EDGE EFFECT ON BIOFERTILIZED PLANTS OF ILEX PARAGUARIENSIS ST. HIL. (YERBA MATE)

ONETTO, ANDREA LILIANA; CASTRILLO, MARIA LORENA; CORTESE, ILIANA JULIETA; BICH, GUSTAVO ANGEL; ZAPATA, PEDRO DARIO; LACZESKI, MARGARITA ESTHER

Rondônia

Simposio; SIMICRON-I Simposio de Microbiologia de Rondônia: Saúde, Ambiente e Innovacao; 2021

Introduction: The response of treatments in a field trial are affected bysoil, weather, plant management, and treatments applied on neighbouringplots. Additionally, experimental parameters measured in the plants in thecenter and the ones on the edge of each plot are also known to showdifferences. This is referred to as ?edge effect? and is of interest for theinterpretation of results since it can help in the selection of plants to besampled and measured that are representative of the experiment.Biofertilizers are products composed of living microorganisms applied tocrops to increase yield. Some of them can persist in the soil and exerttheir effect over a period, either by a direct effect or by altering the soilmicrobial communities in the vicinity of the plant roots. Objective: Thisstudy aimed to evaluate the edge effect on biofertilized plants of Ilexparaguariensis St. Hil. Methods: A field trial was performed with seventreatments: inoculation with two Bacillus altitudinis strains (19RS3 andT 5 S ) , Kosakonia radicincitans (strain YD4), and their combinations(19RS3/T5S, 19RS3/YD4, and T5S/YD4). Non-inoculated plants wereincluded as a negative control. Experimental blocks were set in threeparallel lines (right, centre, and left) of fifteen I. paraguariensis plantseach. One non-inoculated line was used to separate the treatments. Rootsof six-year-old plants were spray-inoculated with 100 mL of a bacterialsuspension adjusted to 0.5 of McFarland?s scale. Inoculation was repeatedthree times during November-December 2017 and again in September-October 2018. Plants were harvested in July 2018 and June 2019. Theharvested leaves of each plant were weighed. Statistical differences wereinvestigated by Analysis of Variance (ANOVA) using the software InfoStatversion 2020 at a 0.05 significance level. Results: For 2018, the ANOVAshowed a significant difference between the centre and border lines ineach treatment (p= 0.0445). Fisher´s Least significant Difference testsshowed the centre lines to be different, with the highest yield per plant(means of 3.67 kg for the centre versus 3.00 and 3.23 kg for the borders),a value for the centre line up to 22.23 % higher than the borders.Although differences for 2019 were non-significant (p-value of 0.0645), adifference of up to 17.19 % was observed for the centre lines (3.00 kg perplant) compared to the borders (2.56 and 2.57 kg per plant). Conclusions:The presence of the edge effect in the field test on biofertilized plants of I.paraguariensis St. Hil was observed. Differences observed in 2018 couldbe explained by a synergistic effect in the centre lines due to theinoculation of the border lines. Plants in the centre would benefit not onlyfrom their inoculation but also from having inoculated plants in theirproximity. The reduction in these differences during the following yearcould be explained by the pre-existing bacteria established in the soil,contributing to reaching an appropriate inoculum for the border lines.Knowledge of these differences will help in the design and analysis offuture experiments to evaluate the effect of biofertilizers on I.paraguariensis .