Mulch and Tillage Relationships in Corn Culture

Abstract Relative effects of soil mulch cover and various tillage practices on corn ( Zea mays L.) yield were studied as functions of previous crop and rainfall on a typic fragiudalf soil. Residues (mulch from previous crops of corn or tall fescue) were removed from the soil prior to tillage, manipulated according to action of the tillage implements, or replaced on the soil surface after tillage. Eight tillage treatments consisted of all possible combinations of moldboard plowing, disking, and post emergence cultivation. Mulch cover produced three times as great a yield effect as any other single variable, with the effect (kg/ha) = 36.2M − 0.00218 MS, where M is percent of the soil surface covered with mulch and S is yield in kg/ha of the plowed plus cultivated treatment. Tillage variables increased yield in order of cultivation > plow > disk, and results are expressed in terms of mulch cover required to produce an equal yield effect. Most tillage and mulch effects were additive. The major reason for mulch and tillage effects on corn yield is assumed to be their influence on soil water content. Possible extrapolation of these results to other soils and climates is discussed.