Elbert C. Dickey

Tillage, Residue and Erosion on Moderately Sloping Soils

ABSTRACT TILLAGE treatments leaving 20% or more of the soil surface covered with residue reduced soil erosion by at least 50% of that which occurred from a moldboard plow system. No-till had the least erosion and tended to have the lowest cumulative runoff. These results were based on rainfall simulation tests on six tillage treatments used on both 5 and 10% slopes in continuous corn production.

Soil Erosion from Tillage Systems Used in Soybean and Corn Residues

ABSTRACT RAINFALL simulation techniques were used to compare soil losses from various tillage systems used on plots where corn and soybeans had been grown the previous season. The two year study was conducted on a silty clay loam soil with a 5% slope and on a silt loam soil with a 10% slope. Five tillage treatments, ranging from a moldboard plow system to no-till, were evaluated for each residue at each site. Tillage and planting operations were conducted up-and-down hill on replicated plots. Total soil loss following 63.5 mm of rainfall applied during a 60 min period averaged more than 40% greater from the soybean residue plots than from the corn residue plots for equivalent tillage treatments on the 5% slope. For the 10% slope, the soil loss ranged from 50% to about 12 times greater for the soybean residue. Equivalent tillage treatments in soybean residue had about 40% less surface cover relative to corn residue, which contributed to the difference in soil erosion. Relationships between residue cover and soil loss showed that a 20% cover of either soybean or corn residue generally reduced soil loss by at least 50% of that which occurred from cleanly-tilled soils. Several tillage systems left more than a 20% cover in corn residue. Only no-till consistently left more than a 20% residue cover following soybeans..

Effects of Tillage on Soil Erosion in a Wheat-Fallow Rotation

ABSTRACT EROSION from alternative tillage systems in winter wheat-fallow rotations was measured using a rainfall simulator. The Nebraska study, conducted at the High Plains Agricultural Laboratory, showed that during the fallow period between harvest and tillage, soil erosion was not affected by the tillage systems studied. However, erosion following tillage was different for the systems evaluated and moldboard plowing with the slope had the largest amount. The no-till system reduced erosion by about 95% during this period. Although contour plowing was effective in reducing erosion when compared to plowing with the slope, no differences were measured between with the slope and contour tillage for the no-till or stubble-mulch treatments.

Yield Comparisons Between Continuous No-Till and Tillage Rotations

ABSTRACT CONTINUOUS use of no-till planting systems may result in reduced yields, especially on finer textured soils that tend to be poorly drained. Soil compaction and poor soil aeration have been identified as possible factors contributing to the lower yields. Research conducted to evaluate tillage rotations on these soils shows that periodic use of the moldboard plow can result in statistically higher yields as compared to continuous no-till. However, use of chisel plow and disk tillage systems following three years of continuous no-till did not result in yield increases. A relationship between cone penetrometer index and yield indicates a trend toward lower yield with higher index values with continuous no-till having the highest index.

Electronic Image Analysis of Crop Residue Cover on Soil

ABSTRACT CLASSIFICATION procedures for using both black-and-white and color imaging systems were developed and tested for determination of percent residue cover on the soil surface from video and slide images. A spectral analysis of the image components was used for determining applicable wavelengths and filters. Color imagery provided an acceptable replacement for manual visual procedures. Black-and-white imagery also worked when appropriate blocking filters were used.

Soil Erosion from Tillage and Planting SystemsUsed in Soybean Residue:Part II - Influences of Row Direction

A rainfall simulator was used to compare soil losses from various tillage and planting systems used in residue from soybeans which had been grown in both wide and narrow spaced rows the previous season. Upand-down hill tillage and planting treatments ranging from a double disk system to no-till planting were evaluated using replicated plots on a silt loam soil in the Nora Series having a 10% slope. Tillage and planting systems used in soybean residue from narrow spaced rows had soil erosion and soil erosion rates that were reduced by approximately SO% compared to the same systems used in residue from wide spaced soybeans. However, the reductions were significant only for the double disk tillage system. There was a trend for the start of runoff to be delayed and for residue cover, accumulated runoff, runoff rate, and sediment concentration to be reduced for tillage systems used in narrow row soybean residue compared to the same systems used in residue from wide spaced rows.

Tillage Factors Affecting Corn Seed Spacing

ABSTRACT AN on-farm survey was conducted in Nebraska to determine factors affecting corn seed spacing unifor-mity. Statistical analysis indicated that relative surface roughness, amount of residue present, amount of preplant tillage, and tillage system were important fac-tors affecting uiformity. Subsequently, replicated tillage plots at eight locations were used to evaluate seed spac-ing uniformity with different planters and tillage systems. Seed spacing coefficient of variation and a planter index developed showed conservation tillage does not significantly reduce seed spacing uniformity.

The Cost of Misapplication of Herbicides

A field survey of 103 private herbicide applicators was conducted during the spring of 1986 in 12 central and eastern Nebraska counties. The results showed that only 30% of the cooperators were applying herbicides within 5% of their intended application rate. Twenty-six percent of the cooperators over-applied herbicides during a single application, with an average cost due to misapplication of

Tillage Influences on Erosion During Furrow Irrigation

3.11/ha (

Tillage And Planting System, Stalk Chopper, And Knife Applicator Influences On Corn Residue Cover

1.26/a). If these values were extended over Nebraska,