Tag: waste

  • Dealing with Pesticide Shortages in 2022

    Dealing with Pesticide Shortages in 2022

    We’ve had dire warnings about possible pesticide shortages and price hikes for 2022. Price hikes are one thing. But if the products we need simply won’t be available, we have a tougher challenge.  It’s time to plan pesticide conservation.

    But first, what’s behind the product shortage?

    Emily Unglesby of dtnpf.com provided an excellent overview of the issue here and here. She said the reasons for the shortage are many-fold and came together in a perfect storm. Starting about 2017 or so, pesticide manufacturers tried to reduce the overall inventory of products to improve logistical efficiencies.  That effort was rewarded in 2019 when a wet spring in the US dramatically reduced seeded area to a low of 165 M acres. The resulting lower demand again provided incentives to reduce inventories. At the same time, US trade sanctions against China in the form of tariffs impacted production and shipment of many active ingredients to US markets. When Covid-19 happened, it affected both production and shipping of many goods, including pesticides. Container shipment costs increased sharply, and the ability to move them to and from ports was hampered. This then coincided with record seeded area in the US of 180 M acres in 2021, creating higher than usual demand. By that time, very little buffer remained in the system. The growth of Enlist E3 and Xtend Flex has placed additional pressure on glufosinate.

    Then two further events occurred. Hurricane Ida forced a shutdown of Bayer’s Louisiana glyphosate plant. And China, in late 2021, legislated a temporary 90% reduction of yellow phosphorus production in Yunnan Province in anticipation of the 2022 Olympic Winter Games. With phosphorus as a fundamental ingredient in glyphosate, glufosinate, and some fertilizers, this loss of production places significant strain on many products. The usual habit of returning unused pesticides to the retailer also became less common amidst shortage news, adding difficulty to planning inventories and demand.

    Shortages of popular herbicides like glyphosate, glufosinate, and clethodim will put demand on alternatives. Spreading out risk by implementing pre-emergent products where possible will pay dividends. But the ability to ramp up production of minor products is just as dependent on the supply chain, and these alternatives may therefore not offer reprieve if ordering is left to the bitter end. Planning ahead and staying in touch with retailers about your plans and your own inventory will assist the entire system in managing production and redistributing existing stocks.

    Safe to say products will be more expensive, and possibly impossible to obtain. Here are some things to consider to minimize the impact.

    1.Grow crops that require less pesticides. Crops which have good genetic resistance to insects and disease will be more likely to cope without a protective spray. Some crops are inherently competitive early on and give less time and space for weeds to become established. Remember that the relative time of emergence is important for crop yield loss from weeds. If crops emerge before weeds, they have the upper hand and will maintain higher yield potential. Crops that can be seeded early will prevent weeds from occupying that niche.

    A competitive crop is the best herbicide.

    2. The most powerful herbicide is a competitive crop. Use agronomic tools that favour good seedling establishment. The usual advice of seeding into a warm, firm, moist seedbed, should we be fortunate enough for the weather to cooperate, applies here. There is value in higher seeding rates to help outcompete weeds. Use fertilizer placement that favours crops, not weeds, such as side banding.

    3. Sample the spray water source and have it professionally tested. After a record drought in western North America, aquifers are low and surface waters have receded. Water quality will probably not be the same it has historically been. Use water conditioners to reduce effect of hard cations and bicarbonates. Ammonium Sulphate (21-0-0-24) at 1% w/v is a general treatment, harder water may require up to 3%.

    Conduct a water test in 2022 and condition spray water if necessary.

    4. Do not use untested mixes of pesticides with specialty foliar fertilizers. These may impact herbicide performance, or worse, result in an incompatible mix.

    5. Use the lowest label rate of product that is relevant for the pest you’re trying to control. Many products have a range of rates depending on the weed species and stage. Scout your fields and take advantage of the lower rate option if you can.

    Invest in logistics and be prepared to respond to a good spray day to get the timing right.

