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Background: Soil animal communities include more than 40 higher-order taxa, representing over 23% of all described species. These animals have a wide range of feeding sources and contribute to several important soil functions and ecosystem services. Although many studies have assessed macroinvertebrate communities in Brazil, few of them have been published in journals and even fewer have made the data openly available for consultation and further use. As part of ongoing efforts to synthesise the global soil macrofauna communities and to increase the amount of openly-accessible data in GBIF and other repositories related to soil biodiversity, the present paper provides links to 29 soil macroinvertebrate datasets covering 42 soil fauna taxa, collected in various land-use systems in Brazil. A total of 83,085 georeferenced occurrences of these taxa are presented, based on quantitative estimates performed using a standardised sampling method commonly adopted worldwide to collect soil macrofauna populations, i.e. the TSBF (Tropical Soil Biology and Fertility Programme) protocol. This consists of digging soil monoliths of 25 x 25 cm area, with handsorting of the macroinvertebrates visible to the naked eye from the surface litter and from within the soil, typically in the upper 0-20 cm layer (but sometimes shallower, i.e. top 0-10 cm or deeper to 0-40 cm, depending on the site). The land-use systems included anthropogenic sites managed with agricultural systems (e.g. pastures, annual and perennial crops, agroforestry), as well as planted forests and native vegetation located mostly in the southern Brazilian State of Paraná (96 sites), with a few additional sites in the neighbouring states of São Paulo (21 sites) and Santa Catarina (five sites). Important metadata on soil properties, particularly soil chemical parameters (mainly pH, C, P, Ca, K, Mg, Al contents, exchangeable acidity, Cation Exchange Capacity, Base Saturation and, infrequently, total N), particle size distrib

Tropical forests play a crucial role in climate regulation due to their high carbon sequestration capacity. However, degradation and disturbances in these forests may result in significant carbon losses. This study focuses on the impact of various biophysical, anthropogenic, and landscape factors on aboveground biomass (AGB) in heavily disturbed landscapes of Côte d'Ivoire (West Africa), a typical low-forest and high-deforestation country. AGB estimates from a National Forest Inventory dataset have been linked to five categories of variables (Climate, Soil, Topography, Landscape, and Human-related) through a random forest modeling approach that addressed collinearity among variables, selected key variables from each category, and used spatial cross-validation to evaluate model performance. The comprehensive model, combining landscape composition, physical soil properties, and climate variables, demonstrated strong performance with an R-squared of 0.62. Notably, the percentage of landscape occupied by forest within a radius of 1000 m (PLAND1000) had a highly significant impact on AGB, exhibiting a notable increase when PLAND1000 exceeded 80 % and a decrease when it felt below 25 %. Soil properties, both physical (Bulk Density and Coarse Fraction) and chemical (soil pH), significantly influenced AGB, too. Interestingly, climatic, topographic, and other anthropogenic variables had minimal relevance in predicting AGB, suggesting that their effects may have been captured by landscape and soil integrative variables. In order to enhance forest preservation and restoration initiatives in the face of deforestation and fragmentation challenges in the West African region, we recommend (i) evaluating the appropriate landscape scale of effect (a 1000 m radius circle being the most significant in this study); (ii) prioritizing the preservation or restoration of dense forest landscapes; and (iii) integrating landscape composition into forest management policies.

