Search Results (982)

Durum wheat straw is an abundant by-product in Mediterranean cereal systems, but its low protein and high fiber content limit its use as ruminant feed. Integrating forage legumes as living mulches in durum wheat may enhance its feeding value through the addition of nutrient-rich legume biomass. A two-year field trial evaluated three forage legumes (Vicia sativa L., Trifolium michelianum Savi, Trifolium subterraneum L.) grown as living mulch with organic durum wheat (Triticum turgidum subsp. durum (Desf.) Husn.) under two NPK fertilization rates (target 60 and 120 kg N ha⁻¹), with or without rhizobial inoculation. Chemical composition and forage quality indices were determined for sole-wheat straw (SB) and legume biomass (LB) and subsequently used to estimate the nutritional characteristics of wheat straw–legume biomass mixtures (TSB). Biomass production was significantly affected by legume species in the first growing season and by legume species and rhizobial inoculation in the second, with Vicia sativa consistently showing the best performances. Correlation analysis showed that increasing LB contribution was significantly associated with all forage quality indices of the resulting TSB. These results indicate that rhizobially inoculated forage legume living mulch may improve the potential use of wheat straw as an on-farm feed resource in Mediterranean organic farming. Full article

Agriculture underpins global food security; yet, inefficient or excessive nitrogen (N), phosphorus (P), and potassium (K) fertilization can generate interconnected environmental pressures. Direct environmental effects are much more extensively documented for N and P than for K, which is more often examined through nutrient imbalance, soil–plant interactions, and its interactions with N and P. This study combines a bibliometric analysis of 3649 articles and reviews indexed in the Web of Science Core Collection (SCIE and SSCI) from 1991 to 2024 with a literature review. The objective is to map the evolution, knowledge structure, and emerging frontiers of research on the environmental effects of agricultural NPK fertilization and to identify the knowledge gaps and priorities for sustainable nutrient management. The analysis shows a sustained growth in publication output, increasing interdisciplinarity, and major research hotspots involving nutrient cycling, environmental impacts, sustainability, and nutrient-management technologies. The synthesis further identifies persistent gaps in integrated N–P–K interactions, the long-term evaluation of precision nutrient management, compound climate-related risks, and the links between scientific evidence and governance. Based on these findings, we develop an integrated NPK environmental-management framework connecting fertilizer inputs, nutrient interactions, soil processes, environmental outcomes, management interventions, and policy support. The combined bibliometric and literature-review approach therefore moves beyond mapping the field to provide a structured basis for future research and more integrated nutrient-management strategies. Full article

The disposal of stone mine tailings (SMTs) near agricultural lands has become a major environmental concern because of their elevated concentrations of environmentally hazardous metals (EHMs). The minimization of the potential detrimental effects of soil pollution on crop cultivation and food safety are the major concerns in modern agricultural practice. Vermitechnology has emerged as a sustainable bioconversion approach for biotically stabilizing mine tailings into a nature-friendly organic amendment. However, the agronomic potential and environmental safety of vermiprocessed stone mine tailings remain poorly understood. To fill this research gap, this study assessed the effectiveness of mine-tailing-derived vermicompost as an organic amendment for Solanum lycopersicum L. (tomato) cultivation. Vermicompost was prepared from both inorganic mine tailings and organic cow dung (1:1 and 2:1 ratios, w/w) together using earthworm Eisenia fetida species. The results demonstrated that the treatment amended with 1:1 vermicomposted tailings supplemented with the recommended dose of chemical fertilizer (T3) outperformed all other treatments by enhancing soil microbial activity, the concentration of bioavailable NPK, improved fruit yield, different biochemical parameters, and reduced post-harvest bioavailable Cr, Ni, Cu, Pb, and Cd concentration. Severity Adjustment Margin of Exposure (SAMOE) analysis indicated estimated dietary risk (Class 5) for Cr (VI) and Cd in tomatoes grown on untreated mine tailings, whereas vermicompost-amended treatments reduced the risk to low or negligible levels. Overall, the findings suggest that vermicomposted stone mine tailings emerged as a potential complementary soil amendment and an eco-friendly strategy which improve crop growth while reducing metal availability and its associated health risks. Full article

