Installation and Use of Gro·Point™
Rule of Thumb for Gro·Point™ Use
It is generally recommended that Gro·Point™ soil moisture measuring sites be located in each irrigation set, or every acre. The site should be representative of the majority of the ground within the set, which can be determined easily by probing the soils in several locations around prospective sites.
Gro·Point™ Use on Hilly Terrain
On hilly ground, Gro·Point™ must be located about one third (1/3) below the high point for the best average reading. However, locating the sensor on the hilltop will probably represent the driest condition in the field and may be used when trying to maximize production in this area. Locating sensors in wet or low areas is not recommended.
Gro·Point™ Use on Row Watered Fields
On row watered fields, simply locate one sensor at one third (1/3) of the run down from the top end, and another sensor one third (1/3) up from the bottom end.
Site Selection for Row Crops
When monitoring row crops, place sensors in the bed directly below plants, or offset four to six inches (15 cm) in the side of the bed. Sensors should not be located in the bottom of the bed, or in the middle between two rows, as fewer roots will be active in this region.
Ideally the sensors should be installed before planting, so that plants and fertilizer are not disturbed during installation. If the sensors are installed after planting, attempt to place them where the roots will grow around the sensor in a uniform manner.
Site Selection for Tree Crops
Gro·Point™ is suited for soil moisture measurement applications for tree crops. Guidelines for use with new plantings, established orchards and vineyards are provided below:
Sensor sites should be located where they will be quickly surrounded by new root growth. This placement is typically one foot (30 cm) to the side and six inches (15 cm) below the soil surface of a nursery transplant. The placement of the Gro·Point™ sensor will likely need to be relocated within three years, when the crop has matured with a full canopy.
When using Gro·Point™ in established orchards, select sites that are representative of typical irrigation application rates and place the sensors one third (1/3) to one half (1/2) the distance from the tree trunk to the limit of the canopy overhang.
Within 30 days, roots will grow into the sensors in 30 days, and moisture readings will be representative of the orchard. This normal growth will result in both accurate soil moisture readings as well as an immediate response to the crop's evapotranspiration.
Typically, vineyards are very deep rooted. Therefore, soil measurement in this environment should occur at depths of four to seven feet and following the guidelines in "Installing Sensors in Deep Rooted Crops" Gro·Point™ sensors must be placed one foot (30 cm) offset from vine row and between two vines. Any roots that suffer damage during installation should regrow within 30 days and maintain accurate soil moisture readings.
Gro·Point™ Sensors Around Drip Irrigation Emitters
Gro·Point™ Sensors are well-suited for use around drip irrigation emitters. The sensors placement must be offset to the side, and/ or between two emitters, or drip irrigation emitters. Sensor placement will be directed by soil type and the horizontal movement of moisture:
- For loam and clay soils, place sensor at two-foot offset
- For sand soil, place sensor at one-foot offset
Sensor must not be position below an irrigation emitter as atypical readings will result.
Gro·Point™ Sensors Around Sprinklers
Gro·Point™ Sensors are well-suited for use around around sprinkler systems and should be placed one-third to one half (1/3 to 1/2) the distance from the sprinkler to the edge of the wetted area. To avoid atypical readings which could result from irregular wetting patterns, Gro·Point™ sensors must be placed in an area that receives uniform water application.
Gro·Point™ in Deep Rooted Crops and Vineyards
Monitoring and regulating the deep soil moisture allows growers to control crop quality as well as the stress related to moisture in vineyards in order to manage the quality of wine grapes.
Installing Sensors in Deep Rooted Crops and Vineyards
Sensors to be placed at depths of four to seven feet (1-2 meters) may be installed using the following technique:
- Auger a hole four to six inches in diameter (10-15 cm) to the desired depth, using a soil auger or post hole digger.
- Place the Gro·Point™ Sensor into the hole vertically, lowering it into place, using the sensor cable.
- Pack the soil carefully around the sensor, so that there are no air pockets. A long piece of pipe or a piece of wood, about two inches square will be useful to help pack the soil into the hole.
- Add water to hole to help eliminate air pockets.
- Install conduit over cable.
- Add six inches more backfill soil.
- Add more water to hole.
- Finish backfilling the hole.
In deep locations, a special length may be required as the standard cable supplied with the Gro·Point™ Sensor will likely not be long enough. Either a special length cable may be ordered or an existing cable may be spliced and lengthened. Ensure that all splices use waterproof wire connectors inside a waterproof electrical box or enclosure.
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