    6. Spray herbicides early. It’s been shown that crop plants can sense the presence of weeds before they compete for resources, causing a physiological adjustment that results in irreversible yield loss. The shorter the time that weeds and crops co-exist, the better. Also, smaller weeds are easier to control. Weeds that escape this early application will need to compete with an established crop and won’t thrive or impact yield as much.

    Smaller weeds are easier to control and may allow a lower label rate.

    7. It’s not advisable to reduce product rates from the one recommended on the label. Although label rates contain a margin for poor conditions, the risk of selecting for polygenic resistance exists. Polygenic resistance occurs when some weeds happen to be slightly more tolerant to the herbicide than the rest of their cohort. These weeds may survive a lower rate, and go on to produce seeds. If these outcross with other survivors, their more tolerant offspring will increase in relative abundance. With further such selections in subsequent generations, weeds become even more tolerant and eventually dominate.

    8. Apply the spray as uniformly as possible. Make sure the spray nozzles are within a 5% flow rate tolerance along the entire boom. If the set is older, consider a wholesale replacement. But the biggest enemy of uniform deposition seems to be turbulence created by wind and driving speed around the tractor unit. Slower wind and travel speeds help somewhat. Variable deposition means that some regions receive up to 50% more than intended, and others receive 50% less. This means weeds in the lower deposit regions may survive the application. The more variable the application, the higher the rate that is needed for acceptable control.

    Slower travel speed reduces variability of the spray deposit, limiting escapes.

    9. Use finer sprays whenever the tank mix contains a contact mode of action product (e.g., Group 1, 6, 10, 14, 15, 22, 27) or targets grassy weeds. Both situations require smaller droplets for best performance. The use of finer sprays may mean fewer hours in the day when drift is acceptable, and as a result, investment in efficient tendering and cleaning as well as overall time management pays dividends.

    10. Make efficient use of the product in the tank, preventing waste. The amount of product being discarded can range to over 10% of the total needed to treat a field, but this can be reduced to 3% with the proper steps. The following are areas where improvement is possible:

    (a) Prime the boom efficiently using sectional shutoffs or better yet, a recirculating boom. These can be primed without any spray leaving the nozzle or boom ends.

    Conserve product by eliminating priming waste with a recirculating boom.

    (b) Measure the spray mix of the last tank accurately, minimizing leftover. Consider the AccuVolume system that weighs the tank contents to the closest gallon. Tanks can be filled with the exact amount, and rates can be adjusted as the leftover becomes apparent on the last passes.

    Accurate measurement of tank volumes prevents leftovers.

    (c) Invest in individual nozzle shutoffs to improve sectional control resolution. These are part of any Pulse Width Modulation system but can also be obtained as air-actuated valves that are very affordable. Such capability is necessary for recirculating booms.

    Nozzle sectional control can save 4 to 5% product use.

    14. Consider an optical spot spray system such as the WEEDit Quadro, the Trimble WeedSeeker, or the John Deere See & Spray Select, available for 2022. These systems are “Green on Brown”, meaning they selectively spray just weeds in a burnoff or chem-fallow. This can save about 70% of the spray depending on weed density. More such systems are on the way, some even offering “Green on Green” that selectively identifies weeds among a crop. The return on investment of these systems is directly related to the pesticide cost, meaning in a year with high pesticide prices they pay off faster. If shortages of product become a reality, a spot sprayer may be the only way that some fields get treated at all.

    Pesticide shortages will not be fun. Unfortunately, their appearance coincides with higher fertilizer prices, meaning crop establishment will need to overcome that factor as well. But there are tools to minimize the impact if we’re willing to implement them. Just as necessity is the mother of invention, scarcity is the father of conservation.

  • How Spot Spraying will Affect Sprayer Design

    How Spot Spraying will Affect Sprayer Design

    Some years ago, a friend recommended that I read The Tipping Point by Malcolm Gladwell. In this book, Gladwell tries to understand why some things catch on, and others don’t. It’s a compelling read full of Gladwell’s trademark stories and his knack to deftly interpret scientific studies. He talks of connectors, mavens, and salesmen, as well as the “stickiness factor”, a measure of how memorable something is, as keys to success of products and ideas. I think of the book often as I ponder the many good ideas in agriculture, many of which never see widespread adoption.

