Author: Paweł Radzikowski radzikpawe@gmail.com
Day 1 of monitoring (29.04.2024): Upon arrival at the German Living Lab, Mr. Paweł Radzikowski from Ogolnopolskie Stowarzyszenie Agrolesnictwa (OSA, Polish Agroforestry Association) met with Ms. Janine Raabe, the farmer of Hof Lebensberg. The precise locations for the sampling sites were determined, and control sites were designated. Surveys were conducted in two agroforestry systems: mixed-fruit and mixed-nut systems. The control for the mixed-nut system was an adjacent field with a fodder crop, while the mixed-fruit system was an adjacent unplanted field. During the on-site discussions, the sampling protocol originally developed in Task 3.2 was decided to adapt to the location conditions. Instead of using a gradient with four distances from the trees, two distances were opted: one immediately adjacent to the trees and the other midway between them. This modification was necessary because the trees had been planted only a year or two before the monitoring began, making their impact primarily noticeable at close distances. Indirect distances were not expected to be significant in this context.
Test plots measuring 30 x 10 meters were established in both systems and their respective controls. The length of 30 meters was chosen because certain biodiversity sampling required the sites to be at least 10 meters apart. Assuming four replicates were desired for each variant, these would be located along a single transect at distances of 0m, 10m, 20m, and 30m. The width of 10 meters was selected due to the 20-meter spacing between the rows of trees. Sampling was planned so that the transect ran alongside the trees and reached the middle of the arable field (see Fig. 1 to 3). The same arrangement was applied to the control area despite the field being uniform throughout.
Fig. 2 Test plots in the mixed-fruit system and the control
Fig. 3 Precise location of the sampling sites in the mixed-nut system
Fig. 4 Measuring the length and width of the test plot
Monitoring commenced using the least invasive methods, namely insect collection. This survey was conducted across three 10-meter transects in each study plot (Fig. 5). A specialized entomological net was utilized, featuring a 1-meter handle and a 30 x 40 cm heart-shaped opening. This design facilitated the collection of insects from both tall vegetation and near-ground surfaces. The net’s collection bag is crafted from fine mesh reinforced with a sturdy material sleeve (Fig. 6). Insects gathered during the survey were transferred into 100 ml containers, euthanized, and preserved using 75% ethanol (Fig. 7). In total, 36 samples were collected, and identification of these insects will be conducted in Task 3.2 at a later stage.
Fig. 5 Location of insect collection transects
Fig. 6 Entomological net in use
Fig. 7 Samples collected using an entomological net
On the first day of monitoring, another task was to deploy traps for insect collection over the next five days. Two types of traps were employed: Barber earth traps and yellow pollinator traps. These traps were spaced every 10 meters along the designated transects, with three traps per variant (Fig. 8). The Barber earth traps, with a diameter of 10 cm, were designed to capture ground insects effectively. Yellow pollinator traps, 30 cm in diameter, were placed directly on the ground due to the low vegetation height. Both types of traps were filled two-thirds full of a solution of clean water and odorless detergent (Fig. 9). This solution formulation ensured the rapid drowning of invertebrates while preventing overflow during heavy rain, with no need for trap covers given the short collection period. Water levels were replenished daily to prevent complete evaporation.
Fig. 8 Location of Barber traps and yellow bowls in the mixed-nut system
Fig. 9 The process of setting yellow bowls and Barber traps
Day 2 of monitoring (23.04.2024): The assessment focused on flora biodiversity and primary production. Within each of the eight transects, four points were selected for phytosociological photos using a 1×1 meter botanical frame (Fig. 10). All plant species were identified, and their abundance was estimated following recommended field protocol guidelines. Data were recorded on field forms (Fig. 11).
Fig. 10 Distribution of biodiversity and biomass sampling in the mixed-nut system
Fig. 11 Botanical frame and field form used in the flora assessment
Biomass within the same meter frames was cut, harvested, and weighed (Fig. 12). This enabled estimating forage crop yield for grazing chickens or assessing ecosystem natural productivity (primary production) if biomass had not been harvested. At the time of monitoring, no yield was obtained from the trees present, nor were the cereal fields sown. Additionally, photographic documentation of individual plant species in each system and their control was conducted (Fig. 13). These photos were uploaded to iNaturalist for species identification verification, which uses algorithms and consultation with specialists. Observations were geotagged to facilitate biodiversity comparisons globally (Fig. 14).
Fig. 12 Forage biomass harvested per 1m2
Fig. 13 Individual photographic documentation of plants
Fig. 14 Observations entered on iNaturalist
Day 3 of monitoring (01.05.2024) – The activities focused on soil depth survey and earthworm collection. Soil blocks measuring 25 x 25 x 25 cm were excavated in areas where biomass had been collected the previous day (Fig. 15). The soil was carefully separated onto a sheet and further excavated to access the subsoil. For deeper soil layers, an Egner sampler was employed as needed (Fig. 16).
Fig. 15 Earthworm collection sites and soil depth measurements
Fig. 16 Measurement of soil depth
The soil spread on the sheet was manually sieved to extract earthworms (Fig. 17). Recovered specimens were preserved in containers filled with 75% alcohol for subsequent weighing and species identification (Fig. 18).
Fig. 17 Cutting soil block and sieving soil for earthworms
Fig. 18 Extraction of earthworms
Day 4 of monitoring (May 2, 2024) – Soil bulk density and permeability measurements were conducted. Samples were taken in triplicate at each designated location (Fig. 19). Prior to sampling, small sections of turf were cleared using a spade. Two types of cylinders were utilized for these assessments. Small cylinders with a 5 cm diameter were driven into the soil to obtain samples for bulk density (Fig. 20). Samples were sealed with lids on both ends and will be sent to the soil laboratory for analysis at a later date.
Fig. 19 Schematic of soil cylinder collection and permeability tests
Fig. 20 Cylinder collection for soil bulk density
Soil permeability was evaluated using 10 cm diameter cylinders driven to full depth into the soil, leaving 2.5 cm exposed with a wooden stopper (Fig. 21). Subsequently, 100 ml of water was poured into the cylinder, and the total infiltration time was measured using a stopwatch. These measurements were recorded on the field data forms.
Fig. 21 Soil permeability measurement
Day 5 of monitoring (May 3, 2024) – The focus was on completing insect trap collection and soil sampling. Insect samples from the yellow bowls and soil traps were strained and transferred to sealed containers with 75% ethanol (Fig. 22). Insect species identification will be conducted at a later stage.
Fig. 22 Collection of insect traps
Soil sampling followed the guidelines of field protocol Task 3.2, with four samples collected in plastic bags from each variant. Each sample consisted of at least five cores taken with an Egner sampler (Fig. 23). Samples were extracted up to a depth of 30 cm. After collection, soil samples were stored in an icebox and deep-frozen upon return from the field trip. Soil parameter analyses will be conducted in the laboratory at a later date.
Fig. 23 Soil sampling scheme (above) and one of the five subsamples (below)
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