AimsPecan (Carya cathayensis Sarg.) is an important forest trees in China, the application of chemical pesticides for disease control has caused severe damage to the soil, including reduced fertility and disruption of microbial communities. Although Trichoderma treatment has been shown to promote plant growth and improve soil quality, its effects on the growth promotion of pecan and the impact on soil microbial communities and physicochemical properties remained unclear.MethodsIn this study, we investigated the impact of T. asperellum TCS007 spore suspension and its fermented crude extract on the growth and development of pecan seedlings. We also explored the effects of TCS007 treatment on the nutrients, enzyme activities, and microbial diversity in the rhizosphere soil of pecan seedlings during their three main growth stages.ResultsTreatment with TCS007 spore suspension or crude extract promoted the growth of pecan seedlings, with significantly higher levels of leaf hormones and defense enzyme activity compared to the control (CK). Moreover, the content of soil organic matter and ammonium nitrogen, as well as the activity of soil enzymes such as catalase and urease, were all significantly higher than CK after treatment, and the soil pH shifted from slightly acidic to slightly alkaline. The results indicated that TCS007 treatment significantly increased the richness of beneficial fungi and bacteria in the soil.ConclusionThe results demonstrated that TCS007 treatment significantly promoted the growth of pecan plants, increased enzyme activity and nutrient content in the soil, and improved the soil micro-ecological environment.

The use of engineered nanomaterials (NMs) as novel antimicrobial agents has garnered significant attention in agriculture. The antimicrobial properties of 5 mg/kg metal oxide (copper oxide and zinc oxide nanoparticles, CuO and ZnO NPs)- and carbon (reduced graphene oxide and multiwalled carbon nanotubes, rGO and MWCNT)-based NMs on two soil-borne fungal pathogens, Fusarium oxysporum f.sp. lactucae (F.o.lact) and Fusarium oxysporum f.sp. lycopersici (F.o.lyco), were evaluated over a 21-day incubation period. Both metal- and carbon-based NMs reduced the dehydrogenase activity (DHA) in Fusarium-infested soil by more than 40% relative to the infested controls; the efficacy of antifungal efficacy was CuO NPs > ZnO NPs > rGO > MWCNT. Similar decreases in the soil activities of urease (UE), sucrase (SC), acid phosphatase (ACP), and polyphenol oxidase (PPO) suggest that NMs could effectively inhibit Fusarium growth in soil over time. The total available metal fractions, including acid extractable fraction, Fe/Mn oxidation state, and the fraction bound to organic matter, were increased by 5.99-7.29% with metal-based NM compared to the infested controls. The Shannon index of microbial communities in the infested soils with metal-based NMs was increased by 12.2-23.5% relative to infested controls. Similarly, carbon-based NMs increased the Shannon index of the fungal community by 10.18-29.86%. Importantly, the relative abundance of Fusarium was decreased with both metal- and carbon-based NMs. These NMs also increased the relative abundance of beneficial microorganisms in infested soil, such as Pseudomonas, which was increased by 29.7-96.2% with metal-based NMs relative to the untreated controls. These findings demonstrate that NMs at appropriate doses could inhibit the Fusarium abundance and subsequent crop damage while simultaneously fostering the development of beneficial microorganisms in soil.