Forage Sorghum Yield Components and Their in vivo Digestibility¹

Abstract

Although the influence of different defoliation management schemes on the productivity and digestibility of summer annual grasses has been studied extensively, little is known about the effects of management on the yield components of these plants. To determine the relative contribution of leaf, stem, and head components to total yield, and to ascertain the digestibility of these plant parts, ‘Sudax SX‐11’ and ‘Trudan’ forage sorghums (Sorghum bicolor (L.) Moench) were seeded in the field in May and in June and subjected to four defoliation schemes: 1) 75‐cm growth cut to a 2.5‐cm stubble and 2) to a 15‐cm stubble; 3) 50‐cm growth cut to a 15‐cm stubble; and 4) early bloom growth cut to a 10‐cm stubble. Dry matter (DM) yields of the first growth and subsequent regrowths, and estimated digestible dry matter (% EDDM) measured with an in vivo nylon‐bag technique, were estimated for leaf blades, culms and leaf sheaths, and inflorescences. Both cultivars produced more DM yields with 75 cm than with 50 cm of growth. Sudax SX‐11 produced less than Trudan when 2.5‐cm rather than when 15‐cm stubbles were used and this was more evident when seeding was delayed one month. Both 50‐ and 75‐cm vegetative growths produced mostly leaf yield of about 80% EDDM throughout the season. Plants cut at early bloom produced much larger DM yields than those cut at vegetative stages. Leaf % EDDM was slightly lower in the early bloom than in the other treatments but stem and head materials were of lower digestibility than leaf blades.

Quality Traits in Forage Sorghum Harvested at Early Head Emergence and at Physiological Maturity1

“…[Sorghum bicolor (L.) Moench 1 sampled at various stages of development or under different management regimes are well documented (1,3,5,6,9). Much less information is available, however, on possible differences among plants of the same genotype and within the same field plot that reach a given developmental stage at different ages in terms cf O:3.ys after planting.…”

Farklı Sulama Suyu Tuzluluk Seviyelerinin Bazı Silajlık Sorgum (Sorgum sp.) Çeşitleri Üzerine Etkileri

“…Bu anlamda hayvan besleme ve endüstri alanındaki öneminin her geçen gün artması, yüksek verimli ve daha kaliteli melez çeşitlerin geliştirilmesi ve adaptasyon sınırlarının genişliği nedeniyle diğer ülkelerde önem kazanmaya başlayan sorgumlar bu noktada yazlık olarak yetiştirilebilecek diğer bir kaba yem kaynağı olarak ön plana çıkmaktadır. Birçok serin ve ılık mevsim yem bitkilerinin yüksek sıcaklıklar ve yetersiz yağışlar nedeniyle dormant olduğu ve sararıp kuruduğu yaz aylarında kaliteli ve besleme değeri yüksek yemler üretmektedirler (Fribourg et al, 1976). Sorgum x sudan otu melezleri hayvancılığı gelişmiş ülkelerde süt sığırı işletmelerinin en önde gelen yem bitkilerinden biridir (Skerman and Riveros, 1990;Sağlamtimur ve ark, 1998).…”

Interactions between Forage Sorghum Cultivars and Defoliation Managements1

“…Harvests at early stages of growth would have penalized Super..chowmaker 235 in compari• son to Sweet Sioux III, and the reverse would have oc• curred if later stage~ of growth had been used to de• termine harve~t time. ----------------S ORGHUM-SUDANGRASS hybrids (Sorghum bicolor (L.) Moench) have the capability of producing high quality forage in mid to late summer when cool-season perennials have low production (4,6). Dairy and some beef operations can benefit from the relatively higher crude protein (CP) yields and dry matter digestibility of these grasses, under some managements, compared with perennial forages in summer.…”