Spatial Distribution of Roots and Water Uptake of Maize (Zea mays L.) as Affected by Soil Structure

Abstract

The incomplete soil exploration by roots is a possible cause of reduced water uptake and the occurrence of strong gradients in water potential between root clusters and the bulk soil. Therefore, the hydraulic or root signal‐elicited behaviors of plants might correspond to a lower water content than that of the bulk soil. Evidence supporting this hypothesis is scarce and often circumstantial due to the lack of appropriate techniques. This work studies the relations of root clustering caused by localized soil compaction and the spatial patterns of water uptake in plants grown on stored water. Five soil structure treatments were compared in 100‐cm high containers: clay‐loam soil (C), sandy‐clay soil (S), sandy clay with large clay‐loam peds (S + LA), sandy clay with small clay‐loam peds (S + SA), and compacted clay‐loam soil (CC). Root length density (RLD) and volumetric water content (θv) (time‐domain reflectometry) were measured in bulk soil and across peds in 2‐cm increments. In the S treatment, plant growth was rapid initially, but green leaf area declined to zero when water was exhausted. Root length density was quite uniform in each layer. In the CC treatment, root density and water uptake were limited and leaf area remained stable throughout the experiment, suggesting that incomplete water extraction was a consequence rather than a cause of reduced plant growth. In the other treatments, when plants had lost all leaves, the water content of peds ranged from 0.23 cm3 cm−3 in the outer 2 cm, where roots were present, to more than 0.30 cm3 cm−3 in the center, scarcely penetrated by roots. Thus, there was incomplete water extraction in the C and S + LA, and to a lesser extent in S + SA treatments. This study shows that large gradients in soil water content occur in cases of root clustering caused by localized soil compaction. These gradients are associated with a reduction in water uptake.

Comprehensive Screening of Some West and Central African Sesame Genotypes for Drought Resistance Probing by Agromorphological, Physiological, Biochemical and Seed Quality Traits

“…However, the diversity of root morphology and architecture in sesame has not been examined until now [49]. Therefore, future research may aim at characterizing the diversity of sesame root morphology and architecture as performed in several crops such as pearl millet [56], maize [57], rice [58] and wheat [59]. And then, understanding the relations root morphology and architecture-function-drought resistance in sesame, would effectively guide breeders in exploiting root traits for drought resistance enhancement in sesame.…”

Water Competition of Intercropped Pearl Millet with Cowpeaunder Drought and Soil Compaction Stresses

“…The reports on the effects of soil compaction on water-uptake by the plants are inconsistent. The water uptake by Kentucky bluegrass (Agnew and Carrow, 1985), pigeon pea (Kirkegaard et al, 1992), and maize (Amato and Ritchie, 2002) was decreased by soil compaction. On the other hand, Lipiec et al (1988) indicated that water uptake by maize was enhanced by higher soil bulk density.…”

Tillage Effects on Corn Soil-plant-water Continuum in Alfisols of Southern Ohio

“…Higher soil water storage is normally observed under NT as compared to CT (Diaz Zorita et al, 2002;He et al, 2006;Bhattacharyya et al, 2008), and higher root length density (RLD) is observed under straw mulch than unmulched plots (Hossain et al, 2008). Mechanical impedance, the resistance offered by the soil matrix against deformation by a growing root, is also a major factor inhibiting root growth (Amato & Ritchie, 2002;Duruoha et al, 2007). Diaz-Zorita et al (2005) observed quadratic response of RLD decrease with increase in soil bulk density.…”