Root Characteristics and Phosphorus Uptake of Maize Seedlings in a Bilayered Soil
- André Chassot and
- Walter Richner *
Under temperate climates, no-tillage results in cooler and denser topsoils than conventional tillage (CT) and in surface accumulation of immobile nutrients. Hence, early growth and functioning of maize (Zea mays L.) roots may be adversely affected. These field conditions were simulated in a controlled environment system, allowing gradients in soil properties between topsoil (0–10 cm) and subsoil (10–50 cm). Combinations of topsoil temperature (Temptop), bulk density (BDtop), and P concentration (Ptop) were applied on maize seedlings grown until the three-leaf stage. Topsoil bulk density and Temptop acted independently on shoot and root parameters but showed some interactions with Ptop An increase in BDtop caused a linear decrease in root length, root mass, and the root/shoot ratio; an increase in root diameters in both topsoil and subsoil; and a concentration of roots in the topsoil. This resulted in a greater contribution of the topsoil roots to the nutrient supply of the shoot, as shown by 15N labeling. Decreasing Temptop reduced shoot and root growth to a similar extent. High Ptop increased length, diameter, and topsoil fraction of roots, particularly at high BDtop There was possibly a trade-off between the adverse effects of low Temptop and the positive impacts of high Ptop on root growth. Shoot P concentration (Pc) was increased by high Ptop and, to a lesser degree, by increasing BDtop The temperature of the topsoil had no effect on Pc It is concluded that in dense, cool soils, particular attention needs to be paid to the P supply of maize seedlings.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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