Quantification of soil biopore density after perennial fodder cropping

Abstract

Plant root traits affect soil biopore (BP) formation. Aims of this study were to measure the effects of fodder crop species with contrasting root traits and duration of cropping on BP density (BPD), and also to address the consistency of these effects over different years focusing on the effects of root decay. Soil BPD was quantified after growing three perennial fodder crop species with contrasting root systems, namely, lucerne (Medicago sativa L.), chicory (Cichorium intybus L.) and tall fescue (Festuca arundinacea Schreb.) for 1, 2, and 3 years with 2 years fallow in two repeated field trials from 2007 to 2014. Total BPD after taprooted fodder crops (421 ± 14 m−1) was significantly higher compared with fibrous-rooted crops (337 ± 12 m−1). Cropping duration did not affect soil BPD. On average, density of medium-sized BP (BPmed; 2–5 mm) increased 14 % after 2 years of fallow, whereas BPD decreased by 5 % for coarse-sized BP (BPcor; >5 mm) after the fallow. Taprooted fodder crops enhanced BP formation into subsoil. Accurate assessment of biopores (BPs) and their persistence must take account of the temporal dynamics, including effects of root decay.