Proceedings
Year
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1. Ammonium Thiosulfate as a Urease Inhibitor- A suggested MechanismA great deal of interest, ard sca~ controversy, has been generaw by my observations (Goos, 1985a; Goos, 1985b; Fairlie and Goos, 1986) that ammonium thiosulfate (ATS, 12-0-0-265) can inhibit soil urease activity when mixed with fertilizers such as urea-ammonium nitrate (UAN) . Preliminary field research (Gascho and Burton, 1987; Fox and Piekielek, 1987; Lamond et al. 1986) has shown some increase in crop yields or N uptah by adding ATS to surface-applied UAN. However, the use of ATS as a urease ... |
2. Calcium Chloride Effects on Nitrogen Uptake by Small GrainsApplying calcium chloride (CaC12) with urea stimulated nitrogen uptake by small grains in six greenhouse studies. The effect was most dramatic for a sandy soil, moderate for a loam soil, and not observed for a clay soil. Allowing the urea to nitrify before plant uptake negated the CaC12 effect. In field studies, these effects were generally not observed, probably because the nitrification of the applied N was too rapid. However, this concept deserves further investigation, for example, when esta... |
3. Can we Afford Not to Ridge Till?A typical farmer response to ridge till is that it is just another method of tillage. My contention is that it is much, much more than that. In my career in this I have had three cbjectives. One is to attapt to create as much balance between famkq ad the enviroment as possible. ?he second is to rrake farming profitable. The third is to make farming easier and fun. I believe with the proper approaches in regards to fertility, chemicals and water management along with the ridge till technique the... |
4. Chemical and Biological Changes Resulting from Soil SubmergenceFlooding of a soil for rice production results in significant short and long term physical, chemical and biological changes in soil properties. These changes may have significant impact of the availability of nutrients for plant growth both for aquatic plants growing in the flooded soil and upland plants on the soil when not under flooded conditions. Chief among these nutritional effects are accelerated nitrogen (N) losses, conversion of phosphorus (P) to more available forms during flooding the... |
5. Compaction - K Fertility Interactions in Corn ProductionSoil compaction is recognized as a significant factor affecting yield in crop production today. The pressure to produce crops profitably has often led gruwers to farm greater acreages, with larger equipment under soil conditions which favor compaction. Effects of compaction are not limited to the surface lay- of a soil but often may be apparent cut much of the root zone. With the interest in soil compaction and its effects on crop growth, a research project was initiated to accomplish the fol lo... |
6. Corn Stem Nitrate N Content-Grain Yield Relationships and Their use as a Basis for Sidedress N Rate RecommendationsThe objectives of this study were to confirm the relationship between nitrate nitrogen (NO3-N) content of basal corn steras and grain yield in Iowa, to establish crltical levels of stem NO3-N content for dtaining various levels of mximum yield, and to perform preliminary calibration of yield responses to sidedressed nitrogen (N) at various levels of st-Rm NO3-N content. Six sites across Iowa with a wide range of physical and environmental conditions were selected. N fertilizer was applied prepla... |
7. Do Hybrids Differ in Response to Differential Levels of Nitrogen Fertilizer?In the absence of other limiting factors, maize yield increases with nitrogen fertilizer application to very high levels. In fact, researchers attempting to maximize maize production have reported a yield -rise at levels of N greater than 300 lbs/acre. Because there are many limiting factors in addition to nitrogen, nitrogen fertilizer must be mged to minimize costs and maximize response. In addition to mging the crup's proctuctivity, recent concerns about high levels of nitrates and other farm... |
8. Effect of Ammonia Knife Spacing on Corn YieldExperiments were conducted at DeKalb on a Drummer sicl, Dixon Springs on a Alford silt loam and Elwood on a Blaunt sicl to evaluate the effect of ammonia knife spacing at varying N rates and on different tillage systems on the yield of corn Nitrogen was awlied at 180 1bs N/acre at bath DeKalb and El& and at 210 lbs N/acre at Dixon Springs in the knife spacing by tillage study. In the rate by knife spacing by time of application study at DeKalb, the preplant nitrogen was placed under where the ro... |
