1,720,993 research outputs found
Tillage effects on properties of Grantsburg soil and growth of corn (Zea mays L.)
No full textA three-year tillage project, involving three treatments of no-tillage (NT), chisel-plow (CP), and moldboard plow (MP), was conducted in Southern Illinois. The objectives of the study were to: (1) determine effects of tillage on properties of a sloping and eroded Grantsburg soil (fine-silty, mixed, mesic Typic Fragiudalf); (2) evaluate effects of tillage on growth and yields of corn; (3) relate the soil property changes as affected by tillage to the growth and yields of corn grown on the plot area on a yearly rotation system; and (4) evaluate the tillage systems for restoration and maintenance of soil productivity. Effects of tillage on mechanical strength were mainly confined to the plow-layer. Soil bulk density was generally higher for NT at planting; however, the bulk density for CP and MP treatments increased later in the season attaining values that were comparable to those of the NT treatment. Tillage reduced soil aggregate stability, organic C, and plant residues remaining at the soil surface at planting. Soil temperature was lower for NT than MP at planting. At planting in 1989, 1990 and 1991, total- and air-porosity were lower for NT than MP. However, later in the season in 1991, NT had higher total- and air-porosity than MP. Plant population was lower for NT as compared to MP during the 1st year, but higher as compared to CP during the 3rd year. Corn grain yield in 1989 was highest for MP and lowest for NT (8400, 9300 and 10500 kg/ha respectively, for NT, CP and MP). The corn yields for 1991 for all treatments were 2300 to 4400 kg/ha lower than for 1989 due primarily to low amount and poor distribution of rainfall as well as insufficient plant available soil water in 1991-growing season.Made available in DSpace on 2011-05-07T12:23:54Z (GMT). No. of bitstreams: 2
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Previous issue date: 1992Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding ([email protected]) on 2011-05-07T14:40:31Z
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Land-use change effects on soil organic carbon, total soil nitrogen, and soil erosion in a temperate forest and grassland
Full text linkThere are several factors that influence the retention of soil organic carbon (SOC) and total soil nitrogen (TSN) including soil texture, climate, slope length and gradient, and current and past land-use. The purpose of this study was to compare by land use the retention of SOC and TSN on sloping landscapes. Two separate paired sites were used in the study, one a forest and cropland on a loess-derived Alfisol in Southern Illinois and the other a prairie and cropland on a Mollisol derived from loess over glacial till in Western Iowa. Tree ring data suggest that the forested site has been intact for about 70 years, although part of the site was used for grazing for a period. A monument marker at the prairie site suggests the location has not been farmed since at least 1946 and states that it has never been plowed; however it may have been used for grazing. The croplands at both sites utilized no-till management and a corn-soybean rotation. SOC and TSN concentrations of several layers and landscape positions were determined to a depth of 1m at the Iowa sites and 0.75 m at the Illinois sites due to the presence of a root-restricting fragipan layer. Fly ash was used as a tracer for physical erosion and levels were determined to a depth of 30 cm for all sites. In Iowa the prairie site had much higher SOC and TSN levels than the cropland at all landscape positions but the toeslope. This difference was seen throughout the full 1 m sampling depth. In Illinois the forest site showed less statistical difference, with the shoulder and lower backslope being the only positions with more SOC stock than the cropland. Again the lowest section of the landscape had more SOC in the cropland. Most of the difference in the forestland was seen in the upper 15 cm. TSN levels for the Illinois sites showed little difference except in depositional areas where the cropland had higher levels. Results suggested that the conversion of prairie to agriculture resulted in a 51% loss of the SOC, a 38% loss of the TSN, and a 37% loss of fly ash across all landscape positions and depths. The cropland of the Illinois site retained about 90% of the SOC, 100% of the TSN, and 54% of the fly ash of the forestland. It was also estimated that conversion of the forest or prairie to cropland would result in the release of 44.6 Mg CO2/ha and 168.7 Mg CO2/ha respectively. If climate change continues to push warmer temperatures north and forests and prairies are converted to cropland the results suggest that soil erosion will increase and SOC stock will decrease in the soil even with the use of no-till management.Submission published under a 24 month embargo labeled 'U of I only', the embargo will last until 2017-08-01The student, Ronald Salemme, accepted the attached license on 2015-07-06 at 08:18.The student, Ronald Salemme, submitted this Thesis for approval on 2015-07-06 at 08:28.This Thesis was approved for publication on 2015-07-06 at 10:53.DSpace SAF Submission Ingestion Package generated from Vireo submission #8346 on 2015-09-29 at 14:59:09Made available in DSpace on 2015-09-29T20:49:44Z (GMT). No. of bitstreams: 2
