Proceedings
Year
| Filter results65 paper(s) found. |
|---|
1. 1989 Agronomic Implications of the 1988 DroughtHistorical Perspective Grain marketing analysts have a rule of thumb that says, "A short crop has a long tail". From the agronomist's point of view, a similar statement could be made for the agronomic implications of the 1988 drought. And coming on the heals of several years of depressed prices, there are some psychological effects that must be considered in working out management plans for farmers for the 1989 growing season. Since the 1988 season broke all previous records for extent and durat... |
2. Agronomic Evaluations of MAP and DAPThe old issue of MAP vs DAP has resurfaced. Although the renewed interest in this issue stems from manufacturing considerations, it would seem appropriate at this point to review our current understanding of agronomic characteristics of these two materials. One of the last reviews done on this subject was part of a review of P sources written by Larry Murphy and presented at the 1979 North Central Extension Industry Soil Fertility Workshop entitled "MAP, DAP, Poly and Rock. The amount of new res... |
3. An Evaluation of Nitrogen Application Methods for Ridge-Planted CornRidge planting is a conservation tillage method receiving some attention in the Midwest at the present time. In this system the crop is planted atop a ridge which was formed by cultivation of the previous year's crop. There is generally no tillage performed between ridge building and the next year's planting. The system is similar to no-till in that large quantities of residue are often present on the soil surface in the spring, most being concentrated in the ridge furrows. Research initiated in... |
4. 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... |
5. 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... |
6. Combining Nitrification Inhibitor TechnologiesTechniques exist for the partial control of nitrification, but few studies have determined the effectiveness of combining more than one technique. A series of experiments compared the nitrification rate of urea granules as influenced by granule size (0.01, 0.1, and 1.0 g/pellet) and dicyandiamide (DCD) addition (0, 1, 2, 5, and 10% of N) . A second series of experiments measured the interactive effects of DCD and ammonium thiosulfate (ATS) on nitrification of liquid fertilizers. Both experiments... |
7. Credibility in Soil Testing- Analytical ResultsIn Illinois, soil testing to help farmers plan line and fertilizer programs are done by cumrnercial testing services. The Agronoiny Department, University of Illinois participates in the State Soil Testing Program in research and coordinating rules. Kecognizing that sources of error in the program may occur in FIELD SAMPLING, ANALYTICAL TESTING, INTERPRETATION OF TEST RESULTS, or FORUMLATION OF RECOMMENDATIONS this paper focuses on ANALYTICAL TESTING. Two quality assurarlce programs in ANALYTlC... |
8. Credibility of soil Testing- Results os the Iowa Task ForceSeveral factors led to the convening of the Iowa Soil Testing Task Force: (1) The Iowa legislature passed the 1987 Groundwater Protection Act; (2) The Big Spring study in northeast Iowa in a Karst topography region revealed presence of pesticides and nitrates in groundwater; (3) Public awareness of contaminants in public water supplies was enhanced by influential newspapers and other publications; (4) Influential publications did major stories on the results of soil test comparison studies of se... |
9. Cropping System Effects on Phosphorus Response of CornToday's corn producer performs less tillage than in the past and predictions indicate that even less will be done in the future. Changes in management practices involving different tillage and residue incorporation practices alter the dynamics of organic matter turnover in soil and may influence the supply of plant nutrients. To maximize efficiency, it is critical that information be available to guide fertilizer management adjustments for specific tillage and rotation systems. A tremendous amou... |
10. DAP vs MAP Manufacturing/Marketing ImplicationsOver the past several years, discussions on the suitability of monoammonium phosphate (MAP) and diammonium phosphate (DAP) as P sources for crop production have been common. In addition to agronomic principles, these discussions have often focused on what the future holds on the availability of these two materials in the marketplace. This discussion will deal with manufacturing and marketing influences on future availability/use, while agronomic comparisons will be made elsewhere. To some, phosp... |
11. Effect of Application N timing and Plant Growth Regulator use in WheatWinter wheat is an important cash crop grown in the Midwestern states. However, progress in yield advancement has been slow compared to advances in other major wheat producing regions, notably Euro~e. This has lead to a competitive disadvantage of USA-produced wheat on the world market. In an effort to enhance wheat productivity and profitability a series of experiments were established in the fall of 1985 to assess the impact of more intensified management practices including the use of multipl... |