    One of these good ideas is spot spraying. Green-on-brown detection was first introduced in the early 1990s. Anyone remember the Concord DetectSpray? It was great but had bad timing, as resistance wasn’t a big issue and glyphosate prices were about to slide. Green-on-brown grew to the NTech (later Trimble) WeedSeeker a few years later. Rometron’s WEEDit built on Trimble’s success and found widespread adoption in Australia in the past ten years. Spot spraying did not gain any traction in North America during this time.

    Australia is unique in many ways, not the least of which is their summer spraying practice. Summer is the hot, dry season where land is typically fallow and weeds are kept in check with herbicide sprays (aaaah, the serenity). Making several passes over a field, combined with the need to control some larger and hardy plants, is expensive, and a spot spray saves much of the cost. The savings can be put to use with more effective herbicide tank mixes that delay the onset of herbicide resistance. Spot sprays pay for themselves in short order Down Under.

    It’s more of a challenge in the northern plains of North America, where the fallow season involves snow cover and burnoff occurs in a short window before seeding and sometimes after harvest. But nonetheless, spot sprays have a fit for many of the same reasons.

    WEEDit is the first system to make serious inroads in North America, with several dozen systems having been retrofitted to high-clearance sprayers. High detection accuracy and hardware reliability is proven in three seasons.

    On March 2, 2021, John Deere entered the Green-on-brown spot spray area with See & Spray Select. This not to be mistaken as competition. Instead, the entry of a major brand provides validation of the concept like only a large manufacturer can. Yes, we’ve reached a tipping point.

    While the first Green-on-brown units are becoming established, Green-on-green, the ability to detect weeds within a crop, continues to be developed around the world. French startup Bilberry has made enough gains in Australia to bring its product to market with Agrifac, where it’s called AIC Plus. In farmer field trials, they have achieved 90 per cent detection accuracy of wild radish in Western Australia, and claim that they are ready for broadleaf weed identification in wheat, barley and oats. Bilberry’s technology will also be seen on Australia’s Goldacres and France’s Berthoud. Other startups, notably Israel’s Greeneye Technology, plan to introduce a Green-on-green system in the U.S. in the near future. Amazone, the German farm equipment giant, partnering with Xarvio and Bosch, announced plans at Agritechnica to have a commercial unit for sale by 2021.

    This technology will have significant impact on sprayer design philosophy. At present, productivity is synonymous with capacity, and large tanks with commensurate heavy and powerful tractor units dominate. Spot spraying savings will depend on weed density and hardware resolution, but 50 per cent to 90 per cent reductions in spray volume can be expected. A 1,600-gallon tank would no longer be necessary. The savings in frame weight and horsepower would be significant, as would the time savings from less intense tendering demands. These savings would offset the lower driving speeds that accompany sensing technologies, and, overall, provide a lower bar for autonomous operation. We may see lighter specialty spot sprayers.

    The savings in brute size will be countered by increased sophistication. Better boom height management is essential for spot spraying, not just for the sensor to properly see the target and estimate the time needed for the boom to reach that spot, but also for the spot spray itself to deliver the right dose. In any fan spray, band width at ground level changes with height, and that, of course, is related to dose. Trailed booms can address this issue easily.

    But not everyone wants a specialty spot sprayer that would require an extra pass over the field. With growing utility of soil residual herbicides, dual tank sprayers—small tank for the spot spray, large tank for the broadcast residual—make sense. Large sprayer frames can accommodate an additional smaller tank, second pump, and plumbed boom easily.

    Plant detection and identification bring other opportunities. Adjusting dose for plant size is one of the first, or for harder to control weed species.

    Spot sprays rely on fast, precise response of the nozzle, and this provided by fast-reacting solenoids that are part of pulse-width modulation (PWM) systems. On a broadcast sprayer, these solenoids can change the emitted dose instantly, within a certain envelope, by altering the duty cycle of the pulse. This, however, works best in the context of a boom with overlapping spray patterns. A single band spray would not change dose with duty cycle as easily.

