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1. High Yield Wheat Management StudiesInterest in high yield wheat management (i.e. intensive wheat management) has increased in Kentucky during the last few years. This interest has been created because of the improved yield potential of newer soft red winter wheat varieties, high yields obtained in inten- sive wheat management research in other states, and the high yields being obtained in Europe with their intensive management inputs. In several of the European countries, average winter wheat yields of 70 bu/acre or higher are common... |
2. Ammonia Band Spacing Effects on Ammonium Persistence in the BandResults from four field experiments (1991 and 1992) showed that anhydrous ammonia (AA) concentration in the band increased NH4-N persistence in the Hord and Sharpsburg soils in 1992, but not in the Cass and Zook soils in 1991. In 1992, average half-life across both soils was increased from 14 days when applied in a 38 cm spacing to 66 days when applied in a 152 cm spacing (every other row) at the high application rate (224 kg N ha-'). A half-life of 66 days indicates 25% of the applied AA would be... |
3. Nitrogen Recommendations for Wheat using the Chlorophyll MeterThe use of a hand held chlorophyll meter showed good promise in helping to make N recommendations for wheat on a field basis. Using 5 site-years on well drained soils over a 2- year period, a correlation index (R2) of 0.88 was found relating the March (Feekes 5) N needed for optimum yield with a differential chlorophyll reading. Research on this method will be continued and expanded to field trials. Soils in less than a well drained class may require a separate calibration or the method may not be... |
4. Effect of N Fertilization on Accumulation and Release of Readily-Mineralized Organic NIncreased nitrogen (N) fertilizer use has generated concern about groundwater contamination by nitrate (NO,?. The objective of this work was to determine how previous N management and cropping system affect fertilizer N use efficiency. Research plots from a long-term N rate study on a silt loam soil were used to evaluate the impact of long term N rates on immobilization and mineralization of fertilizer N. Labeled '5~~,15~~, was applied at rates of 0, 60, 120, 180, and 240 lblacre to subplots of the... |
5. Effect of Rotation on Corn Yield and Economic Returns Under Composted Manure or Fertilizer ManagementThe benefits of growing corn in rotation with other crops as opposed to continuous corn have been mentioned in numerous research and technical publications. The benefits of adding to the crop mix include improved soil structure (Raimbault and Vyn, 1991) and soil nutrient availability (Copeland and Crookston, 1992). especially from rotations that include legumes such as soybeans or legume cover crops. Other benefits include better weed (Bhowmik and Dow, 1982). insect (Benson, 1985) and disease control... |
6. Effect of Subsoil Tillage on Crops Grown in No-Till and Reduced Till ManagementsThree different subsoil tillage experiments were conducted in southern Illinois on soils with root-limiting claypans that restrict crop growth. In the first experiment conducted at the SIU Belleville Research Center, subsoiling to 16 inches depth was compared to no subsoiling in a field that had been in long term, continuous no-till corn production. After 4 years of study, only small corn and soybean yield increases have observed with the tillage (2.0 bu/ac for corn and 1.0 bu/ac for soybeans) .... |
7. Nitrogen Fertigation on SoybeansNutrient requirements for soybeans are greatest as seeds are developing during reproductive pod fill. This peak nutrient demand period physiologically coincides with decreased efficiencies in both symbiotic nitrogen (N) fixation and root efficiency (Brun, 1978). Large N applications during vegetative growth stages limit N fixation and fail to consistently increase grain yields (Fla~ery, 1986). However, smaller N applications during flowering and pod fill have been reported to augment plant N status... |
8. Effect of Time and Rate of N Application on N use Efficiency and Surface Water Contamination with NitratesNitrate levels in excess of the public health standard of 10 mg N/1 in public water supplies along - with concern about hypoxia in the Gulf of Mexico have drawn renewed interest to improving fertilizer N use efficiency. Prior research has indicated that some farmers may be unkaowingly contributing to these problems. The objectives of this research were to: determine the effect of rate and time of N application on nitrate-N concentrations in water from tile lines and to evaluate the effect of previous... |
