Lee Burras

Iowa State University | ISU · Department of Agronomy

Quantifying maize root response to nitrogen (N) fertilizer, soil texture, and weather is crucial to understand complex soil-root-plant processes. We performed a 2-year x 4 locations (sand content range: 5-95%) x N treatments (range: 0 to 336 kg N ha − 1) field experiment in Iowa, U.S. to (1) determine the response of root traits to N fertilizer, an...

This study examines three soil classification systems - Buganda, World Reference Base, and US Soil Taxonomy - in order to evaluate their relative strengths and feasibility for making linkages between them. Nine field sites and 16 pedons were considered across the soil landscapes of the Buganda catena. Each identified field pedon diagnostic horizons...

Corn productivity indices (CSR2T) for representative soils in the Southern Highland Zone of Tanzania were developed. The approaches used were derived from Iowa State University’s CSR2. Consistent with ISU, index points were applied to the pedon based on the USDA Soil Taxonomy subgroup, family particle size class, and available water holding capacit...

Soil erosion and rainfall-induced runoff are well studied yet remain somewhat unpredictable from one natural rainfall to the next, due to interactions between erosion parameters. This study quantified the relationship between annual (2011 - 2016) and individual (2016) rain events with overland flow (runoff) and soil loss in China’s northern “corn-b...

The goal of this study was to understand better the co-play of intrinsic soil properties and extrinsic factors of climate and management in the estimation of saturated hydraulic conductivity (Ksat) in intensively managed landscapes. For this purpose, a physically-based, modeling framework was developed using hydro-pedotransfer functions (PTFs) and...

The catena model is used worldwide to predict soil distribution across hillslopes and is therefore central to soil mapping. However, we found that the soil distribution is hillslope-by-land use dependent, especially in areas of intensive cropping, tile drainage, fertilizers, tillage, and erosion. Soil pH, thickness of mollic colors, organic carbon,...

Afforestation trends were compared between two continentally-distinct, yet similar ecoregions to characterize similarities or differences in forest advancement due to natural and anthropogenic forcings. Temporal changes in forest cover were analyzed using high resolution aerial and satellite photographs for Southeast Iowa, USA, and satellite photog...

Management of soil salinity is an important research field around the globe, especially when associated with the limited water resources. This work aimed to improve the growth and yield of wheat (Triticum aestivum L. CV. Sakha-93) grown under salinity stress. A completely randomized design pot experiment with three replications was conducted in a l...

Management of soil salinity is an important research field around the globe, especially when associated with the limited water resources. This work aimed to improve the growth and yield of wheat (Triticum aestivum L. CV. Sakha-93) grown under salinity stress. A completely randomized design pot experiment with three replications was conducted in a l...

Roselle (Hibiscus sabdariffa L.) is an important tropical and subtropical crop, because of its multi uses in the medicinal purposes as well as food industries. A plot experiment was conducted in a Vertisol in Egypt over two sequential seasons (2013 and 2014) to assess the effect of silicon (Si) fertilization on roselle growth and yield. Specific gr...

Watershed and global-scale nitrogen (N) budgets indicate that the majority of the N surplus in anthropogenic landscapes does not reach the coastal oceans. While there is general consensus that this 'missing' N either exits the landscape via denitrification or is retained within watersheds as nitrate or organic N, the relative magnitudes of these po...

Farming under saline conditions is a must in many places of the world, especially Egypt where approximately one third of the arable land was classified as salt affected soils. The aim of this work was to investigate the effect of salinity on wheat (Triticum aestivum L. CV. Sakha-93) plants’ growth characteristics, biomass, grain yield, and nutrient...

Despite a large body of scientific research that shows that soils change on relatively short time scales under different management regimes, classical pedological theory states that we should expect these changes to occur only in the surface few centimeters and that they are not of adequate magnitude to suggest fundamental changes in pedon characte...

In this study, detailed field experiments were conducted at three hillslopes in southeast Iowa with different agricultural management practices, namely Conservation Reserve Program (CRP), no-till, and conventional till, to identify the effects of land use on saturated hydraulic conductivity, Ksat, variability. On average, 40 measurements per field...

Almost all the studies on clay movement have been focused on downward movement rather than upward except one study that focused on upward movement. Therefore, this study was conducted to assess the impact of different clay suspension concentrations on the upward movement of clay particles. In this experiment, 24 transparent glass tubes with dimensi...

The physiographic region of the Central Russian Upland, situated in the Central part of Eastern Europe, is characterized by very fertile grassland soils-Chernozems (Mollisols in the USDA taxonomy). However, over the last several centuries this region has experienced intense land-use conversion. The most widespread and significant land-use change is...

Previous studies have suggested researchers should use Soil Survey maps to create surficial geology maps where more spatial detail about surficial geology is needed than is available from maps already produced by geologists. Despite the widespread availability of relatively detailed soil maps in the United States, few areas have a surficial geology...

Shelterbelts that were created in place of meadow and meadow-steppe landscapes of the forest-steppe zone of northern continents serve as areas of carbon accumulation and participate in the formation of soil organic matter. In the Great Plains of the United States (in North Dakota, South Dakota, and Nebraska) and on the Central Russian Upland (Belgo...

