Laura Costa Oliveira Almeida

High physiological quality seeds with high germination and vigor are essential for successful soybean (Glycine max L. Merrill) cultivation, ensuring proper establishment and early development. Biostimulants have shown significant potential to enhance soybean performance, especially under environmental stress, such as water deficit, which impairs germination and emergence. This study evaluated the effects of seed treatments with biostimulants and their interaction with insecticide and fungicide on biometrics, nutrition, and biochemical variables during soybean initial development under water deficit conditions. A randomized block design in an 8×2 factorial scheme was employed, comprising eight seed treatments [control (no biostimulant); Imidacloprid and fungicide (Carboxin + Thiram) (IF); three biostimulants (B1, B2, B3); and their combinations with IF] under two water regimes (100% and 50% of pot capacity), with three replicates. Evaluations 21 days after application included germination, emergence speed, root and shoot length, dry matter, and enzymatic activity. Biostimulants, particularly seaweed- and plant extract-based, improved water deficit tolerance, enhancing germination, emergence, biometrics, enzymatic activity (superoxide dismutase, peroxidase, and catalase), and nutrient uptake (P, K, Mg, Cu, Mn, Zn). However, further studies are needed to assess potential adverse interactions between biostimulants, fungicides, and insecticides. Keywords: Glycine max (L.) Merrill; germination; mineral nutrition; water stress. A composição dos bioestimulantes aplicados em tratamento de sementes interfere na emergência de soja sob deficiência hídrica RESUMO: Sementes de alta qualidade fisiológica, com elevada germinação e vigor, são essenciais para o sucesso do cultivo de soja (Glycine max L. Merrill), garantindo o estabelecimento adequado e o desenvolvimento inicial da cultura. Os bioestimulantes têm demonstrado potencial significativo para melhorar o desempenho da soja, especialmente sob estresse ambiental, como o déficit hídrico, que prejudica a germinação e a emergência. Este estudo avaliou os efeitos do tratamento de sementes com bioestimulantes e sua interação com inseticidas e fungicidas na biometria, nutrição e variáveis bioquímicas durante o desenvolvimento inicial da soja sob déficit hídrico. Foi utilizado delineamento em blocos causalizados, em esquema fatorial 8×2, composto por oito tratamentos de sementes [controle (sem bioestimulante); inseticida Imidacloprido e fungicida (Carboxina + Tiram) (IF); três bioestimulantes (B1, B2, B3); e suas combinações com IF] sob dois regimes hídricos (100% e 50% da capacidade de vaso), com três repetições. As avaliações realizadas 21 dias após a aplicação incluíram germinação, velocidade de emergência, comprimento de raiz e parte aérea, massa seca e atividade enzimática. Bioestimulantes, especialmente à base de extratos de algas e plantas, aumentaram a tolerância ao déficit hídrico, promovendo melhorias na germinação, emergência, biometria, atividade enzimática (superóxido dismutase, peroxidase e catalase) e absorção de nutrientes (P, K, Mg, Cu, Mn, Zn). No entanto, estudos adicionais são necessários para avaliar possíveis interações negativas entre bioestimulantes, fungicidas e inseticidas. Palavras-chave: Glycine max (L.) Merrill; germinação; nutrição mineral; estresse hídrico.

Sugarcane plays a crucial role in global sugar and ethanol production. Conventionally, sugarcane propagation involves planting billets. However, Brazilian researchers have introduced the innovative pre-sprouted seedlings (PSS) method, widely used in the MEIOSI (Simultaneously Occurring Interrotational Method) system. Although PSS has several advantages over the conventional method, its sensitivity to water scarcity is a challenge. This study aimed to evaluate the survival and growth of PSS inoculated with Bacillus licheniformis and Bacillus subtilis (PGPB) under different water regimes. The experiment was conducted in the field in a randomized block in strips (split-block) using a 2 × 4 factorial scheme consisting of two inoculation conditions (with and without PGPB) and four water regimes (WR) (0%, 33%, 66%, and 100% of the ideal irrigation). PGPB increased PSS survival (4.17%) and water use efficiency (185.10% under the 0% WR). In addition, inoculation increased root (12.5%, 7.7%, and 16.2% for surface area, area projection, and root volume, respectively) and shoot growth. PGPB also increased nutrient uptake, such as N (60.8% and 18.3% under 0% and 66% WR), P (on average 11.7%), Mn (27.6% and 28.7% under 66% and 100% WR), Zn (111.4% under 0% WR), and Cu accumulation (27.17%), which provided a higher number of stalks per meter and, therefore, a higher multiplication rate in the MEIOSI system. Inoculation proved to be a promising alternative for PSS establishing under water restriction.

