SAFE - SITES Agroecological Field Experiment

More information about SAFE is available at SLU:s web: SITES Agroecological Field Experiment (SAFE)

SAFE, SITES Agroecological Field Experiment, initiated during 2016-2017, builds a unique field facility where entire agroecosystems can be studied. SAFE builds on four agroecosystems representing different cropping systems; a reference system, an organic system, a perennial system and an agroecologically intensified system. A monitoring program runs for levels and quality of yields, soil nutrient status, and soil moisture and temperature along with spectral measurements (NDVI). In this facility SITES can provide data and infrastructure for researchers to address a broad range of scientific questions and disciplines relevant for the scientific community related to ecosystem services. 
At Lönnstorp 14 ha on the most fertile agricultural land in Sweden has been divided into four blocks of cropping systems, creating the SAFE facility (Figure 1). The large area of SAFE allow large agroecosystem representation and possibilities for sub-plots with additional experiments or temporary treatments available for researchers to use in science.

Background on cropping systems and the idea of SAFE
All crops have different nutrient uptake mechanisms and different growth patterns, such as root architecture, developmental stages with different timing and different resistance for pathogens - factors that builds the foundations of cropping systems. A cropping system is defined as an ecosystem where cropping activities are done. A cropping system could be a crop rotation, where a sequence of crops grow one every year on each field or intercrops, where two or more crops in the same field at the same time are rotated to better use the soil resources and reduce success of pathogens.

Crop rotations with annual crops are common in Sweden. The related agricultural management of such systems however include practices with intensive soil disturbance which lead to loss of soil organic matter and nutrients, as well as loss of small mineral soil particles. To control pathogens outbreaks pesticides can be used too.

In the effort of developing a more sustainable agriculture SAFE was initiated as a test-base for other agricultural practices and cropping systems e.g. to include perennial plants that could protect the soils from eroding, and increase the biodiversity by creating more biologically complex systems.

Perennial crops do not need to be re-sown or tilled/ploughed every year, they also provide habitats for possibly beneficial animals, which can e.g. predate on pathogenic organisms. Perennial crops are also expected to better sequester carbon into the soil, since the roots are sustained in the system the whole year as well as year after year. The use of perennial arable crops is a highly innovative method and breeding processes are running in many parts of the world. SITES Lönnstorp cooperate with the Land Institute in Kansas, US, who is one of the leading institutions for this work. At Lönnstorp, the perennial cereal Kernza© is used as a model for perennial cereals and the agroecological implications of this type of crop are studied in the Perennial system.

Other perennials, such as fruit and nut trees, as well as different shrubs, has earlier occurred in the landscape in field borders, field islets, and close to farm buildings. In SAFE these perennials are reintroduced and incorporated in a structured way into the agricultural intensified cropping system, the Agroecologically Intensified system.

Crops host different pathogens and diversified cropping systems could lead to lower success of pathogens, that is, the host specific pathogens will suffer from not having its host in its habitat (in crop rotations) or its host is intermixed with barriers (intercropping). The population of the pathogen will not thrive, which in turn means that both the population growth of the pathogen and the damage to the host crop will be suppressed.

The management elements of rotations, intercrops and perennials are all provided and mixed in SAFE. Contemporary agroecosystems are included as well as potential cropping systems for the future, with the perennial cereal Kernza© and the structurally and functionally diverse crop rotation with shrubs and apple trees. SAFE also includes cover crops to reduce erosion and nutrient leaching as well as adding to the soil organic matter. All cropping systems and sub-plots, except one sub-plot, in the entire SAFE facility are covered every winter.
Figur 1. The SITES Agroecological Field Experiment (SAFE) with the four agroecosystems which are replicated in four blocks (A-D).
Figur 1. The SITES Agroecological Field Experiment (SAFE) with the four agroecosystems which are replicated in four blocks (A-D).
Components in SAFE
The entire SAFE consists of four cropping systems, described below and they are replicated in four blocks (Figure 1). The cropping systems run and are managed accordingly agricultural practice year around.