Particle size fractionation enables a better understanding of soil organic carbon (C) dynamics since it separates fractions that differ in composition, residence time and function. However, this method is time-consuming and tedious; thus, its use has been greatly limited. Our objective was to evaluate the ability of an existing soil spectral library (SSL) from different regions of West Africa to predict the C amount in the fractions (gC kg−1 soil) of the samples in a new target set from Benin. The SSL included 181 samples from five countries, and the target set included 94 samples (depth ≤ 40 cm), most of which were coarse-textured; near-infrared reflectance (NIR) spectra were collected for 2 mm sieved samples (non-fractionated samples). The predicted variables were the C amounts in the non-fractionated soil and in the < 20, 20–50, and > 50 µm fractions (F<20, F20–50, and F>50, respectively). Different methods were tested to optimize the predictions: (i) SSL enrichment with 10 or 15 samples selected from the target set (spiking) and replicated six times (i.e. extra-weighted); (ii) locally weighted (local) partial least squares regression (PLSR), which is calibration by the spectral neighbours with the highest weights attributed to closest neighbours, and was compared to “global” (i.e., common) PLSR, where all calibration samples equally contribute; and (iii) spectrum pretreatments (e.g., smoothing, centring, derivatization). In addition, the intermediate precision of the conventional data (standard error of laboratory; SELint) was estimated through triplicate fractionation of three samples carried out by three operators (one per replicate). When the SSL alone was used for calibration, the predictions were inaccurate for the C amounts in the non-fractionated soil and in F<20; however, the predictions were accurate for the C amounts in F20-50 and F>50, with minimal benefit from the local PLSR over the global PLSR in general. For the non-fractionated soil, F<20, F20–50

Dicyandiamide decreased N2O emissions even under 40°C. Ammonia oxidizers and nirS were well adapted to 40°C in manured soils. Fungal nirK tolerated high temperature better in urea than manure treatment. Compared to nosZII, nosZI adapted to all temperature regardless of fertilization. nirS-denitrifier dominated N2O emissions at high temperature in fertilized soil. Heat waves associated with global warming and extreme climates would arouse serious consequences on nitrogen (N) cycle. However, the responses of the functional guilds to different temperatures, especially high temperature and the cascading effect on N2O emissions remain unclear. An incubation study was conducted to examine the effect of different temperatures (20°C, 30°C, and 40°C) and fertilizer types (urea and manure) on N2O-producers and N2O-reducers, as well as the efficacy of dicyandiamide (DCD) on N2O emissions in a vegetable soil. Results showed that ammonia oxidizers and nirS-type denitrifiers were well adapted to high temperature (40°C) with manure application, while the fungal nirK-denitrifiers had better tolerance with urea application. The nosZ clade I microbes had a strong adaptability to various temperatures regardless of fertilization type, while the growth of nosZ clade II group microbes in non-fertilized soil (control) were significantly inhibited at higher temperature. The N2O emissions were significantly decreased with increasing temperature and DCD application (up to 60%, even at 40°C). Under high temperature conditions, fungal denitrifiers play a significant role in N-limited soils (non-fertilized) while nirS-type denitrifiers was more important in fertilized soils in N2O emissions, which should be specially targeted when mitigating N2O emissions under global warming climate.

The distribution of plant communities in hot desert ecosystems is discontinuous and resembles the pattern of heterogeneous resource patches, known as “fertility islands”. Understanding the key factors that allow plants to establish in these conditions, as well as their associated microbial diversity, is crucial to the comprehension and preservation of these ecosystems. Saudi Arabia in the Arabian Peninsula, is one of the driest regions in the world, with a very low water regime and low soil nutrient contents. The establishment of ecosystems in these arid desert conditions is therefore subject to numerous constraints. Understanding the biotic and abiotic factors linked to the formation of fertility islands, from the perspective of soil composition and its associated microbiome, both in the soil and in the roots of associated plant community, is therefore a fundamental issue for the preservation of these ecosystems. In this study, we analyzed the soil composition between a fertility island and bare soil. The proportions of micro- and macro-elements important for plant nutrition, namely magnesium, phosphorus, potassium and iron were higher in the fertility island. We also observed that soil bacterial and fungal diversity increased in the fertility island. Key taxa such as Rhizobia and Glomeraceae which play important roles in ecosystem functioning were identified in both the fertility island soil and in the roots of the established plant community. These results confirm that plant establishment is linked to soil conditions, in line with the fertility island hypothesis, and that the microbial community in the fertility island differs both in diversity and in composition from that of the bare soil. Fertility islands soils and the roots of established plant community harbor a microbiome potentially crucial to ecosystem functioning, and are of major interest for conservation and agronomy programs.

