No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Precision of a sensor-based variable rate sprayer
Abstract
When spraying plant protection products (PPP) the used amount per spraying is generally based on a pre set dose. Most often fields with variations in crop development are treated uniformly while spraying some patches in these fields would have been sufficient. In order to deal with the variations in crop development and site-specific variations in a field, a sensor-based spray technology was developed; SensiSpray. The system consists of sensors to detect crop variation and a spray system to automatically change spray volume. Electronics and software were developed to use the output signal of the sensor NTech GreenSeeker to adapt spray volume. For the variation of spray volume (50-550 L ha-1) Lechler VarioSelect nozzle bodies were used fitted with four different low-drift venturi flat fan nozzles. Spray deposition measurements were performed to test the sprayer accuracy in adapting spray volume based on the reflection signal per section, using a fluorescent dye (Brilliant Sulpho Flavine) added to the spray liquid. By moving diagonally over stripes of grassland, varying in greenness, longitudinal accuracy and lateral variation in spray deposition was quantified. The system showed to be able to adapt spray volume within 1-2 m in the direction travelled. In the 2007-2009 seasons different potato fields were sprayed and a general use reduction in PPP for potato haulm killing was c. 50%, maintaining efficacy.
... Above each onion bed one GreenSeeker sensor was mounted, which controlled the nozzle bodies. The nozzle bodies were mounted 0.20 m apart and based on an implemented software algorithm relating measured NDVI and the spray volume in switching nozzle combinations (Michielsen et al., 2010) and thus varying spray volume. The sensors were configured at a 10 Hz update rate. ...
The reduction of the emission of plant protection products (PPP) to the environment is an important issue when applying agrochemicals in the Netherlands. Apart from spray drift reduction, more attention is nowadays paid on use reduction as the combination of both means higher levels of emission reduction of PPP, as the amount of spray drift is from a less PPP used. With more precise application methods applying PPP only to the areas where it is needed, the plant, this can be achieved. Canopy Density Spraying (CDS) was therefore used under practical conditions in onions. To show the differences between a CDS-sprayer and a standard application technique, spray deposition measurements were done (following ISO24253-1/2) in three different crop growth stages of an onion crop. The CDS-sprayer was a Homburg Sensispray2.0 based on a Hardi Twin air sleeve boom sprayer with a working width of 5.4 m (three beds of 1.80 m onions) at 30 cm nozzle height. Based on Greenseeker sensors measurements of vegetation index (NDVI), spray volume was adjusted using three nozzles mounted in a Lechler Varioselect nozzle body, switched on or off individually or jointly. Angling of the air sleeve and nozzles towards the crop rows on the bed improved spray deposition compared to a horizontal spray boom and nozzle orientation. In three growth stages spray deposition on the onion leaves was for the CDS spray technique 1.5 to 2.8 times higher compared to that of the standard air-assisted sprayer. Loss to soil surface on top of the bed and on the paths in between the beds was for the CDS sprayer lower than for the standard. Spray deposition above the crop rows was for the CDS sprayer higher than of the standard.
... The sprayer consisted of three sections with a working width of 4.5 m. above each strawberry bed one Greenseeker sensor was mounted, which controlled the nozzle bodies. The nozzle bodies were mounted 0.25 m apart based on an implemented software algorithm relating measured ndvi and the spray volume in switching nozzle combinations (Michielsen et al., 2010) and thus varying spray volume. The sensors were configured at a 10 Hz update rate. ...
The reduction of the emission of plant protection products (PPP) to the environment is an important issue when applying agrochemicals in the Netherlands. Much attention always has been paid to reduce spray drift, however an application having an use reduction in combination with the same level of spray drift reduction implicitly means higher levels of emission reduction of PPP to the surface water, as the amount of spray drift originates from a smaller amount of applied PPP. Therefore more attention is paid nowadays to more precise application methods of PPP applying only to the areas where the PPP is needed, the plant. In strawberries Canopy Density Spraying (CDS) was tested under practical conditions. The benefits for the environment are shown by means of reduced use of plant protection products (PPP) in order to maintain comparable spray distributions as with standard application techniques and maintain good biological efficacy. Angling of the air sleeve and nozzles towards the crop rows on the bed improved spray deposition compared to a horizontal spray boom and nozzle orientation. In both growth stages spray deposition on the leaves was for the CDS spray technique 15%-25% higher compared to the standard air-assisted sprayer. Loss to soil surface on top of the bed and on the paths in between the beds was for the CDS sprayer lower than for the standard. Spray deposition above the crop rows was for the CDS sprayer higher than of the standard.