The Reference System (REF): corresponds to contemporary conventional crop rotation, typical for the region and includes autumn-sown oilseed rape, wheat, and sugar beet, followed by spring barley sowed with grass-legume ley which continue as a cover crop during winter after the barley has been harvested. In the reference system, all four main crops are represented every year in four sub-plots in each block. In the reference system, either the main crop is sown in the autumn or a cover crop is established, except for after sugar beet, which is harvested too late. Therefore, only one crop in the rotation is followed by bare soil during winter.
The Organic System (ORG): corresponds to contemporary organically certified crop rotation, typical for the region. The organic system includes two intercrops. The rotation includes spring barley-lupine intercrop; winter rye sown with grass-legume ley (functions as cover crop two winters and as main crop the summer in between; beetroot; phacelia (functions as cover crop); faba bean-spring wheat intercrop, winter oilseed rape, winter wheat in-sown with grass-legume ley (functions as cover crop two winters and as and main crop the summer in between). In the organic system, four of the main crops are represented every year in four sub-plots in each block. In the organic system, the soil is covered every winter, either by autumn sown crop or cover crop.
The Perennial System (PER): has perennial wheat grass Kernza© as a model for future perennial cereal crops and is grown with and without the legume Medicago sativa (lucerne). The perennial system differs from the other agroecosystems in SAFE primarily in its perennial feature and the following lower management intensity needed. This perennial system only needs soil preparation the first year of establishment, it is only cut to suppress weeds one or two times in the season, and is fertilized to lower extent (with biofertilisers) due to that roots are expected to reach nutrients to a larger depth than annual crops. No pesticides or mineral fertilisers are used in the perennial system.
The Agroecologically Intensified System (AI): follows the crop rotation in the organic system but with a mixture of phacelia and oil radish as cover crop after beetroot and a cultivar mix of winter wheat for increased diversity, as well as a grass-legume mixture with higher diversity than in the organic system. In the AI system, linear elements (strips) with perennial shrubs (several species as wind breaks) and trees (apple trees) add to the structural and functional diversity of the system, and are planted to fit the machine park at Lönnstorp in order to design a system that allow for rational management. In the AI system one main crop is represented, together with the perennial and structural elements, each year in each block.
Demonstration of SAFE. Photo by Hélène Hagerman
Demonstration of SAFE. Photo by Hélène Hagerman
Relevant research fields
The SAFE field facility can be used to address questions in the topics of e.g. agronomy, agroecology, economy, ecology and landscape research. The facility is important for studies of sustainability, climate change, environment, and resilience and facilitates new and existing cooperation between researchers. SAFE is also a convenient meeting place, for demonstration and education activities.
Researchers can perform studies using the plots and establish minor experiments within the experiment. It is possible to focus particular parts of the systems, analyze an entire system or use several or all of the systems for comparative studies.
Examples of research projects that will use SAFE:
Nutrient efficiency in different agroecosystems.
Biological control or occurrence of beneficial organisms in different agroecosystem.
Occurrence of pollinators in different agroecosystems.
Climate change manipulations in sub-plots of the facility.
Short- and long-term changes in soil quality in different agroecosystems.
Intercropping of perennial Kernza© and lucern in SAFE. Photo by Hélène Hagerman
Intercropping of perennial Kernza© and lucern in SAFE. Photo by Hélène Hagerman
SAFE monitoring program
The levels (dry weight of seeds and straw, or root and leaves for sugar beet and beetroot) and quality of yields (N and C content) are recorded annually in each sub-plot for each crop. Soil nutrient status (total soil N, P and C) are recorded at three depths (0-30, 30-60, and 60-90 cm) over the growing season every second year in each sub-plot. Soil moisture and temperature (at 3 cm depth) are recoded hourly over the growing season in each sub-plot. In block A, spectral measurements (NDVI) are done continuously over the whole year in both sub-plots of the perennial system and in the annual wheat in the reference system for SITES Spectral.

At the establishment of SAFE, soil biological, physical and chemical characterization was done. The biological characterization covered earthworms, mites, collembola and nematodes. The physical parameters covered clay, silt, sand and organic matter content (soil texture). The chemical covered soil pH, total N, P, and C; soluble P, K, Na, Ca, and Mg. For more details see the interactive map or contact any of station managers.  
Kernza©  in SAFE before harvest 2016. Photo by Hélène Hagerman
Kernza© in SAFE before harvest 2016. Photo by Hélène Hagerman

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