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1. In-Season Soil Nitrogen as a Predictor of Corn Grain YieldCorn (Zea mays L.) grain yield is closely linked to plant available soil nitrogen (N). Our objectives were to (i) examine the influence of N rate, source, and time of application on N use efficiency with relation to grain yield and total plant N uptake, and (ii) evaluate in-season soil N testing as a tool to determine N rate needs and predict grain yield. During the 2014-2015 growing seasons, 12 fields across Minnesota varying in soil and climate conditions received 1) pre-plant urea (0 to 204... J. Spackman, F. Fernandez |
2. Comparison of Canopy Sensing Technologies for Corn Nitrogen Management in MinnesotaVarious crop canopy sensing tools are being used to manage nitrogen, but their utility to predict N needs in Minnesota remains unclear. The objectives of this study are to compare the effectiveness of different canopy sensing technologies at predicting corn (Zea mays L.) yield at different development stages, and compare their capability to determine in season N deficiency. Six to seven N rates at 35 to 45 kg N ha -1 increments were pre-plant applied in six fields throughout Minnesota and a rate... |
3. 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... |
4. Phosphorus and Water Quality Issues in Lake ErieWhat are harmful algae blooms? Harmful algal blooms (HABs) are so named because they can produce toxins (or poisons) that can cause illness or irritation sometimes even death in pets, livestock, and humans. The term algae is somewhat misleading since HABs are actually cyanobacteria, which are commonly referred to as blue-green algae, and are not true algae. These organisms act like many other plant and use photosynthesis to capture sunlight but unlike most plants and algae some can fix their own... |
5. Active Sensor Orientation Over Corn Rows and Effect on Assessment of BiomassOur long-tern mresearch goal is to develop practical N application systems that use on-the-go remote sensing as a nleans to assess crop N status and only apply N where needed at times when the crop can most efficiently utilize N. Our preliminaty testing of two active sensor systems has shoxl-11 considerable promise for rapid and accurate assessment of canopy N status and crop biomass. In this work, the effect of sensor positioning and orientation over the canopy and their effects on assessment of... |
6. Comparison of Nitrogen Recommendation Models for Corn in Two Cropping SystemsSeveral lnodels exist to generate N recommendations, and the model selected can have both economical and environmental implications. A study was initiated in 1998 to compare the response of corn to N in two ci-opping systenls (corn following corn and corn following soybeans). All plots received a starter N rate of 45 kg N ha-' (2 x 2 placement). and five rates of sidedress N (0, 22, 90, 157, and 224 kg N hi') were applied at gro~vth stage V6 either as anhydrous arnmonia or urea-ammonium rli trate... |
7. In Season RecommendationsWe are testing a prototype high-clearance tractor configured with active crop canopy sensors, drop nozzles with electronic valves, and a variable rate controller as means to deliver in-season variable rates of liquid N fertilizer based on crop needs as an alterative to preplant uniform applications of N. The active sensor we're evaluating is the model ACS-210 Crop Circle made by Holland Scientific. It generates it's own source of modulated light in the amber and near infrared (NIR) bands and then... |
8. Assessment Of Enhanced Efficiency Urea Products On Maize In MissouriUrea is the most commonly used N fertilizer worldwide, but can be easily lost to the environment through ammonia volatilization. Enhanced efficiency fertilizers (EEF) have been developed to help prevent these losses. Field studies were conducted from 2009 to 2011 on a Mexico silt loam (fine, smectitic, mesic, Vertic Epiaqualf) to determine the efficacy of five EEF urea products compare to untreated urea when surface applied to no-till maize (Zea mays L.). Treatments included untreated urea, Agrotain,... |
9. Crop Sensor-Based N Rates Out-Performed Producer-Chosen N RatesOptimal N fertilizer rate for corn (Zea mays L.) and other crops can vary substantially within and among fields. Current N management practices do not address this variability. Crop reflectance sensors offer the potential to diagnose crop N need and control N application rates at a fine spatial scale. Our objective was to evaluate the performance of sensor-based variable-rate N applications to corn, relative to constant N rates chosen by the producer. Fifty-five replicated on- farm demonstrations... |
10. 4R Nutrient Management for Corn Production on Upper Midwest SoilsCorn (Zea mays L.) demand for nitrogen (N) is often met using inorganic fertilizer on Upper Midwest soils. While applying the right rate of fertilizer N normally has the greatest impact on yield and N use efficiency (NUE), selection of the right fertilizer source, placement, and application timing can fine-tune rate recommendations, improve NUE by matching soil N availability to corn demand, and minimize loss to the environment. Given the diversity of corn production environments, the... J. Spackman, F. Fernandez, K. Fabrizzi |
11. Sidedressed swine manure slurry via dragline hose produces comparable corn grain yields as commercial fertilizersSpring in the upper Midwest can be short and often wet, providing challenges for producers to apply manure and plant crops in a timely manner to maximize yield. As a result, producers apply a significant amount of their manure in the fall after the crop is harvested. Fall applied manure has adequate time to mineralize and leave the root zone before next season’s crop can utilize the nutrients the following summer. These nutrients can end up in rivers and other freshwater bodies, decreasing... C. Pfarr, M. Wilson |
12. Stover Removal Effects on Continuous Corn Yield and Nitrogen Use Efficiency Under IrrigationCorn (Zea mays L.) residue or stover is harvested as supplemental feed for livestock and is a primary feedstock for cellulosic biofuels. Limited information is available on corn residue removal effects on grain yield under different nitrogen (N) fertilizer rates, irrigation rates and amelioration practices to minimize soil carbon loss and soil erosion. A study on a silt loam in south, central Nebraska (2011-2016) evaluated potential interactions between stover removal (residue removal,... M. Schmer, V. Jin, A. Sindelar, R. Ferguson, B. Wienhold |
13. Soil Nitrogen Management is Impacted by Soil Texture and WeatherNitrogen (N) is an important nutrient for corn production that is often supplied as inorganic fertilizer, but its use can also lead to environmental degradation. The 4R (right rate, source, time, and placement) approach has been suggested as a framework for N management to improve crop yield and nutrient use efficiency while minimizing environmental contamination. There is not a universal 4R best management strategy, nor should there be because many variables impact N... J. Spackman |
14. Carbon Credit and Sequestration in Agroecosystems; Lessons from Trials in Southern IllinoisA carbon (C) credit is the attribution of net CO2-C equivalent which can be used to decrease climate forcing through a given practice or farming system for a given unit time. Carbon credits allow industries to purchase C that is produced on a farm (i.e., offsets). Carbon can be captured in two ways; (i) by capturing and reducing greenhouse gasses (on a CO2-C equivalent basis), and/or (ii) by increasing soil organic C stocks. Therefore, to enable C credits in the agricultural... A. Sadeghpour, A.M. Weidhuner, G. Burkett, O. Zandvakili, O. Adeyemi, C. Kula, J. Berberich, J. Pike, A.J. Margenot |
15. Fertilizer Derived Nitrogen Dispersion in Minnesota Corn with Rye and Kura Clover Cover CropsWhile ideally all fertilizer nitrogen (N) is utilized by crops, much can be lost to the environment as nitrate (NO3), nitrous oxide (N2O), or ammonia (NH3). To enhance agronomic systems and mitigate environmental N dispersion, best management practices can be utilized. Here, urea was applied to continuous corn at 250 kg N/ha or a 0 kg N/ha control, and with select cover crops (no cover, winter rye, kura clover) to assess practices that may result in optimal fertilizer... J. Kastenbauer, F. Fernández, V. Sharma, R. Venterea, J. Spackman |