&lt;b&gt;Agrosilvopastoral system enhances suppressiveness to soybean damping-off caused by &lt;i&gt;Rhizoctonia solani&lt;/i&gt; and alters &lt;i&gt;Fusarium &lt;/i&gt;and &lt;i&gt;Trichoderma&lt;/i&gt; population density

Alexandre Dinnys Roese,Paulo Justiniano Ribeiro Junior,Louise Larissa May De Mio,Vanderley Porfírio-Da-Silva

doi:10.4025/actasciagron.v40i1.35075

Agrosilvopastoral system enhances suppressiveness to soybean damping-off caused by Rhizoctonia solani and alters Fusarium and Trichoderma population density

Alexandre Dinnys Roese, Paulo Justiniano Ribeiro Junior + Show 2 more

Open Access

https://doi.org/10.4025/actasciagron.v40i1.35075

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Abstract

Integrated crop-livestock systems (ICLS) are sustainable options for agricultural diversification, but there have been few studies on the influence of ICLS on soil microorganisms. This work investigated the influence of agropastoral (AP) and agrosilvopastoral (ASP) systems, compared with a non-integrated crop (CO) on the suppression of Rhizoctonia solani and on the density of Fusarium and Trichoderma propagules. In the first assay, soil samples were inoculated with R. solani and evaluated for soybean damping-off. After this, the soil was sterilized and re-inoculated with the pathogen for a new evaluation. Finally, 10% of the soil in the pots were substituted by newly soil samples collected from the same plots in the field to evaluate de suppressiveness transference by soil samples. In the second assay, native Fusarium and Trichoderma propagules were quantified in semi-selective media. Damping-off incidence in ASP was 70% compared to AP and CO. Evaluations with sterilized and transferred soil samples attributed this suppression to biotic factors. Fusarium propagules were retrieved in the ASP soil at 70% and 60% the amounts in AP and CO soils, respectively. Trichoderma propagules were retrieved in the ASP soil at 150% compared to AP, but similar to CO. The agrosilvopastoral system in the Brazilian subtropics has the potential to reduce pathogens and enhance beneficial microorganisms in the soil.

Highlights

Agricultural diversification including crops and animals grazing in the same area are longstanding production systems and considered the main form of agricultural land use in the world (Bell & Moore2012)
These production systems are included in the definition of Integrated Crop-Livestock System (ICLS) (FAO, 2010)
The objectives of this work were to assess the influence of two Integrated crop-livestock systems (ICLS) arrangements and two N doses on a) the soil suppressiveness to soybean damping-off caused by R. solani, b) the biotic influence on this suppressiveness, and c) Fusarium and Trichoderma propagule density, as biological indicators, in the ICLS soil

Summary

Introduction

Agricultural diversification including crops and animals grazing in the same area are longstanding production systems and considered the main form of agricultural land use in the world (Bell & Moore2012). Agricultural diversification including crops and animals grazing in the same area are longstanding production systems and considered the main form of agricultural land use in the world ICLS are planned systems involving temporal and spatial interactions on different scales with animal and crop exploitation within the same area, simultaneously or disjointedly and in rotation or succession (Moraes et al, 2014). Studies in this area have intensified in recent years due to the benefits these systems bring to the farmer and to the environment when compared to the monoculture. Planned inclusion of tree species in such production systems is still not common, even though this component is clearly encompassed in the definition of ICLS (Carvalho et al, 2014)

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