- Author: Trina Kleist
- Posted by: Gale Perez
AI-trained machines slash labor costs
Experimental robots are reducing the costs of hand-weeding by learning the difference between weeds and lettuce. In addition, steam can clear the soil of fungi and spores that cause lettuce and spinach to wilt, reducing the need for chemical herbicides in the bargain, according to the latest research by Steve Fennimore and his lab at the UC Davis Department of Plant Sciences.
Fennimore, a professor of Cooperative Extension, presented his findings at a recent meeting of the California Leafy Greens Research Board, a body of the state Department of Food and Agriculture, which is helping to fund the work. It was attended by growers, association representatives and educators. This research would help them solve three big problems:
“What everyone is facing is higher costs, fewer personnel and greater difficulty using pesticides due to regulations,” said Fennimore, who also is a specialist with UC Cooperative Extension.
He and team members Richard Smith (UCCE Farm Advisor) and Nelly Guerra (UC Davis Fennimore Lab graduate student) evaluated automated weeders that were trained using artificial intelligence for use in lettuce fields. In tests last year near Salinas, Calif., smart weeders built by FarmWise Labs Inc. and Stout Industrial Technology, Inc., removed between 32 percent and nearly 100 percent of purslane and other weeds, Fennimore said. That reduced the need for hand-weeding between 13 and 62 percent. The weeders proved more cost-effective in fields where there were more weeds, Fennimore added.
The team also tested steam to clear soil of diseases that cause leafy greens to wilt and turn brown at the edges. During trials last summer in the Salinas Valley and in Yuma, Ariz., team members measured soil pathogens before and after steaming the rows where seed is planted. They found significant reduction in the fungus fusarium; in the tiny balls, or microsclerotia, that allow fungus to survive in the soil; and in pythium, a water-born mold. Steam treatments also boosted lettuce yield and reduced weeds. The team collaborated with Mark Siemens, of the University of Arizona.
Building on those successes, Fennimore and team this year are combining steam with standard cultivation to see if they can control weeds 100 percent and reduce hand-weeding to zero.
Media resource: TrinaKleist, tkleist@ucdavis.edu, (530) 754-6148 or (530) 601-6846
Original source: UC Davis Plant Sciences Dept. website
- Author: Ed Perry
- Editor: Anne Schellman
To have your soil analyzed, contact a commercial testing laboratory. For a list of soil laboratories located in Stanislaus, Merced, Fresno, and Merced Counties, visit https://cemerced.ucanr.edu/ClimateSmartAg/HSP/SoilTest/Soil_Testing_Laboratories_in_Fresno_Madera_Merced_and_Stanislaus_Counties/
Vegetable Gardens
For vegetable gardens, the application of a fertilizer containing nitrogen and phosphorus is usually all your soil will need to get your vegetables off to a strong start. Other nutrients like zinc or iron are sometimes deficient or unavailable in certain soils, but they are usually not applied unless plant deficiency symptoms appear.
Diagnosing a Plant Problem
Besides moisture, oxygen is also required in the soil for good root growth. Poorly drained soils often have little oxygen in them because excess water fills all the spaces between the soil particles. My advice to gardeners is to correct drainage problems first, then worry about fertilizers. Often problems with sick and dying plants are caused by overwatering or a lack of good soil drainage than by nutrient deficiencies.
If you have an unhealthy plant, gently dig near the root system and check soil moisture and drainage. Since plant roots need oxygen, roots may suffocate if excess water does not drain quickly. Unfavorable climatic conditions, including temperature extremes and drying winds can also affect plant growth, as well as insect pests and diseases. For small plants, pull up a plant or two and check to see if the roots are healthy.
The best way to keep soil healthy, especially in vegetable gardens is to add compost annually to improve soil health. For perennial crops like fruit trees, annual applications of fruit tree fertilizer in spring can be beneficial.
The UCCE Stanislaus County Master Gardeners Can Help!
If you need help diagnosing a plant problem, take a plant sample to the UCCE office located at 3800 Cornucopia Way Ste A in Modesto. Master Gardeners are available on Wednesdays from 9:00 a.m. to noon in person or by phone (209) 525-6802. You can drop off a sample anytime during business hours or fill out an online survey and attach photos using this link http://ucanr.edu/ask/ucmgstanislaus A Master Gardener will get back to you within 5 days of your request.
If you live in another county in California, you can find your local Master Gardener program by using this link https://mg.ucanr.edu/FindUs/
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County where he worked for over 30 years.
/h4>/h4>/h4>- Author: Richard Smith
- Posted by: Gale Perez
Richard Smith is the UC Cooperative Extension Vegetable Crop Production and Weed Science Farm Advisor in Monterey, Santa Cruz and San Benito counties.
