1,720,988 research outputs found
Impact of residue management and weed management systems on double-crop soybean production systems
No full textResidue and weed management in double-crop soybean (Glycine max) production systems is essential to producing a successful crop. In the Southern Great Plains, double-crop soybean production and utilization of cover crops have been on the rise. Thus, resulting in a a need for information on effective residue and weed management for this system In response to this need, two studies were developed to determine management practices producers could effectively utilize. Trials were conducted in Oklahoma during the 2021 and 2022 growing seasons. The first study in double-crop soybean, indicated that proper weed management through the use of various herbicides can benefit soybean yield. The second study indicated that medium seeding rates have the potential to develop comparable biomass levels as high seeding rates (without compromising nutritional need in which livestock could utilize to graze)
Maximizing land use and productivity in Oklahoma: A comparison of regular, intercrop, and double crop systems
Get PDFIn recent years, crop intensification and increased diversity have emerged as strategies to enhance sustainability and reduce risk in cropping systems. Oklahoma producers are increasingly turning to Modified Relay Intercropping to extend the growing season, aiming for better use efficiency and intensified cropping. A randomized complete block design was conducted at the Mingo Valley Research Station and Lake Carl Blackwell in Oklahoma. The objective was to compare crop yields in a modified relay intercropping system against regular and double-crop systems. In the modified relay system, soybeans were hand-planted into actively growing hard red winter wheat 45 days prior to wheat harvest. The study demonstrated significant impacts on soybean yield and growth parameters. However, predicting in-season variations proved challenging, as factors like unique environmental conditions played a significant role. Intercropping generally outperformed double-crop systems in most cultivars and locations, but inconsistencies existed within each, lacking consistent trends. Despite statistical significance, variations in yield were likely attributed to yearly environmental fluctuations. Oklahoma producers may consider intercropping, but a mechanistic perspective suggests regular season or double-crop soybeans as more secure and dependable choices. In addition, Oklahoma producers have been looking for ways to minimize risk and expand on economic opportunities. Interest in grazing grain sorghum stover has increased in recent years, especially in areas with limited forage availability. However, nitrate content (NO3-) within the stover can cause issues for grazing animals due to nitrate toxicity. A randomized complete block design replicated four times was conducted at the Mingo Valley Research Station near Bixby, OK in 2022. The purpose of this study was to evaluate the impact desiccation has on forage quality and nitrate content (NO3-) accumulation within the grain sorghum residue/stover following harvest. Three treatments were utilized: non-treated, a harvest aid of glyphosate at black-layer, and a harvest aid of glyphosate at 14 days post black layer. Biomass samples were taken at harvest, 30 days post-harvest, and 60 days post-harvest. Grain sorghum stover may not fully meet the nutritional needs for animals even though it is a very viable feed option in terms of cost effectiveness
Effect of the method and rate of planter applied nitrogen on corn and grain sorghum production
No full textIn Oklahoma corn (Zea mays) and grain sorghum (Sorghum bicolor L) account for nearly 20% of all the total value of farmed cropland in the state. Fertilizer, specifically nitrogen (N) is one of the greatest input cost and potential environmental risk points for the central Great Plains producers. It is well documented that preplant N is inefficient and both crops benefit from in-season N management. However, it is also documented in some studies that there is a positive response to planter applied N. The placement and timing of in-season applied N is well researched but there is a lack of data on planter applied N fertilizer in the region and none that evaluates the method and rate of such an application. The objective of this study was to test the impact of the method and rate of planter applied N on plant stand and grain yield of corn and grain sorghum in central Oklahoma. The placement methods evaluated were in-furrow, surface dribble, dry surface broadcast, and “2x2” coulter injected. Nitrogen rates evaluated in this study were 9, 18, and 27 kg N ha⁻¹, as well as a non-fertilized check for a total of 13 treatments. Fertilizers utilized in the study included liquid urea-ammonium nitrate (28-0-0) and Urea (46-0-0). The study was repeated over three growing seasons: 2020, 2021, and 2022 with 2 locations per year in central Oklahoma, USA. Stand counts for the corn averaged 20.3 plants per row (each row was 6 m-1 in length for both