Search Results (406)

This study investigates the production and economic feasibility of biochar for smallholder and family farms in Central Amazonia, with potential implications for other tropical regions. The costs of construction of a prototype mobile kiln and biochar production were evaluated, using small-sized biomass from acai (Euterpe oleracea Mart.) agro-industrial residues as feedstock. The biochar produced was characterised in terms of its liming capacity (calcium carbonate equivalence, CaCO_3eq), nutrient content via organic fertilisation methods, and ash analysis by ICP-OES. Field trials with cowpea assessed economic outcomes, as well scenarios of fractional biochar application and cost comparison between biochar production in the prototype kiln and a traditional earth-brick kiln. The prototype kiln showed production costs of USD 0.87–2.06 kg⁻¹, whereas traditional kiln significantly reduced costs (USD 0.03–0.08 kg⁻¹). Biochar application alone increased cowpea revenue by 34%, while combining biochar and lime raised cowpea revenues by up to 84.6%. Owing to high input costs and the low value of the crop, the control treatment generated greater net revenue compared to treatments using lime alone. Moreover, biochar produced in traditional kilns provided a 94% increase in net revenue compared to liming. The estimated externalities indicated that carbon credits represented the most significant potential source of income (USD 2217 ha⁻¹). Finally, fractional biochar application in ten years can retain over 97% of soil carbon content, demonstrating potential for sustainable agriculture and carbon sequestration and a potential further motivation for farmers if integrated into carbon markets. Public policies and technological adaptations are essential for facilitating biochar adoption by small-scale tropical farmers. Full article

Intensive vegetable farming emits high nitrous oxide (N₂O) due to traffic-induced compaction, highlighting the need for preventing nitrogen (N) losses through better traffic management. This study examined the effects of Controlled Traffic Farming (CTF) and Random Traffic Farming (RTF) on N₂O emissions using intact soil cores (diameter: 18.7 cm; depth: 25 cm) collected from a vegetable production system in Pukekohe, New Zealand. Soil cores from CTF beds, CTF tramlines, and RTF plots were analysed under fertilised (140 kg N/ha) and unfertilised conditions. N₂O fluxes were monitored over 58 days using gas chambers. The fertilised RTF system significantly (p < 0.05) increased N₂O emissions (5.4 kg N₂O–N/ha) compared to the unfertilised RTF system (1.53 kg N₂O–N/ha). The emission from fertilised RTF was 46% higher than the maximum N₂O emissions (3.7 kg N₂O–N/ha) reported under New Zealand pasture conditions. The fertilised CTF system showed a 31.6% reduction in N₂O emissions compared to fertilised RTF and did not differ significantly from unfertilised CTF. In general, CTF has demonstrated some resilience against fertiliser-induced N₂O emissions, indicating the need for further investigation into its role as a greenhouse gas mitigation strategy. Full article

The utilisation of agrifood waste ashes has the potential to enhance the nutrient content of cereal crops, thereby optimising both yield and grain quality. This study investigated rye grain composition, the fermentation efficiency, and volatile compounds in mashes made from crops fertilised with agrifood waste ashes derived from the combustion of corn cob, wood chips, and biomass with defecation lime. The ashes were applied at 2, 4, and 8 t/ha, separately and as mixtures of corn cob (25%) with wood chips (75%) and corn cob (50%) with biomass and defecation lime (50%). Rye mashes were prepared using the pressureless starch liberation method. The starch content in the majority of the rye grains was comparable to the control sample (57.12 g/100 g). The range of ethanol concentrations observed in the fermented mashes was from 55.55 to 68.12 g/L, which corresponded to fermentation yields of 67.25–76.59% of theoretical. The lowest fermentation yield was exhibited by the mash derived from rye cultivated on soil fertilised with a 50:50 mixture of ashes from corn cob and biomass with defecation lime at 8 t/ha. This mash contained more than double the acetaldehyde concentration and total aldehyde content compared to the other samples. These findings demonstrate the potential of using waste biomass ash as a source of macro- and microelements for rye cultivation, enabling the production of agricultural distillates. To ensure high fermentation efficiency and low aldehyde levels, ash dosage and composition need to be established based on experimental optimisation. Full article