    Higher dosing would be an opportunity for multiple nozzle bodies that are able to spray one, two or more nozzles in the same spot simultaneously. These are already widely available and popular in Europe.

    This also brings direct injection into play. Current systems introduce the active ingredient into the boom upstream of the nozzles, affording it time to mix into the water. For true spot spray utility, though, direct injection ought to be at the nozzle. Only then can custom mixes and rates be applied on a spot basis. It’s been done before, if only to show how difficult it would be to deliver uniform doses to a spot spray machine.

    Spot spray sensors have agronomic benefits. By recording the location sprayed, weed patches can be mapped. As plant identification becomes possible, it’s conceivable to obtain plant species and stage distribution maps from the spray pass That would turn the sprayer into a high-resolution crop scouting tool. As machine learning and sensor sophistication grows, other plant and soil parameters can be mapped. The agronomic value of such maps, especially if created over the course of the growing season, is immense. Of course, data density, handling, storage, and analysis will constrain this.

    If the past has taught us anything, it’s that there seems to be a appetite for investment in farm equipment. Sprayers have been the most-used implement on the farm for some time, and their popularity continues despite sharp price increases. These new capabilities will only add value to these implements. Prepare for sticker shock, followed by acceptance and adoption.

    What will a future spot sprayer look like? Although it will have tanks and booms, the level of electronic sophistication will make it so much more versatile we can’t yet imagine all the ways in which it might be used. But it seems to me the situation has tipped and we’re already accelerating toward that future.

  • Putting a Number on Pesticide Waste

    Putting a Number on Pesticide Waste

    Waste (noun): an act or instance of using or expending something to no purpose.

    In agriculture, environment and economy are intertwined. Producers strive to obtain the maximum return on their inputs. They study incremental returns and avoid applying more inputs than necessary, especially if conditions don’t warrant it.  The financial incentive is powerful, and waste is a four-letter word. This applies to seed, fertilizer, and pesticide. Pesticide labels identify the rate needed to obtain the desired result, and there is no incentive to over-apply. In fact, it’s illegal.

    But there are plenty of other places where applications incur waste. As with time efficiency, it’s a good idea to identify where this waste occurs, and the only tool needed is a sharp pencil.

    When might we incur waste in the spray application process?

    • Mixing more than we need because we don’t trust the flow meter or the tank gauge entirely, or don’t know the exact field size.
    • Priming the boom before the first swath.
    • Overlapping due to curvy terrain and coarse sectional control.
    • Spray drift away from the intended swath.

    How big are the losses?

    Let’s say we have a clean sprayer and need to spray 160 acres before moving to a new crop and product. We plan to apply 10 gallons per acre and have a 1,200 gallon tank with a 120 foot boom. That means we need 1,600 gallons of spray mix in total.

    Once we’re at the field we prime the boom. Each sprayer is different, but depending on operator experience, 30 to 50 gallons are usually needed to push product from the tank to the last nozzle. Only part of that is lost to the ground, as boom sections can be shut off as soon as product has reached every nozzle of that section. We’re assuming 0.2 gallons per foot of boom is lost.

    Spraying itself is relatively straightforward. Swath and sectional control handle the overlaps, but in less ideal terrain, double application is known to account for 4 to 5% of the area to reach non-square parts of the field. This is even more likely when the outer section is 10’ or more. Early turn-on of the boom prior to leaving the headland, to allow boom to reach operating pressure, adds to this.

    Air-activated shutoff for individual nozzles reduces section size at a reasonable cost.

    With an average nozzle, we can expect about 2% of the product to airborne drift. Most airborne won’t return to the ground within the field borders, so it’s a complete loss.

    Most of the spray that travels more than 5 m after leaving boom stays airborne and should be considered a total loss from the field.

    As we finish, the pump will draw air before the tank is empty due to sloshing or foaming, and a 50 to 60 gallon remainder may not be unusual. This simulation has assumed 5% of tank volume remains.

    We also need to purge spray from the boom at cleanout, consuming approximately 0.4 gallons per foot of boom. This occurs after the field is completely sprayed and is therefore considered waste.

