Issue link: https://read.dmtmag.com/i/401644
www.goodfruit.com GOOD FRUIT GROWER NOVEMBER 2014 37 Products & Solutions for Agricultural Safety r Chemical Gloves r Full-Face Respirator r Half-Face Respirator r Chemical Splash Goggles r Chemical Resistant Boots r Disposable and Reusable Suits Available Add a Cooling-Vest on hot days as a heat stress precaution www.oxarc.com Washington - Idaho - Oregon - Shop Online 1-800 -765- 9055 Safety First: Follow chemical manufacturer's guidelines for decontaminating the spray suite. Do not use suit if there are cuts, holes, tears, missing snaps, or separated seams. Chemical Protective Suit The sticking point was the cost of the soil samples that were needed in order to calculate how much fertil- izer the machine should apply in the different areas, he said. A soil sample had to be taken for every 100 square feet of ground. "I'm a hundred percent in favor if they could get it down to where the soil samples weren't so expensive," he said. Jim Nelson, who was a fieldman with Cenex at the time and helped develop the small machine, said sev- eral orchardists tried the machine in the 1990s, but it was 20 years before its time. Many orchards still had trees planted at low densities and some were using rill irriga- tion. Growers were happy to use practices their fathers and grandfathers used. An effort to introduce yield monitoring by weighing bins in the orchard also failed to catch on. Now, if the variable-rate applicator was available, Nelson thinks growers would be interested, particularly as there are alternatives to taking lots of soil samples. "It really does work and you got very uniform growth from the trees," he said. "It was phenomenal. It was just before its time. I think the interest in precision ag in tree fruit has completely turned around. In row crops, there's nothing that can't be monitored or done." Also in 1994, Dr. Tim Righetti, then a horticultur- ist with Oregon State University in Hood River, was exploring ways to ensure that trees in an orchard got the appropriate amount of fertilizer. His studies had shown that 75 percent of the trees could be overfertil- ized while the other 25 percent had too little fertilizer. His approach included surveying the orchard from the ground and with aerial photographs to produce a nitro- gen value for each tree. With that information, a fertilizer application could be tailored to meet the need of each tree. He envisioned that the trees would be barcoded and a computer on the fertilizer applicator would read the barcode. Clark Seavert, former superintendent at the Mid-Co- lumbia Research and Extension Center, said Righetti's system was never adopted commercially. Mapped Dr. David Brown, soil scientist with Washington State University, said it's no longer necessary to intensively sample the soil. Typically, before a preplant fertilizer treatment, the variability of the soil would be assessed using an electromagnetic-induction instrument, which measures soil conductivity (see "Precision ag tools"). This can indicate properties such as soil depth, soil texture, and some soil minerals. A near IR probe could also be used. Once the ground is mapped, based on those factors, zones that have similar soil types can be identified. Then, it's only necessary to take one sample to represent areas that have similar soil types. Once the trees are in the ground, fertilizer needs can be inferred from how the crop is growing, which can be assessed through remote sensing. Karen Lewis, Washington State University extension specialist, said adoption of new technologies in tree fruits is often lower than anticipated. "And it's based on the fact that the execution is one more thing they have to do." Growers often think they don't need monitoring tech- nologies, for example, because they can walk or drive up and down their rows and check on tree growth with their own eyes. "Every time we've surveyed growers on adoption of technology, regardless of what it is, the same thing always comes up," she said. "They want to see it's been proven to be reliable and dependable in the field. They want to know it's not a toy—that it contributes to their bottom line and improves fruit quality. What they want is improved fruit quality day in, day out. So somebody has to prove, very robustly, that the technology does that." Bruce Allen, president of Columbia Reach Pack in Yakima, Washington, said he sees benefits in growers having more tools to help them make better decisions. However, even now, growers are making informed decisions based on fairly accurate assessments of their orchards. "Most growers have been around for a long time, so they have lots and lots of experience," he said. "You may not be sitting there going down a list of experiential factors, but it's there in your subconscious—those trees look a little weaker or look a little strong; fruit size looks a little small; the thinning job looks a little excessive— that's based on a huge amount of experience." • right for precision ag