What is the cost?
The cost is £7.50 per hectare. This includes 3 Leaf Area Index maps and 3 Nitrogen application maps. One image is £4.00 per ha. Two images are priced £6.00 per ha.

What crops can it be used on?
If a LAI map and Nitrogen recommendation is required, then this service is available for Winter Wheat only. Canopy development maps can be provided for any crop.

How do I Sign up?
SOYL have a network of trained area managers. If you would like to arrange a meeting to discuss SOYLSense please contact the SOYL Office by phone or email.
Phone: 01635 204190, email: simong@soyl.co.uk.

Is there a minimum order?
The minimum order is 150 ha. Per farm. Fields do NOT have to be adjacent to each other.

What is Leaf Area Index (LAI)?
Leaf Area Index (also known as Green Area Index) is a way of measuring the amount of crop canopy development. If for each square metre of soil there is one square metre of plant biomass (mainly leaves) then the plant has leaf area index of 1. If there are two square metres the leaf area index is two and so on.

How is LAI calculated?
The raw satellite images give what is known as a Normalised Digital Vegetation Index (NDVI). By using algorithms this can be directly converted into an LAI value.

How do I know that the LAI value given is accurate?
The satellite image is converted into an LAI map. Carrying out within field calibrations can then check the accuracy. This involves looking at the LAI maps and choosing locations across the whole range of LAI values (high, medium and low) to visit. At each location the actual LAI is measured by using either digital photography in the earlier stages of crop growth (tillering) or an LAI meter in the later stages of crop growth. These ground-truthed LAI scores are then used to calibrate the original LAI map.

How is the target LAI calculated?
There is no benefit to growing a crop that has a canopy or LAI that is too high. This leads to inefficient use or waste of Nitrogen and causes increased lodging. A canopy that is too small will not intercept enough sunlight and therefore crop yield will be reduced. Therefore there is an ideal LAI between these two extremes. The LAI changes as the crop grows and a different target LAI must be set for each growth stage (GS). Eg GS22 = LAI 0.73, GS31 = LAI 1.9, GS36 = LAI 4.4. The target LAI is based on the HGCA Wheat Growth Guide research programme.

How are the Nitrogen Recommendations calculated?
Nitrogen recommendations are based around the best practice for the farm. The farmer or agronomist will calculate the appropriate rate for the crop in relation to current season. For example 80 kg/ha Nitrogen may be appropriate for 2nd application at stem elongation (GS32). Any part of the crop that is at the target LAI for GS32 will receive 80 kg/ha N. Any part of the crop that is below the target LAI, in other words the canopy is too small, will receive more than 80 kg/ha. Any part of the crop that is above the optimum crop canopy, in other words the canopy is too big, will receive less than 80 kg/ha.

How often are satellite images obtained?
Satellites pass over the UK on a daily basis. There are a number of satellites under different ownership. Images can be purchased from any of these providers. The swath angle of the satellite can vary and dependent on the angle it crosses, different areas of the UK will be covered in any one pass. Satellites pass over the UK in the morning.

What effect does cloud cover have on images?
The satellite uses an optical sensor to get images. It cannot penetrate cloud cover and therefore no images will be available on cloudy days. In the 2005 campaign 90% of all images were successfully obtained.

How do I get my satellite Images?
Images can be delivered via e-mail or through the SOYLSense website. It takes between 2-5 days to obtain an image after a satellite has passed over the UK. The image will then be placed on a website that can be accessed by a customer or can be sent to the customers email address.

How do I get my recommendations?
Parameters (Growth Stages and Nitrogen rates) required to make Nitrogen calculations can be entered on the website and the recommendations calculated immediately and be ready for printing out. Alternatively the parameters can be provided by email or telephone and the Nitrogen recommendations done in the SOYL office. Recommendation maps will then be sent via email.

How do I get my application files?
Application files can be downloaded from the website or provided by SOYL via email/post.

What spreading system compatibility is there?
Files that can be downloaded from the Website are Farmworks, Patchwork, LH Agro, MF Fieldstar, John Deere, RDS. All these GPS controller files plus any not listed on the website can be provide by SOYL via email.

Do I require special equipment?
To use the GPS application files requires a GPS compatible controller. If a customer is already using DGPS kit for P & K spreading, then this kit will not need upgrading and can be used for GPS Nitrogen spreading.
If a customer requires GPS kit and their spreader or sprayer has an implement controller then compatible kits are available starting from 1500. Contact SOYL or your local dealer for more information.

What are anomaly maps?
Anomoly maps compare the LAI values on a particular field with the average LAI within a 50 km radius. Fields with a similar variety, drilling date and soil type are used for the comparison. This allows an assessment against the norm for the region.

What are typical benefits?
Benefits may come from two areas. Less Nitrogen applied to those areas that have too high canopy development. Secondly increased yield due to optimum Nitrogen applied to areas of too low canopy development. Typically these have resulted in benefits of about 15/ha. In the 2005 SOYLSense survey trials showed a benefit ranging from between 11 - 46/ha.

How can I assess the benefits for myself?
Split field trials are simple to set up and allow a comparison of variable rate and farmers normal practice. If yield-mapping systems do not allow this then a comparison of field gross margins with the same varieties and soil type can be made. For example if there are 10 fields of Hereward on a Clay soil, eight could be applied using SOYLSense and two could be applied as normal to act as a comparison.

Is this approach the same as Sensor based tractor-mounted systems?
Most Sensor based systems use a similar technology. The only difference is one set of sensors are mounted on the tractor and one set are on a satellite. Images of canopy development are very similar in comparisons that have been undertaken on farm. The main differences are logistical:
1. PAYMENT. Satellite images are charged by the area. Sensor based systems require an initial capital investment to purchase the equipment.
2. CALLIBRATION and MAINTANENCE. Calibration of images and maintenance of kit is undertaken by SOYL, calibration and maintenance of Sensor equipment is undertaken by the user.
3. APPLICATION SOYLSense will assess the variation in the crop AND the overall growth of the crop. For example the whole field may require more or less fertiliser.
4. TIMING Sensors allow real time application. SOYLSense has a 2 day turnaround but allows assessment of maps and modification if required.

Where does the aerial photography used in the website come from?
Aerial photography used in this website are part of the Millenium project whose owner is Getmapping Plc. Those imagery are kindly provided by Syngenta Crop Protection UK.