Soil nematodes are essential components of the soil food web and are widely recognised as key bioindicators of soil health because of their sensitivity to environmental factors and disturbance. In agriculture, many studies have documented the effects of fertilisation on nematode communities and explored their role in nutrient cycling. Despite this, a key gap in knowledge still exists regarding how fertilisation-induced changes in nematode communities modify their role in nutrient cycling. We reviewed the literature on the mechanisms by which nematodes contribute to nutrient cycling and on how organic, inorganic, and recycling-derived fertilisers (RDFs) impact nematode communities. The literature revealed that the type of organic matter and its C:N ratio are key factors shaping nematode communities in organically fertilised soils. In contrast, soil acidification and ammonium suppression have a greater influence in inorganically fertilised soils. The key sources of variability across studies include differences in the amount of fertiliser applied, the duration of the fertiliser use, management practices, and context-specific factors, all of which led to differences in how nematode communities respond to both fertilisation regimes. The influence of RDFs on nematode communities is largely determined by the fertiliser’s origin and its chemical composition. While fertilisation-induced changes in nematode communities affect their role in nutrient cycling, oversimplifying experiments makes it difficult to understand nematodes’ functions in these processes. The challenges and knowledge gaps for further research to understand the effects of fertilisation on soil nematodes and their impact on nutrient cycling have been highlighted in this review to inform sustainable agricultural practices. Full article

The use of mineral fertilisers has increased in recent years, but this has had a negative effect on the environment, including causing the water in rivers and lakes to become too rich in nutrients, a process known as eutrophication. Current research focuses on producing fertiliser materials that are environmentally friendly. The aim of this study was to examine the impact of novel specialised organic-mineral fertilisers (OMFs: NP 24-12, NP 10-10, and NP 10-10 Zn⁺) on the yield and chemical composition of maize. These fertilisers were compared with a control (no fertiliser) and with other fertilisers (mixture of commercial fertilisers (MCFs): NP 24-12 and NP 10-10) that were used as a reference. All fertilisers increased the SPAD index at the fifth leaf unfolded stage of maize, with the majority (apart from OMF NP 10-10) also increasing it at the panicle emergence stage. MCF NP 10-10 had the most positive effect on the plant height, while OMF NP 10-10 had the least positive effect. All fertilisers had a positive effect on maize growth and development, with MCFs NP 10-10 and NP 24-12 having by far the strongest effect on increasing crop yields. The yield of plants fertilised with OMFs NP 24-12, NP 10-10, and NP 10-10 Zn⁺ was lower than the yields of plants fertilised with MCF NP 24-12 and MCF NP 10-10. OMF NP 10-10 caused a greater increase in the contents of all elements, and OMF NP 24-12 caused a greater increase in most elements (except P and Ca) in maize than MCFs did at an identical NP ratio. OMF NP 10-10 Zn⁺ was found to have a significant impact on the mineral composition of maize, resulting in a decline in Ca and P levels, along with a notable increase in Mg, Zn, and Cu concentrations. The most significant differences were observed for Cu and Zn. The OMFs, notably NP 24-12 and NP 10-10, exhibited a comparatively diminished acidifying impact in comparison with the MCFs. The application of fertilisers resulted in a significant increase in soil nutrient levels, with most fertilisers increasing the soil N, P, and Zn contents. Additionally, the OMFs led to an increase in Cu. However, MCFs NP 24-12 and NP 10-10 reduced the soil Cu and Mn contents. Studies should include other species as they have different needs. Field experiments are also needed. Full article

