Soil microorganisms and their role in the interactions between weeds and crops

Abstract

-The competition between weeds and crops is a topic of great interest, since this interaction can cause heavy losses in agriculture. Despite the existence of some studies on this subject, little is known about the importance of soil microorganisms in the modulation of weed-crop interactions. Plants compete for water and nutrients in the soil and the ability of a given species to use the available resources may be directly affected by the presence of some microbial groups commonly found in the soil. Arbuscular mycorrhizal fungi (AMF) are able to associate with plant roots and affect the ability of different species to absorb water and nutrients from the soil, promoting changes in plant growth. Other groups may promote positive or negative changes in plant growth, depending on the identity of the microbial and plant partners involved in the different interactions, changing the competitive ability of a given species. Recent studies have shown that weeds are able to associate with mycorrhizal fungi in agricultural environments, and root colonization by these fungi is affected by the presence of other weeds or crops species. In addition, weeds tend to have positive interactions with soil microorganisms while cultures may have neutral or negative interactions. Competition between weeds and crops promotes changes in the soil microbial community, which becomes different from that observed in monocultures, thus affecting the competitive ability of plants. When grown in competition, weeds and crops have different behaviors related to soil microorganisms, and the weeds seem to show greater dependence on associations with members of the soil microbiota to increase growth. These data demonstrate the importance of soil microorganisms in the modulation of the interactions between weeds and crops in agricultural environments. New perspectives and hypotheses are presented to guide future research in this area.Keywords: competition, agriculture, mycorrhizal fungi, PGPR, ecology. RESUMO -A competição entre plantas daninhas e culturas é um tópico de grande interesse, uma vez que essa interação pode causar grandes perdas na agricultura. Apesar de alguns estudos nesse tema, pouco se sabe sobre a importância dos microrganismos do solo na modulação dessa interação. As plantas competem por água e nutrientes presentes no solo e a capacidade das espécies em absorver esses recursos pode ser diretamente afetada pela presença de alguns grupos microbianos comumente encontrados no solo. Os fungos micorrízicos arbusculares (FMA) são capazes de se associar com as raízes das plantas, o que afeta a capacidade das diferentes espécies em absorver água e nutrientes do solo, promovendo alterações no crescimento. Outros grupos podem promover alterações positivas ou negativas no crescimento das espécies vegetais, a depender da identidade das espécies microbianas e vegetais envolvidas nas diferentes interações

Chemical and Microbiological Attributes Under Different Soil Cover

“…Microorganisms represent the richest repertoire in chemistry and molecular diversity in nature, providing the basis for ecological processes such as biogeochemical cycles (PANIZZON et al, 2015) and are fundamental for soil quality because they can alter the physico-chemical characteristics of the environment, directly participating in the transformations of nitrogen and phosphorus (MASSENSSINI et al, 2014).…”

Distantly related crops are not better rotation partners for tomato

“…Miller & Menalled, ). Weeds have a higher dependence on microbial associations compared to crops (Massenssini et al., ; Santos et al., ) and domestication of wild plants is thought to have disrupted the mutualistic associations linking beneficial microbes with roots (Pérez‐Jaramillo et al., ). Yet, even though we experimentally controlled for phylogeny, crops and weeds created the same PSF effect on tomato.…”

Activity of Rhizosphere Soil Microorganisms of Sugarcane Cultivars After Spraying of Herbicides: Diuron, Tebuthiuron, Ametryn and Diuron + Hexazinone

“…For the analysis of the inorganic phosphorus solubilization potential of rhizospheric microorganisms and percentage of roots colonized by mycorrhizal fungi were observed differences among all the treatments ( Figure 5). The root colonization by mycorrhizal fungi is a specific interaction, and depends on factors inherent to plant and fungi species (PEREIRA et al, 2013;MASSENSSINI et al, 2013). Also, it is necessary for the microorganism to recognize the plant as a possible host for that symbiosis process occur between them.…”