KOCHIA SCOPARIA EMERGENCE FROM SALINE SOIL UNDER VARIOUS WATER REGIMES

Kochia scoparia (L.) Schrad. invades disturbed soils and serves as a p ioneer species on saline rangelands and sodic mine spoils. The percent germination of kochia seeds declined with increasing salinity, averag ing -3.3%/dS/m between 12 and 30 dS/m. The emergence and early surviva l of kochia seeded into 2 media whose respective saturated-paste extra cts averaged I and 18 dS/m in electrical conductivity (EC(e)) were inv estigated in a greenhouse under simulated rainfall regimes. Water was applied according to 3 average rates: 0.6 mm/day (low); 1.2 mm/day (me dium); 2.5 mm/day (high). These rates were administered in 2 phases. P hase I (14 days) involved low and medium on the nonsaline seedbeds, an d medium and high on the saline seedbeds. Phase II (42 days) followed sequentially on only the saline soil in phase-I:II combinations of hig h-high, high-medium, medium-medium, and medium-high. Kochia seedlings did not emerge under the low rate. Seedlings did emerge from the nonsa line seedbeds when watered at the medium rate, but failed to emerge fr om the saline seedbeds treated only at this rate. Seedlings emerged fr om the saline soil under all regimes that included the high rainfall r ate. About 30 plants successfully emerged from every 100 seeds sown in the seedbeds where EC(e) decreased to 15.7 dS/m or less. Despite the severely saline seedbed, kochia emerged within 3 days at a rate of 8 p lants/day under the Phase I high regime because the water apparently d iluted saline seedbed-solutions sufficiently for germination to occur. Phase II of the medium-high regime stimulated a similar response but only after 13 days under the wetter rate. Kochia's germination and eme rgence favor its addition to seed mixtures designed to establish forag es in saline soils.