Agriculture relies on the widespread application of nitrogen fertilisers to improve crop yields and meet the demands of a growing population. However, the excessive use of these fertilisers has led to significant water quality challenges, posing risks to aquatic life, ecosystems, and human health. This study examines the relationship between synthetic nitrogen fertiliser usage and water pollution while identifying gaps in existing research to guide future studies. A systematic search across databases (Scopus, Web of Science, and Greenfile) identified 18 studies with quantitative data, synthesised using a single-group meta-analysis of means. As the data were continuous, the mean was used as the effect measure, and a random-effects model was applied due to varied study populations, with missing data estimated through statistical assumptions. The meta-analysis found an average nitrate concentration of 34.283 mg/L (95% confidence interval: 29.290–39.276), demonstrating the significant impact of nitrogen fertilisers on water quality. While this average remains marginally below the thresholds set by the World Health Organization (50 mg/L NO₃⁻) and EU Nitrate Directive, it exceeds the United States Environmental Protection Agency limit (44.3 mg/L NO₃⁻), signalling potential health risks, especially in vulnerable or unregulated regions. The high observed heterogeneity (I² = 100%) suggests that factors such as soil type, agricultural practices, application rate, and environmental conditions influence nitrate levels. While agriculture is a key contributor, other anthropogenic activities may also affect nitrate concentrations. Future research should comprehensively assess all influencing factors to determine the precise impact of nitrogen fertilisers on water quality. Full article

At a time of climate change, farmers face difficulties in providing food for a growing population. This results in the overuse of water and fertilisers. The aim of the research was to test the possibility of introducing waste sheep wool fibres into a hydrogel to obtain a stable material that could improve water retention and could serve as a fertiliser material matrix. Wool fibres and hydrogel were chosen because of their ability to store water and their degradability. An evaluation of the swelling degree of different alginate-based hydrogel matrices was performed to select the matrix. The stability and water bonding of hydrogels with different wool fibre content were analysed and evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The microstructure and the effect of fibres on the uniformity of the hydrogel were assessed using SEM and optical microscopy. The degree of water retention in the soil was also evaluated. The results showed that it is possible to incorporate wool fibres into the hydrogel matrix and the wool fibres make the composite porous, which allows water penetration into the material much more easily. This research has shown the possibility of using waste wool fibres as an active ingredient in sustainable fertiliser materials. Full article

The intensification of olive growing has raised environmental concerns, particularly regarding nutrient loss from excessive fertiliser use. In line with the European Union’s Farm to Fork strategy, which aims to halve the soil nutrient losses by 2030, this study evaluates the effectiveness of two sensor-based approaches—proximal sensing with a FLAME spectrometer and remote sensing via UAV-mounted multispectral imaging—compared with foliar chemical analyses as the reference standard, for diagnosing the nutritional status of olive trees. The research was conducted in Elvas, Portugal, between 2022 and 2023, across three olive cultivars (‘Azeiteira’, ‘Arbequina’, and ‘Koroneiki’) subjected to different fertilisation regimes. Machine learning (ML) models showed strong correlations between sensor data and nutrient levels: the multispectral sensor performed best for phosphorus (P) (determination coefficient [$R^2$] = 0.75) and potassium (K) ($R^2$ = 0.73), while the FLAME spectrometer was more accurate for nitrogen (N) ($R^2$ = 0.64). These findings underscore the potential of sensor-based technologies for non-destructive, real-time nutrient monitoring, with each sensor offering specific strengths depending on the target nutrient. This work contributes to more sustainable and data-driven fertilisation strategies in precision agriculture. Full article

