Kochia scoparia L.) and alfalfa (Medicago sativa L.) in saline environments

A greenhouse experiment was conducted to study the effects of saline water irrigation and soil salinity on the growth of kochia (Kochia scoparia (L.) Schrad.) and alfalfa (Medicago sativa L.). The alfalfa production was low, and half of the plants withered and died under soil electrical conductivity of 4dSm(-1). However, high salinity did not affect kochia growth. The mechanism of sodium absorption differs between kochia and alfalfa. Kochia has a salt-tolerance mechanism whereby the sodium concentration in the plant does not increase, regardless of the environmental conditions of the soil. However, the sodium concentration in alfalfa increases with increasing concentrations of sodium in the soil. Accordingly, changes were observed in the salt composition of alfalfa that harmed the plant. Although good kochia growth was observed in soil with limited water irrigation, it is difficult to grow alfalfa using the same quantity and salinity of irrigation water as used for kochia. Kochia can be cultivated using limited water and in highly saline soil in arid and semiarid regions. Furthermore, since kochia cultivation requires limited irrigation water, the plant may suppress the increase in the salinity of the soil and irrigation water. Therefore, in saline soil in arid and semiarid regions, kochia may be promising as an effective forage crop substitute for alfalfa.