Search Results (89)

The aim of this study was to determine the impact of multi-year variations in nitrogen fertilisation (N) and farmyard manure application (FYM) in two 4-year crop rotations, A and B—which differed primarily in terms of their organic matter management systems (A: poor vs. B: enrichment)—on changes in the content of calcium and soil organic carbon at three soil horizons of Luvisols, and on the dynamics of these changes over the past 40 years. Mineral N fertilisation was found to affect the movement of Ca in the profiles of both rotations. Most Ca accumulated in the soil layer at >55 cm in the profiles of both rotations. The total Ca content was similar in both rotations; however, a correlation analysis revealed a stronger relationship between organic carbon and Ca in the enriched-cropping system (rotation B) compared to the poor-organic-matter system (rotation A). In the 0–30 cm soil layer, the correlation coefficient between organic carbon and Ca was r = 0.52 in rotation B, while in rotation A, it was lower at r = 0.23. In deeper layers, this relationship weakened or became non-significant. Under the climatic and soil conditions of Poland, where the phenomenon of nutrient leaching into the soil profile is prevalent, it is extremely important to manage these nutrients in a sustainable way in order to limit their loss. The predominantly sandy texture of the topsoil horizons (0–30 cm) of the Luvisols prevents any significant enrichment of these horizons in Corg, even over a very long period of time, i.e., more than 40 years. Full article

Mostly, phosphorus (P) fertilizers are fixed in the interlayer of soil and become unavailable to crop plants. Combined inorganic fertilizers with organic manures could be a suitable solution to release these nutrients from the soil. P deficiency in soil adversely affected crop growth and development to a larger extent. To check out this problem, present research was conducted over a two-year period to evaluate the efficiency of a combined mixture of inorganic P and organic manure as a better farming strategy, in relation to their sole treatments, for enhancing P availability, plant growth, yield and quality, and soil properties. The inorganic source of P was SSP in the form of P₂O₅, while the organic source was cattle manure mixed with crop residues called farmyard manure (FYM). The experiment consisted of the same six treatments over each year: (i) control (0F+0P), (ii) 45 kg P₂O₅ ha⁻¹ (45P), (iii) 90 kg P₂O₅ ha⁻¹ (90P), (iv) 45 kg P₂O₅ ha⁻¹ + 1000 kg FYM ha⁻¹ (45P+1000F), (v) 1000 kg FYM ha⁻¹ (1000F), and (vi) 2000 kg FYM ha⁻¹ (2000F), using randomized complete block design (RCBD), to five replications. Results demonstrated that the combination of SSP with FYM increased the plant height (27.9%), grain yield (23.4%), and plant P uptake efficiency (43.7%) of maize as compared to sole SSP at 90 kg P₂O₅ ha⁻¹, which occurred due to improved P availability in soil. By comparing sole amendments of P fertilizer sources, FYM-treated plots have performed better in increasing maize growth and yield components such as plant height, dry matter, crop growth rate (CGR), net photosynthetic rate, grain yield, and crude protein (e.g., nitrogen contents); this happened due to enhanced soil chemical properties that might be related to improvement in P level and decreased bulk density of soil. Further, significant positive correlations were exhibited among studied crop and soil data. The plant available P and grain protein contents (N concentration) also showed a significant positive correlation and exhibited higher nitrogen contents under organic amendments of P fertilizer, as compared to inorganic treatments. The study concluded that combined SSP at 45 kg P₂O₅ ha⁻¹ with organic cattle manure at 1000 kg ha⁻¹ has a great potential for enhancing maize productivity under water deficit conditions. Results of this research may further be improved by including rigorous soil samples and field heterogeneity data between the plots and the years, which will provide more clear findings from a combined mixture of organic and inorganic fertilization. Full article