Anthropogenic nitrogen (N) enrichment alters soil biotic (e.g., microbial metabolism) and abiotic (e.g., pH and mineralogy) properties, substantially affecting the persistence and storage of soil organic carbon (SOC). However, the response of relatively persistent mineral-associated organic carbon (MAOC) to N enrichment and the underlying mechanisms are not well understood, leading to significant uncertainties regarding SOC stability under continuous N input. Based on a 15-year field N fertilisation experiment (0, 28.5, 60.0, 72.0 g N m⁻² yr⁻¹), we studied the responses of MAOC to N input and the associated changes in soil mineralogy and microbiology. N fertilisation significantly reduced MAOC content by 16.0%. The loss of MAOC was primarily attributed to soil acidification (pH decreased from 6.4 to 4.2), leading to exchangeable calcium (Ca) leaching and loss of Ca-bound organic carbon by 37.9% on average. Furthermore, N-induced shifts in dominant microbial keystone taxa from K-strategists (e.g., Actinobacteriota and Sordariomycetes) to r-strategists (e.g., Subgroups 4 and 6 Acidobacteriota) impeded the formation of MAOC through the reduction of microbial carbon use efficiency and oxidase activity (e.g., phenol oxidases and peroxidases). These results suggest that keystone taxa play crucial roles in regulating carbon metabolism and are responsible for MAOC reduction. Moreover, our data pinpoint the importance of Ca leaching for SOC destabilisation, particularly in near-neutral and neutral soils. Full article

This study presents the MSPAT (Multispectral Soil Plant Analysis Tool), a device designed for assessing leaf nitrogen concentrations in maize crops under field conditions. The MSPAT includes the AS7265x sensor, which has 18 bands and covers the spectrum from 410 to 940 nm. This device was designed to be portable, using the ESP32 microcontroller and incorporating such functionalities as data storage on a MicroSD card, communication with a smartphone via Wi-Fi, and geolocation of acquired data. The MSPAT was evaluated in an experiment conducted at the Federal University of Ceará (UFC), where maize was subjected to different doses of nitrogen fertiliser (0, 60, 90, 120, 150, and 180 kg·ha⁻¹ N). Spectral readings were taken at three phenological stages (V5, V10, and R2) using the MSPAT, an SPAD-502 chlorophyll meter, and a FieldSpec PRO FR3 spectroradiometer. After the optical measurements were taken, the nitrogen concentrations in the leaves were determined in a laboratory by using the Kjeldahl method. The data analysis included the calculation of normalised ratio indices (NRIs) using linear regression and the application of multivariate statistical methods (PLSR and PCR) for predicting leaf nitrogen concentrations (LNCs). The best performance for the MSPAT index (NRI) was obtained using the 900 nm and the 560 nm bands (R² = 0.64) at stage V10. In the validation analysis, the MSPAT presented an R² of 0.79, showing performance superior to that of SPAD-502, which achieved an R² of 0.70. This confirms the greater potential of the MSPAT compared to commercial equipment and makes it possible to obtain results similar to those obtained using the reference spectroradiometer. The PLSR model with data from the FieldSpec 3 provided important validation metrics when using reflectance data with first-derivative transformation (R² = 0.88, RMSE = 1.94 and MAE = 1.28). When using the MSPAT, PLSR (R² = 0.75, RMSE = 2.77 and MAE = 2.26) exhibited values of metrics similar to those for PCR (R² = 0.75, RMSE = 2.78 and MAE = 2.26). This study validates the use of MSPAT as an effective tool for monitoring the nutritional status of maize to optimize the use of nitrogen fertilisers. Full article

One of the most commonly performed environmental explorations is soil sampling to identify soil properties of agricultural fields, which can inform the farmer about the variable rate treatment of fertilisers in precision agriculture. However, traditional manual methods are slow, costly, and yield low spatial resolution. Deploying multiple robots with proximal sensors can address this challenge by parallelising the sampling process. Yet, multi-robot soil sampling is under-explored in the literature. This paper proposes an auction-based multi-robot task allocation that efficiently coordinates the sampling, coupled with a dynamic sampling strategy informed by Kriging variance from interpolation. This strategy aims to reduce the number of samples needed for accurate mapping by exploring and sampling areas that maximise information gained per sample. The key innovative contributions include (1) a novel Distance Over Variance (DOV) bid calculation for auction-based multi-robot task allocation, which incentivises sampling in high-uncertainty, nearby areas; (2) integration of the DOV bid calculation into the cheapest insertion heuristic for task queuing; and (3) thresholding of newly created tasks at locations with low Kriging variance to drop those unlikely to offer significant information gain. The proposed methods were evaluated through comparative simulated experiments using historical soil compaction data. Evaluation trials demonstrate the suitability of the DOV bid calculation combined with task dropping, resulting in substantial improvements in key performance metrics, including mapping accuracy. While the experiments were conducted in simulation, the system is compatible with ROS and the ‘move_base’ action client to allow real-world deployment. The results from these simulations indicate that the Kriging-variance-informed approach can be applied to the exploration and mapping of other soil properties (e.g., pH, soil organic carbon, etc.) and environmental data. Full article