    So how does this add up? The following table shows the approximate losses associated with five setups.

    Table 1: Spray mix losses during a sprayer operation. Setup 1 = baseline, Setup 2 = low application volume, Setup 3 = baseline with recirculating boom, tank level monitor, and low-drift nozzles, Setup 4 = large area between cleaning, Setup 5 = large area with recirculating boom, tank level monitor, and low-drift nozzles.

    In the first scenario, we spray just 160 acres at 10 gallons per acre. Priming the boom with 0.4 gallons per foot (allowing for all associated feed lines) consumes 48 gallons, but only wastes half of that, or 1.5% of the total volume needed for the field.

    Four percent overlap consumes another 64 gallons.

    If we have 5% of the tank volume left over, that’s 60 gallons. That amount is so small it doesn’t even register on the sight gauge but nonetheless it represents another 4% of the total sprayed amount.

    Upon cleaning the boom, we need to push the spray mix out of all the  plumbing after the pump, as it has nowhere else to go. At an assumed 0.4 gallons per foot, that’s another 48 gallons or 3%.

    If we add to that a conservative 2% drift loss, it sums to a surprising 14% of the total spray volume. For those that use lower water volumes (the second scenario), the volumetric losses are slightly less, but their proportion is higher, now accounting for 23% (!) of the total spray mix.

    In the third scenario, let’s assume we use a recirculating boom that returns the initial prime volume to the tank, eliminating any waste. We’ll also upgrade to individual nozzle sectional control, reducing overlap to 1%. And, since we want to know exactly what’s left in the tank, let’s invest in an AccuVolume system to precisely monitor tank volume. This allows us to make small rate adjustments up or down to be sure as much of the mixed product goes onto the sprayed swath as possible.

    Recirculating booms allows the spray mix to pass through entire length of boom without being sprayed, saving waste during priming and allowing waste-free boom rinses.

    When the sump begins to empty, we can introduce some water from the clean water tank to push the last of the mix to the boom (a continuous rinse system makes this easy).

    An AccuVolume sensor shows the exact volume left in the tank at any slope position and with 1 gallon resolution, allowing greater accuracy when filling and emptying.

    We’ll assume our sump waste is now reduced to 12 gallons. We still need to dispose of the content of the boom somehow, so the recirculating boom offers no saving there. But let’s also add better low-drift nozzles to reduce drift by 50% (now 1% total volume). Total loss is now just 6%.

    Low-drift nozzles such as this AirMix (Agrotop) SoftDrop reduce airborne drift by 50 to 90%.

    The last two rows in the table repeat the first and third scenarios for a larger sprayed area (1000 acres) before a tank cleaning is needed. This doesn’t change the magnitude of the volumetric loss, but reduces its proportion. Percent loss is down by a factor of two from the 160 acre interval, to 3 to 7%.

    Experienced operators might cheat the system a bit by mixing the required pesticide with some extra water to make up for the plumbing waste. Doing so prevents extra pesticide from being consumed, but it doesn’t reduce the inherent inefficiency.

    Lessons

    This exercise suggests that waste from spraying is probably higher than we assumed. If we average the scenarios, there is 10 to 15% waste. At, say, $200,000 spent on pesticide for a single spraying season, that’s $20 – $30,000 worth of product and water hauled that ends up where it doesn’t belong. Beyond the time and money, there can also be environmental consequences depending on how that waste is treated.

    There are some things that can be done.

    • Know the exact area of the field to be sprayed.
    • Study your sprayer plumbing and consider improvements such as recirculating booms and continuous cleanout.
    • Improve monitoring of tank content to allow lower remainders.
    • Consider individual nozzle shutoff to improve sectional control. These are part of Pulse Width Modulation (PWM) systems, but can also be achieved with less expensive valves.
    • Plan spray operations to minimize the amount of product changeovers.
    • Consider direct injection.

    The return on investment for plumbing improvements can be high and result in considerable future savings over the life of the sprayer. It’s worth thinking about.

    Spray Waste WorksheetDownload