The response of corn (Zea mays L.) grain yield (GY) to plant population or seeding rate is well studied. Population recommendations have been previously made by amassing numerous data points to find the optimum plant population. However, the response has not yet been linked with the corn suitability rating (CSR), a measure of soil productivity. We...

The objective of this project was to use detailed soil profile descriptions and soil carbon analyses to determine the soil C sequestration potential of tree planting across climatic gradients in the U.S. Great Plains. Tree windbreak age ranged from 19 to 70 years and age of cultivation from 22 to ~110 years. At each site, soil pits were prepared wi...

Argillic horizons are common in most of the 48 contiguous states of the United States. In Iowa, soils with argillic horizons cover 33.5% of the land area. Fifty-nine percent of the area in Iowa with argillic horizons is in Alfisols (Udalfs and Aqualfs). The remaining 41% is in Argiudolls, Argiaquolls, and Argialbolls. At the county level, the preva...

Recognizing variability in plant growth early can aid in identifying yield-limiting factors such as soil conditions, nutrient availability, and/or environmental limitations. Active sensors have been used to gather reflectance data from crop canopies and used to calculate Normalized Difference Vegetative Index (NDVI) which has been associated with p...

The evolution of automorphic cultivated soils of the Fayette series (the order of Alfisols)—close analogues of gray forest soils in the European part of Russia—was studied by the method of agrosoil chronosequences in the lower reaches of the Iowa River. It was found that the old-arable soils are characterized by an increase in the thickness of humu...

Suspended sediment in rivers, lakes, and streams has been identified as a problem for several reasons. Watershed-scale studies are often conducted to identify primary sediment sources utilizing scale-appropriate soil fingerprinting methods. However, fingerprinting has not been attempted in small-plot runoff experiments to better understand sediment...

Soil surveys are generally treated as static documents. Many soil survey users assume that pedon data generated 30 to 50 yr ago still represents today's soil, as short-term changes in soil properties are perceived to be limited to the soil surface and thus pedologically insignificant. In this study, we re-sampled and re-analyzed 82 pedons with hist...

Black Soils or Prairie Soils – make up about 916 million ha, which is 7% of the world's ice-free land surface. Their distribution strongly correlates with native prairie ecosystems, but is not limited to them. They are most prevalent in the mid-latitudes of North America, Eurasia, and South America. In North America, they cover 200 million ha of th...

Liu, X., Burras, C. L., Kravchenko, Y. S., Duran, A., Huffman, T., Morras, H., Studdert, G., Zhang, X., Cruse, R. M. and Yuan, X. 2012. Overview of Mollisols in the world: Distribution, land use and management. Can. J. Soil Sci. 92: 383�402. Mollisols � a.k.a., Black Soils or Prairie Soils � make up about 916 million ha, which is 7% of the world’s...

The goal of the United States Congress is to replace 30% of United States petroleum with biofuels by 2030. If this goal will be accomplished, it is estimated that 25–50% of the land enrolled in the Conservation Reserve Program (CRP) have its biomass removed. However, the purpose of many conservation practices enrolled in CRP is to improve or mainta...

We developed a highly detailed Quaternary geology map of the Des Moines Lobe, using readily available National Cooperative Soil Survey (NCSS) data. We then compared that map to Quaternary geology maps previously published by geologists for agreement and potential advantages for understanding subtle landform characteristics. The resulting map agrees...

In conventional polygon-based mapping in the United States, it is often found that concepts across geopolitical boundaries (i. e. counties and states) don't match; this mismatch may include both lines and named map units. Of course, soils in the field do not change at these political boundaries. These soil-to-soil mismatches are the result of the p...

Switchgrass (Panicum virgatum L.) is a potential biofuel crop in the midwestern United States. The objective of this experiment was to test the effect of nitrogen application on biomass dry matter yield and fiber and mineral concentrations in large field plots in Lucas and Wayne counties in southern Iowa. Two established switchgrass fields with a p...

The integration of soil survey maps with Geographic Information Systems (GIS) allows for an almost infi nite level of collaboration across disciplines that use information related to soil databases. The ability to link databases with geospatial delineations and to store unique information for individual delineations creates the opportunity for this...

The objective of this research was to describe how landscape position, grazing management, and scale affected overall plant species richness and species richness per functional group in temperate pastures located in the central United States. The effects and interactions of summit, backslope, and toeslope positions and continuous, rotational, and n...

The understanding, prediction, and modeling efficacy of soil organic carbon (SOC) distribution across fields and larger regions requires a large number of samples that are costly to analyze. The objective of this study was to evaluate soil color measurements to predict SOC for agriculture and prairie land uses. Munsell soil color book (B) and chrom...

Rural communities of sub-Saharan Africa are under increasing adaptive pressure resulting from decline in the quality of land resources. To increase food, generate income, and safeguard against risks and shocks, families are engaging in multiple livelihood strategies. This study was conducted to: 1) evaluate livelihood strategies; 2) examine the dyn...