crops) across all sites and treatments. The grain sorghum stands average 36 plants row⁻¹. Overall site years corn grain yields averaged 3.1 Mg ha⁻¹ while the grain sorghum trials averaged 1.8 Mg ha⁻¹ across the six locations. These yield values were well below expected for a managed research study as the state average for the same period was 8.6 Mg ha⁻¹ and 2.37 Mg ha⁻¹ for corn and grain sorghum respectively. The results of this study were that neither stand nor grain yield were statistically impacted by neither the N placement method nor N rate in both corn and grain sorghum. While low yields were expected due to reduced N application rates this research experienced exceptionally low yields and no response to N rate suggesting N was not the limiting factor. Across all site years and crops the environment and weather conditions impacted this study reinforcing the concept of Liebig’s Law of the Minimum. In which yield is control by the greatest limiting factor and in the case of the work, the greatest limiting factor was environment
Effect of nitrogen rate and timing on forage sorghum production and quality
No full textForage sorghum (Sorghum sudanense) is a summer annual sorghum-sudan hybrid that is a high yielding and high-quality source of feed for livestock. Forage sorghum can produce multiple biomass harvests in a single growing season. Because of the high yield of forage sorghum, this crop is a valuable choice for producers in Oklahoma and surrounding regions with heavily dominated livestock production. Applications of nitrogen (N) fertilizer can benefit forage sorghum yield; however, understanding how N application rate and timing affect forage quality such as protein and digestible feed values is critical. Therefore, this project evaluated the effect of N fertilizer rate and timing on forage sorghum biomass yield and quality in north central Oklahoma. The study consisted of five site years of data collected during the 2021, 2022, and 2023 growing seasons, and two harvests were conducted at each site each year. The treatment structure of the study included four N rates and a zero-N check. Three N rates were evaluated as split applications, while all four rates were evaluated as pre-plant applications. N rates ranged from 56 kg/ha⁻¹ to 224 kg/ha⁻¹. The side dress application of N in the split treatments was applied after the first biomass collection. The N source was urea ammonium nitrate (UAN) solution 28 and was broadcast applied. This study found a positive correlation between N applied and biomass produced with no adverse effects on forage quality
Impact of delayed nitrogen application in grain sorghum
Get PDFA majority of grain sorghum production occurs in the central to north west portion of Oklahoma, where the average annual rainfall is at or below 900 mm and precipitation events become less frequent. The environment conditions associated with this region has resulted in yields being highly variable. This variability makes input management a challenge. One of the primary challenges is N fertilization, not only because it is one of the costliest inputs but determining optimum application rates in these conditions can be challenging. Being able to delay the investments of inputs such as N until crop status and final yield potential is better understood in-season could increase crop NUE. In 2006 Oklahoma State University released a Sensor Based Nitrogen Rate Calculator (SBRNC) for grain sorghum. The SBNRC uses in-season NDVI values from the crop and a N rich strip to predict final grain yield and optimum fertilizer N rate. This technique often requires the crop to experience some degree of N deficiency prior to N to application. The objective of this study is to determine the impact of delaying N application after the onset of N deficiencies and the crops ability to recover. In 2019 growing season this study was conducted at three locations in Oklahoma. Two trials were located at Lake Carl Blackwell Research Farm near Perry OK, and one trail at the Cimarron Valley Research Station near Perkins, OK. Three N rates were applied depending upon the yield potential at each location, LCB1 100 kg ha-1, LCB2 134 kg ha-1, Perkins 90 kg ha-1. In 2020 all locations received 100 kg ha-1 N and included a fourth location on a privately own farm (KMF) near Alva, OK. Using ammonium nitrate as the source of nitrogen, only one treatment received pre-plant N all other treatments except for the un-fertilized check received all N in-season. In 2019 initial side dress application was to begin at first sight of visual difference, a difference between the pre-plant and non-fertilized (check) or 28 days after planting (DAP), while in 2020 first application was moved to 21 DAP. Once side-dressing was initiated one treatment received N every seven days until 70 days after the first application for a total of 10 side-dress application timings
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Determining winter canola maturity for harvest
No full textThe Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
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