Farming in 10 years’ time was the theme of the 2017 SIMA event which had a clear focus on innovation, both in the exhibition halls and in a specific area where SIMA invited inputs from universities, research institutes and innovation companies.

Separating the chaff from the grain is just as challenging with these technologies, however, as it ever was on a combine.

Increasing numbers of manufacturers have adopted the language of the digital age, with drones, sensors, big data and “farming four” all featuring in manufacturers literature and presentations, as they strive to ensure that they are not left behind in this rapidly developing area. But how many of these developments are capable of affecting us today? Will they need 10 more years of development or will they disappear over that time frame?

So is the digital age really delivering something new? Before considering specific developments presented at SIMA, it’s worth noting that many of the concepts now being discussed were partly developed a generation or more ago. Even the driverless/automonous tractor, either working on its own or as a slave tractor controlled by another tractor driver in the field, has been around as a concept for more than 50 years. Crop sensing where measurement of light absorption/reflectance is used to indicate growth or crop health has been used since the 1970s.

What is different today is that advancement in sensors, electronics and data analytics has enabled the use of those technologies. With tractors, for example, the GPS technology for controlling autonomous tractors in the field is available for some time, but relying on GPS alone within the field would not be safe. Developments in autonomous cars where other sensors are used to measure and control the car’s position are likely to provide the means to allow autonomous tractors to work safely in the field. But will that bring tangible benefits? As machinery users, we must carefully weigh up costs and benefits before considering their adoption.

In this article, some of the developments in spraying technology seen at SIMA are presented.

Sprayer developments

The sprayer nozzle is the key component of any crop sprayer as it is responsible for the delivery of the product to the crop, weed, insect or soil. Nozzle design affects the size spectrum of the spray droplets, how evenly the spray is applied and how susceptible to drift the spray is.

In recent years, there has been a lot of development in nozzle technology, targeted at reducing drift.

The development of the low-cost air-induction nozzles has been a particular boon to growers, allowing them to achieve more even application in typical Irish weather where wind is often a limiting factor.

But other nozzle technologies that were prevalent at SIMA offer crop sprayers a number of advantages.

Nozzle switching technology

While multi-nozzle holders are commonplace on most crop sprayers, only one nozzle can usually be used at a time and these must normally be manually selected. At SIMA, many sprayers had multiple nozzles at each nozzle mounting point (normally 50cm spacing on the sprayer, but can be 25cm), and these spray nozzles can be switched on/off electronically either by electrically or pneumatically operated solenoids at each nozzle.

In its simplest form (eg Hardi), there may be just two nozzles at each boom point. A combination of a lilac 025 nozzle and a blue 03 nozzle, for example, would allow outputs of from 80 litres/ha to 300 litres/ha to be achieved by using either of the nozzles on their own or both in combination. Adding more nozzles at each point (up to six in total) can give seamless application rate change with less variation in pressures. Alternatively, drift control options can be added by having two or three air induction nozzles fitted alongside two or three standard nozzles. This offers a number of different advantages:

  • Sprayer application rate can be easily and automatically changed without changing spray quality. Without leaving the cab, the rate of application can simply be adjusted by switching on different nozzles or combinations of nozzles.
  • Variable rate application can easily be achieved in the field without changing forward speed. The bigger challenge here though is to find a proven research-based system that will generate the variable application maps, whether that be liquid fertiliser (currently viable) or fungicide/herbicide (no proven systems to date for our production systems).
  • Forward speed can be varied considerably without affecting spray quality. If variable ground conditions require different optimum speeds within the one field, rather than selecting the slower, or a compromise, speed, the forward speed can be varied without compromising spray quality.
  • If the position/angle of the boom can be calculated (using GPS and other sensors), then the application rate variation that occurs while the sprayer goes around headland bends or even gentle corners can be corrected automatically.

    • Among others, Hardi, John Deere, Amazone and Tecnoma displayed this nozzle-switching technology at the SIMA show.

    Nozzle heights

    The height of the boom over the crop can make a big difference to the amount of spray drift that occurs. Keeping the boom low over the crop reduces drift.

    However, the boom height over the crop must be held very steady if it’s held close to the crop. Also closer nozzle spacings (<50cm) are necessary to hold the boom close to the crop. Many of the sprayer manufacturers showed active boom height control where a boom mounted sensor controls the boom height. In cab switching from 50cm to 25cm nozzle spacing was also available on some high-spec sprayers and this allows the booms to be worked much closer to the crop.

    Automated boom height control, coupled with nozzle spacing selection and nozzle size selection, gives the operator a lot of drift control options increasing sprayer efficiency.

    Pulse width modulation

    Pulse width modulation (PWM) offers a single-nozzle method of varying application rate at a specific forward speed without varying pressure and compromising spray quality. With PWM, the flow through the nozzle is pulsed rapidly at a rate of 10 or more pulses per second.

    The length of each pulse can be adjusted to vary the application rate so the nozzle output could be varied from 70 litres/ha to 250 litres/ha, for example, without changing nozzles or pressures.

    AT SIMA, T-jet showed their Dynajet-Flex PWM system but John Deere also showed a PWM system, while Amazone use PWM in their AMASPOT system.

    Boom section control

    While GPS-based boom section control has been with us for a number of years allowing effective automated closing of boom sections at headlands or on short ground, at SIMA there was a definite emphasis on controlling individual nozzles rather than 3m to 6m wide boom sections.

    This allows greater savings to be made in particular situations. This is easy to achieve if the sprayer already has individual nozzle switching as outlined earlier.

    Consequently sprayers incorporating the complementary technologies of nozzle switching, nozzle-based section control and PWM were displayed at the show.

    Spot spraying

    The concept of spot-spraying individual weeds or plants, or even areas within a field, has been around for decades, but getting a way of identifying the weed when it is surrounded by other plants still proves an elusive challenge.

    Amazone has been working on its AMASPOT technology for a number of years and this technology can very effectively identify weeds in stubble or bare soil and spray the individual weed using PWM-type control of individual nozzles.

    While this was very effectively demonstrated on a static rig at SIMA, field conditions that cause spray drift could challenge the system in field use requiring drift reduction approaches to be taken.

    The evolution in precision spraying technology that all of these nozzle technologies represent has the potential to bring benefits to growers immediately.