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United States Department of Agriculture

Agricultural Research Service

2011 Annual Report

1a.Objectives (from AD-416)
Acquire new knowledge important for managing agricultural practices on spatially-variable soil landscapes and for assessing their impacts and sustainability. Develop and evaluate in-field sensing technologies and data interpretation methods for spatially- and temporally-variable soil properties important in assessing and managing soils and crops. Develop, implement at field scale, and assess innovative site-specific management systems for improved profitability and for water and soil quality.

1b.Approach (from AD-416)
In this project, our interdisciplinary team will address key limitations to the overall goal of developing sustainable, site-specific soil and crop management systems. We will investigate spatially-variable soil-plant water relationships on hydrologically complex soils and the use of soil and rhizosphere biological measurements for soil quality assessment. We will explore the use of commercial sensor technology to provide estimates of soil hydraulic properties and of soil quality indicator variables. Building on our previous research, we will combine multiple soil sensor technologies into integrated, on-the-go tools for efficiently mapping within-field soil variability. We will investigate and compare analysis techniques available for understanding relationships between soil and landscape properties and crop yield, and will develop site-specific estimators of productivity that can help assess production risk. Building on our decade of experience in measuring and understanding within-field spatial variability, we will assess the profitability and water and soil quality of site-specific management systems. Management system evaluations will include on-farm research with active participation by crop producers and crop advisors. Products of this research project will include soil quality indicators, sensors for measurement of multiple soil properties, and agricultural and conservation practices specifically designed to deal with landscape variability.

3.Progress Report
This is the final report for project 3622-12610-001-00D, which terminated in June 2011. Follow-on research continues under new project 3622-12610-002-00D. Substantial results were obtained over the five years of this project, including over 50 peer-reviewed publications. Increasing knowledge: Our research showed that conservation practices such as buffer strips and agroforestry practices can have a positive effect on soil quality. Methods developed for this assessment provide promising ways to assess soil quality effects of other management systems. We developed an improved understanding of how landscape position affects soil properties, including plant-available water, compaction, and water infiltration. Particularly significant was the finding that improvements due to perennial cropping systems were highest on eroded backslope areas where crop productivity was lowest. These findings led to new research on targeted perennial biofuel cropping systems in the new project. Developing technology and methodology: We evaluated two important soil sensing approaches – near-infrared (NIR) reflectance and electrical conductivity (EC) – for efficiently estimating important soil properties. We identified sensing ranges and calibration techniques and demonstrated that NIR sensing could quantify multiple soil properties across a range of soil types. We demonstrated that EC could provide reliable estimates of plant available water content and optimized EC-based methods to map topsoil depth across claypan soil landscapes. Based on these results, our new project will combine EC, NIR and other data in a sensor-based approach to soil quality mapping. We established new methodology that allows mapping of sensor-derived soil properties in three dimensions. This approach holds promise to develop digital, quantitative soil maps with higher information content than traditional maps. We compiled a database of over 120,000 acre-years of grain yield map data and developed models relating yield and yield risk to soil and landscape properties. Application of these models will allow evaluating production potential across regions, and may help determine where alternative crops (e.g., perennial biofuel crops) might be more profitable than grain crops. Evaluating management systems: From on-farm experiments conducted over several years, we determined that variable-rate corn nitrogen application based on crop canopy reflectance sensing could generate increased returns of $5 to 50 per acre, through increased yields and reduced nitrogen application. Because results strongly depend on the algorithm (or equations) used to convert sensor readings to application rate, research on developing and evaluating improved algorithms and approaches continues in the new project. We studied the economic and environmental effects of precision conservation on an 88-acre field, which included cover crops, targeted placement of crops on the landscape, and variable-rate nutrient application. Preliminary results showed improvement compared to the previous conventional management on this field, and water quality, soil quality, and crop production monitoring continue in the new project.

1. Improved soil quality under an integrated pecan-forage crop farming system. Soil quality in current agricultural systems must be managed to maximize crop productivity without adversely affecting the environment. Agroforestry, involving production of high-income tree crops, has potential for maintaining soils and the environment when intercropped with perennial forages; however, the soil quality benefits of this integrated system are not well known. ARS researchers at Columbia, Missouri assessed soil quality attributes in a pecan orchard intercropped with perennial kura clover at a farm in the Missouri River uplands in Chariton County, Missouri. Soil samples were collected during 2002-2009 from kura clover alley strips and rows of pecan trees established along the landscape contour, and from adjacent unmanaged grass and intensively tilled sites. Soil organic carbon and nitrogen (involved in multiple soil functions), aggregate stability (improves water infiltration and reduces erosion), and soil shear strength (index of resistance to erosion) increased in kura clover alleys. Microbial enzyme activities, representing soil biological processes, also greatly increased in kura clover soils by the third year after seeding. Our research demonstrates improvement in overall soil quality and soil conservation because tillage was avoided by establishing perennial clover within a pecan production system. This management system can be readily adapted to other agricultural landscapes with soils vulnerable to erosion and degradation related to tillage.