This research was carried out to investigate the effectiveness of using organic fertilizers in improving the organic seed production process and increasing the seed quality needed in organic agriculture production. The experiment was established with organic fertilizers (farmyard manure—FYM, leonardite—L, vermicompost—VC) and the eggplant plant ’Pala-49’ variety and conducted for two years. As a result of the study, vegetative growth height varied between 52.65 and 68.06 cm, plant diameter width ranged from 51.85 to 61.20 cm, fruit height ranged from 14.67 to 21.90 cm, and fruit diameter varied between 4.73 and 6.73 cm. These differences were observed among farmyard manure (FYM), leonardite (L), and vermicompost (VC) organic fertilizer applications. In general, it was determined that the first year gave better results. In terms of parameters, the best result in all parameters was obtained from farmyard manure (FYM) organic fertilizer application. In addition, the nutrient element contents of the seed samples were found to be statistically significant. Organic applications significantly increased the nutrient element content of the seed samples according to the control. The nitrogen content varied between 0.242% and 0.271%, and the phosphorus content ranged between 0.274% and 0.456%. The highest K content was determined in farmyard manure (FYM) application in both years (0.272% and 0.309%). In contrast, Fe, Zn, and Mn contents were 35.1 mg kg⁻¹, 63.7 mg kg⁻¹, and 200.7 mg kg⁻¹ in vermicompost (VC) application in the second year, respectively. The effect of the treatments on soil available nutrient content was also found to be significant. The amount of soil available for plant nutrients was higher in the second year. Full article

The widespread use of metal oxide nanoparticles (NPs) in industrial and household products has raised concerns about their potential soil contamination and its ecological consequences. The purpose of this study was to examine and compare the effects of iron oxide nanoparticles (FeONPs) and zinc oxide nanoparticles (ZnONPs) on the microbial activity and biochemical properties of differently textured soils. A mesocosm experiment was conducted using three soil types–clay loam (CL), sandy clay loam (SCL), and sandy loam (SL) amended with farmyard manure (FYM), ZnONPs and/or FeONPs. The results revealed significant differences in microbial colony-forming units (CFUs) and carbon dioxide (CO₂) emissions in the order of SL > SCL > CL. Compared with those from the unfertilized control, the CO₂ emissions from the FYM increased by 112%, 184% and 221% for CL, SCL and SL, respectively. The addition of ZnONPs and FeONPs notably increased the microbial biomass Zn/Fe, which reflected their consumption by the soil microbes. As a result, microbial CFUs were considerably reduced, which led to a 24%, 8% and 12% reduction in cumulative CO₂ emissions after the addition of ZnONPs to the CL, SCL and SL soils, respectively. The respective decrements in the case of FeONPs were 19%, 2% and 12%. The temporal dynamics of CO₂ emissions revealed that the CO₂ emissions from CL with or without FYM/NPs did not differ much during the first few days and later became pronounced with time. Almost all the studied chemical characteristics of the soils were not strongly affected by the ZnONPs/FeONPs, except EC, which decreased with the addition of these nanomaterials to the manure-amended soils. Principal component analysis revealed that the ZnONPs and FeONPs are negatively corelated with microbial CFUs, and CO₂ emission, with ZnONPs being more toxic to soil microbes than FeONPs, though their toxicity is strongly influenced by soil texture. Hence, these findings suggest that while both these NPs have the potential to impair microbial activity, their effects are mediated by soil texture. Full article

Biochar (BC) serves a vital function in sequestering carbon, improving nutrient cycles, and boosting overall soil quality. This research explored the enhancement of the chemical and physical properties of soil (alkaline) using nitrogen and biochar (from organic and inorganic sources) in a semi-arid climate during the autumn seasons of 2015–2016 and 2016–2017. The study involved applying biochar at various rates (0, 10, 20, and 30 t ha⁻¹) and nitrogen at different levels (0, 90, 120, and 150 kg ha⁻¹) using urea, poultry manure (PM), and farmyard manure (FYM) as nitrogen sources, which were applied to the field in a randomized complete block design with split-plot arrangement. The application of biochar at the highest rate (30 t ha⁻¹) resulted in a significant increase of over 120% in soil organic matter (SOM), soil organic carbon (SOC), and soil moisture content (SMC). Additionally, it increased total soil nitrogen (STN) by 14.16% and mineral nitrogen (SMN) by 9.09%. In contrast, applying biochar at this rate reduced soil bulk density (SBD), pH, and electrical conductivity (EC) by 28.52%, 3.38%, and 2.27%, respectively, compared to the control. Similarly, applying nitrogen at 150 kg ha⁻¹ using FYM significantly improved SOC, SOM, SMC, and SBD. At the same rate, using PM as a nitrogen source enhanced STN and SMN while reducing soil pH and EC. In conclusion, this study shows that applying biochar at 30 t ha⁻¹ combined with nitrogen at 150 kg ha⁻¹, sourced from either PM or FYM, offers great potential for improving soil fertility and promoting carbon sequestration in alkaline soils of semi-arid regions. These findings highlight the value of integrating BC and organic N sources for enhancing agroecosystem sustainability. Thus, this study provides a promising pathway to enhance soil quality, improve crop productivity, and support sustainable agricultural practices in challenging environments. Full article

