Yield monitors are the second most common precision agriculture technology used today. Cotton growers who anticipate collecting yield data this season should take the time to check yield monitor components to ensure accurate data collection...
Auto guidance, a technology that pilots farm machinery via GPS satellites, could help farmers boost productivity and expand their farm operations. Benefits of GPS-based guidance include: reduced skips and overlaps, ability to use in conditions of poor visibility, keeps implements in the same traffic patterns year-to-year (controlled traffic), extends hours of operation, low-skilled tractor drivers, increased yield, energy and time savings, increased application accuracy, and enhanced operation safety.
There are two major categories at which GPS-based guidance is being offered: Navigation aids and Auto-guidance.
Relatively inexpensive navigation aids known as parallel tracking devices or, more commonly, Lightbars, are being used by operators to visualize their position with respect to previous passes and to recognize the need to make steering adjustments. The Lightbars are replacement for foam marker and are suitable for fertilizer and pesticide applications.
Positional accuracy depends on the quality of the DGPS receiver supplying data to it and the driver’s ability to “follow the lights” Most DGPS receivers used with Lightbars are sub-meter accuracy. Price depends on GPS Receiver and options.
More advanced auto-guidance options possess similar capabilities with an additional option to automatically guide the vehicle. The accuracy of the auto-guidance can be described either from a long-term static test (year-to-year accuracy) or short-term dynamic test (pass-to-pass accuracy). Year-to-year accuracy is important when different field operations are expected to be performed using exactly the same passes (such as controlled traffic, harvesting, etc.). On the other hand, many field operations (such as fertilizer spreading, disking, etc.) can tolerate long-term inconsistency of measurements obtained. Therefore, errors expected within 15-minute time intervals are more commonly reported when characterizing less accurate systems. Based on the quality of differential correction and internal data processing, the guiding systems have been separated into three categories:
Sub-meter accuracy usually means approximately 2-4 foot year-to-year and less than 1 foot pass-to-pass errors. The Differential GPS source could be from Coast Guard beacon, WAAS, OmniSTAR, and John Deere StarFire1. The OmniSTAR requires an annual subscription fee. These systems are relatively inexpensive. An example of a sub-meter system while performing tillage, some types of fertilizer and chemical applications, seeding and harvesting. However, operations requiring highly accurate guidance are not feasible with sub-meter level equipment. These devices can be easily transferred between vehicles, so the same steering system can be used on different vehicles.
Decimeter accuracy approximately 4-8 inches year-to-year and 3-5 inches pass-to-pass errors are feasible with decimeter accuracy systems. This can be achieved using either a local base station or dual frequency receivers with private satellite differential correction services, such as OmniSTAR High Performance (HP) or John Deere StarFire 2 (SF2). With the increased performance, operators can use auto-guidance during most of the conventional field practices excluded above.
Centimeter accuracy can be obtained when a local base station or network of base stations with the Real Time Kinematic (RTK) differential correction is used. Both long-term and short-term errors for these systems have been reported around one inch. Vehicles equipped with this high-level An example of a RTK system equipment can be used to conduct strip tilling, drip tape placement, land leveling and other operations requiring superior performance, as well as virtually any other task. In addition to the ability to accurately determine geographic location, auto-guidance systems usually measure vehicle orientation in space, and compensate for unusual attitude, including roll, pitch and yaw.
Growers who anticipate on collecting yield data this season should take the time to check yield monitor components to ensure accurate data collection. Proper calibration is key if management decisions, prescriptions, or profit maps are to be generated from yield data.
The purpose of this guide is to provide growers with some items to consider relative to harvest losses and capacities when operating diggers and combines. Digger setup and operation, along with proper timing often has a greater impact on yield recovery than any other aspect of peanut production; put simply, more revenue can be made or lost during digging than during any other field operation from seedbed preparation to combining. ...
The concept of site specific application of fertilizer is not new. Historically, fields were smaller than they are today and small areas within fields were frequently fertilized differently than the major portion in order to address special requirements for either nutrients used or rate of application. Today, computers and guidance systems have largely replaced techniques like counting rows or looking for atypical areas within a field. In addition, new technologies such as soil EC meter and the yield monitors have increased the awareness of variability within fields.
In general, there are two sampling strategies (grid, zone) that can be used to direct site-specific fertilizer management and lime application. Grid sampling uses a systematic approach that divides the field into squares or rectangles of equal size (usually referred to as "grid cells"). Soil samples are collected from within each of these "cells." The location of each "grid cell" is usually geo-referenced using global positioning system technology. This method is used when variability of soil pH and immobile nutrients within fields cannot be easily identified.
However, soils in our area do not change in squares. Zone sampling uses a more subjective and intuitive approach to divide any field into smaller units. Soil samples collected at random from within each zone are bulked together and analyzed to provide an average sample value for each unit. This approach assumes that variability of soils within a field can be easily identified. The Veris Electrical Conductivity (EC) meter, aerial or satellite photography, and multi-year yield maps can be used to divide production fields into management zones. Information from a yield monitor is essential in identifying zones that should be sampled separately. As with the grid system, sampling points can be geo-referenced.
The "grid" sampling strategy can be used for the following conditions: 1) a measure of non-mobile nutrients is the primary concern; with no movement, distribution will be affected less by topography and other fixed properties; 2) management practices used in the past will override natural variability; and 3) there is a history of manure use.
The criteria that would favor the use of zone sampling are: 1) cost of sampling and analysis is a major concern; zones may be larger than grid cells thereby lowering sampling costs; 2) a measure of mobile nutrients is the primary concern; and 3) there is no history of manure application.