9. Effect of Ammonium to Nitrate Rations of Fertilizers Applied at Various Times Throughout the Growing Season on Yield and Nitrogen Concentrationof CornA number of recent investigations have produced evidenm that the ionic form of N taken up by roots affects the growth of plants. While soil- plants generally take up rest of their N as nitrate, there is evidence that increasing the relative proportion of ammonium in the culture (or soil) solution can enhance growth and yield. Owing to difficulties in prevent* the rapid miaxbial conversion of ammonium to nitrate in soil, this response has nat been well demnstrated in a field situation. The object... |
10. Effect of Chlorophyll Meter Readings on Improving Nitrogen use Efficiency in Corn ProductionChlorophyll meters have received widespread publicity as tools to measure nitrogen status of corn. Less information is available on whether the use of chlorophyll meters will decrease total nitrogen use or increased corn grain yield. One question that remains is, "How low chlorophyll readings need to go before additional nitrogen is needed?" To determine the impact of a 2 and 4% reduction in chlorophyll readings impact on yield (as measured by a SPAD 502 meter) zero, 50, 100, 150 and 200 lbs Nta... |
11. Effect of Intensive Management Practices on Wheat Yields and ProfitabilityConsiderable interest in improving wheat yields and profitability has been shown throughout the U.S. over the past ten years. Much of this interest has resulted from the dramatic yield increases achieved by English producers during that time - an annual increase of 5.0 bushellacre per year (Figure 1). During that same time period, wheat producers in the U.S. have shown a much lower rate of increase in wheat yields - 1.02 bushellacre per year (Figure 2). Missouri growers have been no exception to... |
12. Effect of Three Tillage Systems on Soil Bulk Density and Porespace DistributionMany grain producers in Kentucky use a 3 crop in 2 year rotation of corn fol lowed by small grain-soybeans, and commonly no-ti1 1 the soybeans and corn in order to intensively use sloping land for continuous grain production. Because of the intensity of machinery traffic in this system, grtwxs. are concerned that continuw no-till management may cause compaction, and that such fields may need occasional primary tillage. In order to obtain information regarding this situation, we conducted a test ... |
13. Fertilizer Recommendations- Fact or FictionFertilizers are all important and expensive part of the crop production systenl in Indiana. Indiana farmers spend nearly a half billion dollars each year on fertilizer and lime. The question is. is this expense really nccessary? Farmers obtain fertilizer reconlmendations from a number of sources. Soil testing labs. fertilizer dealers. crop consultants and extension all make fertilizer reconunendations. In many cases the reconlmendations are quite different. Is there a valid reason for these diff... |
14. Flooded Soil Syndrom and P Deficiencies on Four Iowa SoilsSeveral million acres of Midwest cropland were inundated during the floods of 1993. The length of inundation was from a few days to several months. In some areas growing crops were drowned out and other fields could never be planted. As the water receded and acres of barren ground were exposed, the reality of the disaster gave way to concerns for the 1994 crop and the development of Flooded Soil Syndrome. Flooded Soil Syndrome produces' symptoms similar to Fallow Syndrome which was originally id... |
15. Grid Sampling- The Worth of InformationSoil sample collection and chemical analysis is a time honored, scientific procedure for providing information used in determining limestone and nutrient needs in crop production fields. Ln fact, without that information one cannot make appropriate limestone and nutrient input decisions. At best they would be educated guesses. and most likely would be incorrect. Inherently then, in the soil testing process is a worth of the information derived. This worth is dependent upon the test results and t... |
16. Grid Soil Sampling for Precision and ProfitSite specific management of plant nutrients for crop production begins with an inventory of soil test levels in a field. Fertilizer recommendations are based on the expected response to addition of fertilizers as a function of soil test levels. Therefore, the accuracy of site specific fertilizer applications depends on the precision of the soil test map from which the fertilizer recommendations are based. Precision usually increases as fields are divided and sampled as smaller areas. Mapping acc... |
