The adoption of soil-conserving management systems in dryland soft white winter wheat (Triticurn aestivum L.) production areas is limited by concerns that seedbed residues contribute to suboptimal stand establishment. Field trials were seeded in 1990 (Trial 1) and 1991 (Trial 2) near Pendleton, OR, to ascertain seedbed crop residue, seed size, and cuitivar effects on emergence, early growth and development, and yield of soft white winter wheat. Seedbeds were much drier in Trial 2 than in Trial 1. Seed-soil contact was probably reduced in high residue cover, but emergence rate was reduced by seedbed residue in Trial 2 only when seed zone water content was <120 g kg-1. Consequently, plant growth and development were responsive to seedbed residues only in Trial 2. Final stand density and grain yield were not sensitive to seedbed residue level in either trial. Seed size had no effect on laboratory germination, but seedlings from large seed emerged more rapidly in the held. Plants grown from large seed were taller, heavier, and had more tillers than plants grown from small seed. Planting large seed had no effect on grain yield in Trial 1, but plants grown from large seed produced 4.2% greater grain yield than from small seed in Trial 2. Cultivar performance was determined by genetic potential, seed size, and seed quality, and was not differentially influenced by seedbed residue level. Emergence was influenced by coleoptile length which differed among cultivars, but coleoptile length was not related to seed size. Higher levels of seedbed surface residues required to reduce soil erosion in dryland crop production systems do not reduce stand estabfishment or yield of soft white winter wheat.

A rapid, efficient method for separating living wheat (Triticum aestivum L.) roots from dead roots in field soil samples is needed to understand the dynamic nature of wheat root development, because the proportion of living roots is highly variable and often may constitute less than 20% of the estimated length. A soil core, wrapped in a cloth “root bag” with a weave comparable to a 100‐mesh screen (0.149 mm opening) was suspended in a container of water from a wrist‐action shaker. Roots, organic residues, and sand remained in the bag, but fine sand, silt, and clay washed out. Roots and organic material were then decanted from the remaining sand. A 1% aqueous solution of congo red stained the living roots red; nonliving roots remained unstained or were stained a brownish pink. After flotation separation of the stained roots from debris, living root length was estimated. Newman's grid method was modified to measure root length with an accuracy of ±9% as determined with known lengths of string. With these combined techniques of separation, staining, and length measurement, we could determine rooting density with an accuracy of ±9%. When incubated at 15 C, severed living wheat roots could be stained for up to 1 week, but stainability dropped to less than 35% after 5 weeks. Most monocot roots stained more intensely than dicot roots, indicating that monocot‐dicot root separation from the same root medium may faciliate studies of root competition.

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Understanding how winter barley (Hordeum vulgare L.) seeds and seedling plants interact with crop residue in the seedbed is essential for development of planting recommendations for dryland conservation tillage systems. Field trials were conducted in 1990–1991 (Trial 1) and 1991–1992 (Trial 2) near Pendleton, OR, to determine the effects of seedbed crop residue, seed size, and cultivar on emergence, growth, and yield of winter barley. Seedbed residue cover (32–45%) did not affect seedling emergence rate in Trial 1. Seed‐soil contact was apparently reduced in high‐residue seedbeds, but emergence was reduced only when seed‐zone water content was <120 g kg−1 in Trial 2. More water was present in the seedbed at the time of seeding in Trial 1 than in Trial 2. Low‐residue seedbeds were drier than moderate‐ or high‐residue seedbeds at the time of seeding in both trials. Final stand density and subsequent plant growth were not influenced by seedbed residue (up to 49% residue) in either trial. Spike production was reduced by high residue and test weight was reduced by moderate and high residue in Trial 1. Grain yield and plumpness were lowest when barley was sown in low residue in Trial 2. Seedlings produced from large seeds emerged more rapidly and produced higher density stands than small seeds in Trial 1 but not Trial 2. Plants grown from large seed were somewhat larger in spring, but seed size had no other effect on growth or yield. Grain plumpness was greater in plants grown from large seed in Trial 1 but not Trial 2. No differences in stand establishment were detected among the cultivars tested. Higher seedbed residues should not be viewed as detrimental to achieving good winter barley performance in conservation tillage systems.