Root and shoot growth of spring wheat (Triticum aestivum L.) are differently affected by increasing subsoil biopore density when grown under different subsoil moisture

Abstract

A column experiment with five different pore densities (0, 1, 2, 3, and 4 pores column−1) and two varying moisture regimes (comparatively dry and comparatively moist regime) in the subsoil part of the columns was established. In each pore, Lumbricus terrestris was introduced for 28 days before sowing wheat plants. After 40 days of plant growth, watering was stopped to induce progressive topsoil drying. Parameters describing the shoot hydration, mineral uptake, and aboveground biomass were quantified. Root biomass and root length densities (RLD) were measured separately for six soil layers. Under dry subsoil conditions, plants grown under increasing biopore density showed an increase of the RLD and an improved shoot hydration but the aboveground biomass was unaffected. Since RLD but not root biomass was enhanced, it is assumed that roots were able to explore a larger volume of soil with the same amount of root biomass. Thereby, subsoil water likely was used more efficiently leading to an improved hydration. Under moist subsoil conditions, plants grown with increasing biopore density revealed enhanced shoot biomasses and nutrient uptake while the belowground biomass was unaffected. The improved nutrient uptake can be ascribed to, first, the higher subsoil water availability favoring mass flow driven nutrient uptake, and second, to direct and indirect effects of earthworms on the availability of soil nutrients. It is concluded that high biopore abundancies have the potential to improve not only the belowground but also the aboveground biomass. This, however, largely depends on subsoil moisture.

Root and root‐derived biopore interactions in soils: A review

“…Furthermore, Kautz (2015) reported that the density of biopores also had an important effect on crop growth. Under 30% water holding capacity, Koch et al (2021) found that the shoot biomass of wheat increased when the biopore density increased, but not for root biomass. At a given biopore diameter of 0.5 mm, Xiong, Zhang, Guo, et al (2022) reported that a biopore density of 7000 m -2 might better enhance maize root growth than biopore densities of 1750 and 28,000 m -2 in compacted soil.…”

“…Under 30% water holding capacity, Koch et al. (2021) found that the shoot biomass of wheat increased when the biopore density increased, but not for root biomass. At a given biopore diameter of 0.5 mm, Xiong, Zhang, Guo, et al.…”

The pore‐rhizosheath shapes maize root architecture by enhancing root distribution in macropores

“…The effects of artificial pores on root growth of various of plants have been investigated intensively (Atkinson et al, 2020;Colombi et al, 2017;Koch et al, 2021;Pfeifer et al, 2014). Pfeifer et al…”

“…Xiong, Zhang, Guo, et al (2022) found that for 0.5‐mm macropore, a medium density (20 macropores per column) improved maize root growth compared with low (5) and high (80) pore densities. Koch et al (2021) reported that a high artificial biopore density was helpful to improve the root and shoot growth of spring wheat, yet depends on subsoil water content. Although these studies provide important insights into pore‐root interactions, the artificial pores failed to represent old root channels accurately, because biochemical properties of the rhizosheath were not reproduced.…”

Combined subsoiling and ridge–furrow rainfall harvesting during the summer fallow season improves wheat yield, water and nutrient use efficiency, and quality and reduces soil nitrate-N residue in the dryland summer fallow–winter wheat rotation

“…Subsoiling tillage [ST, usually combined with straw mulching (STSM)] plays important roles in agricultural production, especially in dryland regions, as it is able to increase rainfall harvest, crop yield, and efficiency ( Cai et al., 2014 ; Arnhold et al., 2023 ) and address environmental issues ( Zhao et al., 2023b ). Previous studies have primarily demonstrated that ST can influence crop growth and development by reducing soil bulk density ( Ahmad et al., 2009 ; Lampurlanés et al., 2016 ; Sun et al., 2018 ), increasing soil porosity ( Xue et al., 2018 ), enhancing water infiltration ( Liang et al., 2019 ; Qiang et al., 2022 ), increasing soil water usage ( Wang et al, 2022 ; Yang et al., 2022 ), optimizing soil physical properties and fertility ( He et al., 2019 ; Wang et al, 2020 ; Yang et al., 2022 ), improving root characteristics ( Izumi et al., 2009 ; He et al., 2019 ; Koch et al, 2021 ; Arnhold et al., 2023 ), enhancing tiller density ( Lv et al., 2019 ), delaying senescence ( He et al., 2020 ), promoting plant photosynthesis characteristics ( Sang et al., 2016 ; He et al., 2019 ), and facilitating dry matter accumulation and remobilization ( Zhang et al., 2023 ). In the Loess Plateau of China, studies of two 2-year experiments showed that ST during the summer fallow season improved soil nutrient characteristics, wheat growth, and N uptake characteristics, thus not only increasing wheat yield and water use efficiency (WUE), but also optimizing the quality of albumin, gliadin, glutenin, total protein, and sedimentation values and wet gluten contents ( Sun et al., 2013 ; Zhao et al., 2017 ).…”