High - Tech Harvest

The days of farmers sitting around the country store swapping yarns and seat-of-the-pants predictions for the growing season are long gone. Oh, the farmers still talk and spin yarns, but mostly through e-mail and Internet chat sessions. And the conversation today focuses less on creaky-bone predictions of rain and more on precision farming, the Global Positioning System (GPS), the reliability of precise soil samplers, yield monitors and computer interfacing problems

Local Irrigation

Water may be readily available in the soil but not accessible to the plant. Time-release water polymer gels that soak up water and hold it for plant use have evolved into versatile, proven water management tools. Superabsorbent gels on the market today absorb from 30 to 800 times their weight in water. As plants require water, their roots easily withdraw water from the gel material. More than 90 percent of the moisture held in the gel is available to the plant. After the growing season, the products eventually degrade in the soil and disappear. Some gels remain effective through many swell-shrink cycles and can work for five years or more.
 

Soil researchers at Texas A&M University and the USDA Agriculture Research Service (ARS) are developing a computerized irrigation system that measures and calculates how much water to apply every half-hour. The automated time domain reflectometry (TDR) system uses stainless steel probes placed in the ground at varying depths, from a few inches down to several feet. A computer-controlled TDR instrument sends an electronic pulse through a buried cable to the probes. The longer it takes for the pulse to travel through the probes, the more soil water. The probes work in most irrigated agricultural soils and one TDR system can handle up to 241 probes.

A new sprinkler head may help growers apply precisely the right amounts of water and farm chemicals to their crops. The head is designed to avoid over-irrigating, which wastes water and can cause leaching of fertilizer or other chemicals into underground water supplies. Unlike pulsating devices that alternately turn the flow on and off, the variable-rate sprinkler head never completely shuts off the flow. The amount of flow that's blocked is determined primarily by the diameter of a pin that moves in and out of the nozzle without altering the area covered by the spray. The needle is controlled either by an electrical power source or a hydraulic actuator activated by a networked computer. In effect, each area within the sprinkler's reach becomes a garden plot.

The sprinkler head can be incorporated into precision-farming technologies. When an irrigation system delivers fertilizer or other chemicals along with water - a technique known as chemigation - application rates can again be customized to take into account natural variables such as the fertility of different soil types.


Today's high-tech farmer needs to know as much about computers and satellites as he does about agronomy and phases of the moon. Modern precision farming allows farmers to work more efficiently, while obtaining increased yields from their crops. Theoretically, precision farming means using information technologies such as GPS and geographic information system software to gather, store, view and analyze vast amounts of data - which can then be converted into usable knowledge to make better farm management decisions for crop production. Practically, precision farming means that farmers can visualize, identify and control crop patterns from a central computerized location. The goal is to improve profitability and reduce risks. For example, an increasing number of tractors are linked to GPS, so their position can be tracked from a distant office. Land management information in office computers then tells tractors where to go, stop, turn or activate cutting or fertilizing equipment. Through a tractor-based GPS, a farmhand is told when and where to turn to begin tilling each row of a field. This can greatly reduce overlap, which on a large farm saves hours of work. It all works continuously in the field with a 3-in. accuracy, even while the tractor is moving. Here is how the parts of today's high-tech farm work and fit together.


Images from the robot shepherd camera are analyzed by the computer program to find the positions of the robot and flock. Electronic ear tags allow individual pigs to be identified. A high-tech chicken coop meters food and monitors health.


Yield Monitors

The use of GPS in farming has grown beyond the early practice of grid soil sampling and variable rate fertilizer applications to a new, more useful focus on yield monitoring. In precision farming, growers break fields down into regions, or cells, analyzing growth characteristics of each cell and improving crop health and yield by applying precise amounts of seed, fertilizer and pesticides as needed. Many associate precision farming with combine yield monitors, equipped with GPS. Some farmers now use multi spectral imaging to produce gray scale values that are converted to color images showing poor to good vegetation conditions.

Yield monitors can forecast yield as bushels per acre, total pounds, acres per hour worked and grain moisture content. This is all done while the combine is in use, and can be recorded on a memory card for later analysis. Sensors monitor, calculate and record, in real time, each field's yield as the combine harvests the crop. This eliminates having to wait until the entire harvest is complete before projecting yields and making important decisions on how much to store or sell.

Field Scouting

Field scouting uses a portable geographic information system unit that allows farmers to identify and record the location of problems or events that will affect production - including soil differences, insect infestations, fertility deficiencies and weed problems. Remote sensing, and satellite and infrared images also can be employed while scouting fields. Satellites that capture infrared images can look at moisture content and quickly assess the health of a crop before visible damage appears. Soil testing, however, still requires farmers to walk across their fields to take samples.


Smart Spraying

Equipment is now available - and more is being developed - that will allow chemicals to be applied to a single field at variable rates. Sensors monitor tractor speed and adjust the amount of fertilizer or pesticide sprayed on the soil.

Generally, the system records, in 2-second intervals, the amount of pesticide that was applied.

A new "seeing-eye" sprayer for weeds uses a light-reflectance sensor to scan the ground for patterns that match weeds. It then kills them with less herbicide than conventional sprayers use. The eight-row hooded sprayer uses its sensor to distinguish differences in the light reflected from bare soil and from weeds between crop rows. If it "sees" a weed, it sprays it. The sprayer was developed for row crops through a cooperative research and development agreement with Patchen, of Los Gatos, Calif., and ARS scientists in Mississippi.

The Silsoe Research Institute (SRI) in Britain is looking into improving the accuracy with which solid manure is spread onto land. This system, based on a side discharge impeller-type tanker spreader, features an electrohydraulic-operated discharge control door and a novel driveline torque transducer capable of sensing discharge rates in real time. The integrated control system communicates with the tractor and spreader subsystems to control engine speed, gear selection and spreader settings. Once a desired application rate has been selected, the system automatically adjusts the spreader and/or tractor settings.

Sensors also can monitor the speed of a tractor and adjust the seed planter to keep spacing consistent. This ensures optimal spacing, while letting farmhands concentrate on other matters, such as making sure the seed planter does not clog.

Robot Farmhands
 

Automation is even working its way into the barnyard. Research into flock behavior and modeling led a research team at SRI to develop a robot that could enter a field, gather a flock of ducks and steer them safely to a predetermined destination. The robot system includes a robot vehicle, computer and camera. Commands are then sent by radio to the robot, which guides the ducks to the goal. Using ducks, instead of sheep, allowed the trials to take place on a smaller and more convenient scale. Duck flocking behavior is recognized by shepherds as similar to sheep, and ducks are often used in sheep dog training. The project also looked at flock dynamics and how individual animals in a flock behave. Weighing pigs is the most basic guide to quality control but it's time consuming and stressful to both farmers and pigs. SRI has developed the Growth Rate and Conformation Evaluation System, which uses image analysis techniques to watch pigs grow. The image analysis system uses a video camera connected to a computer, mounted over a feeder. The computer measures body area, ham width and ham area, and determines each pig's shape, weight and growth rate. During the 20th century mechanical technology made it possible to feed a rapidly growing American population while keeping the price of food lower than any other place on earth. In this century, making these machines smarter will extend these benefits to the world
	Using satellite data, GPS allows farmers to precisely steer equipment and map the land to be tilled.

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