Performance modeling and seed releasing characteristics of a corn planter metering unit using response surface methodology

The objective of this study was to develop prediction performance functions and determine the seed releasing characteristics of seed meter disks based on metering rate and pitch angle at different levels using Response Surface Methodology (RSM). An AGCO White 9000 planter row unit was tested using two seed shapes and associated disks in controlled laboratory conditions. Experiments were designed based on the two-variable Central Composite Design (CCD), one of the RSM designs. Effects of metering rate and row unit pitch (seed tube tilt angle) in their five levels were investigated, on performance and seed release characteristics. A video recording system allowed simultaneous recording of rear and side views of seed exiting the seed tube on the row unit. A MATLAB program in combination with image processing algorithms was used to analyze video. The performance indicators investigated were quality of feed index (QFI), and multiple and miss indices. Seed release characteristics of interest were side and rear angles and time between seeds. Based on the experimental results, QFI values were found 99.0% (maximum) and 100% (maximum) for using flat and round corn seed disks, respectively. The maximum side angle ranged from 33.5° to 48.3° for the flat seed disk and 33.4° to 47.6° for the round seed disk. The maximum rear angle ranged from 5.1° to 15.1° for the flat seed disk and 6.4° to 17.6° for the round seed disk. In addition to experimental results, model equations were also developed to predict QFI, side and rear angles as functions of metering rate and pitch angle. Quality of feed index functions were maximized and the optimum values of metering rate and pitch angle values were found to be 800 seeds min-1 and -2.6° for the flat meter disks. The optimum values for the round meter disks were a metering rate of 409.4 seeds min-1 and a pitch angle of 0°. © 2017 American Society of Agricultural and Biological Engineers.Oklahoma Agricultural Experiment StationThis research was supported by the Oklahoma Agricultural Experiment Station and TUBITAK (The Scientific and Technological Research Council of Turkey) -

SIMPLIFIED APPROACH FOR DESIGNING LENGTH OF MICROIRRIGATION LATERALS

A simple, direct, and easily adaptable analytical approach was developed for determining the length of the drip laterals laid on uniformly sloping grounds. The emitter flow variation was used as the index of water application uniformity. A dimensionless length design parameter was developed by reformulating the analytical expressions of emitter flow variation of the single inlet lateral and paired laterals. The length design parameter was defined as an implicit function of the pressure loss ratio. The relationship between length design parameter and pressure loss ratio was expressed by the graphs and regression equations. The condition for designing the length of the paired laterals was the length design parameter lying between >= 0 and <= 2.801. In most situations, there will be only one solution of design length of the lateral. When length design parameter is 2.801, there will be numerous solutions of length for both of the single inlet lateral and paired laterals. Based on the ranges of the length design parameter, the design equations of the length of the single inlet lateral and paired laterals were derived with the pressure loss ratio as the design variable. The analytical expressions of inlet working pressure head of microirrigation laterals were also simplified based on the energy gradient line method. When the emitter design flow, emitter flow variation criterion, and lateral diameter were provided, the length and inlet working pressure head of the microirrigation laterals could be easily calculated without performing complex computer operations or tedious computations. A comparison test with two numerical design cases covering various conditions indicated that the proposed approach could produce accurate results as those of the previous methods for practical purposes. By using the developed analytical expressions and regression relationships, the proposed approach provided a more simplified and adaptable design procedure than the traditional methods