Inoculation effects of Nitrospirillum amazonense and biofertilizer in sugarcane / Efeitos da inoculação de Nitrospirillum amazonense e biofertilizante em cana-de-açúcar

In this study, we analyzed the hypothesis that the combination of Nitrospirillum amazonense strain BR11145 with biological fertilizer prepared using Microgeo® and native microbiome from location of the product application results in morphological and nutritional gains for the initial development of sugarcane plants and soil chemistry. For this purpose, pre-sprouted sugarcane seedlings were grown in a greenhouse mesocosm experiment using soil amended with nitrogen/phosphorus/potassium fertilizer. The experimental treatments consisted of: 1) biological fertilizer with the addition of N. amazonense (100 mL ha-1), 2) biological fertilizer without the addition of N. amazonense, 3) inoculation with N. amazonense at a dose of 100 mL ha-1 with 2x108 viable cell mL-1, 4) inoculation with N. amazonense at a dose of 200 mL ha-1 with 2x108 viable cell mL-1, and 5) control, without the addition of biological fertilizer and N. amazonense. The biological fertilizer was applied at dose of 300 L ha-1, which was split at planting (200 L ha-1) and in the post-emergence phase (100 L ha-1). After 164 days of planting, it was detected an increase in leaf length +3, number of green leaves, leaf area and sulfur content in the leaves of sugarcane plants that received the biological fertilizer with the addition of N. amazonense. In conclusion, the combination of N. amazonense with biological fertilizer revealed positive effects through morphological and nutritional characteristics in sugarcane plants during their early stages of development when compared to plants grown only with the inoculation of N. amazonense, biological fertilizer or mineral fertilizers, with few notable positive effects on soil chemistry.

Neste estudo avaliou-se a hipótese de que a combinação de Nitrospirillum amazonense estirpe BR11145 com adubo biológico preparado com base em microbioma autóctone da localidade de aplicação do produto, produzido com Microgeo®, resulta em benefícios morfológicos e nutricionais para o desenvolvimento inicial de plantas de cana-de-açúcar e para a química do solo. Para tanto, mudas pré-brotadas de cana-de-açúcar foram crescidas em mesocosmos num experimento conduzido em casa-de-vegetação com solo enriquecido com fertilizante à base de nitrogênio/fósforo/potássio. Os tratamentos avaliados foram: 1) adubo biológico acrescido de N. amazonense (100 mL ha-1), 2) adubo biológico sem o acréscimo de N. amazonense, 3) inoculação de N. amazonense na dose de 100 mL ha-1 (2x108 células viáveis por mL), 4) inoculação de N. amazonense na dose de 200 mL ha-1 (2x108 células viáveis por mL), e 5) testemunha, sem a adição de fertilizante biológico e N. amazonense. O adubo biológico foi aplicado na dose de 300 L ha-1 sendo esta parcelada no plantio (200 L ha-1) e na fase de pós-emergência (100 L ha-1). Após 164 dias do plantio constatou-se aumento no comprimento da folha +3, número de folhas verdes, área foliar e no teor de enxofre nas folhas das plantas de cana-de-açúcar que receberam o adubo biológico combinado com N. amazonense. Conclui-se que a combinação de N. amazonense com o adubo biológico produzido com Microgeo® revelou efeitos positivos por meio de caraterísticas morfológicas e nutricionais em plantas de cana-de-açúcar durante os seus estádios iniciais de desenvolvimento quando comparadas com plantas crescidas apenas com a inoculação de N. amazonense, fertilizante biológico ou fertilizantes minerais, com poucos efeitos positivos notáveis na química do solo.

A multi-attribute approach to evaluating the impact of biostimulants on crop performance.

An ever-growing collection of commercial biostimulants is becoming available in a wide variety of forms and compositions to improve crop performance. Given the intricate nature of deciphering the underlying mechanisms of commercial products, which typically comprise various biological components, it is crucial for research in this area to have robust tools to demonstrate their effectiveness in field trials. Here, we took a multi-attribute approach to evaluating the impact of biostimulants on crop performance. First, we assessed the impact of a biostimulant on the soil and rhizosphere microbiomes associated to crops in eight reference farms, including corn (3 farms), soybean (2), cotton (2) and sugarcane (1), in different biomes and production contexts in Brazil and Paraguay. Second, we modeled a set of integrated indicators to measure crop responses to biostimulant application, including five analytical themes as follows: i) crop development and production (9 indicators), ii) soil chemistry (9), iii) soil physics (5), iv) soil biology (6) and v) plant health (10). Amplicon 16S rRNA and ITS sequencing revealed that the use of the biostimulant consistently changes the structure of bacterial and fungal communities associated with the production system for all evaluated crops. In the rhizosphere samples, the most responsive bacterial taxa to biostimulant application were Prevotella in cotton; Prauserella and Methylovirgula in corn; and Methylocapsa in sugar cane. The most responsive fungal taxa to biostimulant use were Arachnomyces in soybean and cotton; and Rhizophlyctis in corn. The proposed integrated indicators yielded highly favorable positive impact indices (averaging at 0.80), indicating that biostimulant-treated fields correlate with better plant development and crop performance. Prominent indices were observed for indicators in four themes: soil biology (average index 0.84), crop production (0.81), soil physics (compaction reduction 0.81), and chemical fertility (0.75). The multi-attribute approach employed in this study offers an effective strategy for assessing the efficacy of biostimulant products across a wide range of crops and production systems.