Organic fertilization is a key strategy for improving soil structure and fertility in China’s Vertisols, yet the trade-offs among soil quality enhancement, grain yield performance, and nutrient use efficiency under different organic amendment regimes remain insufficiently elucidated. Based on a unique 43-year field fertilization experiment, this study systematically evaluated the effects of long-term chemical fertilization (NPK) alone, low-dose (NPKLS) and high-dose straw incorporation (NPKHS), combined chemical fertilizer with cattle manure (NPKCM), and pig manure (NPKPM) fertilization on soil physical, chemical properties, crop yields and plant nutrient utilization efficiency. The results showed that NPKCM and NPKPM significantly improved soil physical properties by reducing soil bulk density, improving soil pore structure, and enhancing soil water retention capacity and saturated hydraulic conductivity. Although long-term manure application led to slight soil salt accumulation, the rate of accumulation remained substantially lower than that associated with commercial organic fertilizers and did not approach the crop salinity damage threshold, suggesting low ecological risk. Compared with NPK treatment, manure amendment effectively counteracted soil acidification induced by prolonged chemical fertilization, while also significantly increasing soil total phosphorus and available phosphorus content, and elevated the proportion of active phosphorus (PAC). The improved soil phosphorus activation capacity and comprehensive soil quality further contributed to substantial increases in wheat grain yield under NPKCM and NPKPM treatments. Despite these agronomic benefits, the additional nitrogen and phosphorus inputs from manure resulted in soil nutrient surpluses, which considerably reduced nitrogen and phosphorus partial factor productivity as well as agronomic efficiency. In contrast, straw incorporation treatments (NPKLS, NPKHS) sustained stable crop yield without notable declines in nutrient efficiency, positioning them as a greener and more sustainable approach to balancing grain production with resource use efficiency. These findings highlight the need to integrate nutrient credits from manure into fertilization program. Given the 43-year evidence, fertilization strategy should consider not only the nutrients supplied by manure but also the quantities exported through harvested products, with adjustments based on annual soil fertility analyses. Such nutrient budgeting is essential to maximize fertilizer use efficiency, prevent excessive phosphorus accumulation, and maintain balanced soil fertility over time. Full article

Since arable-land availability is limited worldwide, research on other sustainable practices to improve crop productivity is needed. Seaweed extracts are known for their crop growth- and yield-promoting properties and as a sustainable solution. The application of three seaweed extract brands (Acadian, Afrikelp, and Kelpak) was tested on three crops under field (common bean) and screen-house (bell pepper and tomato) conditions for two consecutive seasons/crops. The study was conducted as an RCBD with five blocks using a drip irrigation system. The three seaweed extracts + water-only (control) treatments were randomly distributed in each block. The extracts were applied to the foliage five times in each growing season at a 1:75 extract/water dilution rate and all crops received N-P-K fertilizer based on the recommended rates for each crop. Analysis of variance and Tukey’s mean separation were conducted on the collected data. All three extracts significantly outperformed the control across all crops and seasons. For bush bean, seaweed treatments significantly increased SPAD, yield, and protein content, with the treatment order Afrikelp > Acadian ≥ Kelpak > Control. For tomato, significant improvements were observed in SPAD, yield, and fruit weight, with yield increases driven primarily by fruit count and average; the treatment order was Afrikelp > Kelpak ≥ Acadian > Control. For bell pepper, SPAD, yield, and BRIX were significantly increased, with the treatment order Afrikelp > Kelpak > Acadian > Control. Overall, Afrikelp consistently produced the highest responses across all crops, achieving up to 48.8, 60.3, and 58.6% yield increases for bush bean, tomato, and bell pepper, respectively. The results showed that seaweed extract can serve as a sustainable amendment for crop improvement. Full article

