Laser Based Density Detection of Standing Wheat Stubble

Penetration of a laser beam through wheat stubble was used as a measure of stubble density. A low power, heliumneon laser was positioned perpendicular to travel direction. A photo detector was used to determine penetration duty cycle after the beam passed through the stubble. Penetration duty cycle measured on a simulated wheat crop gave a good indication of crop density. The laser beam appeared to penetrate the simulated crop at densities where direct transmission was blocked. Some reflection of the laser beam occurred through simulated wheat stalks and off the filter on the sensor. Tests in standing wheat stubble offered little indication that the detector could accurately indicate crop density. Correlataon coefficients between stalk density and detector readings ranged between 0.60 and 0.07. A statistical model was developed to describe the system and eliminate the affect of hidden stalks. The model demonstrated the insensitivity experienced at higher stubble densities.Agricultural Engineerin

Replicability of nitrogen recommendations from ramped calibration strips in winter wheat

Ramped calibration strips have been suggested as a way for grain producers to determine nitrogen needs more accurately. The strips use incrementally increasing levels of nitrogen and enable producers to conduct an experiment in each field to determine nitrogen needs. This study determines whether predictions from the program Ramp Analyzer 1.2 are replicable in Oklahoma hard red winter wheat (Triticum aestivum). Predictions are derived from 36 individual strips from on-farm experiments—two pairs of adjacent strips at each of nine winter wheat fields in Canadian County, OK. The two pairs of strips within each field were between 120 and 155 m apart. Each strip was analyzed three times during the 2006–2007 growing season. Nitrogen recommendations from Ramp Analyzer 1.2 are not correlated even for strips that were placed side by side, and recommendations from strips in the same field show no more homogeneity than randomly selected strips throughout the county. The results indicate that ramped calibration strips are unlikely to produce accurate nitrogen requirement predictions at any spatial scale, whether at the county level or for subsections of a single field. In contrast, a procedure that uses only measures from the plot with no nitrogen and the plot with the highest level of nitrogen applied does show replicability. Thus, improvements in the ramped calibration strip technology are needed if it is to become viable.Fertilizer; Nitrogen; Precision agriculture; Ramped calibration strip; Winter wheat

DETECTING GRAIN FLOW RATE USING A LASER SCANNER

Detecting and measuring agricultural material flow is important in a wide range of applications in agricultural engineering, such as material handling, food processing, yield monitoring, and fertilizer spreading. In these applications, flow rate is determined by measuring material mass or volume as a function of time. Although different materials require detection, the methods for a given material type (e.g., granular) can be similar. Researchers have developed methods such as impact based sensors, radiometric-based sensors, and optical methods to detect and measure material flow. Abdul Rahim and Green (1998) studied an optical-fiber sensor (containing 32 light sources and 32 light detectors) in a tomographic measurement system to measure the flow of dry solids (sand or 3 mm plastic chips) in a gravity-drop system with an 81 mm diameter pipe and pneumatic conveyor. Their results showed linearity between flow rate and output voltage up to 0.5 kg s-1 mass flow rate. They concluded that increasing the number of optical-fiber sensors resulted in better accuracy, and the sensors had a linear response to the increased concentration of solids

LABORATORY EVALUATION OF A TURN COMPENSATION CONTROL SYSTEM FOR A GROUND SPRAYER

The ability to compensate sprayer nozzle flow across a horizontal boom has the potential to mitigate the problem of inaccurate chemical application rate due to lateral speed differences when sprayers are turning. A laboratory testing platform and procedure were developed and tested with a commercial turn compensation control system for a ground sprayer. Virtual paths consisting of simulated GPS signals representing right and left turns separated by straight segments were simulated with four turning radii (75%, 125%, 250%, and 500%) based on boom width. Actual application rates from 11 nozzles spread across the boom were measured using load cells in real time and were compared with desired application rate. Mean flow rate and coefficient of variation by nozzle position for each segment of the test paths showed a general consistency between the expected application rate and actual application rate for most nozzles at most cases with a small discrepancy for a few nozzles. Application errors were within the accepted ±10% range specified by ASABE. This study contributes to the formation of a test standard for turn compensation control systems calibration in the future

Strip-till considerations in Oklahoma

The 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

Types of on-farm demonstrations

The 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

A Method to Evaluate Seeder Performance

Evaluating in field seeder performance is challenging and sometimes requires destructive methods. An alternative method for evaluating seeder performance based on nonlinear regression was developed. This method yields parameters that describe seeder performance, such as emergence rate, initial emergence data, and emergence percent. These parameters are easy to explain to the practitioner. The proposed method was compared to a widely used method to assess emergence rate. Results assessing emergence percent were comparable between the two methods. There were differences between the emergence rate index and emergence rate determined from the proposed method. These differences were expected since the emergence rate index encompasses more information than simply the rate of emergence

Replicability of nitrogen recommendations from ramped calibration strips in winter wheat

Ramped calibration strips have been suggested as a way for grain producers to determine nitrogen needs more accurately. The strips use incrementally increasing levels of nitrogen and enable producers to conduct an experiment in each field to determine nitrogen needs. This study determines whether predictions from the program Ramp Analyzer 1.2 are replicable in Oklahoma hard red winter wheat (Triticum aestivum). Predictions are derived from 36 individual strips from on-farm experiments—two pairs of adjacent strips at each of nine winter wheat fields in Canadian County, OK. The two pairs of strips within each field were between 120 and 155 m apart. Each strip was analyzed three times during the 2006–2007 growing season. Nitrogen recommendations from Ramp Analyzer 1.2 are not correlated even for strips that were placed side by side, and recommendations from strips in the same field show no more homogeneity than randomly selected strips throughout the county. The results indicate that ramped calibration strips are unlikely to produce accurate nitrogen requirement predictions at any spatial scale, whether at the county level or for subsections of a single field. In contrast, a procedure that uses only measures from the plot with no nitrogen and the plot with the highest level of nitrogen applied does show replicability. Thus, improvements in the ramped calibration strip technology are needed if it is to become viable

Replicability of nitrogen recommendations from ramped calibration strips in winter wheat

Ramped calibration strips have been suggested as a way for grain producers to determine nitrogen needs more accurately. The strips use incrementally increasing levels of nitrogen and enable producers to conduct an experiment in each field to determine nitrogen needs. This study determines whether predictions from the program Ramp Analyzer 1.2 are replicable in Oklahoma hard red winter wheat (Triticum aestivum). Predictions are derived from 36 individual strips from on-farm experiments—two pairs of adjacent strips at each of nine winter wheat fields in Canadian County, OK. The two pairs of strips within each field were between 120 and 155 m apart. Each strip was analyzed three times during the 2006–2007 growing season. Nitrogen recommendations from Ramp Analyzer 1.2 are not correlated even for strips that were placed side by side, and recommendations from strips in the same field show no more homogeneity than randomly selected strips throughout the county. The results indicate that ramped calibration strips are unlikely to produce accurate nitrogen requirement predictions at any spatial scale, whether at the county level or for subsections of a single field. In contrast, a procedure that uses only measures from the plot with no nitrogen and the plot with the highest level of nitrogen applied does show replicability. Thus, improvements in the ramped calibration strip technology are needed if it is to become viable

No-till wheat production in Oklahoma

The 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