Growth of AR in the presence of biochar as soil amendment:

short-term effects in a clayey Rhodic Ferralsol in the BS

Contact: PhD Student Márcia T. de Melo Carvalho Centre for Crop Systems Analysis Wageningen University, The Netherlands E-mail: marcia.demelocarvalho@wur.nl

a. Biochar applications did not influence grain yield of aerobic rice; b. LAI and TDM was negatively related to biochar rates above 16 Mg/ha; c. The optimal N rate was 46 kg/ha to achieve a grain yield above 3 Mg/ha.

Influence of biochar and N rates on leaf area index (LAI) and total shoot dry matter (TDM) at 72 DAS:

Influence of N and biochar rates on yield and spikelet fertility:

The Brazilian savannah (BS): 46% is covered by Ferralsols.

Aim: to report single season effects of biochar application coupled with N fertilisation on AR growth and grain yield in a clayey Rhodic Ferralsol in the BS.

Aerobic rice (AR): rain fed, grown on well drained soils.

The biochar: a by-product of charcoal made from Eucalyptus sp. (pieces<2mm) incorporated into 0.2 m soil depth, six months prior sowing rice.

The native clayey Rhodic Ferralsol in the field experiment:

Constraints for AR in the BS: erratic rainfall, low N recovery.

Difference in soil moisture in 0.1 m soil depth between treatments with biochar (8, 16 and 32 Mg/ha) and without biochar over the growing season:

Averaged soil ammonium and nitrate availability (mg/kg) in 0.1 m soil depth over the growing season:

NH4+ 0.06349 N (p ≤ 0.05) + 16.83

NO3- 0.5002 char (p ≤ 0.001) + 0.3357 N (p ≤ 0.001) + 43.85

Treatments: 4 levels of N (0, 30, 60 and 90 kg/ha) and biochar (0, 8, 16 and 32 Mg/ha). Season: Dec. 2008 to Feb. 2009.

Conclusions:

●0 □30 ∆60 ○90

●0 □8 ∆16 ○32

●0 □8 ∆16 ○32