12. 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... |
13. Effect of Climatic Variability on Grain YieldsThere are three cycles in climate and weather that affect the north central part of the United States. They are (1) a long term cycle of global temperature changes; (2) an 18.5 year wet and dry cycle; and (3) the El Ni�o cycle. ... |
14. Effect of Date of Planting on Method of P Performance for Winter WheatSeed and knifed P (dual placement) have usually performed similarly on winter wheat (Triticum aestiviuum L.), but in some years seed applications have been found to be superior to knifed P. Three winter wheat experiments were established on low available P soils in southeast Nebraska to study the effect of date seeding on seed and knifed P (dual placement) performance. Three rates of P (11, 22, and 33 kg P ha-') were seed and knife applied on three seeding dates in 1987. Data indicated that the ... |
15. Effect of Nitrogen Rate and time of Application on Mefluidide Treated Smooth BromeLivestock producers who graze beef cattle or dairy animals usually have an abundance of pasture during spring when cool-season grasses grow rapidly. As hot, summer weather arrives, cool-season grasses cease vegetative growth and produce seed. Forage quality decreases as the grasses become dormant. Without alternative pastures or forages, cool season pastures become over-grazed and cattle performance is reduced. Using pastures composed of warm-season grasses that produce maximum dry matter during... |
16. Effect of Time of N fertilizer Application on Corn Grain Yield in IowaThe current concern about the impact of nitrogen (N) fertilizer use on the environment has caused a shift in the thinking about N management. Crop producers are interested in techniques (application methods) that will maximize the amount of N fertilizer harvested in the crop, and conversely minimize the amount remaining in the soil after harvest. Split applications or sidedress applications are common approaches currently being studied as a way to increase the efficiency of N fertilizer manageme... |
17. Effects of Chloride Rates and Sources on Winter Wheat in KansasOn wheat, and some other cereal grains, chloride has been reported to have an effect on plant diseases, either suppressing the disease organism or causing the plant to be able to withstand infection. It is hypothesized that yield increases are due to these effects. Researchers from several states have been able to show yield increases from chloride containing fertilizers. The most common source is potassium chloride, KC1. In many cases, soil test potassium levels are high, and most soil test re... |
18. Environmental Sulfur Sources as Inputs for Predicting Sulfur NeedsCrop responses to sulfur fertilization have been damstrated in mt states in the midwest, but the frequency of these responses is relatively lm. Sulfur deficiencies are usually confined to areas where one or mre of the follcrwing conditions exist: (1) Sandy or shallow soils; (2) Low soil organic matter content; (3) No recent manure applications; (4) Low atmospheric sulfur deposition; (5) High crop sulfur requirement. Although diagnostic tests to predict crop response to applied sulfur are an cbvi... |
19. 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... |
20. Fertilizer use in the Future- A University PerspectiveOver the last few years, several agrodc, economic, political, environmental and sociological trends have begun to eruerge which will significantly affect fertilizer use in the next decade and perhaps beyond. The wide-spread use of fertilizers is a relatively recent developmt. Over the past 40 years, farmers repeatedly saw the benefits of fertilizer applications and developed a faith in their need. Hwever, the 1990's are not the 1950's. As point& out by Dean L. M. Walsh in a recent paper in Deale... |
21. 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... |
22. 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... |
23. 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... |
24. 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 co... |
25. 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... |
26. 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... |
27. Influence of Tillage and Placement on the Location of Phosphorus in the Root ZoneIn recent years, the ridge-till planting operation and the use of the chisel plow have developed into the most widely accepted planting systems for conservation tillage in Minnesota. While there is opportunity to incorporate plant nutrients in the chisel plow system, previous studies have shown that this incorporation is shallow when compared to the moldboard plow system. The ridge-till system, on the other hand, offers only limited possibilities for fertilizer incorporation. Typical broadcast a... |