17. Horse Manure ManagementIt is common in the United States to find large concentrations of horses being stabled in suburban counties, immediately adjacent to large cities. Wood sawdust is one of the most common bedding materials used for horses. The high CIN ratio present in horse manure and hardwood sawdust mixtures makes this material problematic for use in agronomic or horticultural production. The high CIN ratio can induce a nitrogen deficiency in growing crops, due to the inmobilization of soil nitrogen by micro-or... |
18. Improved N Use Efficiency for Wheat in Southwest IndianaAbout one-third of the wheat acreage in Indiana is grown in southwest Indiana. During most years this area of Indiana receives exoessive precipitation during the late winter and spring gruwth period for wheat. This presents problems with losses of available soil nitrogen (N) through leaching and/or denitrification and law uptake of N by the crop even on fields which have been well-fertilized. These experiments were condtucted in 1986 and 1987 to evaluate fall, mid-winter and late-winter topdress... |
19. Influence of Seed Placed Fertilizer on Corn, Soybean and Sunflower EmergenceSix phosphorous fertilizer materials were placed with corn, soybean and sunflower seed to determine their influence on seed injury and emergence. Fertilizer rates used were 0, 12.5, 25, 50 and 100 Ib/A P,O, as dry TSP (0-46-O), MAP (1 1-55- 0), DAP (18-46-0) or liquid 10-34-0, 7-21-7 and 9-18-9. Seed emergence ranged from 0 to 100% depending on crop, fertilizer rate and materials used. Corn was most tolerant of fertilizer injury while soybean was extremely sensitive with stand reduction with eve... |
20. Influence of Soil Nitrate Nitrogen and Fertilizer Nitrogen on Wheat Grain Yield and ProteinWheat producers have recently shown a great deal of interest in grain protein levels. 'Ikis interest has developed prkily because of the relatively lqe protein premium available the last several years (Table 1). Nitrogen is a primary component of protein and needs to be added for most soils to produce high yielding, high protein wheat. The objectives of this study were to detennhe the effects of soil nitrate nitrogen and fertilizer nitrogen on wheat grain yields and protein levels. ... |
21. Interaction of Potassium Fertilization and Row Width for SoybeansIn the past several years the row width of soybeans has decreased substantially. As row width decreases the amount of soil between rows for soybean roots to explore and from which to extract nutrients has decreased. Also many acres in the Midwest have little or no fertilizer added in the soybean year but rely on residual nutrients left from the previous crop. In this study the effect of row width and method of potassium fertilization for soybeans was investigated. ... |
22. Iowa's 1987 Groundwater Protection ActThe law is the result of public concern about contamination of Iowa's groundwater resources. Data from all over the state have shown that agricultural chemicals are finding their way into -ter. The law calls for spending $64.5 million over 5 years on programs to prevent groundwater contamination from agricultural chemicals, sinkholes, agricultural drainage wells, municipal and irdustrial wastes, landfills, household chemicals, and buried chemical and petroleum storage tanks. Three fourths of the... |
23. N Loss Under Excessive Water ConditionsThe impact of excessive soil moisture on N availability was reasonably well understood at the end of the 19th century when Wiley (1896) commented " Even in the case of rainfall. which may carry the soluble plant food below the arable soil, there may not be any notable loss. especially if such a downpour be followed by dry weather. But in case of heavy rains, producing a thorough saturation and leaching of the soil. the losses in a field lying fallow during the summer will be very great and it is... |
24. Nitrogen Management for no-till Grain SorghumField experiments evaluating the effects of nitrogen management for no-till dryland grain sorghum were coacted in 1985 and 1986. Nitrogen rates (0, 50, 100 lbs N/A and placement methods for urea ammonium nitrate solution (UAN) have been evaluated in eastern Kansas. Placement methods have included surface broadcast, surface banded, pressure injected, and knifed. Results to date shm that nitrogen consistently increases yields and tissue and grain N contents, and that method of UAN placement produc... |
25. Nitrogen Management for No-Till Production SystemsNitrogen management practices including rates and sources were evaluated in high residue no-till production systems involving corn and grain sorghum. A urease inhibitor, N-(n-butyl) thiophosphoric triamide (NBPT) was evaluated. This research also assessed the impact of type of previous residue on performance of surface applied N. A chlorophyll meter was evaluated as an in-field N assessment tool. Results to date indicate that NBPT is effective in improving the performance of surface broadcast ur... |