Sugarcane plays a crucial role in global sugar and ethanol production. Conventionally, sugar-cane propagation involves planting billets. However, Brazilian researchers have introduced the innovative pre-sprouted seedlings (PSS) method, widely used in the MEIOSI (Simultaneously Occurring Interrotational Method) system. Although MPB has several advantages over the con-ventional method, its sensitivity to water scarcity is a challenge. The study aimed to evaluate the survival and growth of PSS inoculated with Bacillus licheniformis and Bacillus subtilis under differ-ent water regimes. The experiment was conducted in the field in a randomized block in strips (split-block) using a 2×4 factorial scheme consisting of two inoculation conditions (with and without bacteria) and four water regimes (0%, 33%, 66%, and 100% of the ideal irrigation). The bacteria increased the PSS's survival and water use efficiency in the field. In addition, inocula-tion increased root and shoot growth, as well as the nutrient uptake such as N, P, Mn, Zn, and Cu, which resulted in a higher number of stalks per meter and, therefore, a higher multiplica-tion rate in the MEIOSI system. Inoculation proved to be a promising alternative for establishing PSS under water restriction.

Sugarcane is one of the main crops in Brazilian agriculture. It has high economic and productive potential, but its current productivity is still lacking due to poor nutritional management in both the soil and the plant. Zinc (Zn) directly affects tillering and plant growth, which are critical factors to sugarcane productivity and ratoon longevity. Thus, this research aimed to evaluate the effects of Zn chelate doses (185, 260, and 330 g ha⁻¹) and two application methods (furrow and foliar applications) on the tillering, yield, and quality of sugarcane. The Zn chelate fertilization via furrow at a dose of 330 kg ha⁻¹ provided increases of 13.59%, 17.6%, and 17.0% in stalk height (SH), stalk (TSH) productivity, and sugar (TPH) productivity, respectively. In contrast, Zn foliar application at a dose of 260 g ha⁻¹ provided increases of 3.71%, 20.7%, and 17.0% in SH, TSH, and TPH, respectively. The optimal Zn chelate fertilization in sugarcane cultivation can be performed at a dose of 330 g ha⁻¹ via furrow application at planting or at a dose of 260 g ha⁻¹ via foliar application 145 days after planting.

Appropriately using phosphorus (P) for the fertilization of sugarcane is critical to achieving high productivity because it is one of the most limiting nutrients in agricultural cropping systems. Thus, the objective of this research was to evaluate the morphological, biochemical, and yield responses of sugarcane, and the soil microbial–chemical properties, under the use of organomineral fertilizer (OF) associated or not with Bacillus velezensis strain UFV 3918 (B) combined with mono ammonium phosphate (MAP) doses. The experimental design used was completely randomized, consisting of eight treatments [Control (3/3 MAP); OF (without MAP); OF + 1/3 MAP; OF + 2/3 MAP; OF + 3/3 MAP; B + OF + 1/3 MAP; B + OF + 2/3 MAP; B + OF + 3/3 MAP] and four replicates. B + OF + 1/3 MAP provided increases in accumulated soil basal respiration (11.9%), carbon of microbial biomass (35.9%), fluorescein diacetate (12.7%), arylsulfatase (25.5%), and acid phosphatase (10.1%) activity compared to the control, which implied in higher shoot and total biomass. These results present a potential strategy for sugarcane fertilization, using bacteria in combination with OF to improve P nutrition and growth in sugarcane with reduced economic and environmental impact.