Response of Crops to Sulfur under Greenhouse Conditions

Abstract

AbstractTwo to four crops were grown in sequence in three series of pots on two soils, Charlottetown fine sandy loam (Chfsl) and Queens sandy clay loam (Qscl). The rates of applied S to the soils were: 0, 50, 100, and 150 ppm. None of the crops grown in the first sequence responded to S, but crops grown in later sequences responded to S in varying degrees. Sulfur applications resulted in about 2‐ to 4‐fold increases in the yield of rutabaga roots (Brassica napobrassica, Mill. cv. ‘York’). The plants deficient in S had thin roots and the leaves were reddish‐yellow with scorched edges. The kernel and straw yields of barley (Hordeum distichon L., cv. ‘Volla’) and wheat (Triticum aestivum L., cv. ‘Opal’) increased substantially with the addition of S. The S‐deficient plants of barley and wheat were lighter in color with thin stems. Alfalfa (Medicago sativa L., cv. ‘Saranac’) responded to S, with increases of much greater magnitude in the second and third cuts than those in the first cut. The S‐deficiency symptoms, noted as stunting and general yellowing of the entire plants, were mostly confined to the second and third cuts. Four‐ to five‐fold increases in cauliflower (Brassica oleracea botrytis L., cv. ‘Snowball’) yield with S3 and S4 treatments were obtained on Qscl, while on the Chfsl the yields decreased at S3 and S4 levels of S. The yield decreases on the Chfsl were caused by a severe Mo deficiency. Sulfur‐deficient cauliflower plants were stunted with general yellowing of leaf edges. The available soil SO4‐S levels of 2.0 and 2.4 ppm for alfalfa third cut and barley were in the deficiency range. The deficiency levels for wheat and cauliflower would likely be below 2.8 and 4.0 ppm, respectively.