The edible oil self-sufficiency rate of China is only approximately 30%, with rapeseed as the largest source of edible oil, contributing more than half of the total edible vegetable oil. Therefore, it is very important to achieve high rapeseed yield to ensure supply security. Fertilizer is one of the key factors affecting rapeseed yield and quality, and the appropriate use of fertilizer is essential for ensuring both high yield and high quality. To investigate the effects of fertilizer rates on the growth, yield, and quality of rapeseed, 18 rapeseed varieties were grown under two fertilizer input levels: normal fertilizer (NF, 15-15-15 NPK compound fertilizer at 600 kg·ha⁻¹) and high fertilizer (HF, 15-15-15 NPK compound fertilizer at 1200 kg·ha⁻¹). Agronomic traits, physiological indicators, yield, and quality of these varieties were systematically analyzed in this study. In addition, transcriptomic data from stems collected at the silique stage were used to identify key differentially expressed genes (DEGs), and the correlations between the expression levels of these candidate genes, physiological indicators, agronomic traits, and yield were examined. Compared with the NF treatment, the HF treatment promoted rapeseed growth during the bolting stage (except for root collar diameter). At harvest, 27.8% of the rapeseed varieties showed a significant increase in the number of effective branches per plant, while 33.3% exhibited significant increases in both the number of effective siliques per plant and the yield per plant. Among these varieties, Z01, Z02, Huayouza 50, and Huayouza 652 showed the greatest overall yield increases. The oil content decreased in 88.9% of the varieties, whereas the unsaturated fatty acid content increased in 77.8%, and the protein content increased in 94.4% of the varieties. Under HF treatment, superoxide dismutase activity in leaves at the bolting stage and peroxidase activity in leaves at the initial flowering stage both increased significantly (by 19.07% and 10.41%, respectively). The content of thiobarbituric acid-reactive substances (expressed as malondialdehyde equivalents) in stems at the initial flowering stage increased significantly (by 138.39%). In addition, catalase activity in leaves at the 3- to 4-leaf stage reached its highest value among all treatments (27.31 U·g⁻¹·min⁻¹·FW). The KEGG enrichment analysis indicated that the DEGs were significantly enriched in secondary metabolite biosynthesis, plant hormone signal transduction, plant–pathogen interactions, and metabolic pathways. Through screening against the NCBI database and subsequent validation by RT-qPCR, we ultimately identified four candidate DEGs: BnaC05g02370D, BnaC09g49910D, BnaC03g45470D, and BnaA04g00130D. Among these four varieties, catalase activity and malondialdehyde content in rapeseed stems at the initial flowering stage showed significant positive correlations with yield (r = 0.738 and r = 0.894, respectively). BnaC09g49910D maintained a consistently positive correlation with yield under both the HF and NF treatments (r = 0.977 and r = 0.806, respectively). In contrast, the direction of the association for BnaC05g02370D reversed depending on the fertilizer level (r = −0.858 under HF vs. r = 0.443 under NF). Catalase activity and the content of thiobarbituric acid-reactive substances in stems at the initial flowering stage and the expression levels of BnaC05g02370D and BnaC09g49910D in stems at the silique stage are associated with yield to varying degrees. These indicators can be used as candidate traits for assessing rapeseed yield potential under different fertilizer input levels. Full article

The excessive use of conventional NPK fertilizers can reduce nutrient use efficiency due to nutrient losses, emphasizing the need for controlled-release fertilizer systems. This study aimed to prepare and evaluate olive pomace-derived biochar (BC) as a carrier for nitrogen–phosphorus–potassium (NPK) fertilizer and assess its effects on nutrient release and lettuce performance. Biochar was produced by pyrolysis at 400 °C and loaded with NPK fertilizer. The BC/NPK composite was characterized using Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), nutrient-release behavior was evaluated in deionized water and soil. The cumulative nutrient release reached 64% in deionized water and 91% in soil. Under greenhouse conditions, BC/NPK applied at 100% and 75% NPK rates increased lettuce fresh weight, plant height and leaf number to 163.33 and 183.67 g, 23.00 and 23.67 cm, 34 and 36, respectively. Moreover, BC/NPK reduced nitrate accumulation in lettuce leaves, with nitrate concentrations decreasing in outer leaves to 10 and 0.73 mg g⁻¹ and in inner leaves to 2 and 1.33 mg g⁻¹ at the 100% and 75% rates, respectively. These findings demonstrate that olive pomace-derived BC/NPK is a promising slow-release fertilizer capable of improving crop performance while supporting sustainable nutrient management and agricultural waste valorization. Full article