Information on the long-term effects of the addition of organics and fertilizers to wheat under the pearl millet–wheat cropping system with semi-arid conditions in north-western India is still lacking. The present research was conducted in an ongoing field experiment initiated during Rabi 1995 at the Research Farm of Chaudhary Charan Singh at Haryana Agricultural University, Hisar. After 25 years, the impacts of nutrient management practices on soil fertility and wheat productivity were evaluated. The experiment comprised a total of eight treatment combinations viz. half and full doses of recommended fertilizers (N and P), organic manures (FYM: farmyard manure, POM: poultry manure, and PRM: press mud) alone and in combination with NP fertilizers. The conjoint application of organic manure and chemical fertilizers resulted in a positive influx of nutrients via increasing total organic carbon (TOC), available N, P, K, and S, which ranged from 0.46 to 1.42%, 122.70 to 194.70, 15.66 to 74.92, 340.5 to 761.2, and 15.26 to 54.63 kg ha⁻¹ in surface soil (0–15 cm), respectively. Carbon fractions and crop yield were significantly improved by adopting integrated nutrient management (INM). The TOC showed a positive and significant correlation with C fractions (r > 0.92) and with soil-available N, P, K, and S (r > 0.77) content. The data also revealed a strong relationship between TOC and soil-available (0–15 cm) nutrients i.e., available N (R²= 0.769), available P (R² = 0.881), available K (R² = 0.758), and available S (R² = 0.914), respectively. Thus, practices that increased TOC were also beneficial in enhancing the availability of the nutrients in the soil. A positive and highly significant correlation was also found among wheat yield, nutrient (NPKS) content, and uptake. A polynomial relationship between grain yield and grain N (R² = 0.962), P (R² = 0.946), and K (R² = 0.967) content, and between straw yield and straw N (R² = 0.830), P (R² = 0.541) and K (R² = 0.976) content was obtained. Integrated use of PRM_7.5 followed by FYM₁₅ and POM₅ coupled with NP fertilizers proved best, which could be beneficial for obtaining nutritious and highest wheat yield (grain: 6.01 t ha⁻¹ and straw: 7.70 t ha⁻¹) coupled with improved fertility within a sustained manner under the pearl millet–wheat sequence in prevailing semi-arid conditions of the North Indian state of Haryana. Full article

The stability and yield of barley grain are affected by several factors, such as climatic conditions, fertilisation, and the different barley varieties. In a long-term experiment in Prague, Czech Republic, established in 1955, we analysed the weather trends and how weather, fertilisation (10 treatments in total), and different barley varieties affected grain yield and stability. A total of 44 seasons were evaluated. Trends in mean, minimum, and maximum temperatures from 1953 to 2023, as well as sunshine duration from 1961 to 2022, showed statistically significant increases. The trend for annual precipitation from 1953 to 2023 was not significant, but changes in precipitation were recorded via seasonal precipitation concentration indexes. The unfertilised Control and farmyard manure (FYM) provided the lowest mean yields. Mineral fertilisers (NPK) and FYM+NPK increased grain yield, ranging from 4.9 t ha⁻¹ to 5.5 t ha⁻¹. Three notable correlations between weather conditions and yields were observed: (1) June precipitation (r = 0.4), (2) minimal temperature in July (r = 0.3), and (3) sunshine duration in May (r = −0.5). According to the linear–plateau response model, the reasonable N dose is 55 kg ha⁻¹, resulting in a mean yield of 6.7 t ha⁻¹ for the contemporarily used barley variety Sebastián. Full article

