ForewordThe United States Department of Agriculture (USDA) and the United States Department of Energy (DOE) both place high importance on developing resources and conversion technologies for producing fuels, chemicals and power from biomass. The two departments are working together on several aspects of bioenergy. This report is the third to be produced from joint collaboration. This and other reports can be found at: http://www.eere.energy.gov/biomass/publications.html.The website for biomass feedstock research sponsored by the DOE's Office of Energy Efficiency and Renewable Energy Office of the Biomass Program (OBP) can be found at: http:// bioenergy.ornl.gov/. More general information about OBP's feedstock research program can be found at: http://www.eere.energy.gov/biomass/ biomass_feedstocks.html.The website for research and development sponsored by the USDA Forest Service can be found at: http://www.fs.fed.us/ research/.

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No‐till corn (Zea mays L.) yields in the central Corn Belt often are limited by slow soil warming caused by surface crop residues. A 3‐yr experiment with a split‐plot design was conducted near Ames, IA, to determine corn response to seed‐row residue removal. Whole‐plot treatments were a factorial combination of two tillage systems (no‐till and moldboard plow) and three residue types (corn, soybean [Glycine max (L.) Merr.], and fiberglass insulation). Residue was removed from bands of various widths (0, 8, 16, 32, and 76 cm) centered on the seed row for five split‐plot treatments. Corn seedlings reached 50% emergence 0.5 d earlier in plots with soybean residue than in those with corn residue. No‐till seedlings reached 50% emergence 0.8 d sooner and 50% tasseling 0.9 d sooner than in the mold‐board‐plow system. Residue removal from the seed row had greater effects on plant growth and yield than either tillage or residue type. Seed‐row residue removal reduced days to 50% emergence and tasseling, increased plant height, decreased grain moisture and barrenness, and increased yield. Removing residue from a 16‐cm wide band resulted in corn yields that were only 3% less than those from bare soil. Plant responses to width of the residue‐free band were described by logarithmic functions. Seed‐row residue removal may allow a compromise between erosion protection and crop yield.

Research on growth responses of corn (Zea mays L.) to environmental conditions associated with conservation‐tillage systems has not been extensively conducted. Therefore, the objectives of this study were to evaluate effects of various tillage systems (fall moldboard plow, till‐plant, no‐till ridge with and without previous‐crop residue) and early planting on growth and productivity of several corn genotypes (including two heterogeneous breeding populations that were improved for cold tolerance by recurrent selection). The experiment was conducted for 2 years on a loam soil (Typic Hapludoll), and planting dates were 1 Apr. 1974, and 30 Apr. 1975. Conservation‐tillage systems were associated with lower midafternoon soil temperatures (at 5‐cm depth) during the early growing season and more variability in depth of seed placement. Also, seedling and juvenile plant growth, final plant densities, and grain yields were lower in conservation‐tillage systems. These differences were accentuated in the early planting environment of the 1974 experiment. With a relatively normal planting date and equal final plant densities (the not affected by tillage treatment. There was no interaction between tillage method and com genotype. Usually, genotypes with vigorous seedling and juvenile plant growth and high final plant stands produced highest grain yields in all tillage environments. In the central U.S. Corn Belt, therefore, optimum corn grain yields in conservation‐tillage environments will be obtained by the use of planters that assure uniform seed depth and genotypes that display vigorous plant growth and development.