Data for: Crop rotation phase has a greater impact on soil biology than crop rotation diversity
Description
In this study, the link between plant diversity and soil biodiversity was investigated in an arable cropping system by comparing the soil biological community structure and biomass in crop rotations with different degrees of diversity: A Simple rotation (2 plant species), a Moderate rotation (4 plant species), and a Diverse rotation (10 plant species). A field experiment was established in 2013 at the Crop Research Unit, University of Reading, Sonning, UK (51°28’50.8”N 0°54’07.3”W). The experiment was laid out in a split-plot randomized complete block design, where a block containing all three rotations (Simple, Moderate, and Diverse) was replicated four times. Each rotation treatment comprised four 12 m x 10 m subplots, representing the four different phases (i.e. years) of the rotation. The design of the experiment relies on a space-for-time substitution, so that each phase in the crop rotation is represented by one of the four subplots in the rotation at any one time. All 48 subplots of the experiment representing all three diversity levels and all four crop phases were sampled for soil the fauna survey in June 2017. Nematodes were collected to represent microfauna, Collembola and mites to represent mesofauna, and earthworms to represent macrofauna. In 2016 only the 12 plots where the crop was winter wheat at phase 3 of the rotation were sampled for soil characterisation (C, N, pH) and soil microbial community assessment (Phospholipid Fatty Acid analysis). In the Simple rotation these plots were previously cropped with two years of wheat. In the Moderate rotation they were previously cropped with a year of oilseed rape (OSR) following a year of wheat. In the Diverse rotation they were previously cropped with a year of spring beans (after a brassica winter cover crop) following wheat under-sown with a legume mixture. Soils were sampled from the middle three strips of selected subplots in June 2016 and all plots in June 2017, taking five 15 cm deep cores in a ‘W’ layout and homogenising these into one composite sample per plot.
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Soil Characterisation The soil samples were sieved to 2 mm and air-dried. Subsamples of 10 g each were shaken in 25 ml Ultrapure water for 15 min and the pH was measured using a pH electrode. For measurement of total C and N, subsamples were ball-milled and analysed by Dumas dry combustion. Soil microbial community assessment Cores of 15 cm depth were used to collect 5 soil samples per plot from selected plots in a ‘W’ layout across the three middle strips of each subplot using a gouge auger and homogenising these into one composite sample per subplot for phospholipid fatty acid (PLFA) analysis. Microbial community structure and biomass were assessed using PLFA profiles following the methods described in Struijk, M., Whitmore, A.P., Mortimer, S., Shu, X. and Sizmur, T., 2023. Absence of a home-field advantage within a short-rotation arable cropping system. Plant and Soil, 488(1), pp.39-55. Nematodes Five 30 mm diameter soil cores were collected from the middle three strips of each subplot using a gouge auger and combined in one composite sample. Duplicate subsamples were then prepared per plot for extraction of nematodes using a modified version of the Baermann funnel method. A 100 ml sample of soil was placed in a plastic supporting sieve lined with one ply of tissue paper. The sieve was placed in a plastic 18 cm diameter pot saucer. Ultrapure water was added to the soil to keep it moist but not saturated and nematodes were collected in the clear solution in the saucer. 1 ml aliquots were analysed for nematodes in a petri dish with an inverted microscope to determine nematode abundance. The first 25 specimens counted were identified to trophic level (bacterial feeder, plant parasite, or predator) based on mouthparts, to determine the proportion of each group. Microarthropods A 10 cm deep core of 9.8 cm diameter was collected from each plot to collect Collembola and mites. Each core was then placed upside down and extracted for three days under a hot lamp in Tüllgren funnels, allowing microarthropods to drop through a 2 mm mesh into collection receptacles containing 70% ethanol. Collembola specimens were identified by x10 stereo microscope to the orders Poduromorpha, Entomobryomorpha and Symphypleona, and mite specimens were identified to the Orders/Suborders Prostigmata, Mesostigmata and Oribatida (which included Astigmatid mites). Earthworms A 20 cm × 20 cm × 20 cm soil pit was excavated from each plot and transported to the lab, where it was hand sorted for earthworms. Juveniles were distinguished from adults based on the absence of a saddle and then adults (and some juveniles) were identified to species level. The biomass of each species was recorded. Five litres of mustard solution (6 g L-1 Coleman’s mustard powder) was poured into each soil pit immediately after excavation and observed to retrieve deep-burrowing anecic earthworms, but none were retrieved from any of the plots sampled.
Institutions
- University of Reading
Categories
Funders
- University of ReadingUnited Kingdom
- Waitrose Agronomy Group
- Biotechnology and Biological Sciences Research CouncilUnited KingdomGrant ID: Case Studentship GS13-87