9. Effect of Changing the Rotation Sequence in a Long Term Tillage and Fertility StudyA continuous experiment was conducted fiom 1970 to 1999 to determine the long term effects of fertilizer application and tillage practices on soil acidity, organic matter and nutrient changes, and crop responses. Four tillage treatments were evaluated: continuous conventional: alternate till (two years no-till: one year conventional); continuous chisel till; and continuous no-till. Five fertilizer treatments were also evaluated (Ib ac-' N-P205-K20): check, 0-0-0; 175-0-0 broadcast; 160-0-0 broadcast... |
10. The Illinois Nitrogen Soil TestNitrogen fertilizer recommendations for corn production are often estimated on the basis of a realistic yield goal, with adjustments to allow for N credits fiom other sources, such as legumes or manure. A yield-based recommendation may have merit on a long-term basis. but under- or over- fertilization is apt to occur in any given growing season since soil N availability is not taken into account. Insufficient application of N can have serious economic consequences for the farmer, whereas excessive... |
11. Update on the Illinois N TestEstimation of plant-available N is complicated enormously by the dynamic nature of soil N, owing largely to the effects of temperature and moisture supply on N-cycle processes. Numerous biological and chemical methods have been proposed as an index of soil N availability (Brernner, 1965; Keeney, 1982; Stanford, 1982; Bundy and Meisinger, 1994), but none has been adopted widely for soil testing. Biological methods are necessarily time-consuming because of the need for incubation, and the results represent... |
12. Relationship Between Response Indices Measured In-Season and at Harvest in Winter WheatCurrent methods for making nitrogen recommendations in winter wheat (Triticum aestivurn L.) do not adjust for in-season temporal variability of plant available non-fertilizer nitrogen (N) sources. The purpose of this study was to compare the use of different nitrogen response indices determined in-season @INDVI and RIPLANTHEIGkm) to the nitrogen response index measured at harvest (RIHARvEST). In addition, this study evaluated the use of the in-season response indices for determining topdress nitrogen... |
13. The Analysis of Nitrogen and Plant Population InteractionsNitrogen and plant population are significant factors for corn production. Accurate nitrogen fertilizer and seeding rate recommendations are essential for optimizing profitability for the fmer and minimizing nitrogen losses. Research and development of yield response curves provide important information that can be used to understand the relationships between these inputs (nitrogen fertilizer and corn seeds) and output (grain yield). Over the varying levels of inputs. yield response functions can... |
14. Corn Response to Anhydrous Ammonia rate, Timing, and Inhibitor use: A RevisitationField experiments were conducted from 2001 through 2003 at three southern Illinois locations to obtain more current data on the effects of anhydrous ammonia rates. application timing, and nitrapyrin (N-Serve) use on corn. Nitrogen rates of 0. 60, 120, and 180 lbs Nlac \\ere evaluated at three times of application (fall, spring pre-plant, and sidedress) with and without nitrapqrin. Corn yield results suggest that fall anhydrous ammonia application is inferior to spring application even if nitrapyrin... |
15. Field to Market: The Alliance for Sustainable AgricultureField To Market®: The Alliance for Sustainable Agriculture Field To Market® is a diverse alliance working to create opportunities across the agricultural supply chain for continuous improvements in productivity, environmental quality, and human well-being. The group provides collaborative leadership that is engaged in industry-wide dialogue, grounded in science, and open to the full range of technology choices.... |
16. Do Soil Nitrogen Tests Relate to Nitrogen Mineralization in First-year Corn Following Alfalfa?Corn (Zea mays L.) is the most frequent first-year crop grown following alfalfa (Medicago sativa L.) in the Upper Midwest. In the majority of cases, first-year corn does not respond to fertilizer N, but sometimes large amounts are needed to optimize yield. The pre-sidedress and Illinois soil N tests (PSNT and ISNT, respectively) are early-season tests used to predict corn yield response to fertilizer N. These tests measure specific fractions of soil N and define a critical concentration to separate... |
