Proceedings
Year
| Filter results22 paper(s) found. |
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1. 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... |
2. 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... |
3. 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... |
4. 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... |
5. 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... |
6. 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... |
7. 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... |
8. 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... |
9. 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... |
10. 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... |