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ABSTRACT Most studies concerning biochar, which can enhance chemical, physical, and biological soil qualities and increase crop yields, are short-term experiments in controlled environments with temperate regions and sandy soils. Biochar amendment benefits for clayey soils in tropical climate regions are uncertain. Herein, field conditions in clayey soil were investigated for 28 months. Eucalyptus biochar was obtained from charcoal production and incorporated in soil with disc plows (0.00–0.20 m). Treatments comprised six single biochar application amounts–0 (control), 10, 20, 30, 40, and 50 Mg·ha-1. The experiments were conducted in April 2016, and corn was cultivated in 2016/17 and 2017/18. Soil samples were collected in 2018 for macro/micronutrient, bulk density, porosity, macroporosity, microporosity, water availability, and soil penetration resistance evaluations in the 0.00–0.05-, 0.05–0.10-, 0.10–0.20-, 0.20–0.30-, and 0.30–0.40-m layers. Chemicals P, K and Ca increased compared to the control. The K and Ca increases were related to the biochar composition (6% K and 2% Ca). Soil bulk density decreased by 0.07 kg·dm-3, and macro/microporosity (total porosity) increased linearly by 2.5% in the 0.05–0.10-m layer with increasing biochar application amount. Soil penetration resistance was unaffected. For each 1 Mg·ha-1 of biochar applied, a 500-L·ha-1 increase in available water occurred, which may be important for crops with low water demand and to overcome water restriction periods. chemical physical yields shortterm short term uncertain Herein 2 months 0.00–0.20 000020 0 00 20 (0.00–0.2 m. m . m) amounts0 amounts amounts– control, control , (control) 10 30 40 5 Mg·ha1. Mgha1 Mgha Mg·ha 1. Mg ha 2016 201617 17 2016/1 201718 2017 18 2017/18 201 macromicronutrient macro micronutrient macro/micronutrient porosity macroporosity microporosity availability 0.00–0.05, 000005 0.00–0.05 05 0.00–0.05- 0.05–0.10, 005010 0.05–0.10 0.05–0.10- 0.10–0.20, 010020 0.10–0.20 0.10–0.20- 0.20–0.30, 020030 0.20–0.30 0.20–0.30- 0.30–0.40m 030040m 0.30–0.40 layers P 6% 6 (6 Ca. Ca) 007 07 0.0 kg·dm3, kgdm3 kgdm kg·dm 3, kg dm 3 kg·dm-3 macromicroporosity total 25 2.5 0.05–0.10m 005010m amount unaffected Mg·ha1 Mg·ha- applied 500L·ha1 500Lha1 Lha 500 L·ha L 500-L·ha- occurred periods 0.00–0.2 00002 (0.00–0. (control 4 ha1 20161 2016/ 20171 2017/1 00000 0.00–0.0 00501 0.05–0.1 01002 0.10–0.2 02003 0.20–0.3 40m 030040 0.30–0.4 ( 0. dm3 kg·dm3 kg·dm- 2. 10m 500L 500L·ha 500Lha 500-L·ha 0.00–0. 0000 (0.00–0 2017/ 0050 0.05–0. 0100 0.10–0. 0200 0.20–0. 03004 0.30–0. 0.00–0 000 (0.00– 005 0.05–0 010 0.10–0 020 0.20–0 0300 0.30–0 0.00– (0.00 0.05– 01 0.10– 02 0.20– 030 0.30– 0.00 (0.0 0.05 0.10 0.20 03 0.30 (0. 0.1 0.2 0.3 (0