Arbuscular mycorrhizal fungi, phosphorus and organic residues in Peltophorum dubium (Spreng.) Taub. seedlings.

Studies have underscored a growingdemand for innovative practices in the cultivation of seedlings from forest species, with a notable emphasis on the utilization of organic waste, inoculation with arbuscular mycorrhizal fungi (AMF), and phosphate fertilization. This study aimed to evaluate the impact of organic residues, inoculation with AMF, and phosphorus on the growth and quality of Peltophorum dubium (Spreng.) Taub. seedlings. Two independent experiments were conducted. In Experiment I, treatments included inoculation with various AMF species: control (without inoculation), Clareoideoglomus etunicatum, Rhizophagus heterosporum, Rhizophagus clarum, and MIX (a combination of the three AMF species), all in conjunction with varying doses of phosphorus (0, 60, 120, 180, and 240 mg kg-1 soil). In Experiment II, treatments comprised a control group (without AMF) and inoculation with Glomus clarum, Gigaspora margarita, Gigaspora albida, Clareoideoglomus etunicatum, and MIX (a combination of the four AMF species), each associated with four substrates: S1) soil + coarse sand - SCS, S2) SCS + poultry manure, S3) SCS + cattle manure, and S4) SCS + sheep manure. Peltophorum dubium seedlings exhibited heightened growth with the inoculation of R. heterosporum, R. clarum, and MIX. Positive responses were observed in seedlings when exposed to organic residues, particularly sheep manure, resulting in increased biomass production and enhanced Dickson quality index. The AMF inoculation, specifically with R. heterosporum, R. clarum, and MIX, provided optimal growth conditions for P. dubium seedlings. Remarkably, the utilization of organic residues, notably substrates with chicken manure and cattle manure, exerted substantial positive effects on both growth and quality of P. dubium seedlings.

Foliar application of silicon sources and shading levels in Peltophorum dubium (Spreng.) Taub.

Depending on the intensity and ecological successional classification of plants, light availability can become an unfavorable condition for producing high-quality seedlings. We hypothesized that applying silicon sources might contribute to inducing tolerance to different shading levels for Peltophorum dubium (Spreng.) Taub. seedlings. Two independent experiments were developed: I) the application of five doses of silicon oxide (SiO2: 0.0; 1.0; 2.0; 4.0; and 6.0 g L-1); and II) the application of five doses of potassium silicate (K2SiO3: 0.0; 5.0; 10.0; 15.0; and 20.0 mL L-1 of water). Both were associated with three shading levels: 0% (direct sunlight), 30%, and 50%. In experiment I, we observed that seedlings were more responsive to shading levels and had little influence from foliar application of SiO2, with higher growth, biomass, and quality values when grown under direct sunlight (0% shading). In experiment II, the foliar application of 20.0 mL L-1 of K2SiO3 contributed to greater heights under 0% and 30% shading. Meanwhile, under 50% shading, the dose of 5.0 K2SiO3 favored the species' growth. The application of K2SiO3 favored the increase in the dry mass of the aerial part (DMAP). The highest biomass production and seedling quality occurred under 0% and 30% shading. The 50% shaded environment was most unfavorable to the growth and quality of P. dubium seedlings. Even though the seedlings were not very responsive to silicon sources, K2SiO3 provided a greater response than SiO2. High-quality seedling production is favored when the seedlings are grown under direct sunlight (0% shading).

Produtividade de vinagreira, pimenta rosa e carobinha cultivadas em sucessão a mucuna preta e feijão de porco / Productivity of roselle, Brazilian peppertree, and carobinha grown in succession to black velvet bean and jack bean

RESUMO O uso de adubos verdes e/ou de plantas de cobertura é uma técnica que vem sendo difundida para o cultivo de espécies medicinais, por garantir a sustentabilidade do solo agrícola, ser flexível em seu uso e por melhorar a atividade biológica do solo. O objetivo do trabalho foi avaliar o uso de culturas de cobertura para incrementar a produção de massa de plantas de vinagreira, pimenta rosa e carobinha. Foram avaliadas duas espécies de leguminosas tropicais (mucuna preta e feijão de porco) como cobertura do solo e uma testemunha (sem cultura de cobertura) e três espécies medicinais (vinagreira, pimenta rosa e carobinha). O experimento foi arranjado em esquema de parcelas subdivididas, tendo nas parcelas as coberturas vegetais e nas subparcelas, as plantas medicinais. As plantas para a cobertura vegetal foram propagadas por semeadura direta no local de cultivo, enquanto as medicinais foram transplantadas diretamente entre a palhada da cobertura vegetal. A produção da mucuna preta foi de 8,37 t ha-1 de massa seca e do feijão de porco, de 14,37 t ha-1 de massa seca. O uso das culturas de cobertura contribuiu para uma maior biomassa microbiana do solo. As produções de massas frescas de folhas, caules e frutos de vinagreira e de frutos da pimenta rosa foram maiores quando cultivadas em sucessão às coberturas vegetais do solo, independente da espécie. As produções da carobinha foram semelhantes quando cultivadas em áreas com ou sem a cobertura. Visando à maior produtividade da vinagreira e pimenta rosa, são indicadas as culturas antecessoras feijão de porco e mucuna preta.

ABSTRACT The use of green manure and/or cover crops is a technique that has been widespread for the cultivation of medicinal species, since it ensures the sustainability of agricultural soil, is flexible in its use, and improves biological activity in the soil. The purpose of this study was to evaluate the use of cover crops to increase biomass production of roselle, Brazilian peppertree, and carobinha plants. Two species of tropical legumes (black velvet bean and jack bean) were evaluated as ground covers, and also assessed were one control plot (without cover crops) and three medicinal species (roselle, Brazilian peppertree, and carobinha). The experiment was arranged in a split-plot design, where the plots had cover crops and the subplots contained the medicinal plants. The plants for the cover crop were propagated by direct sowing in the growing site, while the medicinal ones were transplanted directly between the cover crop. The dry mass production of the velvet beans and jack beans were 8.37 t ha-1 and 14.37 t, respectively. The use of cover crops contributed to the increased microbial biomass of the soil. The production of dry mass of leaves, stems, and fruits of roselle and fruits of Brazilian peppertree were higher when grown in succession to the crop cover for the soil, regardless of the species. The production of carobinha was similar when grown in areas with or without the cover. To increase the yield of roselle and Brazilian peppertree, preceding crops of jack bean and black velvet bean are recommended.