26. Nitrogen Placement in No-till CornPlacement of nitrogen (N) fartilizers on no-till corn was evaluated in various single and multiple N rate experiments at the Belleville and Carbondale Research Centers of Southern Illinois University from 1983 to 1993. In 15 experiments in which granular urea placement was compared, ear leaf N and grain yield were essentially the same whether urea was broadcast or concentrated in surface bands near corn rows. Only a 2 bu/ac average yield advantage was observed for banding versus broadcasting ure... |
27. 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 ... |
28. No-till Corn Response to N Fertilizer Sources and Placement Methods- A Summary of Southern Illinois ResultsExperiments were conducted in southern Illinois from 1984-1986 to evaluate the placement efficiency of several N fertilizers used in no-till corn production. Such information has become of meaningful importance as producers strive to obtain the greatest possible returns from their N fertilizer investment and to obtain yields and a level of profitability equal to that of more conventionally produced corn. Also, in the near future, no-tillage will become an important tool for many farmers in south... |
29. Optimum N Rates for Corn Production as Influenced by Crop RotataionFertilizer N efficiency in corn production has become a'hot' research topic in the 1980's. Increased concerns of nitrate-N entering the groundwater and the potential for improving the profitability of corn producers are the impetus for fine-tuning fertilizer N recarmnendations. Crop production factors such as improved diagnostic techniques, full utilization of symbiotic N fixation, and crop rotation have been gaining widespread research support throughout the United States. The adoption of crop ... |
30. Predicting Fertilizer Nitrogen Requirements for Corn in OntarioThe nitrogen fertilizer requirement of a crop under field conditions is influenced by numeraus factors including soil, climate and managanent variables. Most of these factors are very difficult, if not impossible to predict in advance. The major factors influencing nitrogen fertilizer nquhment are (Gch and Haynes, 1986); 1. the requirement of the crop for N as determined by its yield (or yield patential) , 2. the availability of fertilizer N or the fertilizer use - efficiency, and 3. the amount ... |
31. Preplant vs. Weekly Applications of N-P-K FertilizersMany studies have compared time of fertilizer application to corn, but few have looked at weekly applications of complete N-P-K fertilizers. Often only one nutrient is looked at individually making sure that the other nutrients of concern are adequately supplied. In some instances the ratio between the nutrient in question and other nutrients may be greatly out of proportion, thus resulting in an imbalance ard less than maximum response. Is it possible to add N-P-K nutrients in a certain ratio o... |
32. Remote Sensing Techniques to Identify N Deficiency in CornNitrogen management remains a primary concern for corn production. Environmental consciousness has increased the need for diagnostic techniques to identify N deficiencies to guide corrective measures or to provide feedback on management practices. This study was designed to evaluate several techniques that measure reflectance from corn plants to detect N stress. The experiment was located in Central Nebraska and involved four hybrids and five N rates. Leaf reflectance, canopy reflectance, and ae... |
33. Soil Carbon and Nitrogen Changes in a Long Term Cropping Systems StudyConserving soil C and N appears to a reasonable objective in the choice of a cropping system. Many long-term studies have been conducted where the effects of rotation or cropping system on soil C, N and other nutrients have been evaluated. A cropping systems study was initiated in 1972 on Michigan's lake bed area to 1) evaluate how often sugar beet and dry bean could be grown in a rotation and 2) determine how much crop residue needed to be returned to the soil to maintain productivity. Soil sam... |
34. Soil Fertility Research- MissouriRather than focus on one item for this years' report I thought an overview of some of the Missouri soil fertility work would be of interest. Our workgroup. though informal and scattered over campus. tries to meet weekly to provide some continuity. Much of the work is driven by grants with specific foci. For example. Newell Kitchen has reported to this group on MSEA a joint agency project to study pesticide and N movenlent into ground and surface water in a central Missouri watershed. ... |
