For a group of soils having variable clay content but nearly uniform clay‐fraction mineralogy, relative hydraulic conductivity in the presence of mixed‐salt solutions decreased markedly with increasing clay content, particularly at the lowest salt concentrations employed. The stability of a group of Hawaiian soils under high‐sodium, low‐salt conditions was greatly reduced by partial removal of the free iron‐oxides. Replacing the Ca in percolating NaCl‐CaCl2 solutions with Mg measurably decreased soil hydraulic conductivity, although the effect was often negligible when comparisons were made at equivalent exchangeable‐sodium‐percentages.

Scarcity of good-quality water for landscape irrigation is a major concern in arid and semiarid regions as a result of the competition with the urban population. Competing claims from urban, agricultural, environmental, and industrial groups leaves less water or water of lower quality for use in landscape maintenance. Although degraded waters, high in both salinity and alkaline pH, may challenge plant establishment and growth, these waters must be considered as valuable alternatives to the use of fresh water resources for landscape sites. The objective of the present study was to determine the effect of irrigation with saline water, with and without pH control, on the mineral ion relations of three marigold cultivars: Flagstaff, Yellow Climax, and French Vanilla. Treatments were five electrical conductivities of irrigation water (ECw): 2, 4, 6, 8, and 10 dS·m−1, and two pH levels: 6.4 and 7.8. Plants of ‘French Vanilla’ and flowering stems of ‘Flagstaff’ and ‘Yellow Climax’ were harvested at flower maturity. Leaves of the taller cultivars, Flagstaff and Yellow Climax, were collected separately from the main axis and from the lateral stems, whereas in ‘French Vanilla’, leaves were combined. Total sulfur, total phosphorus, Ca2+, Mg2+, Na+, K+, Cl−, Fe2+, Zn2+, Cu2+, and Mn2+ concentrations in leaf and stem tissues were determined. The three marigold cultivars were strong Ca2+-accumulators and this response was more evident at the lower pH level. However, leaf Ca2+ tended to decrease as salinity increased despite a threefold increase in substrate Ca2+. Leaf Mg2+ increased as salinity increased and main stem leaves of the taller cultivars accumulated more Mg2+ than leaves on the lateral branches. The reverse was true for leaf K+; leaves on the lateral branches were stronger K+-accumulators than those on the main stem. Potassium concentrations in leaves of marigold irrigated with waters at pH 6.4 tended to decrease as ECw increased. Marigold seems to possess an efficient Na+ exclusion mechanism, which restricts Na+ accumulation in the leaves. Patterns of total phosphorus accumulation in leaf tissues were not consistent over the range of ECw treatments. Among the micronutrients, Fe2+ and Mn2+ tended to be partitioned to the younger rather than the older leaves. The decrease in marigold growth was associated with nutrient ion imbalance as demonstrated by the reduction in K+ concentration and the increase in Mg2+ and Cl− in leaf tissue. Despite the reduction in growth, the aesthetic value of the cultivars was not detrimentally affected by application of saline waters with ECw values as high as 8 dS·m−1.