28. Integrated Farm Management Demonstration Program in IowaThe Integrated Farm Management (IFM) Demonstration Program was established by the landmark 1987 Iowa Groundwater Protection Act. The five-year program, funded through 1992, is a cooperative effort involving various state agencies, Iowa State University and Iowa farmers. The program coordinators, many of whom are Iowa State Extension Service staff and scientists, work with farmers to help them implement best available technology that protects the environment and conserves energy. The goal of the ... |
29. Intensive Wheat Managent in the Corn BeltIntensive wheat management (ICX) is based on European cropping systems including narrow row spacing, precise seeding rates, multiple nitrogen (N) fertilizer application, fungicide application for disease control, and plant growth regulator (PGR) application for lodging control. Components of this cropping system were compared to current recommended management (CRM) practices with 12 varieties during 1986-87. The purpose for the experiment was to determine the responsiveness of soft winter wheat ... |
30. Managing Field Soil Fertility VariationsFertilizer and crop production inputs are most often applied as a single blanket application rate across an entire field. Yet variations in field conditions including soil characteristics and measured crop yield are known to exist and often in a systematic, fashion. Grid soil sampling for fertility variations, plant analyses, and color photography were found to be most useful tools for assessing manageable field variations. Increased profit and environmentally sound improvements in fertilizer us... |
31. 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... |
32. Nitrate Soil Testing Correlation and Calibration Eastern Corn BeltCurrent economic and environmental concerns have increased the interest in developing methods to help manage nitrogen (N) fertilizers as efficiently as possible. There is a concern that fertilizer N that remains in the soil following harvest may be leaching below the root zone of crops and eventually ending up in groundwater. Agronomists throughout the corn belt are actively evaluating methods to manage N fertilizer as efficiently as possible.... |
33. Nitrate Testing ClinicsThirty-eight nitrate testing clinics were held in 36 Michigan counties in the spring of 1989. A mobile testing van was equipped for nitrate analysis of soil and water samples. Over 2,200 soil samples and 1500 water samples were analyzed for nitrate N using the nitrate ion-specific electrode. More than 50 percent of the soil samples . contained less than 30 lb of nitrate N in the surface two feet. Only 35 percent of the 1,100 fields were given a nitrogen credit based on the residual nitrate test.... |
34. Nitrogen Fertilizer Requirements for No-till cornConservation tillage is associated with higher surface crop residue levels, larger more stable soil aggregates, and generally higher surface soil water contents compared to conventional tillage. The changes in residue management and overall soil water regime under conservation tillage may result in different spatial distributions (laterally and with depth) of nutrients. In general, nitrogen fertilizer applied as broadcast urea is not recommended for no-till systems because of the possibility of ... |
35. Nitrogen Management for Cool Season Grass ProductionStudies were initiated in 1985 on established smooth bromegrass and tall fescue to evaluate urea granule size effects on forage production and quality. Other work, evaluating N source by previous source effects and UAN placement methods and the addition of ATS, was conducted on established smooth bromegrass. Nitroger1 rates were also evaluated in all these studies, and the addition of N significantly increased forage yields and N concentrations in each study. Use of large (1.0g) urea granules pr... |
36. 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... |
37. Nitrogen Management for Winter Wheat in MissouriEight site years of data have been collected to evaluate nitrogen rate and timing for intensively managed winter wheat in Missouri. Variables have included rates up 160 lbs N per acre applied as all fall, all spring, or split in a fall and spring or fall plus two spring applications. Results have pointed to the split applications of rates at 80 to 120 lbs N per acre as providing greatest consistency and economic return to the grower. Maximum yield has generally been obtained with the 3 way split... |
38. 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... |
39. 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 ... |
