Trichoderma spp. are an alternative to increase plant growth and as biological control agents of diseases.  Biochar added to soil and Trichoderma can result in the enhancement of crop development and can aid in preventing fertilizer run-off, improving plant health, retaining soil moisture, and helping plants through drought periods. However, a knowledge gap remains regarding the combined effect of biochar and Trichoderma on soil quality and crop growth. The objective of the present study was to evaluate this combined effect and show a new approach of biochar as a route of T. aureoviride (T) inoculation. We evaluated three sources of biochar, bean husks, coffee grounds, and coffee husks, with or without T and additional control that was devoid of biochar and T. The association of all biochar sources with T showed a significant increase in watermelon growth and soil quality. Biochar coffee grounds with T increased urease, β-glucosidase, and total organic carbon, showing the potential of this combination in these processes. Watermelon plants cultivated in soil with coffee grounds and T   showed plant length and shoot dry biomass increases of 129% and 192%, respectively. Thus, this study found that biochar use plays an important role in the effectiveness of T. aureoviride applications and is a new instrument for sustainable agriculture.

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The use of biochar can bring benefits such as long-term carbon sequestration and water use efficiency, being an alternative for semiarid regions. The objective of this study was to evaluate the impact of coffee biochar applied in sandy Entisol on maize growth, and soil chemical, microbial and biochemical attributes. The experimental design was completely randomized, distributed in a 2 x 4 + 1 factorial scheme, two types of wastes coffee ground (MCG) and coffee husks (MCH), four doses (4, 8, 12 and 16 Mg ha -1 ) and control (CONT), without biochar. All treatments received organic fertilization with manure. Coffee biochar applied to sandy soil cultivated with maize, as predicted, increased the total soil C content, mainly coffee husk biochar that increases twice the C content compared to the control. Nutrient and some enzyme activities of soils were improved with increasing coffee biochar doses. Microbial biomass of soils amended with the biochars MCH16 and MCH12 showed an increase of 100 and 116%, respectively. This study demonstrated a clear response of the soil nutrients, microbial community and enzyme activities related to types and doses of biochar. Therefore, the use of coffee biochar is recommended for increasing the quality of sandy soils in the Brazilian semi-arid.

O biochar é produto da degradação térmica de materiais orgânicos na presença limitada de oxigênio (pirólise), e sua adição aos solos influencia nos atributos químicos, físicos e em comunidades microbianas. A produção do biochar pode ser uma alternativa para o reaproveitamento de resíduos da agro-indústria. O objetivo do presente estudo foi avaliar o impacto de resíduos gerados na indústria de biodiesel (puro e transformado em biochar) nas atividades enzimáticas, atributos químicos e microbiológicos do solo arenoso. O experimento foi distribuído em esquema fatorial 5 x 5, sendo o primeiro fator constituído por: apenas o solo (controle); resíduo de Graviola (RG), resíduo de Pinha (RP) biochar do resíduo de graviola (BG) e biochar do resíduo de pinha (BP) e o segundo fator, cinco tempos de incubação 0, 30, 60, 90 e 120 dias após incubação (DAI), com 4 repetições. Foram avaliados, atributos químicos do solo, carbono da biomassa microbiana (CBM) e atividades enzimáticas (uréase, fosfatase acida e alcalina). Solos tratados com RG apresentaram um incremento na urease aos 120 DAI (3,8 vezes maior que o controle). A aplicação de BG ao solo no tempo 0 incrementou os teores de fosfatase ácida, fosfatase alcalina, uréase e CBM (1,1; 1,2; 1,4 e 1,1 vezes) e o pH (1,2 vezes). Solos que receberam BP apresentaram incrementos no pH, CBM aos 120 DAI, fosfatase alcalina aos 120 DAI e uréase aos 60 DAI. Ambos os resíduos e biochar de graviola contribuíram para a qualidade bioquímica, microbiológica e química do Neossolo regolítico arenoso. Impact of biochar Residues from the biodiesel industry on the attributes of a sandy soil A B S T R A C TThe current call for the use of renewable energy generates a quantity of waste that, if not handled correctly, can cause environmental damage. For this reason, research that aims to reuse these residues to be applied in agriculture has been carried out, such as those that transform such wastes into biochar. Biochar is a product of pyrolysis and its addition to soils has an influence on chemistry, physics and microbial communities. The objective of the present study was to evaluate the impact of seed cake (pure and transformed into biochar) on the enzymatic activities, chemical and microbiological attributes of the sandy soil. The experiment was distributed in a 5 x 5 factorial scheme, the first factor being: only the soil (control); Graviola residue (RG), Pine cone residue (RP) Biochar of graviola residue (BG) and Biochar of pine cone residue (BP) and the second factor, five incubation times 0, 30, 60, 90 and 120 days after incubation (DAI). Soil chemical attributes, microbial biomass carbon (CBM) and enzymatic activities (urea, acid and alkaline phosphatase) were evaluated. RG treated soils showed an increase in urease at 120 DAI (3.8 times greater than the control). The application of BG to the soil at time 0 increased the levels of acid phosphatase, alkaline phosphatase, urea and CBM (1.1; 1.2; 1.4 and 1.1 times) and pH (1.2 times). Soils that received BP showed increases in pH, CBM at 120 DAI, alkaline phosphatase at 120 DAI and urea at 60 DAI. Soursop biochar contributed to the biochemical and microbiological quality of the soil, demonstrating its greater potential for agricultural use compared to the others.Keywords: biochar, soil chemistry, enzyme activity, incubation

The melon belongs to the family of commercially important cucurbitaceous in the world. However, the production of this crop can be very problematic in some places due to management practices and the climatic instability. Amongst the different options available to overcome these obstacles, the use of biochar often promoted for providing multiple benefits to crops, could contribute in holding more water and nutrients in soil and therefore improve the plant growth. A second way to try to improve the plant development was to use Trichoderma (TRI) known as aiding in seed germination, and being an excellent biological control agent against plant pathogenic pests. So, the objective of this study was to evaluate the benefits of the association of biochar and TRI on the initial growth of melon and the effects on the quality of a sandy Entisol. We quantified the effects of these associations through biometric growth in melon plants and chemical, microbial, and enzymatic activities of the biogeochemical cycles in the soil. An experiment in a completely of randomized design was performed in a factorial scheme (3 x 2 + 1) with three sources of biochar (bean husk (BH), coffee ground (CG), and coffee husk (CH)) inoculated with (T+) or without (T-) TRI and additional controls When the coffee grounds (CG) and bean husks (BH) biochar with T+ soil was inoculated, the fresh weight (number of leaves), dry weight, length (of roots and branch), soil acid and alkaline phosphatase, total organic carbon, phosphorus, magnesium, potassium, and pH were all increased. Moreover, T. aureoviride inoculated CG biochar compared to the control increased the shoot length and dry biomass of the melon plant in 30 and 22% between 22 and 30 %. The soil that received coffee husks (CH) biochar and T+ showed higher microbial biomass carbon. However, the melon plants responded more to the type of biochar than to the T. aureoviride inoculation, possibly due to the short growth time of melon. Results of BH biochar inoculated with T. aureviride in sandy soil showed improved efficiency on melon growth and increased soil quality.