35. Soil Fertility to Ameliorate Plant Stress from Root Feeding InsectsCorn rootworms (Diabrotica spp.) are the most serious insect pests of maize (Zea mays) in the United States. Larval stages ofthese insects feed upon maize root systems causing plant lodging and grain yield reductions. Newly developed area-wide corn rootworm adult suppression methods, which reduce pesticide rates used against this pest complex by greater than 90 percent, do not completely eliminate rootworm populations. If maize producers had the option of using crop production practices that imp... |
36. Soil Nitrate Test Performance on Medium and High-Yield Potential SoilsImproved N recommendation methods for corn (Zea mays L.) are essential for increased profitability and reduction of potential N losses to the environment. A 4-yr study (49 site-yr) was conducted to evaluate the performance of preplant (PPNT) and pre-sidedress soil nitrate tests (PSNT) for predicting optimum N rates for corn at sites with inorganic and organic N inputs. Soil samples were obtained before planting (PPNT) and when corn was 6 to 12 inches tall (PSNT). and analyzed for nitrate-N. Corn... |
37. 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 i... |
38. Starter Effects on Corn Grown on Previously Flooded SoilsThe devastating floods of 1993 prompted a great deal of concern about crop production in those areas the following year. These concerns were prompted both by scientific information (Fixen et al. 1984: Vivekanandan and Fixen, 1991) and by farmer observations from prior flood experience. In response to these concerns. projects, observations. and experiments were undertaken. These included collection of soil samples for chemical analysis in the fall of 1993, observations of corn grown in 1994 on fl... |
39. Survival of Plant Growth Enhancing Root Fungi, Vesicular-Arbuscular Mycorrhizae, After Flooding and Extended FallowIn 1993. large areas of the Midwest and Great Plains were inundated with water. Plant phosphorus (P) deficiency is often a problem after such an event. Soil and plant samples were collected from sites which had been flooded and fallowed in 1993 in Missouri and Iowa. Plants from soil which low levels of starter fertilizer applied were P deficient. The application of 80 Ib P /A as starter fertilizer produced plants which were not P deficient. The flood and fallow problem was associated with the lo... |
40. The Growth of MEY in Spring Wheat CountryAny ag orientated news source looked at in recent weeks in North Dakota or western Minnesota has had some kind of a MEY related story. The MEY usually has been identified as 19naximum economic yield," but recently some use of I1most efficient yield" has been seen. Yes, spring wheat country has a new buzz acronym - MEY. How did such a buzz term for tbis amount of press/news coverage develop in the spring wheat region? The kickoff for MEY club deve1-t ocaured on November 25, 1986. Before that was ... |
41. The Role of Combine Yield Monitors in Nutrient ManagementA grain yield map is one of the key elements of site-specific crop management. Knowledge of spatial yield variations can serve three basic functions. First, a yield map can illuminate problems with drainage, fertility, diseases, or weed infestations that may have gone unnoticed by the producer. Secondly, a yield map is a feedback tool that will encourage a grain producer to compare different fertility treatments, planting rates, or other variations in cultural practices. Third, a yield map can d... |
42. Water Quality Issues and Activities in MinnesotaWithin the last few years there has been considerable public concern over the occunrence of nitrates (NO;) in bath ground and surface waters. ?his is especially significant since 50% of drinking water for the U.S. tames fm g-muthter supplies and this increases to 85% in the rural areas (CAST, 1985). The issue has at tirrres becaw emotioml and fingers have been pointed regarding the cause of nitrates in our water supply. Consequently, steps are being taken to establish the relationship between N... |
43. Water Quality Issues in NebraskaThe primary water quality issue in Nebraska at this the is related to groundwater as opposed to surface water. Groundwater provides irrigation for over 7 million acres of land in Nebraska and is the drinking water source for almost a1 1 of Nebraska's domestic and municipal water users. In rural areas groundwater provides about 85% of the drinking water (Cast, 1985). Numerous reports of groundwater contamination led to its emeqence as a major environmental issue for the 1980,s. Govenrment agenci... |