Detecting the causes of variability in ley fields to increase the efficiency of fertiliser management

The aim of this project is to increase the efficiency of fertiliser use on farms growing leys and will contribute important information on the differences between areas that do and do not respond to nitrogen fertilisation. To be able to gather this information the project is split into three different activities:

Activity 1. Survey of historical data

Gather existing historical spatial data from farmers’ fields, including satellite images and tractor mounted YNS maps. Using this information, we will identify low and high production areas that over a number of years are either persistent or transient. 

Activity 2. On-farm sampling using satellite images

Collect samples from eight farms across Sweden, chosen based on the results from the historical data (Activity 1). We will sample high production areas and both persistent and transient low production areas in the field to compare the two area types.

Activity 3. On-farm field experiments 

Set up fertiliser experiments in four locations to assess the response of low and high production areas in ley fields to different fertiliser treatments. Use satellites and spectrometers to distinguish between areas that will respond to nitrogen and those that will not. Determine what is the most effective way of allocating fertiliser in a ley field.

Solutions to this problem will benefit both advisors and farmers as it will bring more information and knowledge that will improve the prospects of precision ley farming.

Background

Ley comprises the largest area of agricultural land use in Sweden, and is the most important source of forage for livestock industries. They are commonly sown as mixtures of grass and legume, which produce a forage higher in protein with less added nitrogen fertiliser. 

The Yara N-Sensor (YNS) has been a part of Swedish precision agriculture for more than 20 years, and is mainly used for fertilisation of wheat. It is to some extent also used for fertilisation in leys, but there is limited research on this topic and very few farmers use the equipment in ley crops. When mapping a field using a tractor mounted YNS, it is possible to detect low production areas. The reason why these areas are producing low amounts of biomass could be low nitrogen availability, but it could also be something not identified by the sensor, such as soil compaction, waterlogging, or another nutrient deficiency. It is important in precision agriculture that the correct measures are taken in the right place and at the right time. Spreading extra fertiliser on a spot that will not be able to utilize it, is wasteful and bad for the environment. 

Farmers have expressed a need to know the cause of low production areas in leys, whether they are transient (they tend to occur in different areas across years) or persistent (they tend to occur in the same areas across years), and what are the implications for management practices. The purpose of this study is therefore to differentiate between low production areas that will benefit from more fertiliser and low production areas that will not respond to more fertiliser application.

Collaboration

This project is a collaboration between the Department of Crop Production Ecology at SLU, Lantmännen, Yara, and DataVäxt.

Contact

Julianne Oliveira, Researcher
Department of Crop Production Ecology, Crop production science
Swedish University of Agricultural Sciences
julianne.oliveira@slu.se, +46 907868724, +46 767637129

Sanna Bergqvist, PhD student
Department of Crop Production Ecology, Crop production science
Swedish University of Agricultural Sciences
sanna.bergqvist@slu.se, +46907868726, +46730675037

David Parsons, Professor
Department of Crop Production Ecology, Crop production science
Swedish University of Agricultural Sciences
david.parsons@slu.se, +46 907868714, +46 730893445