Corn (Zea mays L.) was grown on a loam soil on the same plots annually for a period of 6 years, comparing no tillage, tillage in alternate years, and conventional tillage. Equal annual applications of phosphate mixed in the tilled soil and applied to the surface of untilled soil resulted in more available phosphorus accumulation in the upper 5 cm of the untilled soil. The total amount of available phosphorus for the upper 20 cm of soil was greater in untilled soil despite the fact that available phosphorus was lower than in tilled soil in two of the 5‐cm increments below the surface layer. Potassium availability was not affected by tillage or method of application. Soil compaction after six years as based on bulk density showed no difference related to tillage. The maintenance of high yields of corn in successive years without tillage was shown. There was no benefit from tillage in alternate years as compared with no tillage. An average increase in corn grain yields and equal or better stover yields from no tillage as compared with conventional tillage was found. The need for more frequent liming with the no‐tillage method was demonstrated.

Winter cover crops for sod‐planted corn (Zea mays L.) were studied in 11 location‐year field experiments in Virginia during the 1962–1966 period. Conventionally tilled corn with cover crop turnplowed and sod‐planted corn were also compared. Rye (Secale cereale L.) was the most satisfactory because of superior winter hardiness, susceptibility to herbicidal killing, and the production of relatively large amounts of persistent mulch. Wheat (Triticum aestivum L.) and oats (Avena sativa L.) were comparable as mulches except at higher elevations where oats winterkilled. Barley (Hordeum vulgare L.) was the least satisfactory winter grain tested because of resistance to herbicides. Inclusion of crimson clover (Trifolium incarnatum L.) or hairy vetch (Vicia villosa Roth.) in winter grain seedings slightly increased mulch forage but not corn yields. In general, highest corn yields occurred where largest amounts of cover crop mulch occurred, except for Italian ryegrass (Lolium multiflorum Lam.). The additional mulch produced by late versus early killing of particular cover crops tended to increase corn yields, though not always significantly. Planting corn in rye stubble after removal of forage for hay or silage reduced corn yields an average of 47% in three of seven comparisons with rye left as mulch, while yields in the remaining four were comparable. Yields of sod‐planted corn in rye sod averaged 44% higher than conventionally tilled corn in 4 of 13 comparisons and were comparable in the remaining nine. More soil moisture was found under sod‐planted corn than under conventionally tilled corn, especially during the first half of the growing season. Corn yields were increased or at least maintained, in comparison to conventional tillage, by sod‐planting in rye over a wide range of soil and moisture conditions, with the added advantages of improved soil and water conservation.

Surface application of fertilizer for no‐tillage (Zea mays L.) corn is probably the most convenient method. The relative efficiency of fertilizer applied in this manner has been undetermined, however. Field experiments on three soil types in Virginia suggest that fertilizer efficiency for no‐tillage corn with surface application was higher than for conventionally tilled corn with an equal disked‐in application. No‐tillage resulted in a 9‐year average yield increase of 25.6% on Lodi silt loam, a 6‐year average increase of 13.7% on Davidson clay loam, and a 5‐year average increase of 39.0% on Cecil clay loam. In addition to increased yields, larger amounts of residual N, P, and K, as well as organic matter, were found in no‐tillage soil in several cases.

Corn (Zea mays L.) grown under the no‐tillage system was compared with that grown under (1) systems involving increased amounts of tillage for 2 years, and (2) conventional turnplow tillage over a 6‐year period. Plant growth and yield of corn generally increased with decreasing degrees of tillage in the 2‐year test. Yields from no tillage during the 6‐year period were comparable to or ranged from 18 to 39% above yields from conventional turnplow tillage. Soil moisture measurements indicated that the dead sod mulch provided by the no‐tillage procedure was highly effective in reducing evaporation and runoff from the soil surface.

Because the absence of tillage precludes the mixing of lime with soil when no‐tillage corn (Zea mays L.) is grown, an experiment was conducted to determine if surface application would be effective. Information on the subject is not presently available but is needed to guide growers in neutralizing soil acidity caused by high rates of nitrogen applied to corn. Field studies over an 8‐year period compared continuous no‐tillage corn with surface‐applied lime to continuous conventionally tilled corn with lime incorporated into the soil. Comparisons of the two tillage methods were also made without lime to determine the degree of response to lime. Lime increased corn yield more than twice as much in no‐tillage culture as in conventional tillage. Lime was essential for highest yields with both tillage methods but the yield increase due to surface applied lime in no‐tillage culture averaged 31.3%, compared to a 13.5% yield increase due to incorporated, lime in conventional tillage culture. Associated with the larger yield increase from lime in the no‐tillage culture were 1) a higher pH in the 0 to 10‐cm soil layer (averaging 6.4 in no‐tillage compared to 6.0 in conventional tillage) in the eighth year; and 2) larger increase in exchangeable Ca and a reduction in exchangeable AI in the 0 to 10‐cm layer. The pH and exchangeable Ca and AI in the 10 to 20‐cm soil layers from tilled and nontilled soil were almost identical. A highly significant correlation was found between maturity of the corn and yield increase due to lime. Thus, it appears probable that the principal mechanism for the yield reduction caused by the lack of lime was reduced growth. This was especially apparent in early growth stages but was partially overcome later. It was more noticeable in no‐tillage corn than in conventionally tilled corn. At harvest, the increase in dry matter content of no‐tillage corn ears which was caused by lime was larger than that in conventionally tilled corn. Water use efficiency for the increased corn grain yield due to lime in no‐tillage was calculated to be almost three times that in conventional tillage.