Biochar and mucuna increase papaya plant growth and nutrition, as well as soil fertility

ABSTRACT The association between biochar and green manure in the papaya crop may be a promising management technique, mainly in its first growth stage. This study aimed to evaluate the effects of biochar and green manure (Mucuna aterrina) on the growth and nutrition of Carica papaya seedlings, as well as on soil fertility. The experiment followed a randomized block design (5 blocks), in a 2 x 2 factorial arrangement: with and without mucuna and with and without biochar. The biochar or mucuna application significantly increased the papaya plant shoot and root growth, as well as the chemical features of the soil, whereas their joint application did not provide synergistic effects, except for the leaf P concentration. The application of biochar and biochar + mucuna enabled a fast initial increase in plant height. However, it also showed a visible N deficiency, despite the increased N, P, K, Ca and Mg accumulation and use efficiency in the plants. The effect of the biochar/mucuna joint application is synergistic for the leaf P content and plant height. The individual or joint application of biochar and mucuna increases the papaya plant growth and nutrition and maintains the soil fertility.