Extended soil surface drying triggered by subsurface drip irrigation decouples carbon and nitrogen cycles and alters microbiome composition

• DOI: 10.3389/fsoil.2023.1267685
• Publication Date: 2023-11-18T11:54:10Z
• Authors: Deirdre Griffin-L...; Daoyuan Wang; Amélie C. M. Gaudin; Blythe Durbin-Joh...; Matthew L. Settles; Kate M. Scow
• Keywords: Soil carbon; Growing season; Agroecosystem

Introduction Irrigation management dramatically alters soil water availability and distribution could impact microbial communities carbon (C) nitrogen (N) cycling to an even greater degree than observed in rainfed systems. Adoption of subsurface drip irrigation (SDI) California’s Mediterranean agroecosystems provides agronomic benefits but wets only a portion the volume near root zone, leaving rest dry throughout growing season. In contrast, traditional furrow (FI) has periodic wetting events with more homogenous moisture distribution. With conversion precision methods, how will microbiome respond changes availability, is their response influenced by C N resource levels? Methods field experiment California, we compared SDI FI’s effects on evaluated long-term organic conventional systems outcomes. Throughout season, samples were collected at two depths (0-15, 15-30 cm) three distances from bed center (10, 25, 45 where tape located. Results At harvest, soils irrigated using had lower biomass (MBC) under FI surface showed build-up soluble relative MBC edge, indicating reduced uptake. Community composition edge also diverged between FI, favoring Actinobacteria former Acidobacteria Gemmatimonadetes latter. Regardless type, areas highest alpha diversity indices. Response was similar systems, though higher MBC, DOC, abundance Proteobacteria fungal lipids, regardless irrigation. Discussion Prolonged conditions appeared limit access resources changed community composition. As seen non-agricultural severity frequency changes, adaptation communities, affect response. Decoupling pools may increase potential for losses DOC nitrate first winter rains this climate.