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The research reported here provides data on the effects of crop residues on the surface of no-till soil upon the soil environment and resulting biological activity, including crop growth. For maize (Zea mays L.) and soya bean [Glycine max (L.) Merr.] production in eastern Nebraska, U.S.A. (4 years of data), increasing crop residue rate decreased maximum soil temperatures at the soil surface by at least 5°C, and generally increased soil water storage by at least 50 mm. Availability and uptake of nitrogen from the soil organic matter and applied fertilizers (and for soya bean from decomposition of crop residues) were increased by increasing the crop residue rate from 0 to 150% of the quantity left after grain harvest of the previous crop. Hardly any of the nitrogen in maize residues was used by the next crop. These changes in the soil environment resulted in less stress on crops produced on residue-covered soil than for those on bare soil. Consequently, each Mg ha-1 of crop residues on the soil surface increased grain and stover production by approximately 120 and 270 kg ha-1 for maize, and 90 and 300 kg ha-1 for soya bean, respectively. Results show that there are major direct crop growth benefits from leaving crop residues on the soil surface, in addition to cumulative benefits that may result from reduced erosion losses and enhanced soil organic-matter contents.