Soil Electrical Conductivity as a Crop Productivity Measure for Claypan Soils

Abstract

Inexpensive and accurate methods for spatially measuring soil properties are needed that enhance interpretation of yield maps and improve planning for site‐specific management. This study was conducted to investigate the relationship of apparent profile soil electrical conductivity (ECa) and grain yield on claypan soils (Udollic Ochraqualfs). Grain yield data were obtained by combine yield monitoring and ECa by a mobile, on‐the‐go electromagnetic (EM) induction meter. Investigations were made on four claypan fields between 1993 and 1997 for a total of 13 site‐years. Crops included five site‐years of corn (Zea mays L.), seven site‐years of soybean [Glycine max (L.) Merr.], and one site‐year of grain sorghum [Sorghum bicolor (L) Moench]. Transformed ECa (l/ECa was regressed to topsoil thickness giving r2 values > 0.75 for three of the four fields. The relationship between grain yield and ECa was examined for each site‐year in scatter plots. A boundary line using a log‐normal function was fit to the upper edge of data in the scatter plots. A significant relationship between grain yield and ECa (boundary lines with r2 > 0.25 in nine out of 13 site‐years) was apparent, but climate, crop type, and specific field information was needed to explain the shape of the potential yield by ECa interaction. Boundary line data of each site‐year fell into one of four condition categories: Condition 1–site‐years where yield increased with decreasing ECa; Condition 2–site‐years where yield decreased with decreasing ECa; Condition 3–where yield was less at low and high ECa, values and highest at some mid‐range values of ECa; and Condition 4–site‐years where yield variation was mostly unrelated to ECa. Soil ECa provided a measure of the within‐field soil differences associated with topsoil thickness, which for these claypan soils is a measure of root‐zone suitability for crop growth and yield. Research Question Grain yield mapping has demonstrated to farmers that much of the yield variability within fields seems to be associated with soil and landscape properties. A basic premise for a successful site‐specific management program is that the causes of grain variability can be identified and quantified, hopefully by using automated sensors or devices. An inexpensive and accurate method for spatially measuring soil properties that explain variability in grain crop production would greatly enhance the interpretation of yield maps and improve planning for site‐specific management. Apparent soil electrical conductivity (ECa) obtained using mobile on‐the‐go sensors has been suggested as one such measure. The objective of this research was to evaluate claypan ECa as a measure of the relative within‐field variability of grain crop production. Literature Summary Many procedures have been examined for measuring the effects of soil and landscape properties on crop production. Traditional soil surveys give a general understanding of the impact that soil mapping units have on crop productivity. Slope position and landform are topographic features t...

Apparent soil electrical conductivity mapping as an agricultural management tool in arid zone soils

“…Other soil properties that have also been successfully mapped using EC a data include clay content (Williams and Hoey, 1987), depth to clay layers (Doolittle et al, 1994), and moisture content (Sheets and Hendrickx, 1995;Kachanoski et al, 1988). Additionally, yield potential has been shown to be directly related to EC a data in many applications (Jaynes et al, 1993;Sudduth et al, 1995;Kitchen et al, 1999;Johnson et al, 2003).…”

Impact of rhizome quality on Miscanthus establishment in claypan soil landscapes

“…The DTC was measured on each soil sample as the depth from the surface to the beginning of the argillic horizon. The soil EC a at these sample locations was linearly correlated to the measured DTC to develop a calibration equation to convert all soil EC a values to DTC, similar to procedures outlined in Kitchen et al (1999) and Sudduth et al (2010).…”

“…The three large plots used in this study were each 18 m wide × 189 m long (0.34 ha) and were oriented on a west-facing slope so that each plot contained one replication of three nonrandomized landscape position treatments of a typical claypan soil landscape. The three landscape position treatments in each plot were summit, backslope, and footslope as defined in 1991 by Kitchen et al (1999) using DTC mapping and soil EC a methods as previously described for the Columbia site.…”

“…In addition, they are environmentally vulnerable, being more subject to erosion and topsoil loss than other soils (Scrivner et al, 1985;Kitchen et al, 1999;USDA-NRCS, 2006). One U.S. Midwest soil especially vulnerable to degradation is the Major Land Resource Area 113 Central Claypan Area (USDA-NRCS, 2006).…”

“…Of these, three were funded by the USDA through the former Missouri Farmers Association Oil Biomass (Columbia, Missouri) in 2012 to assist growers in establishing over 5,000 ha of M. × giganteus in central and southwestern Missouri, and in northeastern Arkansas. Within these three BCAP project areas, M. × giganteus was planted following cropland, pasture, and conservation reserve program land on soils that had historically experienced notable degradation and diminished grain crop productivity (Scrivner et al, 1985;Kitchen et al, 1999;USDA-NRCS, 2006).…”