Topsoil Hardening: Effects on Soybean Root Architecture and Water Extraction Patterns
- PDF / 1,374,846 Bytes
- 13 Pages / 595.276 x 790.866 pts Page_size
- 93 Downloads / 163 Views
ORIGINAL PAPER
Topsoil Hardening: Effects on Soybean Root Architecture and Water Extraction Patterns Guillermo E. Peralta 1 & Miguel A. Taboada 1,2 & Adriana Kantolic 3 & Gerardo Rubio 1,4 Received: 2 April 2020 / Accepted: 25 June 2020 # Sociedad Chilena de la Ciencia del Suelo 2020
Abstract Topsoil hardening is one of the major causes of poor root growth although its effects on subsoil roots are still not well-known. Our aim was to examine the effects of topsoil hardening on the growth and functioning of shallow and deep roots of soybean plants. Two rain shelter experiments were conducted in two consecutive years. Plants were grown in topsoil monoliths (0–20 cm) with low (LR) or high mechanical resistance (HR), extracted from adjacent no-tillage cropping fields, and placed above 180 cmhigh containers filled with a sandy loam soil. The effects of topsoil hardening were largely regulated by the level of water stress. In stressed plants, HR conditions reduced total aboveground biomass (up to 13%), total root biomass, root length density, and root surface area (up to 23, 38, and 37% respectively). Mechanical impedances reduced root biomass and length in both shallow (0–20 cm) and very deep layers (+ 160 cm). No changes were observed in specific root length or specific surface area. Plants growing in HR topsoils showed lower total water extraction but greater specific water uptake rates (29–47% higher in year 1 and 2 respectively). No clear architectural (i.e., root density) or morphological (i.e., specific root length/area) responses of enhanced root foraging capacity were observed in subsoil roots. However, soybean root system responded through functional mechanisms (i.e., specific water uptake) which partially attenuated the negative effects of mechanical impedances. Keywords Soil physical degradation . Soil mechanical impedance . Root architecture . Water uptake . Root development . No-tillage . Soybean
1 Introduction The plant root system acclimates to environmental constraints through changes in size, morphology, and spatial distribution (Rellán-Álvarez et al. 2016; Rubio and Lynch 2007). Among the environmental constraints crop roots face in the field, one of the most common is the soil degradation associated to
* Gerardo Rubio [email protected] 1
National Scientific and Technical Research Council (CONICET), Godoy Cruz, 2290 Buenos Aires, Argentina
2
National Institute of Agricultural Technology (INTA) Soils Institute, Nicolás Repetto y de los Reseros s/n; 1686 Hurlingham, Buenos Aires, Argentina
3
School of Agriculture, Oilseed Crops, University of Buenos Aires (UBA), Av. San Martín, 4453 Buenos Aires, Argentina
4
INBA (CONICET-UBA) and Soil Fertility and Fertilizers, School of Agriculture University of Buenos Aires Av. San Martín 4453, C1417DSE Buenos Aires, Argentina
agricultural practices. Continuous monoculture of crops with reduced levels of residues, for instance, impairs the soil environment through undesirable changes in physical and biological soil properties, such as decrease in soil micr
Data Loading...
