Proceedings
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1. Spacial Variability of Soil Test Phosphorus in a Northern Corn Belt FieldFor some time, an increasing number of fertilizer dealers, crop consultants, and farmers have reported substantial year-to- year variability in soil test values for phosphorus (P) and potassium (K). Frequently, this variation could be explained by such factors as extremes in soil moisture content at the time of sample collection. In many situations, however, this variation was due to the fact that soil samples were not collected from the same location in the field in two consecutive years. The introduction... |
2. Estimating Second- and Third Year Nitrogen Availability from Dairy manure: It is common practice to repeatedly apply dairy manure to the same fields. To accurately assess the total plant availability of rnanure nutrients, it is necessary to account for the nutrients remaining in soil fiom previous years applications. A corn (Zea mays) field experiment has continued since 1998 on a Plano silt loam. Residual manure N availability was estimated for two and three years after a single rnanure application fiom differences in whole-plant N uptake using 1) fertilizer N equivalence... |
3. Relationship Between Soil P and P in Surface Runoff and Subsurface Drainage- An Overview of Ongoing ResearchNonpoint source pollution fiom agricultural fields has the potential to accelerate eutrophication of fieshwater ecosystems. In a report of water quality in the United States, the Environmental Protection Agency sited agriculture as the primary source of pollution in 60% of impaired river miles, 30% of the impaired lake acres and 15% of estuarine square miles @PA, 1998). Phosphorus, in particular, has received much attention due to its role as limiting nutrient in many fieshwater ecosystems (Correll,... |
4. Arbuscular Mycorrhizal Dynamics Throughout Corn Growing SeasonPhosphorous is an essential plant nutrient and is the second most common fertilizer nutrient applied in crop production. The role of mycorrhizal fungi in phosphorous (P) nutrition of corn (Zea mays L.) in high fertility soils in unclear. A study was conducted to determine the effect of extractable P on myco~hizal biomass and to evaluate the temporal dynamics of mycorrhizal fungi during the growing season in two irrigated corn fields in Nebraska. The objectives were addressed by the installation of... |
5. Skip-Row Configuration and Plant Density Effects on Sorghum Grain Yield and Yield Component in Southern NebraskaEqual spacing of sorghum rows typically results in the highest grain yield when soil water is adequate throughout the season, but skip-row plan ting may be a means to reduce water deficits during reproductive growth stages. We evaluated the effect of skip-row planting configuration and plant population density on grain yield, yield components and water use efficiency at five locations in a transect across southern Nebras ka where annual mean precipitation ranges from 300 to 900 mm yr -1. Three row... |
6. Residue Harvest Effect on Irrigated, No-till Corn Yield and Nitrogen ResponseImmobilization of applied N is expected when much high C:N crop residue remains in the field as is typical following corn grain harvest. Immobilization of N is expected to be less if crop residue is less. The effect of reduced immobilization on N availability may more than compensate for N removed in residue harvest. Therefore, applied N requirement for a following corn crop may be less if crop residue is reduced through harvest. Residue removal decreased the economically optimal N rate (EONR) by... |
7. 4R Phosphorus Management for Soybeans in the Northern Frontier: Rate and Placement Effects on Plant Stand, Biomass and Seed YieldVery little research has been conducted to determine the best rate, source, placement, and timing of P fertilizer for modern soybean cultivars grown in the Canadian Prairies. Preliminary results of the two years of field studies at 10 locations in Manitoba showed that typical agronomic rates of seed row P did not decrease plant stand and seed yield at any sites; nor was seed yield increased at any site, even with Olsen P concentrations as low as 3 ppm.... |
8. Irigated Soybean Response to Nitroen Applied During Early Pod FormationHigh yield soybean ( Glycine max L.) has a high rate of N uptake during grain fill with maybe 2/3 of the N derived from the atmosphere. The rema ining needs to come from the soil. Previous research has found that the probability of response to N applied at early pod development (R3) for yield trials, including 44 with mean yield >60 bu/A, we re conducted in Nebraska to determine effect on soybean yield of applying N and S to the soil at R3. With 27 lb/A N applied and >60 bu/A yield, mean yield increases... |
9. Corn Residue Harvesting Effects on Yield Response to N FertilizationProducers have many choices of diverse tillage practices for their corn (Zea mays L.) production systems. However, no-till has become an important soil management practice to help reduce water and wind erosion, as well as nutrient runoff, while conserving soil moisture for crop use. No-till systems also help farmers by saving labor and time, as well as reducing farm costs due to less equipment and fuel consumption. Nevertheless, no-till production is typically more successful and has higher crop... |
10. Foliar Fertilizer and Pyracolstrobin Fungicide Combinations for CornIncorporating a foliar applied fert ilizer with fungicide application could reduce application costs, improve disease suppression, increase nutrient re sponse, and enhance the management of crop response to environmental conditions within th e growing season. A two-year field trial was initiated in 2008 at three sites in northeast, southeast and northwest Mi ssouri. Treatments consisted of a factorial arrangement of 13 diffe rent commercially-available foliar fertilizers containing both macro- and... |