2. Mathematical models for high-resolution soil data. High-resolution soil physical and chemical property data are needed to develop an improved understanding of how variable soils affect plant growth, land-use sustainability, landscape hydrology, and water quality. Efficient collection of high-resolution data is facilitated by new and developing soil-profile sensors that generate many readings as they penetrate the soil to a depth of a few feet in just a few seconds. Data are generally collected with these sensors at a multiple locations within a study area. Collectively the information from multiple locations can be used to develop high-resolution maps of soil properties. In this research, ARS scientists at Columbia, Missouri used special mathematical functions called “peak functions” to model sensor-measured soil profile properties and to describe their variation in three dimensions. This procedure, along with innovative in-field soil sensing methods, offers those who manage soil systems a whole new way of mapping soils. High-resolution digital soil property maps developed from this approach could be used by farmers and consultants to guide management decisions, and by researchers as input data for agroecosystem models.

3. Soil compaction can be managed with poultry litter amendments. Soils in crop fields are often compacted from heavy farm machinery travelling over the field during planting, weed and pest control, and harvest operations. Compaction weakens soil structure causing poor water infiltration and aeration and reduced soil biological activity, which is critical for providing nutrients for plant growth and maintaining good soil structure. In cooperation with colleagues at the University of Missouri, ARS scientists at Columbia, Missouri evaluated the use of a readily available agricultural resource, poultry litter, as a soil amendment to minimize effects of compaction on soil structure and biological activity. Soil compaction created by pulling a 3.2-ton water wagon over the field greatly reduced soil microbial activity and functional diversity (ability to use a wide range of energy or food sources and release plant nutrients)and degraded soil structure (increased bulk density). However, addition of poultry litter offset the detrimental effects of compaction by providing readily available carbon that maintained microbial activity and diversity, and maintained a stable soil structure. Results suggest that poultry litter, which is applied to over 5 million acres in the U.S., is an effective soil amendment that can be used to maintain plant nutrient availability on compacted soils by providing good soil structure for microbial activity.

Review Publications
Chung, S., Jung, K., Sudduth, K.A. 2011. Estimation of Korean paddy field soil properties using optical reflectance. Journal of Biosystems Engineering. 36(1):33-40.

Bronson, K.F., Scharf, P.C., Kitchen, N.R. 2011. Use of GIS-based site-specific nitrogen management for improving energy efficiency. In: Clay, D.E., Shanahan, J.F., editors. GIS Applications in Agriculture, Volume Two, Nutrient Management for Energy Efficiency. Boca Raton, FL:CRC Press. p. 359-384.

Adamchuk, V.I., Viscarra Rossel, R.A., Sudduth, K.A., Schulze Lammers, P. 2011. Sensor fusion for precision agriculture. In: Thomas, C., editor. Sensor Fusion - Foundation and Applications. Croatia:In-Tech. p. 27-40.

Delgado, J.A., Secchi, S., Groffman, P., Nearing, M.A., Goddard, T., Reicocky, D., Lal, R., Salon, P., Kitchen, N.R., Rice, C., Towery, D. 2011. Conservation practices to mitigate and adapt to the effects of climate change. Journal of Soil and Water Conservation Society. 66(a):118A-129A.

Sudduth, K.A., Kitchen, N.R., Myers, D.B., Drummond, S.T. 2010. Estimating depth to argillic soil horizons using apparent electrical conductivity. Journal of Environmental & Engineering Geophysics. 15(3):135-146.

Pengthamkeerati, P., Motavalli, P.P., Kremer, R.J. 2011. Soil microbial activity and functional diversity changed by compaction, poultry litter and cropping in a claypan soil. Applied Soil Ecology. 48(1):71-80.

Zobiole, L.H., Oliveira, R.S., Kremer, R.J., Constantin, J., Bonato, C.M., Muniz, A.S. 2010. Water use efficiency and photosynthesis of glyphosate-resistant soybean as affected by glyphosate. Journal of Pesticide Biochemistry and Physiology. 97(3):182-193.

Zobiole, L.H., Bonini, E.A., Oliveira, R.S., Kremer, R.J., Ferrares-Fihlo, O. 2010. Glyphosate affects lignin content and amino acid composition in glyphosate-resistant soybean. Acta Physiologiae Plantarum. 32(5):831-837.

Kremer, R.J., Kussman, R.D. 2011. Soil quality in a pecan – Kura clover alley cropping system in the midwestern USA. Agroforestry Systems. 83(2):213-223.

Scharf, P.C., Shannon, D.K., Palm, H.L., Sudduth, K.A., Drummond, S.T., Kitchen, N.R., Mueller, L.J., Hubbard, V.C., Oliveira, L.F. 2011. Sensor-based nitrogen applications out-performed producer-chosen rates for corn in on-farm demonstrations. Agronomy Journal. 103(6):1683-1691.

Last Modified: 11/28/2015
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