Variety and maturity affect amaranth forage yield and quality

Little information is available on the forage potential of improved amarant h (Amaranthus sp,) cultivars, Our objectives were to determine the effect o f maturity on forage yield and forage quality of A, cruentus L. and A. hypo chondriacus L, and to evaluate forage quality of leaf, stem, and infloresce nce fractions at two maturity stages. Field experiments were conducted on a Waseca silt loam (fine-loamy, mixed, mesic Cumulic Haplaquolls) and on a W aukegan silt loam (fine-silty over sandy skeletal, mixed, mesic Typic Haplu doll). Amaranth dry matter yield was 1.3 tons/acre at 8 wk after planting ( WAP), increased with each subsequent harvest, and peaked at 4.4 tons/acre a nd 4.1 tons/acre at 16 and 14 WAP in 1988 and 1989, respectively. Forage qu ality decreased as maturity increased from bud to flowering, Crude protein (CP) was greatest (average of 23%) at 8 WAP when amaranth was vegetative an d decreased with maturity to about 13%. Forage neutral detergent fiber (NDF ) and acid detergent fiber concentrations (ADF) were about 36 and 26% at 8 WAP and increased as plants matured. Amaranth had nearly equal proportions of leaf and stem material when vegetative. When harvest was delayed until i nflorescence development, the leaves averaged only 13.4% of the total forag e and stems averaged 42.9%, Leaves had greater CP and less fiber concentrat ion than stems. The decline in whole plant quality with maturity was associ ated with a decrease in CP concentration of leaf and stem fractions and an increase in both NDF and ADF concentrations of stems. Amaranth entries diff ered in forage quality, but vegetable types were not superior to grain type s.