Automated weeders remove weeds inside the three- to five-inch-wide uncultivated band left around the seedline by standard cultivation. Automated weeder technology has improved significantly over the past decade. All automated weeders use 1) cameras to detect plants, 2) a computer to process the image and make decisions about which plants to keep and which to remove and 3) a kill mechanism. Kill mechanism that operates in the seedline used by currently available machines are either a split blade that opens around keeper plants and closes between keeper plants, a spinning blade that avoids the keeper plants by placing them in a notch in the blade or a spray application of an herbicide. Autoweeders being used in the lettuce industry include: Robovator (Denmark), Steketee (Netherlands), Ferrari (Italy), Garford (England), Naio (France) and FarmWise, (USA, Photo 1) and Stout (USA, Photo 2). The machines are particularly effective for use with transplanted vegetables because recognizing the difference between the crop and the weeds is easier given the initial size difference between the transplants and germinating weeds.
One key motivating factor to the use of autoweeders is the scarcity of available labor to weed fields, and in that sense, automate weeder technology has arrived at a critical time in the agricultural industry. Clearly automated weeders are useful to growers because they remove weeds, but this technology is currently quite expensive, and growers need to make decisions on when it is economically advantageous to use them. Currently, automated weeders are either purchased by growers or a service company provides autoweeding for a fee. Ideally, auto weeders would remove all the weeds from a field and not require any further follow-up hand weeding. However, this is not always the case because some weeds are missed because they are too close to the crop plants and cannot be removed without risking injury to the crop (Photo 3). In addition, in direct seeded lettuce production which requires thinning the lettuce to the desired stand, double lettuce plants (Photo 4) frequently are left following thinning and must be removed by a subsequent weeding operation.
In lettuce production fields, growers try to remove as many weeds as possible from the field to reduce weed seed production and keep future weeding costs low. As a result, they will normally send in a crew even after using an automated weeder. Using the autoweeder will help to speed up subsequent hand weeding operations (Table 1), but the grower faces a weeding bill from both the hand weeding and autoweeding operation. In Figure 1, we looked at initial weed populations and the impact of autoweeding on subsequent hand weeding time. This data shows that when weed populations are low, autoweeding does not speed up subsequent weeding as much as when initial weed populations are higher.
The most clear-cut scenario for autoweeders is when they remove enough weeds to forego subsequent hand weeding. This can and does happen, even in the intensely managed cool season vegetable production fields. But in cases where subsequent hand weeding or double removal is necessary, autoweeding may add an additional cost, especially in fields that have low weed populations. However, even in cases with low weed populations, growers may be motivated to use autoweeders because they help manage scarce labor resources and facilitate crews to quickly and efficiently complete follow-up weeding operations.
- Author: Terry Pellegrini
But wait! Did you know that cucumbers are actually fruits? Botanically speaking a fruit should have at least one seed and grow from the flower of the plant. Because of this definition cucumbers are classified as fruits because they contain tiny seeds in the middle and grow from the flower of the cucumber plant. While I will always consider it a veggie - as I do that other “fruit” the tomato – knowing its proper classification makes my inner Master Gardener very happy.
Growing cucumbers is relatively easy, although they do take some care. They need plenty of sunshine, loose and nutrient dense, slightly acid soil. Adding several inches of compost or aged manure into the soil, worked in to a depth of about 6 inches, is usually all it takes to make them happy. They do not like frost so plant your seeds after the threat of frost has passed – about March 20th here in the Central Valley. If you are planting a vining variety place your trellis first, before planting your seeds or transplants to avoid disturbing the roots of the plants later on. Also cucumbers HATE being watered by sprinklers (trust me, I learned this one the hard way). Water only at the base of the plant - I use a drip system that the cucumbers seem to love.
Bush varieties need a little extra care as the immature cucumbers can die or get slimy if they sit on wet soil or in water all day. A good layer of mulch around the base of the plant and then under the maturing leaves will keep your cukes out of harm's way.
Harvesting your cucumbers will vary in timing and size depending on the variety, but on average it takes between 55 and 70 days. Your seed packets or the information that accompanies your transplants should tell you when to pick your cucumbers. But no matter the variety, always clip off your cucumbers, don't pull off or twist them. This can damage your plants and may discourage it from producing more flowers and thereby less cucumbers. With care, your plants should give you several harvests, especially if your succession plant your cucumbers – planting one to two weeks apart.
Once harvested, the fun begins. Your cucumbers can be added salads, made into sandwiches, and can be eaten straight from the vine (yes, you can eat the skin – be certain to wash it first). I love to make fresh tzatziki sauce for dipping and of, course, pickles! Fermented or refrigerated, dill or sweet, a pickle made from those from your own garden are extra special.
