TY - JOUR
T1 - Biochar amendment to coarse sandy subsoil improves root growth and increases water retention
AU - Bruun, Esben
AU - Petersen, Carsten Tilbæk
AU - Hansen, Emilie
AU - Holm, Jens
AU - Nielsen, Henrik Haugaard
PY - 2014/3
Y1 - 2014/3
N2 - Crop yields and yield potentials on Danish coarse sandy soils are strongly limited due to restricted root growth and poor water and nutrient retention. We investigated if biochar amendment to subsoil can improve root development in barley and significantly increase soil water retention. Spring barley (Hordeum vulgare cv. Anakin) was grown in soil columns (diameter: 30 cm) prepared with 25 cm topsoil, 75 cm biochar-amended subsoil, and 30 cm un-amended subsoil lowermost placed on an impervious surface. Low-temperature gasification straw-biochar (at 0, 0.50, 1.0, 2.0, and 4.0 wt%) and slow pyrolysis hardwood-biochar (at 2 wt%) were investigated. One wt% can be scaled up to 102 Mg/ha of char. After full irrigation and drainage, the in-situ moisture content at 30-80 cm depth increased linearly (R2 = 0.99) with straw-biochar content at a rate corresponding to 0.029 m3/m3/%. The lab determined wilting point also increased linearly with char content (R2 = 0.99) but at a much lower rate (0.003 m3/m3/%). Biochar at concentrations up to 2% significantly increased the density of roots in the 40-80 cm depth interval. Addition of 1% straw-biochar had the most positive effect on root penetration resulting in the highest average root density (54% coverage compared to 33% without biochar). This treatment also resulted in the greatest spring barley grain yield increase (22%). Improving the quality of sandy subsoils has global potentials, and incorporation of the right amount of correctly treated residues from bioenergy technologies such as straw-biochar is a promising option.
AB - Crop yields and yield potentials on Danish coarse sandy soils are strongly limited due to restricted root growth and poor water and nutrient retention. We investigated if biochar amendment to subsoil can improve root development in barley and significantly increase soil water retention. Spring barley (Hordeum vulgare cv. Anakin) was grown in soil columns (diameter: 30 cm) prepared with 25 cm topsoil, 75 cm biochar-amended subsoil, and 30 cm un-amended subsoil lowermost placed on an impervious surface. Low-temperature gasification straw-biochar (at 0, 0.50, 1.0, 2.0, and 4.0 wt%) and slow pyrolysis hardwood-biochar (at 2 wt%) were investigated. One wt% can be scaled up to 102 Mg/ha of char. After full irrigation and drainage, the in-situ moisture content at 30-80 cm depth increased linearly (R2 = 0.99) with straw-biochar content at a rate corresponding to 0.029 m3/m3/%. The lab determined wilting point also increased linearly with char content (R2 = 0.99) but at a much lower rate (0.003 m3/m3/%). Biochar at concentrations up to 2% significantly increased the density of roots in the 40-80 cm depth interval. Addition of 1% straw-biochar had the most positive effect on root penetration resulting in the highest average root density (54% coverage compared to 33% without biochar). This treatment also resulted in the greatest spring barley grain yield increase (22%). Improving the quality of sandy subsoils has global potentials, and incorporation of the right amount of correctly treated residues from bioenergy technologies such as straw-biochar is a promising option.
U2 - 10.1111/sum.12102
DO - 10.1111/sum.12102
M3 - Journal article
SN - 0266-0032
VL - 30
SP - 109
EP - 118
JO - Soil Use and Management
JF - Soil Use and Management
IS - 1
ER -