Proceedings
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1. Overview of Soil Fertility Research in Ontario, 1991The major areas of focus in soil fertility research at the Department of Land Resource Science, University of Guelph over the past year have concerned increased nuhent use efficiency and environmental impact. These studies have examined the development of nitrogen soil test for corn, nitrate movement to groundwater, the fate of manure N, the placement of phosphorus fertilizer and the role of VA mycorrhizae in plant phosphorus numtion. The following is a summary of the projects being conducted in... |
2. Reducing the Severity of Phyophthora Root Rot Damage in Soybeans with Selected Management OptionsPhytophthora root rot of soybeans (PRR) is a major concern for soybean growers in south-central and southeastern Minnesota, where it can be responsible for major yield reductions. In these regions, PRR is generally a serious problem when soybeans are grown on poorly drained soils and/or there is a moderate amount of rainfall within 2 to 3 days of planting. Previous research has shown that PRR causes a reduction in the number of harvestable plants per acre and this is the major contributing factor... |
3. In-Field Determination of Anhydrous Ammonia Applicator Accuracy in NebraskaLiquid and dry fertilizer applicators have been studied for their application patterns and precision. However, anhydrous ammonia (AA) applicators are generally considered less accurate. Due to the difficulty of calibration, actual application errors have not been documented. In order determine if AA applicators were delivering the intended application rate, a standard AA nurse tank was fitted with load cells, temperature, pressure, travel speed and travel distance sensors. Initial data from 55 farmer... |
4. Hybrid and Potash Effects on Root Growth in Ridge-till CornPotassium deficiency symptoms often appear in ridge-till and no-till corn even when soil test values for potassium are high. Certain hybrids are morc sensitive to the problem than others. Two techniques were used to assess root activity arid density in a three year experiment at the West Central Experiment Station, Morris, MN. We compared two tillage systems (fall chisel and ridge till). two hybrids (Pioneer 3732 and 3737) and three fertilizer treatments (control and 40 IbIA banded or broadcast K,O).... |
5. Nitrogen and Water ManagementIt is difficult to separate N and water management when developing improved management systems for irrigated corn production. This is because adequate supplies of both N and water are critical for crop growth, but excesses of either or both can threaten ground water quality. Several N and water management systems were established at the Nebraska Management Systems Evaluation Area (MSEA) project to evaluate the impact of improved irrigation and N fertilizer management practices on production and/or... |
6. Soil Phosphorus Chemistry- Agronomic and Environmental ApplicationsPhosphorus (P) has been a heavily researched topic in soil science for many years. For example, a search of the AGMCOLA database from 1970 to present turned up nearly 6000 citations under the key words soil and phosphorus. The fact that P is essential to all forms of life has promoted these research activities. as one would expect. In addition, the complexity of the soil P cycle has yet to be fully understood and appreciated by the scientific community. Further, while early research focused on correcting... |
7. Corn and Soybean Grain Yield and Concentration of Potassium in Plant Tissues and Soil as Affected by Potassium FertilizationResearch in the Midwest has shown that K fer tilization tends to increase plant K uptake by corn and soybean and the K concentration of vegeta tive tissues. Several studies found that K fertilization usually increases the K concentrati on of vegetative plant parts, often regardless of the soil-test K (STK) level a nd grain yield response (Malla rino et al., 1999; Borges and Mallarino, 2000; Yin and Vyn, 2002a, 2002b; Borg es and Mallarino, 2003; Yin and Vyn, 2003). It is well known that the K concentration... |
8. The Nitrogen Index as a Tool to Reduce Nitrogen Loss to the EnvironmentContinued population growth creates a need for increased productivity of agricultural systems around the world. Increased agricultural productivity will be needed to support a population that is anticipated to have an additional 2.5 billion people by the year 2050. Nitrogen was part of the 20th century�۪s green revolution. Nitrogen continues to be essential for the viability and sustainability of agricultural systems that are important for feeding the growing global population. It is well known... |
9. Soybean and Corn Yield Response to Fertilizar Placement and Tillage SystemNutrient availability and, consequently, yields can be strongly influenced by tillage system and fertilizer placement. Also, different genotypes and rooting systems can affect nutrient uptake and plant growth. The objective of this study was to evaluate fertilizer placement and tillage system effects on yields in soybean and corn with different varieties/hybrids. The experiment was established in two locations in Kansas and the experimental design was a randomized complete block with a split-plot.... |
10. Quantifying the Effects of Nutrient Management and Cover Crops on Soil Microbial Communities and Soybean ProductionAgricultural productivity relies upon microbial communities to cycle nutrients from soil to plant yet little information is available concerning how nutrient management and cover cropping practices influence microbial activity and crop production. Lack of consistent soybean (Glycine max L.) yield response to applied fertilizer has resulted in a need to further investigate management practices focused upon enhancing soil biological activity which in turn may feed the crop. A field study was initiated... |
11. Mitigating Phosphorus Movement from Agricultural FieldsAgriculture is often cited as the primary factor for the high P loads polluting Lake Erie and Ohio�۪s watersheds, but the contributions of agriculture as a system, a combination of tillage, best management practice (BMP) and fertilizer source rather than an industry is unknown. This study supplied either commercial fertilizer or poultry litter to tilled or no-till production systems with their corresponding BMPs of incorporation and cover crops, respectively, to determine the P lost via surface... |
12. 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 |
13. Cereal Rye Cover Crops Mitigate Soil Phosphorus Stratification from Long-term No-tillageMinimal or no-tillage is a widely adopted soil conservation practice and has been documented to reduce soil erosion, increase soil organic matter, and even reduce nutrient losses. Without tillage cultivation, however, phosphorus (P) can become stratified in surface soil layers and this may limit availability to crops or even increase bioavailable-P losses. Our primary objective was to measure the long-term (12-year) effects of long-term no-tillage (NT), cereal rye cover crops (CC), and their interaction... R.W. Barker, M.J. Helmers, M.D. Mcdaniel |
14. The Iowa Nitrogen InitiativeThe Iowa Nitrogen Initiative is a private-public partnership with a vision to provide Iowans with the best nitrogen science for the benefit of productivity, profitability, and environmental performance. We are working alongside agricultural service providers, farmers, and their advisors to design, execute, and interpret hundreds of coordinated on-farm, scientifically robust nitrogen rate trials every year. In 2024, we conducted more than 400 scientifically robust, fully replicated trials. Data... S. Archontoulis, M. Castellano, M. Miller, M. Baum, R. Osman |