(1)

This study aimed to investigate the influence of chemical and structural characteristics of biochar on the development of rice plants grown in fragile sandy soil. An experiment was carried out in pots with the application of four doses (0 ton ha-1; 10 ton ha-1; 20 ton ha-1; 30 ton ha-1) of eucalyptus biochar from four artisanal sources (B1, B2, B3, and B4). Fresh root mass increased by 0.56% with the application of biochar B4 and decreased with the application of biochars B1, B2, and B3 (23.3%; 18.3%; 19.9%). The fresh mass of sheath and leaves decreased by an average of 23.6% and 27%, respectively, with the application of all biochars. Root dry mass increased by 7.8% with the application of biochar B4 and decreased with the application of B1, B2, and B3. The sheath dry mass and leaf dry mass decreased by an average of 20.2% and 25.1%, respectively, with the application of all biochars. The nutrient content, specifically P, K, and N, increased with the application of B1, B2, and B3. The application of biochar B4 (30 ton ha-1) lessened the damage to the photosynthetic apparatus and promoted physiological recovery. The beneficial effect of biochar B4 occurred at a dose of 30 ton ha-1 in the reaction centers, increasing photochemical efficiency in photosystem II. Root development was stimulated by the application of biochar B4, increasing root area by 55% (10 ton ha-1) and 56% (20 ton ha-1 and 30 ton ha-1). The total length increased by 48% with the application of biochar B4 and by 27% with biochar B2 (30 ton ha-1). The length of thick roots and the total root volume were less affected by the treatments, with increases of approximately 11% and 7%, respectively. Although most treatments did not result in higher biomass production compared to the control, there was a notable increase in nutrient content in the aboveground portion, particularly with the application of biochar B2. Furthermore, improvements in photosynthetic parameters and root morphology were observed, particularly when biochar B4 was applied. Overall, the findings of this study indicate that biochars B2 and B4, at rates of 20 and 30 ton ha-1, respectively, hold promise for enhancing cultivation in vulnerable Planosols in the Rio de Janeiro region of Brazil. However, to fully understand the effects on soil properties in different crops and the economic implications of implementing biochar in agriculture, further long-term and large-scale research is necessary.

来源平台：JOURNAL OF SOIL SCIENCE AND PLANT NUTRITION