Biology subjects

Thonar, C.

Publications and source records attributed to Thonar, C..

3 recordsLinked to original sources

bioRxiv2025

From Synthetic to Biological Nitrification Inhibition: Advancing Stabilization of Organic Fertilizers

Fertilizer type plays a critical role in nitrogen (N) cycling, influencing nitrous oxide (N2O) emissions, soil mineral N dynamics, and microbial communities. Understanding these interactions is essential for developing sustainable fertilization strategies that balance agricultural productivity with environmental protection. This study examined the effects of mineral and organic fertilizers (OFs) on N transformations and evaluated the efficiency of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) in mitigating N2O losses. Results showed that OFs exhibited variable impacts on N2O emissions depending on their composition and C/N ratio. DMPP effectively reduced nitrification-driven N2O emissions, particularly in treatments with high ammoniacal N content. However, its efficiency was limited with animal-based OFs, suggesting a complex interaction between fertilizer properties and inhibitor effectiveness. DMPP had not direct impact on soil microbial diversity but specifically targeted the Nitrosomonaceae family and Nitrospira class. Beyond synthetic inhibitors, biological nitrification inhibition (BNI) emerged as a promising alternative, which we explored using rhizospheric soils from wheat landrace Persia 44 and white mustard (cv. Pole Position, Verdi). These soils significantly reduced N2O emissions, particularly when combined with OFs. The integration of BNI with organic fertilizers, especially liquid digestate, represents a promising strategy for reducing N losses while maintaining soil fertility. This study underscores the need for tailored fertilization strategies that combine chemical and biological tools to optimize N use efficiency and support environmentally sustainable agriculture.

plant biology↗

bioRxiv2024

Tensions in tillage: Reduction in tillage intensity associates with lower wheat growth and nutritional grain quality despite enhanced soil biological indicators

Dryland ecosystems are particularly susceptible to the adverse effects of intensive agriculture, with intensive tillage exerting a major impact on soil health and its biotic components. The implementation of less disturbing soil management practices can be essential for preserving the soil environment and maintaining the diverse communities of microorganisms, micro- and mesofauna, which are essential contributors to soil fertility. In this study, we assessed soil chemical properties, soil biodiversity and functionality, and wheat crop growth across a tillage gradient encompassing no-tillage (NT), minimum tillage (MT), and standard tillage (ST). Results showed that NT resulted in increased soil macronutrient levels compared to MT and ST. In general, reduced tillage increased the abundance of soil biota, with significantly higher levels of bacterial and fungal marker genes observed in MT and NT compared to ST. Nematode abundance increased by 25% in MT and 50% in NT, compared to ST and predatory acari were significantly more abundant in NT, while numbers of total acari were higher in both NT and ST compared to MT. Community structure analysis revealed that tillage strongly influenced bacterial, fungal and acari community composition, reflecting a gradient of soil disturbance intensity. Corresponding to the increased abundance of soil biota, reduced tillage increased microbial activity and soil functionality along the disturbance gradient. This was evident in the potential activity of carbon, nitrogen and phosphorus cycling enzymes, as well as the microbial capacity for carbon utilisation. In addition, evidence of the formation of biocrust as a possible source of carbon input was found. Furthermore, we observed important wheat pathogens to decrease and fungal antagonists to increase in NT compared to ST. Despite enhanced soil biological indicators under reduced tillage, wheat growth, nitrogen uptake and grain B vitamin contents were higher in ST compared to NT. In addition, we observed a shift in technological grain properties across tillage practices. The higher root:shoot ratio (an indicator of nitrogen deficiency) and median root diameter (hormone-driven lateral expansion) in NT suggest that soil compaction could be a potential cause of reduced wheat performance. These results suggest that despite improved soil biological indicators, other factors such as a low rates of N mineralization potential and prevalence of soil compaction may be limiting wheat performance in NT systems. HighlightsO_LIEnhanced microbial activity and functionality under reduced tillage C_LIO_LITillage intensity shaped community structure of microbes, nematodes and acari C_LIO_LISoil biocrust development under NT may increase soil organic carbon C_LIO_LIRoot traits revealed soil compaction and nutrient limitation in NT systems C_LIO_LIReduced tillage impaired wheat quality and changed technological grain properties C_LI

ecology↗

bioRxiv2024

Low-input soil management increases yield and decreases CO2-emissions but aggravates risk of nitrate leaching and diseases in winter wheat cropping systems under climate change

Empirical data is key to anticipate the impact of climate change on cropping systems and develop land management strategies that are sustainable while ensuring food security. Here, the combined effects of projected increases in temperature, atmospheric CO2-concentrations, solar irradiation and altered precipitation patterns on winter wheat cropping systems were investigated using an Ecotron. Experimental plant-soil systems were subjected to three different climatic conditions representing a gradient of ongoing climate change implementing the weather patterns of the years 2013, 2068, and 2085 respectively. The wheat plants were grown in two differentially manged agricultural soil types: one with long-term low organic matter (OM) inputs and the other one with long-term high OM inputs. In the low OM system, the risk for plant diseases and nitrate leaching was increased, but it outperformed the high OM system with higher yields and lower CO2-emissions. Developing high-yielding cropping systems leveraging the CO2-fertilisation effect without sacrificing environmental health will therefore require further refined of management practices to improve nutrient cycling and reduce greenhouse gas emissions. One possibility is adapting crop rotations and cover crops to the shorter wheat cycle observed in the future climates to replenish soil nutrients and break disease cycles. Further, in both here studied soil types the wheat plants developed natural coping mechanisms against environmental stressors, such as enhanced root growth and increased levels of proline and silicon. Unravelling the molecular mechanisms that trigger such inherent plant defences is a further interesting target for breeding future crops. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=177 HEIGHT=200 SRC="FIGDIR/small/626142v2_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@fefc32org.highwire.dtl.DTLVardef@5f6757org.highwire.dtl.DTLVardef@1799ca4org.highwire.dtl.DTLVardef@11aec5c_HPS_FORMAT_FIGEXP M_FIG C_FIG

ecology↗