Theoretical evidence that root penetration ability interacts with soil compaction regimes to affect nitrate capture

Abstract

Background and Aims Although root penetration of strong soils has been intensively studied at the scale of individual root axes, interactions between soil physical properties and soil foraging by whole plants are less clear. Here we investigate how variation in the penetration ability of distinct root classes and bulk density profiles common to real-world soils interact to affect soil foraging strategies. Methods We utilize the functional-structural plant model OpenSimRoot to simulate the growth of maize (Zea mays) root systems with variable penetration ability of axial and lateral roots in soils with 1) uniform bulk density, 2) plow pans, and 3) increasing bulk density with depth. We also modify the availability and leaching of nitrate to uncover reciprocal interactions between these factors and the capture of mobile resources. Key Results Soils with plow pans and bulk density gradients affected overall size, distribution, and carbon costs of the root system. Soils with high bulk density at depth impeded rooting depth and reduced leaching of nitrate, thereby improving the coincidence of N and root length. While increasing penetration ability of either axial or lateral root classes produced root systems of comparable net length, improved penetration of axial roots increased allocation of root length in deeper soil, thereby amplifying N acquisition and shoot biomass. Although enhanced penetration ability of both root classes was associated with greater root system carbon costs, the benefit to plant fitness from improved soil exploration and resource capture offset these. Conclusions While lateral roots comprise the bulk of root length, axial roots function as a scaffold determining the distribution of these laterals. In soils with high soil strength and leaching, root systems with enhanced penetration ability of axial roots have greater distribution of root length at depth, thereby improving capture of mobile resources.

In silico evidence for the utility of parsimonious root phenotypes for improved vegetative growth and carbon sequestration under drought

“…These parameters vary with soil depth and are interpolated between the depths to avoid discontinuities along the border between two soil layers. Using the root impedance model added to OpenSimRoot in ( Strock et al., 2022 ), we capture the impact of soil bulk density on root growth. Also included are models that consider the effect of soil water status on soil penetration resistance, with wetter soils being easier to penetrate.…”

In silicoevidence for the utility of parsimonious root phenotypes for improved vegetative growth and carbon sequestration under drought

“…These particular includes soils differing in bulk density, texture, and hydraulic properties. Using the root impedance model added to OpenSimRoot in Strock et al (2022), we capture the impact of soil bulk density on root growth. Also included are models that consider the effect of soil water status on soil penetration resistance, with wetter soils being easier to penetrate.…”

De invloed van bodemverdichting op dewater- en luchthuishouding in de bodem en op de plantontwikkeling : literatuuronderzoek

“…Het indringingsvermogen van zijwortels kan bijvoorbeeld belangrijk zijn, omdat dit worteltype het grootste deel van de lengte van het wortelstelsel in de meeste bedektzadigen (angiospermen) uitmaakt (Zobel et al, 2007;Schneider et al, 2017). Het indringingsvermogen van axiale wortels bepaalt echter uiteindelijk hoe deze zijwortels van een hogere orde in tijd en ruimte verdeeld zijn in de bodemmatrix (Strock et al, 2022).…”