Variety and Maturity Affect Amaranth Forage Yield and Quality

Abstract

Little information is available on the forage potential of improved amaranth (Amaranthus sp.) cultivars. Our objectives were to determine the effect of maturity on forage yield and forage quality of A. cruentus L. and A. hypochondriacus L. and to evaluate forage quality of leaf, stem, and inflorescence fractions at two maturity stages. Field experiments were conducted on a Waseca silt loam (fine‐loamy, mixed, mesic Cumulic Haplaquolls) and on a Waukegan silt loam (fine‐silty over sandy skeletal, mixed, mesic Typic Hapludoll). 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 and 4.1 tons/acre at 16 and 14 WAP in 1988 and 1989, respectively. Forage quality decreased as maturity increased from bud to flowering. Crude protein (CP) was greatest (average of 23%) at 8 WAP when amaranth was vegetative and 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 inflorescence development, the leaves averaged only 13.4% of the total forage and stems averaged 42.9%. Leaves had greater CP and less fiber concentration than stems. The decline in whole plant quality with maturity was associated with a decrease in CP concentration of leaf and stem fractions and an increase in both NDF and ADF concentrations of stems. Amaranth entries differed in forage quality, but vegetable types were not superior to grain types. Research Question There is often a shortage of quality forage during the summer in the Midwest. Amaranth has potential as an alternative summer forage source, but its forage yield and forage quality potential have not been evaluated. Our objectives were to evaluate the effect of maturity on forage yield and quality of diverse amaranth entries and to determine the quality of leaf, stem, and inflorescence of amaranth harvested at two stages of maturity. Literature Summary Amaranth, a warm season crop, is used extensively throughout the world as a grain and vegetable food for human consumption. It has not been evaluated in the Midwest as a forage crop. Several reports indicate that Amaranthus species have relatively high forage quality that is similar to quality of alfalfa forage. Amaranth entries have been developed for grain and vegetable production. Study Description Field studies were conducted in 1988 and 1989 in southern Minnesota on silt loam soils. In one study, four amaranth entries (two grain and two vegetable types) were established in spring, and forage yields were measured at 2‐wk intervals from 8 wk after planting (WAP) until a frost (32°F) in the fall. Forage sub‐samples were analyzed for crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF). In a second study, nine amaranth entries were harvested at two stages: at late vegetative to early bud, and at m...

Forage Nutritive Value of Various Amaranth Species at Different Harvest Dates

“…Neutral detergent fiber increased with harvest date (Table 3), similar to that reported by Walters et al (1988) and Stordahl et al (1999) The greatest change (550 g kg −1 ) in NDF from 42 DAP to 112 DAP was observed in A. hybridus (Greece) and the lowest (210 g kg −1 ) in A. hypochondriacus (Colorado).…”

“…Another surprise was that A. cruentus (Mexico), a visibly stemmy and woody plant in the latter part of the season, still had the second lowest (225 g kg −1 ) ADF when averaged over harvest date. This was unexpected because Stordahl et al (1999) reported a decline in whole plant quality with maturity associated with an increase in stem NDF and ADF concentration.…”

“…The increased digestibility of the vegetable‐type accessions may have been due to the presence of a greater number of leaves and stems observed and they were visibly more succulent than the stems of the grain‐type accession, especially earlier in the season. Some amaranth forage has nearly equal proportions of leaves and stem when they are in the vegetative stages (Stordahl et al, 1999).…”

“…Several studies (Stordahl et al, 1999; Lehmann, 1990; Pond and Lehmann, 1989; Senft, 1979; Cheeke and Bronson, 1979; Odwongo and Mugerwa, 1980; Yue et al, 1987) have shown that amaranth nutritional qualities are superior to those of the common cereals and forage crops. Arguably, the most important nutritional quality of a grain is its protein content and quality.…”

Some Quality Traits of Different Wild Plants

“…Crude protein contents were changed from 12.12% (Acar and Guncan, 2002) to 20.65% (Kaya et al, 2004) in Poligonum aviculare. Stordahl et al (1999) have pointed out in Amaranth species (A. cruentus L. and A. kypochondriacus L.) at 8 weeks after planting, crude protein, ADF and NDF percentages were found (23, 26 and 36%) respectively. In Amaranthus retroflexus dry matter, crude ash and crude protein percentage reach to 18.2%, 22.8%, 3.4% (Sekeroglu et al, 2006).…”