A well-designed tree-based culture provides multiple benefits, aiding in achieving sustainable development goals (SDGs), especially SDG1 (no poverty), SDG2 (zero hunger), SDG13 (climate action), and SDG15 (life on land). A split-plot field experiment near Solan, Himachal Pradesh, tested the following Grewia optiva tree spacings as main plots: S₁ 10 m × 1 m, S₂ 10 m × 2 m, S₃ 10 m × 3 m, and sole cropping (S₀—Open) of pea (Pisum sativum L.). Pea cultivation included the following six fertilizer treatments as subplots: control (no application), farmyard manure (FYM), vermicompost (VC), Jeevamrut, FYM + VC, and the recommended dose of fertilizers (RDFs), each replicated three times. The results indicated that the leaves, branches, total biomass, carbon density, and carbon sequestration rate of G. optiva alleys at 10 m × 1 m were greater than those at the other spacings. However, peas intercropped at 10 m × 3 m produced the highest yield (5.72 t ha⁻¹). Compared with monocropping, G. optiva-based agroforestry significantly improved soil properties. Among fertilizers, FYM had the highest yield (6.04 t ha⁻¹) and improved soil health. The most lucrative practice was the use of peas under a 10 m × 1 m spacing with FYM, with economic gains of 2046.1 USD ha⁻¹. This study suggests integrating pea intercropping with G. optiva at broader spacing (10 m × 3 m) and using FYM for optimal carbon sequestration, soil health, and economic returns, and this approach is recommended for the region’s agroecosystems. Full article

Utilizing yield, profitability, and environmental sustainability in terms of soil quality as the goal variables, we created a methodological protocol for a thorough assessment of nutrient management (NM) technologies for feasibility and optimized fenugreek production employing organic sources of nutrients in the acid soil of Northeast India. Five organic nutrient management technologies were tried and tested comprising T₁: absolute control; T₂: 2.5 t ha⁻¹ vermicompost (VC) + 250 kg ha⁻¹ lime; T₃: 5 t ha⁻¹ farmyard manure (FYM) + 250 kg ha⁻¹ lime; T₄: 10 t ha⁻¹ FYM + 250 kg ha⁻¹ lime; and T₅: 5 t ha⁻¹ VC + 250 kg ha⁻¹ lime with four replications laid out in a randomized block design for two consecutive growing seasons during 2018–2020. Results indicated that across the differential levels of organic amendments (treatments) employed, the addition of maximum doses of VC and FYM, in general, excelled over the other treatments concerning fenugreek seed yield, its yield attributes, soil properties, and better economic returns. Thus, the overall findings elucidated that the addition of higher doses of organic amendments (VC and FYM) can sustainably improve fenugreek productivity, soil properties, and economic returns for fenugreek growers in the acid soil of Northeast India. Full article

Enhancing soil fertility and maize productivity is crucial for sustainable agriculture. This study aimed to evaluate the effects of tillage practices, nitrogen management strategies, and acidified hydrochar on soil fertility and maize productivity. The experiment used a randomized complete block design with split-split plot arrangement and four replications. Main plots received shallow tillage and deep tillage. Subplots were treated with nitrogen (120 kg ha⁻¹) from farmyard manure (FYM) and urea, including control, 33% FYM + 67% urea (M_U), and 80% FYM + 20% urea (M_F). Acidified hydrochar treatments H₀ (no hydrochar) and H₁ (with hydrochar, 2 t ha⁻¹) were applied to sub-sub plots. Deep tillage significantly increased plant height, biological yield, grain yield, ear length, grains ear⁻¹, thousand-grain weight, and nitrogen content compared to shallow tillage. M_U and M_F improved growth parameters and yield over the control. Hydrochar effects varied; H₁ enhanced yield components and soil properties such as soil organic matter and nitrogen availability compared to H₀. Canonical discriminant analysis linked deep tillage and M_U/M_F nitrogen management with improved yield and soil characteristics. In conclusion, deep tillage combined with integrated nitrogen management enhances maize productivity and soil properties. These findings highlight the importance of selecting appropriate tillage and nitrogen strategies for sustainable maize production along with hydrochar addition. These insights guide policymakers, agronomists, and agricultural extension services in adopting evidence-based strategies for sustainable agriculture, enhancing food production, and mitigating environmental impacts. The implication of this study suggests to undertake long-term application of hydrochar for further clarification and validation. Full article