17. Minnesota Long-Term Phosphorus Management Trials: Phase I, The Build PeriodPhosphorus (P) fertilizer recommendations are usually made using one of two philosophies, Build and Maintain or Sufficiency. In recent years, the Sufficiency approach has been questioned because of concerns of reducing soil test levels and yield sustainability and whether it has the same yield potential as the Build and Maintain approach. Trials were initiated in 2010 at six locations across Minnesota to develop various soil test P Interpretation Classes in replicated experiments. The initial phase... |
18. A Smorgasbord of Preliminary Results from Field Trials in OntarioField scale trials may be established to support lo cal needs, but the results seldom reach a wider audience. This paper summarizes two recent fiel d studies by staff of the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) on fertilizer use in soybeans and corn. A study of starter fertilizer response in soybeans found that yield responses to fertilizer tended to be relatively small, and seldom large enough to cove r the cost of the added fertilizer. A second study of ammonia volatilization... |
19. Re-Evaluating Rate, Time, and Placement of Urea and Other Nitrogen Sources in MinnesotaUrea is increasingly an important nitrogen (N) source in Minnesota. Approximately 43% of our farmers use urea as their major N source. In the southwestern, south-central and west-central areas approximately 45% of the N is applied in the fall, 50% is applied in the spring, and 5% is applied at sidedress. While most of those that use urea as the major N source apply it in the spring, approximately 4% do the major application with urea in the fall and there are others that apply some of their N... F. Fernandez, K. Fabrizzi, J. Vetsch, D. Kaiser |
20. 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 |
21. Nitrogen Application, Biological N Fixation, and N UptakePrevious collaborative research in the Midwest has shown that there is likely little to no need of N for soybean, except under certain conditions (such as when low soil moisture limits N fixation, or when low initial soil nitrate-N limits overall N availability). However, none of the site-years used in this synthesis analysis were on sandy soils. Because sandy soils supply little nitrate-N, the potential impact of N on crop yield is greater in sandy environments than on silt loam soils. However,... A.M. Walters, M.D. Ruark, J.M. Gaska, C. Zegler, S.P. Conley |
22. Soil Phosphorus Fractions and Legacy after Long-term Fertilizer Placement in a Corn-Soybean RotationPhosphorus (P) fertilizer placement can affect plant P uptake during the growing season, however, the long-term interaction of placement and plant root P uptake can also affect soil P pools. The objective of this study was to evaluate the influence of long-term P fertilizer placement on soil P pools (labile, moderately labile and non-labile) and legacy soil P accumulation under a corn (Zea mays) -soybean (Glycine max (L.) Merr.) rotation. A field study was conducted for ten years from 2006-... M. Coelho, D. Ruiz diaz, G. Hettiarachchi, F. Hansel |
23. Phosphorus and Potassium Response In No-Till Corn and Soybean ProductionCurrent UWEX fertilizer recommendations and plant analysis interpretation guidelines were developed prior to the release of GMO corn. There is some concern amongst University soil fertility specialists and industry agronomists that corn and soybean response to P and K fertilizer applications may be different with modern corn hybrids and soybean varieties. In addition, in the UW recommendation system, an estimate of the amount of nutrients removed in the harvested portion of the crop is used to... C. Laboski, T. Andraski |
24. Corn uptake of soil- and fertilizer-derived nitrogen in response to rate and timing of fertilizer application.While nitrogen (N) fertilizer is essential for high-yielding corn (Zea mays L.) production, over-application or application of fertilizer N before rapid corn N uptake may result in N loss that negatively impacts the environment and reduces fertilizer use efficiency. To better understand how fertilizer rate and application timing impact corn grain yield and fertilizer recovery in the soil-corn system, six two-year field studies were conducted at Minnesota field sites of contrasting soil... |
25. Comparative Effects of Herbicide, Nitrogen Inhibitors and Nitrogen Source on Nitrification and Corn YieldNitrogen management in crops can be challenging due to nitrogen transformations and losses in soil, such as nitrification and denitrification. Nitrification is the conversion of ammonium (NH4+) to nitrate (NO3-) by ammonia oxidizing bacteria (AOB), Nitrosomonas and Nitrobacter. Nitrates can be lost through leaching during heavy precipitation. Nitrification inhibitor products are used to temporarily slow the nitrification process by... W. Neels, A. Jhala, B. Maharjan, R. Little, J. Iqbal |