Description of the subject. Farmers' knowledge is a significant source of information about cultivated soil knowledge. Objectives. This paper focuses on farmers in the Alaotra Lake Region in Madagascar to identify their knowledge of the soil and soil fertility and to propose a conceptual framework for developing participatory approaches. Method. The methodology is based on surveys conducted with 100 farmers randomly selected within five Communes (villages) to (i) study their knowledge on soil, (ii) design local soil map, and (iii) identify local soil fertility assessment. For each task, an exploratory survey with non-directive individual interviews followed by more in-depth surveys with semi-directive individual interviews and restitution workshops were conducted. Results. The results revealed two types of local soil classifications according to toposequence. Twelve and nine local soil types were identified respectively in the southern zone and in the northern zone. Moreover, farmers used 14 main local indicators to assess the fertility of these soils. Farmers' soil classification was found to comply with previous pedological studies and even provided complementary details to the reference French Soil Classification (CPCS). Finally, the local soil fertility indicators have been proved to be identical to those used by other farmers in other countries and are scientifically validated to be effective. Conclusions. This paper offers a new conceptual framework that may be effective for agricultural development service and scientific research in other contexts. It provides a foundation for supporting a common language between farmers and researchers, one that may prove instrumental in future projects including the co-conception of sustainable, innovative agricultural practices.

Micronutrients are essential to plants, and enhancing their availability is one of the agronomic challenges to improving crop quality and yield. This study, under controlled greenhouse conditions, compares tomato plants' responses to two different micronutrient EDTA-chelated formulations, one of them including a newly developed fulvate–lignosulfonate coating. Growth, yield, and several physiological parameters, including photosynthetic gas exchange, water-use efficiency, leaf nutrient content, leaf greenness and the effective quantum yield of photosystem II, were measured to compare their efficiency. The results showed that the new coated formulation significantly improved growth and most of the determined physiological parameters. At the end of the experiment, higher foliar levels of Fe (2.4-fold) and Mn (2.9-fold) were measured, revealing increased availability of lignofulfonate-complexed micronutrients compared to the traditional fertiliser. Moreover, the photosynthesis rate and stomatal conductance were 9- and 20-fold higher, respectively, than when using the standard fertiliser. In conclusion, the new coated fulvate–lignosulfonated fertiliser provided a more suitable source of micronutrients for tomato plant fertilisation, allowing for higher yields, which correlated with a generally improved physiological response.

Biochar is more and more widely recognized as a promising agricultural amendment improving yield and ecosystem services in a range of different contexts. However, underlying mechanisms contributing to biochars benefits, notably biochar–root interactions, and their mediation by biochar's diverse properties remain unclear and poorly quantified. This study aimed to examine and quantify the interactions between biochar properties and plant traits and their effect on plant performance. To gain a better understanding of biochar–plant interactions and their role in biochar overall effects, biochars with contrasted physical and chemical properties were applied to soils during a 3-month greenhouse experiment with barley (Hordeum vulgare L.). Barley biomass as well as several belowground morphological and physiological traits and aboveground traits related to nutrient acquisition were measured. A multivariate structural modeling approach was employed to quantify interactions between biochar properties and plant traits, and their feedback effect on plant biomass. Interactions between biochar chemical and physical properties and barley carboxylate release rate and their contribution to biochar effects were underlined. Among the plant traits examined the release of carboxylate appears as the best proxy to plant biomass following biochar addition, highlighting sparsely reported interactions between total carboxylate release rates and biochar ash content. Multivariate structural modeling offered elements of understanding for the complex interconnected mechanisms involved in biochar influence and their relative contribution. Adopting this approach across a wide range of species and contexts could contribute to ensure more reliable biochar benefits.