Promoção de crescimento de sorgo granífero combinado com cepas de Trichoderma spp e doses de nitrogênio e fósforo

Abstract

Sorghum is the fifth most produced grain worldwide and essential for food security, especially in arid areas. Brazil is the ninth largest producer. The plant requires nutrients such as nitrogen and phosphorus, and the use of fertilizers, including biofertilizers with Trichoderma, improves its growth and agricultural sustainability. More research on biofertilizers in sorghum is needed. The objective was to evaluate the growth of grain sorghum with different strains of Trichoderma spp. in response to doses of nitrogen (N) and phosphorus (P). Two distinct experiments were conducted, one for N and the other for P, both carried out at the State University of Goiás, South Campus, University Unit of Ipameri-GO. The experimental design used for both experiments was in a factorial scheme (4 x 5) in randomized blocks, with four treatments and five doses. For the nitrogen experiment, stabilized and conventional urea was used, with or without Trichoderma harzianum, in nitrogen doses (50, 70, 90, 110, and 130 kg ha-1), plus 100 and 70 kg ha-1 of P2O5 and KCl, respectively. For the phosphorus experiment, stabilized phosphorus and single superphosphate were used, with or without Trichoderma harzianum, in phosphorus doses (10, 80, 150, 220, and 290 kg ha-1), plus 100 and 70 kg ha-1 of N and KCl. In both experiments, the characteristics of plant height (ALTP), Falker chlorophyll relative index (IRC), flowering (FLOR), stem diameter (DIAMC), stem fresh mass (MFC) and leaf fresh mass (MFF), and grain dry mass (MSG) were evaluated. The results showed that the combination of Trichoderma harzianum with different doses of nitrogen and phosphorus significantly influenced the characteristics of sorghum. Stabilized urea with Trichoderma harzianum (T2) excelled in plant height and stem diameter, while T4 achieved better results in fresh mass, and T3 in dry mass. Additionally, the combination of stabilized phosphorus (P35) and Trichoderma harzianum (T2) proved superior in various analyses of sorghum development, promoting height, stem diameter, and dry mass. The concentration of 105 kg ha-1 N with T2 is the most recommended.