40. Nitrogen Soil Test for Corn in OntarioIt is generally believed that for high yielding crops such as corn. the N requirements are much larger than variations in the N supplying capacity of soil. In Ontario, fertilizer N recommendations are based on the requirements of the crop and, for some crops, the expected yield goal. Nitrogen credits are given for past management such as manure application and legumes in rotation. The credits are deducted from the economic rate of N. In a recent analysis of all existing fertilizer N crop respon... |
41. Nitrogen Source Affects Manganese Nutrition of No Till CornA study evaluating response of no-till continuous corn to different rates of N as injected anhydrous ammonia and broadcasted urea-ammonium nitrate solution (UAN) was conducted on a Canfield silt loam near Wooster, Ohio. Repeated use of anhydrous ammonia on this naturally acid soil resulted in relatively large concentrations of Mn (often > 200 ug/g) in corn plant ear leaves at silking. Ear leaf Mn concentrations were less when UAN was used. For both N source treatments, ear leaf Mn concentrations... |
42. Nitrogen Test Development Soil N Levels in 1989The developnent of a N test that can be used for fertilizer recamrendations of corn in the eastern areas of Minnesota is needed for environmental and econcmic reasons. A multi-site project was initiated in 1989 to extensively examine soil sampling time and depth as well as N forms in the soil. This will then enable statistical models to be develaped using one or mre of the variables. A subset of the entire project is reported--concentrating on the sites allowing the calibration of the soil N tes... |
43. Perspective on Sustainable Agriculture- Sustaining Agribusiness in a Changing Rural EnvironmentAgriculture is an evolving industry -- it responds to market forces, tc improvements in technology, to government programs. LlJe also see changes as 3 result of new technologies, improved information about how to efficiently raise crops and livestock, and more integration with other sectors of society. In agriculture, as in arty business, to stand still is to fall behind the rest of the industry. !!le nnoed to be ready to adapt to change, to face ned rl-zli- ties, and even to initiate cnange in ... |
44. Phosphorous Management for Wheat ProductionProfitable wheat production depends on many factors, including a sound phosphorus (P) management program. Except for sunlight and water, soil fertility generally represents the most limiting factor in crop yields. Even with perfect weather and climatic conditions, a farmer that does everything right except to meet the nutrient needs of the crop will never reach optimum yield potential. Water, N, and P are generally the dominant yield limiting factors for wheat in the United States. Potassium, S,... |
45. Probability of Success for Practices to Minimize Water Quality ProblemsI would like to spend my time this morning reviewing with you some of the practices and appraoches research has suggested as being useful in controlling quality of both surface water and groundwater. Given the limited time available, I will highlight only a few of the study findings, and confine my remarks primarily to the problems of nitrogen pollution of groundwater and phosphorus contamination of surface waters. This limited review is prompted more by what I perceive to be the major interests... |
46. Quantitative Risk AssessmentThank you for giving me the opportunity to speak to you today about carcinogens in drinking water and water quality standards. In the United States today, many if not most public water supplies contain chemicals that cause cancer in animals when, in laboratory tests, the animals are exposed to high levels of the chemical. Elost of these chemicals are man-made, but there are exceptions, such as the chlorinated methanes and, probably, related compounds. These chemicals are the byproducts of chlori... |
47. 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... |
48. Residual Soil NO3 N Variability Sampling Interpretation and Effect on Corn YieldResidual nitrate-N (NO3-N) in the soil profile (crop root zone) is seldom uniformly distributed. There is lateral as well as vertical variability. Numerous factors influence variability. Some of them are: 1) any factor that influences water movement through the soil such as - soil texture, compacted zone, topography and water distribution under irrigation - 2) previous crop, 3) fertilizer history (organic and inorganic sources) and 4) sampling time - caused primarily by factors influencing miner... |
49. Response of No-till Corn to Urease Inhibitors and Placement of N SourcesN(n-buty1)thiophosphoric triamide (NBPT) and ammonium thiosulfate (ATS) were investigated as urease inhibitors when added to urea and urea-containing N sources and applied to no- ill corn. Significant - f yield increases, some in excess of 20 bu ac , were observed with NBPT treatment of the N fertilizers. Lack of a yield response from NBPT, when it occurred, was usually associated with a rain event of major proportions soon after fertilizer application. ATS showed considerably less promise as a ... |
