Submitted to: Subtropical Plant Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/8/2003
Publication Date: 12/18/2003
Citation: Makus, D.J. 2003. Salinity and nitrogen levels can affect the agronomic performance, leaf color and mineral nutrients of vegetable amaranth. Subtropical Plant Science. 55:1-6. Interpretive Summary: Vegetable amaranth is a warm-season green that is grown for local markets and also imported into the United States. The production potential for vegetable amaranth has not been documented in high EC (saline) soils common in the Southwestern U.S. This study demonstrated that vegetable amaranth was moderately tolerant when grown in high salt amended soil. Increasing levels of supplemental nitrogen fertilizer improved yield and leaf color.
Technical Abstract: A study was undertaken to determine the level of salt tolerance of vegetable amaranth (Amaranthus tricolor L.) to a Leadvale soil amended with NaCl to give salinity levels of 0.17, 0.34, 0.74, and 3.11 dS/M (0-15 cm depth). Nitrogen, as NH4NO3, was split-applied at 0, 135, and 270 kg/ha. Twenty-one day old plants of USDA PI 2153 were transplanted on 17 August and harvested 13 September 1988. Increasing soil salinity increased soil test NO3, K, Zn, quadratically (Q), Na and Mn linearly (L), and decreased Fe, Mg, and Ca(L) in soil sampled 14 September. Adding N increased residual soil test NH4, NO3, K, Fe, and Mn(L). Addition of NaCl and N decreased soil pH (Q) and (L), respectively. Plants in 3.11 dS/M soil had reduced stand, yield, height, leaf area, hue, and leaf pigments. Leaf chlorophyll a:b ration increased and chlorophyll:carotenoid ration decreased in plants grown at the highest soil salinity level. Increasing N rates increased leaf area, pigments, and chlorophyll:carotenoid ratio (L), but decreased plant stand (Q) and chlorophyll a:b ratio (L). Increased soil salinity increased leaf blade Na and Cl(Q) and B(L), but decreased leaf blade NO3(Q) and Ca, and Mg(L). Applying increased N increased leaf blade TKN, NO3, Fe, and B(L), but decreased Ca, Mg, and Cl(L). In conclusion, soil NO3 was poorly utilized by amranth grown in high salinity soil.