Using desi-cow waste products like Jeevamrit under natural farming is widespread among farmers for improving soil biology and productivity. Jeevamrit enhances soil chemical and microbiological properties without needing a large quantity of farmyard manure (FYM) as a sustainable farming practice with a reduced carbon footprint. Despite its traditional use, Jeevamrit faces criticism due to a lack of scientific evidence. This study investigated the comparative effect of Jeevamrit and chemical fertilizers on the growth and yield of marigold cv. Siracole. The experiment employed a randomized block design (RBD) with three replications. The mother block of marigolds was raised for both the summer and winter seasons. From this mother block, three harvesting flushes were taken and propagated from cuttings. The rooted cuttings were planted at monthly intervals and evaluated for flowering parameters and compared to those treated with RDF (30:20:20 N, P, and K g/m²). Soil supplied with Jeevamrit showed enhanced bacteria (26.33%), fungi (18.92%), and actinomycetes (31.21%) populations compared to the recommended dose of fertilizers (RDF) (i.e., N–P–K @ 30:20:20 g m⁻²). Jeevamrit-treated plants have a more marketable flower yield per square meter (3.98%) and a longer shelf life (9.93%) compared to RDF. The study concludes that Jeevamrit @ 2 liters m⁻² is a sustainable and effective alternative to traditional fertilizers for enhancing marigold production in the mid-hills of Himachal Pradesh, where natural farming is already accepted. Full article

Sustainable management practices are crucial for the longevity of a monoculture vineyard, especially in the context of a changing climate. Therefore, soil management practices in a vineyard (T: tillage, T+FYM: tillage + farmyard manure, G: grass strips, G+NPK1: grass strips + rational rates of NPK, and G+NPK2: grass strips + higher rates of NPK) were tested in a temperate climate of Slovakia (Central Europe) under specific soil conditions (Rendzic Leptosol). We investigated the influence of continuous cropping on soil chemical properties and microbial communities during the dry and warm year of 2022. The results showed that the soil pH was higher by 19%, 21%, 24% and 13% in T, T+FYM, G and G+NPK1, respectively, compared to G+NPK2. The lowest soil organic matter (SOM) content was found in T, and it increased in the following order: T < T+FYM < G+NPK2 < G+NPK1 < G. Similarly, the lowest abundance of soil culturable bacteriota was found in T and it increased in the following order: T < T+FYM = G+NPK2 < G+NPK1< G. Culturable bacteriota was identified using mass spectrometry (MALDI-TOF MS Biotyper). The most numerous species group was Bacillus, followed by Lactobacillus > Staphylococcus > Pseudomonas. The most frequently isolated species were Bacillus megaterium (16.55%), Bacillus cereus (5.80%), Bacillus thuringiensis (4.87%), and Bacillus simplex (4.37%). Positive relationships between SOM and soil culturable bacteriota were found in the G and G+NPK1 treatments. Temperature also affected soil culturable bacteriota in all soil management practices, most significantly in G+NPK1. Overall, the best scenario for the sustainable management of a productive vineyard is the use of grass strips. Full article

Sewage sludge can be used as an organic amendment as long as it is ensured that there is no risk of environmental contamination or risk to public health. In this study, sewage sludge from two wastewater treatment plants (WWTPs) subjected to two disinfection and stabilization treatments [40% (mass/mass), calcium oxide, and calcium hydroxide] and their respective untreated sewage sludge were used. Three control treatments were also added: conventional farmyard manure (FYM), a nitrogen (N) mineral fertilizer (ammonium nitrate 34.5% N) applied at a rate of 50 kg N ha⁻¹ (N50) (the same rate of all organic amendments), and an unfertilized control (N0), totaling nine treatments. Lettuce (Lactuca sativa L.) was cultivated in pots for two growing cycles. The dry matter yield (DMY) was higher in the N50 treatment (13.5 and 10.6 g plant⁻¹ in the first and second growing cycles, respectively), followed by sewage sludge (10.8 to 12.4 and 8.4 to 8.7 g plant⁻¹), FYM (8.5 and 7.2 g plant⁻¹), and the control (7.7 and 6.0 g plant⁻¹). The DMY was related to the N provided by the different treatments, assessed by the N and nitrate concentrations in tissues, N uptake, and apparent N recovery (ANR). Sewage sludge, due to its high N concentration and low carbon (C)/N ratio, mineralized rapidly, providing a significant amount of N to plants, as well as other nutrients, such as phosphorus (P) and boron (B). FYM, with a higher C/N ratio, provided less N to plants, also due to the short duration of the lettuce growing cycle. Alkalized sewage sludge increased soil pH and calcium (Ca) availability for plants. Fertilizer treatments minimally influenced cationic micronutrients. Heavy metals in the initial sewage sludge were below the threshold values established in international legislation, and the levels in soil and lettuce tissues were generally not higher than those in other treatments. Both of the sewage sludges used in this study showed high fertilizing value and very reactive behavior, making nutrients available much more quickly than FYM. This information is relevant to consider in defining their agricultural use. Full article

