A soil's inherent erodibility, which is a major factor in erosion prediction and land‐use planning, is a complex property dependent both on its infiltration capacity and on its capacity to resist detachment and transport by rainfall and runoff. The relations of these capacities to soil physical and chemical properties were investigated in a 5‐year field, laboratory, and statistical study including 55 selected Corn Belt soils. Properties that contributed significantly to soil‐loss variance included percentages of sand, silt, clay, and organic matter; pH, structure and bulk density of plow layer and subsoil; steepness and concavity or convexity of slope; pore space filled by air; residual effects of sod crops; aggregation; parent material; and various interactions of these variables. An empirical equation was derived for calculating the universal soil‐loss equation's erodibility factor K for specific soils. Tests of the equation against soils of the older erosion‐research stations, for which the erodibility factor is known, substantiated its general applicability over a broad range of medium‐textured soils.

Little information is available that evaluates long-term use of a range of tillage systems and different cropping sequences on poorly drained soils. This study relates corn (Zea mays L.) growth and yield to several reduced tillage systems used with continuous cropping and a corn-soybean (Glycine max L.) rotation. Experiments were conducted on Chalmers silty clay loam (fine-silty, mixed, mesic Typic Haplaquoll) with 40 g kg-• organic matter for 12 yr, and Clermont silt loam (fine-silty, mixed, mesic Typic Ochraqualf) with 10 g kg-• organic matter for 7 yr. Both soils are nearly level and poorly drained. Tillage systems compared included moldboard plowing, chisel plowing, ridge planting, and no-till planting. Shallow disking (10 em) was also included at the Clermont site. On the high organic matter Chalmers soil, continuous no-till corn was 25 em shorter at 8 wk, 2% wetter at harvest, and 9.2% lower in yield compared to plowing. Data for chisel and ridge systems were intermediate between plowing and no-till. No-till yields were consistently lower than those for plowing after the first 4 yr. When following soybean, no-till corn was 7 em shorter at 8 wk, 1% wetter at harvest, and 2.6% lower in yield than corn under moldboard plowing. Corn growth and yield from chisel and ridge treatments were equal to those with plowing when in rotation. On the low organic matter soil in continuous notill corn, plant growth and yields were reduced for the first 3 yr, but were equal or better, compared to plowed corn, for the final4 yr. In rotation, no-till corn was equal to plowed corn the first 3 yr and significantly better in 3 of the last 4 yr. Yields with intermediate tillage were similar to plowed yields for continuous and rotational cropping. The relative advantage for no-till planting with time on the low organic matter soil is attributed to improved soil physical properties.

In the mid‐1960‘s farmers were considering no‐plow tillage as a way to cut production costs and achieve more timely planting, and environmentalists were promoting conservation tillage as a primary means of cutting erosion losses. There was an obvious need for a more detailed evaluation of where no‐plow tillage methods were adapted in the Corn Belt. The objective of this research was to determine corn (Zea mays L.) production potential of tillage systems that varied in amount of residue cover and surface roughness on a range of soil types and in different climatic situations. Chisel, till, strip rotary, and strip coulter planting systems were compared with conventional and limited tillage on plowed ground from 1967 through 1970. Experiments were located on sandy loam and loam soils in northern Indiana, silt loam and silty clay loam in eastern Indiana, and on a high silt soil in southern Indiana. There was a latitude range of 290 km in experiment locations. Percent stand was 80% or higher with all systems on sandy loam and loam soils. Chisel and rotary on silt loam, and wheel track, chisel, till and rotary systems on silty clay loam produced 65 to 70% stands and were significantly below conventional at the 5% level. Soil temperature at 10 cm for the first 8 weeks after planting for coulter vs conventional planting was 3.8 C lower in northern Indiana and 2.7 C lower in southern Indiana. However, mean soil temperature for all systems was 3.7 C higher in southern Indiana. Systems with intermediate tillage had intermediate soil temperatures. Corn growth at 8 weeks after planting with no‐plow systems was delayed in northern and eastern Indiana, compared to conventional tillage, with strip rotary and coulter systems having slowest growth. Coulter and strip rotary systems produced fastest corn growth from 4 to 8 weeks after planting in southern Indiana. Four‐year mean grain yields show a 1000 kg/ha advantage for till planting, but no significant variation among other systems on sandy loam (northern Indiana). The yield increase for till planting may have been due to the ridging done at cultivating time. Other systems were not cultivated. At the same location on poorly drained dark loam, yields from strip rotary and coulter systems were significantly lower, at the 5% level, than grain yields from other systems. On poorly drained fine‐textured soils in eastern Indiana, mean yields for all no‐plow systems were lower than mean yields for plow systems, partly due to poor weed control. Four‐year mean yields on the rolling silt loam soil in southern Indiana were not significantly different, although differences among systems within each of the 4 years were significant at the 5% level. Results indicate that with good management, chisel, till, strip, rotary, and coulter systems are adequately adapted on the rolling high silt soils of southern Indiana and on well‐drained loam or sandy loam soils in central and northern Indiana. The no‐plow systems, as used in these tests, were not adapted on poorly drained, fine‐textured so...

The effects of six rates of applied wheat straw mulch on infiltration and erosion were studied on a highly permeable Wea silt loam with 5% slope. Series of simulated rainstorms totaling 6.25 inches at an intensity of 2.5 inches per hour were used to evaluate the treatments. Mulch applications of 1, 2, and 4 tons per acre maintained very high infiltration rates resulting in essentially no erosion. The %-and %-ton mulch application lost 3 tons and 1 ton of soil per acre, respectively, whereas the check (no mulch) treatment lost 12 tons per acre. Benefits which were indicated from the mulching were: (1) reduced soil surface sealing as evidenced by higher infiltration rates, and (2) decreased rainfall and runoff energy for particle detachment and transport as evidenced by reduced soil content in the runoff.

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