Reliable establishment of direct-seeded onion requires coordinated control of sowing geometry, nutrient supply, crop protection, and resource use. This study combined Hartley-4 optimization of a four-section, multi-row ridge seeder with a two-year randomized complete block experiment comprising ten fertilization × crop-protection treatments. Engineering tests at 5.2, 6.4, and 7.6 km h⁻¹ identified a central operating setting at 6.4 km h⁻¹ that maintained a sowing depth of 1.5–2.0 cm and depth variability below 0.5 cm. In field plots, chemical protection with vermicompost produced the highest mean total yield (25.54 t ha⁻¹), whereas chemical split NPK maximized marketable and standard yields. Biological split NPK showed the greatest two-season yield retention (0.780), although biological protection was associated with higher downy mildew severity. The biological biocomplex treatment ranked highest under the author-defined EIQ-adjusted resource-efficiency screening index, but sensitivity analysis showed that intermediate rankings depended on aggregation assumptions. The optimized design provides manufacturers with validated parameter ranges and gives users a constant-speed platform for comparing crop-management programs. Future research should test the seeder across contrasting soil textures and speeds and directly measure field capacity, fuel use, and long-term agronomic performance. Full article

This paper presents the design and preliminary field validation of a portable, low-cost Internet of Things (IoT) station for georeferenced soil nutrient profiling in agricultural environments. The proposed system integrates a digital RS-485 NPK soil sensor, an ESP32 microcontroller, and a SIM7000G GSM/GPS module to enable on-site acquisition and real-time transmission of nitrogen (N), phosphorus (P), and potassium (K) measurements using the MQTT protocol. Data are serialized in JSON format and transmitted to a ThingsBoard cloud platform for remote storage and visualization. The portable architecture supports manual spatial sampling across multiple locations without reliance on fixed infrastructure, making it suitable for small- and medium-scale agricultural contexts with limited connectivity. Preliminary testing in a controlled lemon plantation demonstrated stable GSM connectivity, successful geotagging, and consistent cloud-based visualization, with an average acquisition–transmission cycle of 30–45 s per measurement. Spatial heat maps generated from collected data illustrate the system’s capability for indicative nutrient mapping. Although laboratory-grade validation is ongoing, the results confirm the technical feasibility of integrating low-cost sensing, cellular communication, and georeferenced data acquisition into a compact IoT unit. The system establishes a foundation for future calibration, large-scale field validation, and decision-support applications in precision agriculture. Full article

Sweet corn is an important vegetable crop due to its high nutritional value and increasing demand for fresh consumption and food processing. This study evaluated the effects of different fertilization systems on the yield and nutritional quality of sweet corn cultivated under the pedoclimatic conditions of the Crișului Negru Meadow, Bihor County, Romania. A field experiment was conducted in 2024 using a randomized block design arranged in a Latin rectangle with four fertilization treatments: an unfertilized control (V1), organic fertilization with farmyard manure compost (V2), mineral fertilization with NPK (V3), and mineral fertilization with NPK supplemented with micronutrients (V4). Kernel quality was assessed by determining ash, crude protein, fat, fatty acids, carbohydrates, total sugars, energy value, and reference intake. Data were analyzed by analysis of variance (ANOVA), and treatment means were compared using Tukey’s HSD test at p < 0.05. The fertilization regime significantly affected most nutritional parameters. The highest values were recorded in V4, with significant increases in crude protein (24.54%), fat (24.00%), fatty acids (26.32%), total sugars (50.20%), energy value (15.42%), and reference intake (15.32%) compared with V1. In contrast, carbohydrate content was not significantly affected by the fertilization treatments, while mineral content remained comparable to the control only in V4. Overall, mineral fertilization supplemented with micronutrients proved to be the most effective strategy for improving the nutritional quality of sweet corn and represents a promising sustainable fertilization approach for cultivation under the environmental conditions of the Crișului Negru Meadow. Full article

