ELEMENTAL SULFUR IMPREGNATED WITH IRON AS A FERTILIZER SOURCE FOR KENTUCKY BLUEGRASS

Elemental sulfur (S) impregnated with Fe (S-Fe) fertilizer was evaluated on Kentucky bluegrass (KBG; Poa pratensis L.) in three glasshouse studies: (1) with/without Fe as S-Fe, ferrous sulfate (FS), or iron-ethylenediamine-N,N'-bis(2-hydroxyphenylacetic acid) (Fe-EDDHA) to soil (49 kg Fe ha(-1)), or foliar Fe-EDDHA (5 kg Fe ha(-1)) on two cultivars; (2) 0, 49, 197, or 592 kg Fe ha(-1) of S-Fe deep mixed or surface mixed on two soils; (3) 0 or 49 kg Fe ha(-1) applied as S-Fe on four cultivars. A field study comparing 0 and 49 kg Fe ha(-1) applied as S-Fe to KBG was also conducted. Soil applied S-Fe was assimilated in shoots as efficiently as Fe-EDDHA applied to soil or foliage. Shoot Fe increased significantly with increasing S-Fe in a curvilinear response when deep mixed with soil and in a linear response when surface applied. However, no Fe source tested impacted yield or verdure in these studies.