A small effect of conservation agriculture on soil biodiversity that differs between biological kingdoms and geographic locations

Summary Larger easily visible animals and plants are negatively affected by agrochemicals used for intensive food production, but we do not understand the general spatial and temporal effects of agrochemicals on the multitudes of bacteria, fungi and small invertebrate animals that underpin ecosystem productivity. We sequenced the 16S, ITS2 and COI DNA barcode regions from 648 New Zealand vineyard soil samples managed under either conventional or low-agrochemical-input conservation approaches across two regions and three seasons in one year and discovered at least 170,000 phylotypes (taxa) with >97% genetic identity. Management approach correlated with a significant 2-10% difference in the abundances of phylotypes that differed over regions and seasons. While the data show agrochemicals do not have a large effect on soil biodiversity on average, the important finding is that the magnitude of impact differs between taxa types and locations, and some taxa most affected also influence the quality of agricultural produce.