The rapid growth of insect farming generates significant volumes of insect frass, a novel organic by-product. Utilizing frass-based organo-mineral fertilizers represents a sustainable alternative to synthetic fertilizers, yet long-term agronomic efficacy and residual effects require further field validation. This study evaluated pelletized organo-mineral formulations for conventional and organic agriculture, derived from Hermetia illucens and Tenebrio molitor frass. Eight field treatments were evaluated: an unfertilized control; an inorganic NPK fertilizer (150 kg N ha⁻¹); a biostabilized municipal solid waste compost at two nitrogen rates (150 and 300 kg N ha⁻¹); and two novel insect-frass-derived organo-mineral fertilizers (VHTI and VHTO) applied at a standard product dose (1000 kg ha⁻¹) and an N-equivalent dose (150 kg N ha⁻¹). Application of organo-mineral and organic treatments at the same nitrogen dose (150 kg N ha⁻¹) doubled cabbage yield compared to the unfertilized control and significantly outperformed the conventional inorganic treatment. These formulations demonstrated enhanced nitrogen and phosphorus use efficiencies, reflecting improved synchronization between nutrient release and crop demand. Furthermore, organo-mineral formulations significantly increased soil available phosphorus without adversely affecting key soil quality parameters. The Integrated Soil–Crop Response Index (ISCRI) confirmed a superior overall agroecosystem response for these treatments. These findings provide important theoretical insights into nutrient synchronization mechanisms in organo-mineral fertilizers, alongside practical applications for sustainable cabbage production. Consequently, frass-based pelletized fertilizers represent a highly sustainable, circular, and efficient alternative to optimize horticultural yield and nutrient use efficiency while enhancing soil health, ultimately supporting the valorization of insect farming by-products as viable substitutes for synthetic fertilizers. Full article

Reliable tools for assessing soil nutrient availability are essential for the accurate determination of fertilizer application rates. The aim of this study was to evaluate the reliability of commercially available electrochemical sensors for the real-time determination of water-soluble N, P, and K in soil as indicators of nutrient supply to crops. The experiment was conducted under both greenhouse and field conditions using seven probe models. Four probes (designated 1–4) were equipped with three sensors for the measurement of N, P, and K. Probes 5, 6, and 7 were equipped with sensors for N, P, K, electrical conductivity (EC), pH, soil temperature, and soil moisture, although probe 7 was manufactured by a different company. Each probe was inserted into 4 L pots filled first with a clay-loam soil and subsequently with a sandy soil. The soils were irrigated with nutrient solutions containing different concentrations of N, P, and K in order to modify nutrient concentrations in the soil solution and compare sensor readings with values obtained through standard chemical analyses. The results showed no significant correlation between probe readings and soil N, P, or K concentrations in either clay-loam or sandy soils. At the same time, all probes exhibited a constant relationship among N, P, and K readings regardless of soil texture or nutrient concentration. This finding suggests that the probe algorithms rely on a single measured variable that is subsequently converted into multiple output variables using fixed conversion coefficients. In conclusion, the NPK probes tested in this study were unable to provide reliable real-time measurements of soil N, P, and K concentrations. Full article

Nitrogen (N), phosphorus (P), and potassium (K) are important nutrients limiting cotton yield. Although N, P, and K fertilization is an important practice for improving cotton productivity, their fertilizer use efficiencies remain insufficiently evaluated in Xinjiang, China. In this study, field experiments were conducted at 57 sites across the major cotton-growing areas of Xinjiang during 2021–2022. Four fertilization treatments, PK, NK, NP, and NPK, were established to evaluate cotton yield response, nutrient accumulation, and fertilizer use efficiencies of N, P, and K under different soil fertility conditions. The results indicated that the cotton yield in both southern and northern Xinjiang significantly increased under NPK treatment, with mean yields of 6300 and 7361 kg ha⁻¹, respectively. The use efficiencies of N, P, and K were 39.8%, 19.5%, and 51.4% in southern Xinjiang, and 40.3%, 20.2%, and 66.1% in northern Xinjiang, respectively. For every 100 kg of seed cotton produced, nutrient uptake was 4.64 kg N, 1.43 kg P₂O₅, and 3.67 kg K₂O in southern Xinjiang, and 4.74 kg N, 1.48 kg P₂O₅, and 4.58 kg K₂O in northern Xinjiang, indicating relatively high N and K requirements but lower P demand in cotton production. Cotton yield in southern Xinjiang was significantly and positively correlated with soil alkali-hydrolyzable N. In northern Xinjiang, cotton yield was significantly and positively correlated with soil organic matter, alkali-hydrolyzable N, and available K, but negatively correlated with available P. Overall, cotton yield was mainly positively affected by soil organic matter, alkali-hydrolyzable N, and available K, whereas K use efficiency was significantly and negatively correlated with N and K rates. The suitable N, P, and K rates for cotton were 285, 120, and 106 kg ha⁻¹ in southern Xinjiang, and 243, 101, and 91 kg ha⁻¹ in northern Xinjiang, respectively. Based on soil fertility classification of cotton fields, the recommended N, P, and K rates were 256–313, 96–117, and 125–153 kg ha⁻¹ in southern Xinjiang, and 219–267, 97–119, and 136–166 kg ha⁻¹ in northern Xinjiang, respectively. Accordingly, reducing N and P inputs in southern Xinjiang, maintaining N and P at appropriate levels in northern Xinjiang, and moderately increasing K are recommended to achieve coordinated improvements in yield stability and N, P, and K use efficiencies. Full article