In the period of 2016–2018, two series of field studies on organic sugar beet growing (Beta vulgaris L.) were carried out in northern Poland on Luvisol loamy soil (medium–heavy) soil in Bałcyny and Płonne. The aim of this study was to decrease the yield gap between organic and conventional beets. Factors to increase the yield of organic beet were differentiated fertilization (cattle farmyard manure (FYM), compost, and Bioilsa) and choice of varieties (Eliska, Jampol, and Sobieski). The reference point was the conventional cultivation of the same sugar beet varieties, fertilized with manure and NPK mineral fertilizers, the prevailing standard of sugar beet cultivation in Poland. High sugar beet root yields exceeding the average yield in Poland by 25–30% were obtained in both studies, both in conventional and organic cultivation. Higher root and white sugar yields were obtained in the study conducted at Płonne (with similar soil conditions to those at Bałcyny), but they were characterized by higher temperatures during the growing season. The lowest root yields in both experiments were obtained by fertilizing the organic beet with compost (66.1 t per ha in Bałcyny and 78.13 t per ha in Płonne), which were 10.8% and 8.5% lower than the conventional crop, respectively. Higher root yields in organic cultivation were obtained by fertilizing the sugar beet with FYM, which reduced the differences from conventional beet to 7.7% in the study in Bałcyny and 2.1% in the study in Płonne. Thus, the results showed no need to convert cattle FYM to compost. The highest root yields in organic cultivation were obtained by fertilizing the sugar beet with Bioilsa N 12.5 supplemented with mineral fertilization of K, Mg, and S (Patentkali). This fertilization provided a yield of 78.1 t of roots per ha in Bałcyny, which is a reduction in the yield gap to 1.4%, a statistically insignificant value. Moreover, in the study at Płonne, organic sugar beet fertilized with Bioilsa and Patentkali yielded 86.7 t of roots per ha, compared to 85.6 t per ha of conventional beet, so a yield gap was not seen here. The choice of varieties was also of great importance for root and pure sugar yields in both farming systems. The lowest yields were obtained from the Eliska variety, and at Bałcyny, a change of beet cultivar to Jampol increased the organic root yield from 68.8 t per ha to 76.0 t per ha, while reducing the yield gap from 10.1% to 2.2%. At Płonne, replacing the Eliska variety with Jampol reduced the yield gap between organic and conventional roots from 6.6% to 0.3%. Full article

Trends in soil organic carbon (SOC) were analyzed in the soils from the oldest Czech long-term field experiment, the Prague-Ruzyně Long-Term Fertilizer Experiment, conducted on Haplic Luvisol since 1955. The aim of the work was to compare the long-term dynamics of SOC in contrasting crop rotations and different fertilization regimes. The trial design includes two crop rotations (CR): simple CR with two-year rotation of sugar beet and spring wheat, and multi-crop rotation (MCR) with nine crops. Four fertilization treatments were chosen for SOC analysis: unfertilized control, only mineral fertilization (NPK), farmyard manure application (FYM), as well as FYM and NPK application. SOC content was significantly affected by both fertilization and crop rotation practices. In the simple CR, both the unfertilized control and the NPK treatment exhibited a consistent decline in SOC content over the study period, with percentages decreasing from an initial 1.33% in 1955 to 1.15% and 1.14%, respectively. Although the FYM and FYM + NPK treatments showed an increase in SOC content in the 1990s, a gradual decline was recorded in the last two decades. This decrease was not observed in MCR: positive C balances were recorded in all treatments within MCR, with the largest increase in SOC stock occurring when NPK was combined with FYM. In contrast, over the last decade, C balances have decreased in simple CR for all treatments except FYM. This trend coincides with changes in the local climate, particularly rising temperatures. The results indicate that diversified crop rotations and FYM fertilization are effective in mitigating the negative impacts of changing environmental conditions on SOC stocks. Full article