50. 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... |
51. 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. ... |
52. 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... |
53. 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... |
54. Soil Nitrate Testing- A Guide for Adjusting Michigan Nitrogen Recommendations for CornPrevious attempts to use soil nitrate tests in Michigan for adjusting N fertilizer recommendations for corn have been less than satisfactory. Soil tests were typically performed on fall or spring samples taken weeks or months prior to planting. The use of residual nitrate to adjust N fertilizer recommendations in the semi humid regions of the U. S. has never been considered very re1 iable because of the large fluctuation in soil nitrate from the time of sampling to the time of maximum uptake. So... |
55. Soybean Response to Potassium Rates and PlacementSoils of northeast Missouri in heavy soybean producing counties have generally become depleted of available potassium. Reason for depletion can largely be pointed to soybean production and a general perception that soybeans do not respond to direct fertilizer application. With a significant portion of the soybean acres in east and northeast Missouri being tenant farmed, efficiency and utilization of direct fertilizer application by the current crop is even more important to the grower. Band appl... |
56. 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... |
57. 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... |
58. 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... |
59. Sustainable Agriculture- A PerspectiveThere is little evidence tos uggest that agriculture as practices in a variety of ways is not sustainable. We think of sustainable agriculture as a management system that uses inputs ... both those available as natural resources on the farm and those purchases externally ... in the most eficient manner possible to obain productivity and profitabilty from a farming operations, while minizing advers effects on the environment. Several groups have published materials suggesting techniques that shou... |
60. The Components of Sustainable AgricultureSustainable agriculture has become a rallying phrase for many concerned about agricultural profitability and environmental quality in the rural sector. Advocates of sustainable agriculture seem to be convinced that the policies and structure of the agricultural industry are responsible for increasing environmental problems, low farm profitability, declining farm numbers, and reduced quality of life in rural America. The agricultural popular press has published numerous stories about those concer... |
61. The Effect of Tillage and Soil Test and Applied K on Corn and Soybean ProductionThe buildup-maintenance fertility concept for P and K has a strong theoretical basis, but much of the research from which it was derived was not designed to accurately determine the true maintenance requirement. Most of that research was confounded by an annual application at set rates irrespective of yield obtained. Experience in recent years has shown that on some soils the K soil test has not consistently accounted for past additions of fertilizer. In addition, applications equivalent to crop... |
62. The Nitrate Soil Test in South DakotaThe nitrate nitrogen soil test has been used for more than 15 years for making nitrogen fertilizer recommendations in South Dakota. Minimal leaching and denitrification due to a relatively dry climate has helped make this test a good predictor of nitrogen fertilizer needs. The test and nitrogen recommendation system is based on a two foot deep soil sample and a calibrated nitrogen requirement for common crops grown in South Dakota (Table 1). Extensive field plot data shows that the two foot deep... |
63. 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... |
64. Use of Near infrared-NIR- Reflecctance for Improving Nitrogen Management in Spring WheatAdvancements in agricultural technology are providing both producers and researchers with improved tools for farm management d ec is ion making . Reduced profit margins are requiring farm managers to use these advanced tools to optimize input management in order to improve prof it levels. Fertilizer nitrogen (N) is a major input foi spring wheat in the Great Plains. Each year, many farmers fertilize spring wheat with nitrogen to improve seedling vigor and plant developmenl. Nitrogen is a major n... |
65. Yield and N Concentraions of Corn with Different N Sources Applied at Different timesA number of recent investigations have produced evidence that the ionic form of N taken up by roots affects the growth of plants. While soil- grown plants generally take up most 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 preventing the rapid microbial conversion of ammonium to nitrate in soil, this response has not been well demonstrated in a field situation... |