Balanced fertilization is essential for improving the growth and productivity of Sapindus mukorossi plantations. In this study, a three-year “3414” fertilization experiment was conducted in a six-year-old plantation of the new S. mukorossi cultivar ‘Yuanhua’ to evaluate the effects of nitrogen, phosphorus, and potassium fertilization on vegetative growth, fruit yield, yield stability, and gross output value. Fertilizer levels were set at 0, 300, 600, and 900 kg N ha⁻¹, 0, 250, 500, and 750 kg P₂O₅ ha⁻¹, and 0, 200, 400, and 600 kg K₂O ha⁻¹. NPK fertilization promoted tree height, ground diameter, crown width, and fruit yield compared with the unfertilized control. Among the 14 fertilization treatments, N₁P₁K₂ produced the greatest mean annual increment in tree height, N₁P₂K₁ produced the greatest ground-diameter increment, and N₂P₂K₁ produced the greatest crown-width increment. Fruit yield was highest under N₂P₂K₂ in 2021 and 2022 and under N₂P₂K₁ in 2023. The highest three-year mean yield was obtained under N₂P₂K₂, reaching 1278.93 kg ha⁻¹, and the highest yield stability index was observed under N₂P₂K₂ and N₂P₁K₂. Gross output value showed a pattern consistent with fruit yield, with N₂P₂K₂ producing the highest values in 2021 and 2022 and N₂P₂K₁ producing the highest value in 2023. Among the tested fertilization combinations, N₂P₂K₂, corresponding to 600 kg N ha⁻¹, 500 kg P₂O₅ ha⁻¹, and 400 kg K₂O ha⁻¹, showed the best overall performance for six-year-old S. mukorossi ‘Yuanhua’ plantations under the conditions of this study. These findings indicate that balanced NPK fertilization can improve vegetative growth, fruit yield, yield stability, and gross output value in S. mukorossi ‘Yuanhua’ plantations. Full article

Background: In the coming decades, the agricultural system will increasingly rely on organic amendments to sustain crop production, maintain soil health and ensure long-term food security. While inorganic fertilizers remain widely used for vegetable production due to their rapid nutrient availability, their prolonged application has been shown to degrade soil quality, disrupt microbial communities and limit the nutritional quality of harvested produce. Consequently, there is a growing need to explore organic alternatives such as biochar and poultry manure that can enhance both crop productivity and functional quality. Objective: This study aimed to determine the influence of different application rates of biochar (5/T₁, 10/T₂, and 20/T₃ t/ha), poultry manure (10/T₁, 20/T₂, 30/T₃ t/ha), and NPK (2:3:4) as control on the metabolomic profile of tomato fruit. Methods: The metabolomic profile was determined using 1H-nuclear magnetic resonance (NMR). Results: Common metabolites across biochar rates included allantoin, asparagine and betaine, while rate-specific released metabolites such as inosine (T₁), epicatechin (T₂) and kynurenine (T₃) were also identified. Similarly, poultry manure showed an array of metabolites at the highest application rate, with metabolites such as cellobiose, creatinine and maltose, while histamine (T₁) and ADP (T₃) were also detected as distinct metabolites. Full article