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Previous issue date: 2015-07-06Embargo set by: Seth Robbins for item 89441
Lift date: 2017-09-29T20:50:34Z
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Predicting Crop Yields and Productivity Indices for Illinois Soils
No full textComparing established (Circular 1156) crop yields with predicted 1970s crop yields, generated from soil property models from base and benchmark soils, predicted high R2 values of 0.90 for corn, 0.90 for soybean, 0.81 for wheat, 0.81 for oat, and 0.88 for hay. These crop yield models were tested with 167 supplementary soils from nine selected counties representing the crop reporting and weather districts for Illinois. The equations explained 50% of the yield variation for corn, 47% for soybean, 41% for wheat, 33% for oat, and 47% for hay. Outliers (greater than +/-2 SD) were identified for further analysis. The relationship between crop yields, versus time (years) were established using regression analysis. Crop yield trends and magnitude of change were estimated for 66 countries in the northern region and for 36 counties in the southern region for the time period between 1976 and 1995. The magnitude of crop yield change by region was added to the 1970s predicted and established yields to generate the 1990s predicted and established yields. These yields were compared against 10-yr averages for the 1990s as reported in IAS for the nine test counties. As in the 1970s comparisons, predicted yields were closer to reported IAS yields than those established in Circular 1156 and projected to 1990s. There were no significant differences between the nine county predicted 1990s yields and the IAS 1990s yields for corn, soybean, and wheat.Made available in DSpace on 2015-09-28T16:22:35Z (GMT). No. of bitstreams: 2
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Previous issue date: 1999Embargo set by: Seth Robbins for item 88962
Lift date: Forever
Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDsRestricted to the U of I community indefinitely during batch ingest of legacy ETDsU of I Only122 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1999
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Tillage Effects on Soil Properties and Crop Production in Southern Illinois
No full textThe Harris et al. (1996) soil quality index (SQI) model was tested and modified according to local and regional conditions by changing the threshold limits and standardized scoring functions (SSF) for soil quality indicators. Soils that had been in 8 years of the NT system had SQI of 0.64 as compared to 0.52 in the CP and MP systems. The MP system had a higher rooting relations rating than the NT system whereas the NT system had better water (erosion resistance) and nutrient relations rating than the MP system. The MP and the CP systems had water relation rating of 0.25 and 0.21 than the NT system (0.60) showing that residue on soil surface is important for protection of soil against erosion. (Abstract shortened by UMI.).Made available in DSpace on 2015-09-28T16:22:33Z (GMT). No. of bitstreams: 2
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Previous issue date: 1997Embargo set by: Seth Robbins for item 88949
Lift date: Forever
Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDsRestricted to the U of I community indefinitely during batch ingest of legacy ETDsU of I Only129 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1997
Predicting Crop Yields and Productivity Indices for Illinois Soils
No full text122 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1999.Comparing established (Circular 1156) crop yields with predicted 1970s crop yields, generated from soil property models from base and benchmark soils, predicted high R2 values of 0.90 for corn, 0.90 for soybean, 0.81 for wheat, 0.81 for oat, and 0.88 for hay. These crop yield models were tested with 167 supplementary soils from nine selected counties representing the crop reporting and weather districts for Illinois. The equations explained 50% of the yield variation for corn, 47% for soybean, 41% for wheat, 33% for oat, and 47% for hay. Outliers (greater than +/-2 SD) were identified for further analysis. The relationship between crop yields, versus time (years) were established using regression analysis. Crop yield trends and magnitude of change were estimated for 66 countries in the northern region and for 36 counties in the southern region for the time period between 1976 and 1995. The magnitude of crop yield change by region was added to the 1970s predicted and established yields to generate the 1990s predicted and established yields. These yields were compared against 10-yr averages for the 1990s as reported in IAS for the nine test counties. As in the 1970s comparisons, predicted yields were closer to reported IAS yields than those established in Circular 1156 and projected to 1990s. There were no significant differences between the nine county predicted 1990s yields and the IAS 1990s yields for corn, soybean, and wheat.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD
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