Soil & Tillage Research

Article	Citations
Deep tilling and localized liming improve soil chemical fertility and sugarcane yield in clayey soils	182
Zero-valent iron addition stimulated straw-derived carbon accumulation in submerged soil	147
Loss and conservation of soil organic carbon and nutrients in arid and semiarid China during aeolian dust emissions	135
Control of landscape position on organic matter decomposition via soil moisture during a wet summer	130
Does spontaneous cover crop increase the stocks of soil organic carbon and nitrogen in commercial olive orchard?	122
Future warming-induced phosphorus loss mitigated by land conversion and degradation	100
Investigating spatial relationships of soil friability and driving factors through co-regionalization with state-space analysis in a subtropical watershed	96
Effect of hardpan on the vertical distribution of water stress in a converted paddy field	90
Using ground-penetrating radar to investigate the thickness of mollic epipedons developed from loessial parent material	90
Editorial Board	88
Physical properties of technosols at brown coal mine wastes in Eastern Siberia	88
Editorial Board	87
A 44-year balanced fertilizer application affected rill erosion resistance by changing humus, aggregates, and polyvalent cation	84
A comparison of preferential flow characteristics and influencing factors between two soils developed in the karst region of Southwest China	80
Development of pedotransfer functions for predicting hydraulic parameters of van Genuchten model by incorporating environmental variables on the Qinghai-Tibet Plateau	79
Long-term straw return increases fungal residual contribution to soil microaggregate nitrogen pool: An eco-enzymatic stoichiometric study	79
Hydraulic and pore functions of differently textured soils modified by biochar from different parts of the mango plant	74
Biogeochemistry of dissolved organic matter and inorganic solutes in soil profiles of tropical pasturelands	69
Long-term manure application to improve soil macroaggregates and plant-available nitrogen in a Mollisol	66
Carbon accumulation dynamics and development processes of peatland established after the Changbaishan Millennium eruption	66
Plow layer management during the fallow season can enhance the wheat productivity and resource utilization in a semi-arid region	65
Effect of different underlying surfaces on hydraulic parameters of overland flow	65
A high-resolution physical modelling approach to assess runoff and soil erosion in vineyards under different soil managements	62
Effects of long-term fertiliser application on cropland soil carbon dynamics mediated by potential shifts in microbial carbon use efficiency	61
Micro/nanobubble-aerated drip irrigation affects saline soil microenvironments and tomato growth by altering bacterial communities	61

