Author(s)

Tim Dresemann¹, Miriam Athmann^1,2, Lukas Heringer¹, Timo Kautz³

¹INRES-Agroecology and Organic Farming, University of Bonn, Bonn, Germany.
²Experimental Farm Wiesengut, Hennef, Germany.
³INRES Soil Science, University of Bonn, Bonn, Germany.

Round shaped, continuous vertical pores (CVPs) in the soil are typically created by roots and earthworms. CVPs with diameters > 2 mm are abundant in many agricultural soils. We hypothesized that potential effects of CVPs on shoot growth of winter wheat (Triticum aestivum L.) increase with: 1) decreasing availability of water and 2) decreasing availability of nutrients in the topsoil. We conducted a microcosm experiment with different irrigation regimes (Irr+/Irr-) and P concentrations (P+/P-), with or without artificially created continuous vertical pores (CVP+/CVP-). Winter wheat was cultivated for 16 weeks. In the bulk soil, presence of CVPs resulted in decreased root length in 20 - 40 cm but increased root length in 40 - 60 cm soil depth. In general, total root length of winter wheat in 20 - 60 cm soil depth was higher when CVPs were present or when P concentrations in the topsoil were elevated. Presence of CVPs generally had a positive effect on shoot dry matter and N uptake of wheat. In columns with high phosphorous concentrations but low soil moisture in the topsoil, presence of CVPs increased shoot dry matter by 66%; in contrast, the beneficial effect of CVPs on shoot dry matter was only 39% in columns with high nutrient concentrations and high soil moisture in the topsoil. In total numbers, however, the effect of CVPs on P uptake into the shoot was more pronounced when P concentrations in the topsoil were elevated. We conclude that CVPs can promote the exploration of the solid soil phase by high root-length densities, but adequate nutrient supply in the topsoil is essential.

Subsoil, Mechanical Resistance, Drought Stress, P Supply, Nutrient Acquisition

Dresemann, T. , Athmann, M. , Heringer, L. and Kautz, T. (2018) Effects of Continuous Vertical Soil Pores on Root and Shoot Growth of Winter Wheat: A Microcosm Study. Agricultural Sciences, 9, 750-764. doi: 10.4236/as.2018.96053.