2007 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. 4.Accomplishments Soil biology is partly affected by genetically-modified (GM) soybeans. Soybeans genetically modified to resist Roundup herbicide are planted on over 90% of U.S. soybean acreage yet a full assessment of effects of GM soybean on soil biological processes has not been conducted. We determined the effects of GM soybean treated with Roundup on certain biological processes under variable soil moisture conditions. Most of the measurements including decomposition showed no effect of Roundup or GM soybean at any soil moisture; however, a specific fungal group, Fusarium, consistently infected roots of soybean receiving Roundup at all soil moistures at a higher incidence than with no Roundup. Results indicate that general biological measures such as decomposition could not detect effects of GM soybean but specific microbial groups (Fusarium) were more sensitive indicators of the effects. This information is important in helping understand the occasional production problems observed with GM soybean and in developing improved crop management for avoiding crop growth reductions when GM soybean is included in the production system. (NP:202, Component: Soil Biology, Problem Area 7: Managing Pesticides in Soil.) Cropping system and landscape position affect claypan soil hydraulic properties. Knowledge of the interactions between rainfall and the different soils found across a landscape and managed under contrasting cropping systems (with variables such as different rotations, different tillage practices, and grain crops vs. grass crops) is needed for understanding and modeling water movement in watersheds. We demonstrated that the depth of the claypan horizon in the soil profile was the main controlling factor for practically all sub-soil hydraulic properties. Cropping practices also affected soil hydraulic properties, but mostly in the top 4 inches of the soil and not equally at all landscape positions. Most importantly, this research showed that the greatest improvements in infiltration were achieved on backslope positions managed in permanent grass (such as with the Conservation Reserve Program (CRP)) or hay crops. The findings of this research show that landscape position and management practices interact, and both are important for characterizing hydraulic properties and developing targeted soil-water conservation practices. This understanding will benefit the general public because many watersheds in the U.S. Midwest empty into lakes and rivers used for drinking water and recreation and will benefit producers as new management systems are developed that embrace long-term crop sustainability goals. (NP:202, Component: Soil Water, Problem Area 2: Soil Management to Improve Soil Structure and Hydraulic Properties.) Electrochemical sensing of soil macronutrients. The conventional practice of soil sample collection and analysis is costly and time consuming when applied at the intensity needed in variable-rate fertilizer management systems, and a more efficient approach would be to sense soil macronutrient status as a machine moves across a field. We identified soil nitrate, phosphate, and potassium ion-selective electrode (ISE) sensors that, when used with the Kelowna multiple-element extracting solution, accurately quantified nutrient levels in laboratory solutions. With proper calibration procedures, the ISE sensors could also accurately measure the nitrate, phosphate, and potassium levels typical in agricultural soils. This combination of sensors and the associated extracting solution could be incorporated into an overall nutrient sensing system that would then be used to target fertilizer to sub-field areas where it would be beneficial, and to reduce fertilizer application in sub-field areas where nutrient levels are already sufficient. Such a system could provide lower food production costs and reduced environmental impacts, benefiting both producers and consumers. (NP:202, Component: Nutrient Management, Problem Area 4: Nutrient Management for Crop Production and Environmental Protection) 5.Significant Activities that Support Special Target Populations None. 6.Technology Transfer Number of active CRADAs and MTAs 2 Number of web sites managed 1 Number of non-peer reviewed presentations and proceedings 38 Number of newspaper articles and other presentations for non-science audiences 5 Review Publications Chung, S., Sudduth, K.A. 2006. Soil failure models for vertically operating and horizontally operating strength sensors. Transactions of the ASABE. 49(4):851-863. Hong, N., Scharf, P.C., Davis, J.G., Kitchen, N.R., Sudduth, K.A. 2007. Economically optimal nitrogen rate reduces soil residual nitrate. Journal of Environmental Quality. 36:354-362 Jang, G., Sudduth, K.A., Hong, S.Y., Kitchen, N.R., Palm, H.L. 2006. Relating hyperspectral image bands and vegetation indices to corn and soybean yield. Korean Journal of Remote Sensing. 22(3):183-197. Jiang, P., Anderson, S.H., Kitchen, N.R., Sadler, E.J., Sudduth, K.A. 2007. Landscape and conservation management effects on hydraulic properties on a claypan-soil toposequence. Soil Science Society of America Journal. 71:803-811. Jung, W., Kitchen, N.R., Anderson, S., Sadler, E.J. 2007. Crop management effects on water infiltration for claypan soils. Journal of Soil and Water Conservation. 62(1):55-63. Jung, W., Kitchen, N.R., Sudduth, K.A., Anderson, S.H. 2006. Spatial characteristics of claypan soil properties in an agricultural field. Soil Science Society of America Journal. 70(4):1387-1397. Jung, W., Kitchen, N.R., Sudduth, K.A. 2006. Relationship of soil profile strength and apparent soil electrical conductivity to crop yield. Korean Journal of Soil Science and Fertilizer. 32(2):109-115. Kim, H., Sudduth, K.A., Hummel, J.W. 2006. Sensing nitrate and potassium ions in soil extracts using ion-selective electrodes. Journal of Biosystems Engineering. 31(6):463-473. Kim, H., Hummel, J.W., Sudduth, K.A., Birrell, S.J. 2007. Evaluation of phosphate ion-selective membranes and cobalt-based electrodes for soil nutrient sensing. Transactions of the ASABE. 50(2):415-425. Kremer, R.J. 2007. Deleterious Rhizobacteria. In: Gnanamanickam, S., editor. Plant-Associated Bacteria. Bordrecht, The Netherlands: Kluwer Academic Publishers. p. 335-357. Martin, N., Bollero, G.A., Kitchen, N.R., Kravchenko, A.N., Sudduth, K.A., Wiebold, W.J., Bullock, D.G. 2006. Two classification methods for developing and interpreting productivity zones using site properties. Plant and Soil. 288(1-2):357-371. Mungai, N.W., Motavalli, P.P., Kremer, R.J. 2006. Soil organic carbon and nitrogen fractions in temperate alley cropping systems. Communications in Soil Science and Plant Analysis. 37:977-992. Patthra, P., Motavalli, P.P., Kremer, R.J., Anderson, S.H. 2007. Soil compaction and poultry litter effects on factors affecting nitrogen availability in a claypan soil. Soil & Tillage Research. 91(1):109-119. Scharf, P.C., Kitchen, N.R., Sudduth, K.A., Davis, J.G. 2006. Spatially variable corn yield level is a weak predictor of optimal nitrogen. Soil Science Society of America Journal. 70:2154-2160. Souza, E.G., Scharf, P.C., Sudduth, K.A., Hipple, J.D. 2006. Using a field radiometer to estimate instantaneous sky clearness. Brazilian Journal of Agricultural and Environmental Engineering. 10(2):369-373 Yildirim, S., Birrell, S.J., Hummel, J.W. 2006. Laboratory evaluation of an electro-pneumatic sampling method for real-time soil sensing. Transactions of the ASABE. 49(4):845-850. Means, N.E., Kremer, R.J. 2007. Influence of soil moisture on root colonization of glyphosate-treated soybean by fusarium species. Communications in Soil Science and Plant Analysis. 38:1713-1720.