Spatial distribution of maize roots by complete 3D soil monolith sampling

• Published in: Plant and soil Vol. 315; no. 1-2; pp. 297 - 314
• Main Authors: Kuchenbuch, Rolf O, Gerke, Horst H, Buczko, Uwe
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.02.2009; Springer; Springer Netherlands; Springer Nature B.V
• Subjects: Agrology; Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; Biological and medical sciences; Biomass; Biomedical and Life Sciences; bulk density; Cereal crops; Corn; Ecology; Fundamental and applied biological sciences. Psychology; Life Sciences; Line intersect method; Maize (Zea mays L.); Nutrient uptake; Nutrients; Organic soils; Plant growth; Plant Physiology; Plant roots; Plant Sciences; Plants; Regular Article; Root length density; Root mass; Roots; Row spacing; Sand soils; Soil density; Soil depth; soil physical properties; Soil samples; Soil Science & Conservation; Soil volumetric sampling; Soil water; Soils; Spatial distribution; Spatial variability; L.; Row spacing; Soil volumetric sampling; Spatial variability; Corn; Line intersect method; Maize; Soil bulk density; Root mass; Root length density; Corn, Line intersect method; Soil volumetric sampling, Spatial variability; Maize (Zea mays L.); Row spacing, Soil bulk density; Soil plant relation
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-008-9752-8

The spatial distribution of root length density (RLD) is important for water and nutrient uptake by plants and biomass allocation in the soil. Experimental root assessment is, however, mostly based on methods that encompass only small fractions of the soil volume. The aim of this study was to characterize the three dimensional (3D) spatial distribution of RLD in the soil of a maize crop for plots of 37.5 and 75 cm row spacing. At each plot, a 3D soil monolith of 70 x 40 x 30 (=84,000) cm³ was completely sampled in form of 84 cubic samples of 10 cm edge length. Roots were washed from the soil and RLD was determined using the line intersect method. In 2004, mean RLD values were 0.41 cm cm⁻³ for narrow and 0.34 cm cm⁻³ for wide row spacing at row closure (55 days after planting; DAP) and 0.74 cm cm⁻³ (1.37 cm cm⁻³ in 2003) for narrow and 0.77 cm cm⁻³ (0.96 cm cm⁻³ in 2003) for wide row spacing at tasseling (104 DAP). The CV values for RLD of 48% to 72% in 2004 were first higher for wide than for narrow row spacing but at the later growth stage (tasseling) lower for wide than for narrow. For individual vertical soil slices, CV values for RLD were about 40-60%, irrespective of the orientation of the slice. The results suggest that RLD was related mainly to the spatial location and the plant row structure, and not governed unambiguously by SBD or SWC. The spatially distributed maize root data suggest that variability of RLD parallel to plant rows is not negligible. Any simplified use of 1D or 2D vertical samples at separate locations may lead to erroneous estimations of RLD profiles.