The number of headed tillers is an important yield component in cereal grain production. Studies are needed to assess effects of environmental stress and genetic factors on tiller production and abortion in the field. The system for quantifying cereal leaf and tiller development described in this paper permits such studies to be done more definitively than was previously possible because each leaf and tiller on the plant is given a unique designation. The system developed on wheat [Triticum aestivum (L.) em. Thell.] is suitable for other cereals. Leaves are numbered acropetally, with the first foliar leaf being L1 and the coleoptile L0. Tillers are named for the leaf with which they are associated, e.g., T1 and TO. Subtillers have two digit designations, and third order tillers have three digit designations. Culm development is described by counting the number of fully expanded leaves and the fraction of the length the newest developing leaf measures relative to its predecessor. A stem with 6.2 leaves has six fully developed leaves and a seventh leaf one‐fifth as long as the sixth. The developmental time or phyllochron for each leaf on the plant is the same in any given environment, and leaves and tillers unfold in a set and orderly pattern. The rate of this unfolding is primarily determined by environment. Stress causes tillers to be omitted or delayed, compared to unstressed plants.

Better characterizations of cereal root systems are needed for water extraction models, for relating root and shoot development, and for describing the root systems of individual tillers. This paper presents a naming system for root axes of wheat (Triticum aestivum L. em. Theil). Each axis is described by the number of the node with which it is associated and by the direction of its growth with respect to the leaf borne at the node. Plants were grown in the field on a Walla Walla silt loam (coarse-silty, mixed, mesic family of Typic Haploxerolls). Examination of the upper 10 em of roots indicated that root axes were produced at predictable times with respect to shoot development. The number of roots on any culm (Y) could be calculated from the number of leaves on the culm (X) (Y = 1.95 X -3.06, r 1 = 0.9). The presence of lateral roots could be predicted if data were plotted to relate root axis development to a phyllochron or degreeday scale.

Seed reserves are essential for germination of cereals including wheat, but the contributions of the endosperm and its associated aleurone layer to postgermination seedling development remain to be elucidated. Winter wheat (Triticum aestivum L. em Thell. ‘Stephens’) was grown for 36 d in a controlled environment from kernels of three sizes, and from kernels where part of the endosperm had been excised prior to sowing to study the contributions of seed reserves to seedling development. Excision of endosperm delayed the first two phyllochrons, prevented outgrowth of the coleoptilar tiller, and slightly delayed the appearance of the next two tillers. Plant dry weight, leaf numbers and dimensions, number of nodal roots, and total number of tillers were all affected by endosperm excision. The combined area of the first two leaves was linearly correlated with aleurone area for all seed treatments. Areas of later‐formed leaves and final dry weight of seedlings were directly related to the areas of the first two leaves. Thus, the aleurone layer, in addition to seed reserves, is important for the enlargement of the first two leaves, with subsequent seedling development controlled by the size of the first two leaves under the conditions used in this study.

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Long‐term field experiments (LTE) are ideal for predicting the influence of agricultural management on soil organic carbon (SOC) dynamics and examining biofuel crop residue removal policy questions. Our objectives were (i) to simulate SOC dynamics in LTE soils under various climates, crop rotations, fertilizer or organic amendments, and crop residue managements using the CQESTR model and (ii) to predict the potential of no‐tillage (NT) management to maintain SOC stocks while removing crop residue. Classical LTEs at Champaign, IL (1876), Columbia, MO (1888), Lethbridge, AB (1911), Breton, AB (1930), and Pendleton, OR (1931) were selected for their documented history of management practice and periodic soil organic matter (SOM) measurements. Management practices ranged from monoculture to 2‐ or 3‐yr crop rotations, manure, no fertilizer or fertilizer additions, and crop residue returned, burned, or harvested. Measured and CQESTR predicted SOC stocks under diverse agronomic practices, mean annual temperature (2.1–19°C), precipitation (402–973 mm), and SOC (5.89−33.58 g SOC kg−1) at the LTE sites were significantly related (r2 = 0.94, n = 186, P < 0.0001) with a slope not significantly different than 1. The simulation results indicated that the quantities of crop residue that can be sustainably harvested without jeopardizing SOC stocks were influenced by initial SOC stocks, crop rotation intensity, tillage practices, crop yield, and climate. Manure or a cover crop/intensified crop rotation under NT are options to mitigate loss of crop residue C, as using fertilizer alone is insufficient to overcome residue removal impact on SOC stocks.