Analysis of agricultural soils from a long term factorial study. Michael Parr's PhD

The Nafferton Factorial Systems Comparison (NFSC) study at Nafferton Farm in Northumberland, United Kingdom is a multifactorial experiment that has been running since 2001. Due to the evolving nature of this project over two decades, the plots have been subjected to changes in cropping inputs on a near yearly basis, providing a unique opportunity to measure the legacy effects of multiple treatments, as well as any potential interactions between them, on present day soil health through analysis of the soil microbiome and soil chemistry. 32 aggregated 0-30cm soil core samples were taken in October 2020 shortly after drilling and were stored at -20c. DNA was then extracted using DNeasy PowerMax Soil kit and amplified using ITS1 and 16S primers, before being subjected to Illumina sequencing by synthesis. DNA reads were then grouped into ASVs and taxonomically identified. UniFrac, ANOVA, and other statistical analyses were used to quantify the legacy effects of previous year’s treatments, as well as their longevity , against common measures of the microbiome including species number, species diversity, and community composition. This study quantifies the long-term effects of previous agrochemical treatments, tillage methods, and crop rotations upon the present soil microbiome, and discusses how these may need to be considered during the adoption of organic and no-till/zero till practices.