Improving nitrogen use efficiency (NUE) is critical to advancing sustainable cereal production, particularly under Mediterranean conditions where environmental pressures challenge input-intensive practises. This study evaluates NUE in Tritordeum, a climate-resilient wheat–barley hybrid, using a holistic experimental approach that integrates pre- and post-harvest soil analyses, including an electrical conductivity (EC) assessment, plant and seed nutrient profiling, and an evaluation of yield performance and nitrogen ratio dynamics. Four treatments were tested: conventional urea (T1), urea with an urease inhibitor (NBPT) (T2), urea with a nitrification inhibitor (DCD) (T3), and an unfertilised control (C). While conventional urea achieved the highest yield (1366 kg ha⁻¹), enhanced-efficiency fertilisers (EEFs) improved nutrient synchronisation and seed nutritional quality. Specifically, EEFs increased seed zinc (T2: 34.93 mg/kg), iron (T1: 33.77 mg/kg), and plant potassium (T2: 1.66%; T3: 1.61%) content, and also improved nitrogen remobilisation (elevated Nplant/Nseed ratios). EEFs also influenced soil properties, increasing organic matter (T3: 2.75%) and EC (T3: 290.78 μS/cm). These findings suggest that while EEFs may not always boost yield in the short term, they contribute to long-term soil fertility and nutrient density in grain. This study underscores the importance of synchronising nitrogen availability with Tritordeum’s phenological stages and highlights the crop’s suitability for sustainable, low-input agriculture under climate variability. Full article

Aiming to address a series of problems caused by inefficient nitrogen fixation in soybean within the maize–soybean rotation system under cold-region conditions in Heilongjiang Province, China—such as reduced crop yields, declining soil fertility, and increased dependence on chemical fertilisers—this study investigated the partial substitution of chemical nitrogen fertilisers with bio-organic fertilisers at replacement rates of 10%, 20%, and 30% during soybean cultivation. The treatments included bio-organic fertilisers (OB1, OB2, OB3), inactivated bio-organic fertilisers (O1, O2, O3), Bacillus subtilis (B1, B2, B3), and a control (CK) with the conventional application of chemical fertilisers. In the rotational maize cropping phase, a 50% nitrogen reduction was applied. The results showed that replacing 20% of soybean nitrogen fertiliser with bio-organic fertiliser (OB2 treatment) yielded the most significant increase in productivity and economic return. Compared with CK, the OB2 treatment increased soybean yield by 26.56%, maize yield by 26.69%, and nitrogen fertiliser use efficiency by 3–5%. According to the GRA-TOPSIS model, the OB2 treatment demonstrated the greatest capacity to improve quality and efficiency in the maize–soybean rotation system. At the soybean maturity stage, the OB2 treatment increased soil total organic carbon, available phosphorus, and soil protease activity by 25.36%, 22.20%, and 87.50%, respectively, compared with CK. At maize maturity, soil ammonium nitrogen and soil protease activity increased by 80.24% and 62.47%, respectively. Bio-organic fertilisers combine the benefits of organic fertiliser substrates with those of functional microorganisms. Correlation, cluster, and interaction analyses revealed that the synergistic mechanisms between maize–soybean rotation and bio-organic fertilisers in cold regions are primarily reflected in improved soil quality, enhanced nutrient cycling efficiency, increased nitrogen fixation in soybean root nodules, stimulated microbial activity, and greater resilience to environmental stress. Sustainable agricultural production in cold regions can be achieved through the integrated functioning of these system components. This study provides a theoretical basis for enhancing yield and efficiency in maize–soybean rotation systems under cold climatic conditions. Full article