11. Impact of Phosphorus and Potassium Fertilization on Corn and Soybean Productivity and Soil Nutrient LevelsA common production practice in the Eastern Corn Belt is to supply enough phosphorus (P) and potassium (K) in the fall prior to corn planting to satisfy the nutrient needs of both corn and soybeans in a rotation. This practice is most likely a viavle option for fields with more than adequate soil nutrient levels, but on marginal fields this practice may be limiting production (specifically with regard to K). Two field experiements were estabished to evauate the impact of P and K fertilization... K.A. Dietrick, R.W. Mullen, C.E. Dygert |
12. Integrating Management Zones and Canopy Sensing for Improved Nitrogen Recommendation AlgorithmsActive crop canopy sensors have been studied as a tool to direct spatially variable nitrogen (N) fertilizer applications in maize, with the goal of increasing the synchrony between N supply and crop demand and thus improving N use efficiency (NUE). However, N recommendation algorithms have often proven inaccurate in certain subfield regions due to local spatial variability. Modifying these algorithms by integrating soil-based management zones (MZ) may improve their accuracy... J. Crowther, J. Parrish, R. Ferguson, J. Luck, K. Glewen, T. Shaver, D. Krull, L. Thompson, N. Mueller, B. Krienke, T. Mieno, T. Ingram |
13. Comparison of Ground-Based Active Crop Canopy Sensor and Aerial Passive Crop Canopy Sensor for In-Season Nitrogen ManagementCrop canopy sensors represent one tool available to help calculate a reactive in-season nitrogen (N) application rate in corn. When utilizing such systems, corn growers must decide between using active versus passive crop canopy sensors. The objectives of this study was to 1) determine the correlation between N management by remote sensing using a passive sensor and N management using proximal sensing with an active sensors. Treatments were arranged as field length strips in a randomized complete... J. Parrish, R. Ferguson, J. Luck, K. Glewen, L. Thompson, B. Krienke, N. Mueller, T. Ingram, D. Krull, J. Crowther, T. Shaver, T. Mieno |
14. Topsoil Thickness Effects on Phosphorus and Potassium Dynamics on Claypan SoilsDue to variable depth to claypan (DTC) across landscapes, nutrient supply from subsoils, and crop removal, precise P and K fertilizer management on claypan soil fields can be difficult. Therefore, a study was performed to determine if DTC derived from soil apparent electrical conductivity (ECa) could be used to improve P and K management for corn (Zea mays L.) and soybean (Glycine max [L.]). Research was conducted on a claypan soil at the University of Missouri’s... L. Conway, M. Yost, N. Kitchen, N. Kitchen, K. Sudduth |
15. Respiration as a Measure of Soil Health: Challenges and OpportunitiesIn recent years, respiration has become a commonly-used soil health metric. It has been used as a standalone predictor of soil N supplying capacity and in conjunction with other metrics to assess overall soil health. However, the sources of variation underlying respiration itself have not been thoroughly assessed. We show that across growing regions in California, respiration was unable to accurately predict soil N supply. The R2 values were much higher in fields that had received a recently-incorporated... J. Wade, S. Culman, T. Hurriso, W. Horwath, R. Miller |
16. Corn Response to Phosphorus Fertilization and Evaluation of Soil Test Methods in Kansas SoilsPhosphorus is a critical nutrient in corn (Zea mays L.) production, and limitation in P availability can result in significant yield reduction. The objective of this study was to evaluate corn response to phosphorus fertilization and evaluate multiple soil test methods in Kansas soils. The study was conducted in 13 locations across Kansas during 2021. Fertilizer treatment consisted of five rates of phosphorus (P) fertilizer (0, 30, 60, 90, and 120 lbs. P2O5 acre–1), using mono-ammonium... G. Roa , D. Ruiz diaz |
17. Evaluation of Plant Tissue Analysis to Assess Phosphorus Nutritional Status in Corn and SoybeanPlant phosphorus (P) tissue analysis can be used to identify the nutritional status and potential response to P fertilization. This study aimed to determine critical P tissue concentration at different growing stages for corn and soybean. The experiment was conducted across multiple corn and soybean locations in Kansas. Tissue samples were collected as whole plant V6 stage and ear leaf R1 stage in corn, whole plant V4 stage, and trifoliate R3 for soybean. Plant tissue samples were dried, ground,... G. Roa, D. Ruiz diaz, B. Rutter |
18. Assessing Sulfur Response, Utilization Efficiency, and Diagnostic Tools for Corn in KansasEfficient sulfur (S) utilization is crucial for crops' productivity and the sustainability of agricultural systems. This study aims to evaluate the effect of sulfur application on corn production across various Kansas sites and determine how sulfur fertilization affects different growth parameters and diagnostic tools for corn. The study was conducted over the 2021-2022 growing seasons, with a comprehensive field experiment carried out across 26 sites in Kansas. A randomized complete block... G. Roa , D. Ruiz diaz |
19. Developing a Sustainable Sufficiency ParadigmSustainable conservation practices must align agronomic productivity and environmental protection goals to facilitate widespread and consistent adoption on-farm. Agricultural phosphorus (P) management is a critical control point for detrimental environmental consequences of P loss in surface runoff from agricultural fields. Reduced P fertilizer inputs are recognized as an effective and necessary control measure to limit P loss; however, current P fertilizer recommendation systems do not support... M.A. Bourns, N.O. Nelson, D. Ruiz diaz, G. Roa |