- Author: Elizabeth Mosqueda
- Author: Richard Smith
- Author: Steven Fennimore
- Posted by: Gale Perez
Elizabeth Mosqueda is an Assistant Professor at the California State University, Monterey Bay.
Richard Smith is a Vegetable Crop Production and Weed Science Farm Advisor with UC Cooperative Extension.
Steve Fennimore is a Cooperative Extension Weed Specialist at UC Davis.
BACKGROUND
Automated weeder technology has evolved significantly over the past decade. The technology used by auto weeders is similar to that used by the auto thinners: cameras detect plants, a computer processes the image and makes decisions about which plants to keep and which to remove and then activates the kill mechanism. Automated weeders remove weeds from inside the uncultivated band (3-5 inches wide) left around the seedline and unreachable by standard cultivation. The kill mechanism used by the currently available machines is either a split blade that opens around keeper plants (e.g. Robovator and Steketee IC) or a spinning blade that avoids the keeper plants by placing them in a notch in the blade (e.g. Garford Robocrop). In 2015, evaluations found that Robovator and Steketee IC autoweeders removed 51% of the weeds in the seedlines and reduced follow up hand weeding time by 37%. From these studies we observed that auto weeders were not miracle workers, in that they required a relatively low to moderate population of weeds in order to operate effectively. As such good weed control in prior rotations or a good preemergent weed control program was needed to keep weeds at a moderate level. However, new developments in crop/weed detection may improve this issue. In addition, auto weeders do not remove all the weeds in the seedline because they cannot remove weeds that are too close to the crop plants without risking damaging them. And finally, the automated weeders are currently not capable of removing lettuce doubles in direct seeded lettuce fields, and as a result, it is still necessary to have a crew pass through the field following the passage of the auto weeder, if for no other reason than to remove double lettuce plants. The main impact of the auto weeders is to reduce the amount of time that follow up hand weeding/double removal takes. This then brings up the hard question for a grower – does the reduced amount of time that follow up weeding/double removal takes, make up for the cost of running the automated weeder through the field. What is the economic threshold to run an autoweeder?
In 2020 we evaluated two new autonomous weeders. These machines are designed to run without a driver and are intended to be set up to weed a field on their own. In these studies, the machines always had someone accompany them through the fields, as auto weeding lettuce fields is still in the research and development phase. We conducted, evaluations of the Naio Dino platform (Photo 1) and the FarmWise Titan (Photo 2). We evaluated initial weed populations and subsequent follow-up hand weeding to better understand the relationship between weed pressure and the time savings for subsequent hand removal of weeds and doubles.
METHODS
Two trials were conducted with the Naio Dino autonomous robotic platform equipped with finger weeders and five trials were conducted with the FarmWise Titan autonomous weeder which used a split knife that closes between crop plants, thereby taking out weeds in the seedline, and opens around the keeper plants. Auto cultivation was carried out following thinning (except Dino Trial No. 2 was cultivated prior to thinning) and were compared with standard cultivation which leaves a 4-5 inch wide band around the seedline. Pre and post cultivation weed and stand counts were made of a 6-inch wide band around the seedline to determine the efficacy of standard and auto cultivation. Weeding time of the treatments was evaluated by measuring the time it took members from a commercial hand weeding crew to pass through the treatment rows. Weeding time was then converted to hours per acre. Stand counts and harvest evaluations were conducted to determine if the auto weeders caused damage to the stand or to crop plants. See Table 1 for trial details.
RESULTS
Naio Dino evaluations: This cultivator used finger weeders and removed more weeds from the seedline than standard cultivation (Table 2). It reduced weeding time in trial No. 2 and did not reduce the stand or mean head weight of the lettuce.
FarmWise Titan evaluations: Five trials were conducted with this implement. The FarmWise Titan removed a higher percent of weeds from the seedline in all trials and reduced subsequent hand weeding time in three of four evaluations. More time was required to hand weed fields with higher initial weed populations (Figure 1). According to the data in Figure 1, at high weed densities, subsequent weeding time was reduced using an auto weeder by 12% for each increase in weed density of 10/m2. The FarmWise Titan did not significantly reduce the stand of lettuce or reduce the mean head weight of lettuce.
Overall, auto weeders removed about twice the number of weeds than standard cultivation from the 6-inch band around the seedline and reduced subsequent hand weeding/double removal by 4 hours/acre (Table 3). They did not reduce the stands of lettuce or affect mean head weight of lettuce and were therefore, did not damage lettuce plants to a significant degree. In general, the use of auto weeders appears to be clearly justified in fields with higher weed densities. However, other pressures may also spur the move to automated weeders such as increasing labor costs and lower labor availability.