Much of the land area in southern Iowa is used for perennial pastures that are dominated by cool-season grass species. These species are well adapted to the soils and climate and have become naturalized within the region. Biomass produced from these pastures might potentially be used as a feedstock for cofiring with coal to supplement supplies of d...

Accurate characterization of soil properties across a field can be difficult, especially when compounded with the diverse landscapes used for pastureland. Indirect methods of data collection have the advantage of being rapid, noninvasive, and dense; they may improve mapping accuracy of selected soil parameters. The objective of this study was to de...

The productivity of grasslands depends in part on their diversity of species and functional composition. Our objective was to examine the effects of three landscape positions (summit, backslope, and toe-slope) and three stocking systems (continuous, rotational, and non-grazed) on species diversity and percentage of cover of grass, legume, and weed...

Legumes establish and persist on backslope landscape positions but fail on summits and toeslopes in southeastern Iowa pastures, suggesting that these pastures be managed site specifically. Visual delineation of landscape positions, however, can be difficult, and char- acterization of spatial variability through soil sampling is expensive. Creation...

ing variable rate technologies. To accomplish this, quan- titative soil color parameter-SOC predictive equations The quantification of soil organic C (SOC) concentrations is be- will need to be developed, most likely for specific soil- coming increasingly more desirable because of environmental and economic concerns regarding the reactivity of SOC...

The inherent variability of pasturelands makes it difficult to sample soils and accurately characterize a pasture. Indirect methods such as soil electroconductivity (EC) can be used to rapidly, noninvasively, and inexpensively quantify soil variability. The objective of this study was to determine if rapidly collected, georeferenced soil informatio...

Renewable bioenergy could be supplied by high yielding grass crops, such as switchgrass (Panicum virgatum L.). Successful development of a bioenergy industry will depend on identifying cultivars with high yield potential and acceptable biofuel quality. The objective of this study was to evaluate 20 switchgrass populations in a field study planted i...

LOI (Nelson and Sommers, 1982; Combs and Nathan, 1998; Kimble et al., 2001). Dry combustion, measuring Samples of 255 noncalcareous A, Ap, and AB horizons from se- CO2 evolved from organic matter oxidized in a high lected major land resource areas (MLRA) in the north central USA were used to develop equations for predicting organic C content, as te...

We sought to establish soil carbon contents at the field level in the Chariton Valley with this study. Four land uses were of special interest: switchgrass fields, row cropped fields, woodlots, and pastures. The study was broken into two projects with one project focused primarily on switchgrass and the other on pastures. Field methods entailed tra...

Long-term urban tree growth is crucial because of the need for tree-derived benefits and high placement costs. This study was conducted in five U.S. midwestern states to examine how tree characteristics are related to community population level and land-use type. Age, height, diameter, and average growth rates for the last decade were measured on 3...

Based on this idea, greater legume richness and diversity may aid legume contributions to pasture swards used Pastures typically have diverse landscapes, and resulting soil condi- for animal production. tions and plant composition can vary within small area units. This study was performed to quantify the spatial variation in legume contri- Informat...

Several environmental factors influence tree growth at any site. The objective of this study was to examine the relationship between biotic and abiotic factors and tree growth rate (mean ring width averaged over the last 10 years) in settings ranging from urban to rural. Six “clusters”, each with five communities and two rural parks, were sampled i...

Students often encounter difficulties during the transition from high school to college, which, in turn, adversely affect stu-dent retention and success in college. In response, some college programs have developed learning communities as a means to fos-ter a greater sense of belonging, improve success among new freshmen, and reduce the cost of stu...

The objectives of this study were to identify the genesis of Kalsow Prairie Mirna mounds and to compare on-mound and off-mound soil properties. Kalsow Prairie is a 60 ha uncultivated prairie remnant in north-central Iowa. A 4 ha zone near the center of Kalsow Prairie containing 59 mounds was selected for detailed field study. Field methods included...

Expanding phyllosilicates have been identified in soils of western Ohio for >40 yr, yet little is known about the origin or properties of these clays. The objective of this study was to ascertain the origin of the smectite component of the expanding phyllosilicates from a representative Udalf-Aqualf-Aquoll toposequence derived from Peoria loess in...

Two minor moraine basins in Story County, Iowa, were examined to determine the extent and effect of postglacial erosion on the present landscape and stratigraphy. The data were used to calculate a gross annual rate of postglacial erosion. The basin with modern relief of 2.7 m had a 0.9 Ma ha -1 yr -1 erosion rate and the basin with modern relief of...

Soil organic carbon (SOC) content and soil quality are increasingly important factors in many policy decisions yet both remain elusive to spatially quantify. This study sought to quantify each by comparing three soil map units (SMU) from each of two soil series, Clarinda and Seymour. These SMU's represented different erosion classes. SMU's under a...

Abstract Soil organic carbon (SOC) content and soil quality are increasingly important factors in many policy decisions yet both remain elusive to spatially quantify. This study sought to quantify each by comparing three soil map units (SMU) from each of two soil series, Clarinda and Seymour. These SMU’s represented different erosion classes. SMU’s...