Many of today’s innovative materials used to carry trace elements (TEs) are derived from chelates. Most of the materials used for this purpose have been produced on the basis of EDTA, which is not considered to be environmentally friendly due to its high persistence. Research is therefore being carried out to produce materials that do not pose an environmental risk. Therefore, a study was carried out to determine the effects of newly developed innovative materials with embedded biodegradable and environmentally safe chelates (IDHA—iminodisuccinic acid—and N-butyl-D-gluconamide ligands) containing copper, molybdenum and iron on the yield, biometric characteristics and chemical composition of soybean and selected soil properties. It is difficult to find publications on their effects in soybean cultivation. The greatest increase in soybean leaf greenness index (SPAD) was found after the addition of pure Salmag^® (Sal.^®). The effect of the chelates on the SPAD index was lower, with Sal.^® + Fe chelate having the greatest effect during the vegetative development stage and Cu chelate having the greatest effect during the flowering stage. Sal.^® + Cu, especially with Fe, accelerated pod and seed ripening in the last vegetative stage of soybean. Sal.^® + Cu had the most favourable impact on plant height, pure Sal.^® on the pod number per plant, Sal.^® + Fe on the seed number per pod, Sal.^® with Mo and Fe chelates on soybean seed yield, and pure Sal.^® on fresh weight remaining above-ground part yield, while pure Sal.^® and Sal.^® + Fe had the most favourable impact on dry weight aerial yield. The fertiliser materials (especially Sal.^® + Cu) generally increased the N content of the tested soybean organs and the Cu content of the other above-ground soybean parts (especially those containing chelates) and had an antagonistic effect on the Mg content of the soybean above-ground parts. Sal.^® + Cu also had a negative effect on the Fe content of other above-ground soybean parts. Sal.^® + Fe had a positive impact on the iron content, and Sal.^® + Mo had a positive impact on the molybdenum content of soybean. The applied fertilisers had little effect on the contents of Cu, Mo and Fe in the soil. There was only a significant increase in the Cu content of the soil after the addition of Sal.^® + Cu and a significantly smaller increase under the influence of Sal.^® without chelates, as well as an increase in the Mo content of the soil with Sal.^®. The present study confirms the beneficial impact of the novel materials with chelates. It has been demonstrated that the presence of materials containing Mo and, in particular, Cu has a considerable effect on the yield and quality characteristics of soybeans. Full article

The restrictions imposed by the European Green Deal on Europe are expected to make Europe climate-neutral by 2050. In this context, this article examines the current efforts to reduce emission levels, focusing on available international scientific papers concerning European territory, particularly Poland. The study paid special attention to the sector of agriculture, which is considered a key contributor to greenhouse gas generation. It also analysed the impact of various tillage techniques and the application of organic and inorganic fertilisers, e.g., nitrogen fertilisers, digestate, or compost, on the emissions of greenhouse gases and other environmentally harmful substances. Although there are few scientific articles available that comprehensively describe the problem of greenhouse gas emissions from agriculture, it is still possible to observe the growing awareness of farmers and their daily impact on the environment. The current study demonstrated that agricultural activities significantly contribute to the emissions of three main greenhouse gases: carbon dioxide, nitrous oxide, and methane. The tillage and soil fertilisation methods used play a crucial role in their emissions into the atmosphere. The use of no-tillage (or reduced-tillage) techniques contributes to the sustainable development of agriculture while reducing greenhouse gas emissions. The machinery and fuels used, along with innovative systems and sensors for precise fertilisation, play a significant role in lowering emission levels in agriculture. The authors intend to identify potential opportunities to improve crop productivity and contribute to sustainable reductions in gas emissions. Full article