The wild blueberry industry can spend as much as $868 CAD per ha per year on the application of agrochemicals and with some 93,000 ha in production in North America, this equates to $80 million CAD per year. A pressing need to reduce input costs has resulted in the development of a smart sprayer for spot-application of agrochemicals in wild blueberry fields. A commercial boom sprayer (1135 L storage tank) and a 13.7 m sprayer boom was modified and retrofitted to control each nozzle individually. The principle components of the smart sprayer were nine micro eye digital color cameras mounted on the sprayer boom 0.15 m in front of the sprayer nozzles, custom controller, custom developed image processing software featuring a touch screen interface, Midtech legacy 6000 flow controller and a ruggedized computer.
The smart sprayer presents significant advantage from both an environmental and economic perspective. This paper presents the economic analysis which was conducted to determine the potential savings for spot-applications using the sprayer. The cost analysis compares the smart sprayer with other commercially available sprayer technologies and includes, base sprayer, additional technology, training, usage, repair and maintenance. The cost of additional technology has been analyzed based on savings from agrochemical usage, fresh water, tractor fuel and operator time. The three boom sprayers used in this study had agrochemical input costs ranging from $1139 ha-1 to $2110 ha-1 over a two year production cycle of a typical wild blueberry field.
A low basal N application combined with in-season adjustment of the sidedressNrate has been proposed as a means to saveN in growing potato (Solanum tuberosum L.). We hypothesize that a measurement of canopy reflectance provides information which can be used to adjust sidedressNrate. The objective of our work was to develop and test a canopy reflectance-based Nsidedress system for potato in humid climates. In four years of experiments with ware potato on a sandy soil it was determined that the reflectance index WDVI correlates well with N uptake, that sidedressN should be applied at around the time of canopy closing, and that the sidedressNrate should be calculated as the difference between a (fixed) desired N uptake and a reflectance-based measurement of N uptake. The calculated N saving in these experiments was between 10 and 109 (average 56) kg N ha−1. The reflectance-based Nsidedress system was tested at an additional two locations, with ware potatoes on a loamy soil and with starch potatoes on a sandy soil, in two further years of experiments. N saving in these experiments was between 8 and 88 (average 44) kg N ha−1. In both sets of experiments, yields with the sidedress system were generally at the same level as yields obtained with recommended Nrates (basal N only). We conclude that the reflectance-based sidedressN system allows saving of N while maintaining yield
When using variable-rate application (VRA), tractor-mounted sensors are typically used to measure crop status. Crop status can also be measured with a satellite-based sensor. In both cases a vegetation index derived from the sensor measurements is used as an indicator of the amount of crop biomass. The first objective of this study was to establish a relationship between the Weighted Difference Vegetation Index (WDVI) in potato as measured with a nearby, ground-based crop reflectance meter on the one hand and WDVI as measured with remote, satellite-based sensors on the other hand. It was found that groundbased WDVI and satellite-based WDVI are strongly and linearly related, thus making it feasible to calculate herbicide rates for potato haulm killing on the basis of satellite-based measurements. The scale at which VRA is applied is an important determinant of the reduction in input use. The second objective was to estimate the potential to reduce herbicide use for potato haulm killing as a function of the size of decision units, using the above-mentioned relationship, satellite imagery of 13 potato fields and a previously developed decision rule for herbicide rate. It was found that when the size of the decision unit was 15 m × 15 m (the size of an ASTER pixel), a reduction in herbicide use of at least 50% would be achieved in one out of every two of the fields, and a reduction of at least 33% would be achieved in all fields. When the size of the decision unit was 30 m × 30 m, a reduction of at least 33% would be achieved in one out of every two of the fields. In conclusion, satellite-based crop reflectance measurements can be used instead of ground-based measurements for determining herbicide rate for potato haulm killing. When the size of the decision unit is not larger than 30 m ×30 m, a 50% reduction in herbicide use for potato haulm killing can be achieved with VRA
ResearchGate has not been able to resolve any references for this publication.