Dynamics and influencing factors of soluble organic nitrogen in paddy soil under different long-term fertilization treatments	61
Spatio-temporal evolution of water erosion in the western Songnen Plain: Analysis of its response to land use dynamics and climate change	59
Combined impact of no-tillage and cover crops on soil carbon stocks and fluxes in maize crops	58
A chemotaxis-haptotaxis coupled mechanism reducing bacterial mobility in disturbed and intact soils	57
Legume-based crop diversification reinforces soil health and carbon storage driven by microbial biomass and aggregates	57
Response of soil microbial biomass C, N, and P and microbial quotient to agriculture and agricultural abandonment in a meadow steppe of northeast China	57
Changes in micronutrient concentrations under minimum tillage and cotton-based crop rotations in irrigated Vertisols	57
Depth-dependent patterns in the C:N:P stoichiometry of different soil components with reclamation time in coastal poplar plantations	56
Roots are the key for soil C restoration: A comparison of land management in the semiarid Argentinean Pampa	53
Soil respiration and net carbon flux response to long-term reduced/no-tillage with and without residues in a wheat-maize cropping system	52
Interpretation of uniaxial, confined compression test data for agricultural topsoils	51
Biosolids and conservation tillage for rainfed wheat farming in dry Mediterranean climates	51
Editorial Board	51
Analysis of phosphorus forms on different soil types using heterogeneous isotope exchange reaction	50
Examining the land leveling impacts on the physical quality of lowland soils in Southern Brazil	50
Nutrient supplementation changes chemical composition of soil organic matter density fractions in desert steppe soil in northern China	50
Modeling and digital mapping of shallow water table depth using satellite-based spectral and thermal data: Introducing a framework for digital shallow water table mapping	50
Ammonia volatilization measured with the IHF method in a rainfed arable crop: Evaluation of tillage intensity and the number of experimental replicates	50
Yield, soil Nitrogen content and weed control in six years of conservation agriculture on-farm field trials in Southwest Germany	49
Morphology-based mechanism of desiccation cracking in soil and montmorillonite	49
Effects of earthworm activities on soil nutrients and microbial diversity under different tillage measures	49
Effect of modified bentonite on copper migration via bank soils in the Jialing River, Southwest China	47
Wind erosion after steppe conversion in Kazakhstan	47
Improving nitrogen use efficiency and reducing environmental cost with long-term nutrient expert management in a summer maize-winter wheat rotation system	47
Combining rotary and deep tillage increases crop yields by improving the soil physical structure and accumulating organic carbon of subsoil	47
Control of snow mold damage of winter wheat by snow compaction (Yuki-fumi)	46
Physiological-biochemical responses of wheat to blending controlled-release potassium chloride and soluble potassium chloride	46
Soil health assessment for different tillage and cropping systems to determine sustainable management practices in a humid region	45
Long-term effects of crop rotation, tillage, and fertilizer nitrogen on soil health indicators and crop productivity in a temperate climate	44
Soil loss estimation using RUSLE model: Comparison of conventional and digital soil data at watershed scale in central Iran	44
Pyrolysis of different organic feedstock combinations as soil amendments enhances the reclamation of saline-sodic soil	44
The impact of paleoclimatic on the structural strength of loess paleosol sequences and its implications for tillage on the Loess Plateau: A case study from Luochuan profile	44
Organic fertilizer substitution increased soil organic carbon through the association of microbial necromass C with iron oxides	44
The effect of long-term soil surface mulching on SOC fractions and the carbon management index in a semiarid agroecosystem	42
Green manure provides growth benefits for soil mesofauna by promoting soil fertility in agroecosystems	42
Response of leaf, litter, and root ecological stoichiometries to grazing exclosure duration on the Qinghai-Tibetan Plateau	42
Particulate organic carbon is more sensitive to nitrogen addition than mineral-associated organic carbon: A meta-analysis	42
Long-term excessive phosphorus fertilization alters soil phosphorus fractions in the acidic soil of pomelo orchards	41
Soil compaction alleviation by deep non-inversion tillage and crop yield responses in no tilled soils of the Pampas region of Argentina. A meta-analysis	41
Forest productivity and associated soil ecosystem services remain altered 15years after mechanized site preparation for reforestation with Pinus radiata	40
Applications of Computed Tomography (CT) in environmental soil and plant sciences	40
Microbial role in enhancing transfer of straw-derived nitrogen to wheat under nitrogen fertilization	40
Border row effects on the distribution of root and soil resources in maize–soybean strip intercropping systems	40
The role of roots traits of climax community species to shear strength in the Loess Hilly Region, China	39
Straw retention combined with phosphorus fertilizer promotes soil phosphorus availability by enhancing soil P-related enzymes and the abundance of phoC and phoD genes	39
A deeper look at crop residue and soil warming impact on the soil C pools	39
A tale of two systems: Does reducing tillage affect soil health differently in long-term, side-by-side conventional and organic agricultural systems?	39
Editorial Board	38
Impacts of landscape factors on gully retreat and its morphological characteristics in hilly areas of Northeast China	38
Divergent accumulation of microbial necromass and plant lignin phenol induced by adding maize straw to fertilized soils	38

Enzyme activities and microbial nutrient limitations in response to digestate and compost additions in organic matter poor soils in the Marches, Italy	38
Editorial Board	37
Efficacy of earthworm casts on sediment and nitrate loss with runoff in the Chinese Loess Plateau	37
Alteration in surface energy balance fluxes induced from long-term disk-tilled versus no-till management in maize production	37
The application of amendments improves properties of salt-affected soils across China	37
Editorial Board	36
Pull-out characteristics of herbaceous roots of alfalfa on the loess in different growth stages and their impacts on slope stability	36
Evaluation of nutrient spatial distribution and heavy metal pollution improvement in small-scale farmland under the action of biochar and microbial organic fertilizer	36
Prediction of soil organic matter using VNIR spectral parameters extracted from shape characteristics	36
Response of soil organic carbon stock to land use is modulated by soil hydraulic properties	36
The effects of fine roots and arbuscular mycorrhizal fungi on soil macropores	36
Assessing the impact of soil shrinkage and pore size dynamics on rice crop yield in expansive clay soils	35
Residual effects of phosphogypsum rates and machinery traffic on soil attributes and common-bean (Phaseolus vulgaris) yield in a no-tillage system	34
Integration of tillage indices and textural features of Sentinel-2A multispectral images for maize residue cover estimation	34
Ammonia-oxidizing bacteria are the primary N2O producers in long-time tillage and fertilization of dryland calcareous soil	34
Evaluation of soil organic matter from integrated production systems using laser-induced fluorescence spectroscopy	34
Effects of nutrient fertilization and soil tillage on soil CO2 emissions in a long-term grassland experiment	34
Centennial scale temporal responses of soil magnetic susceptibility and spatial variation to human cultivation on hillslopes in Northeast China	33
Effects of gravel cover on the near-surface airflow field and soil wind erosion	33
Fungal necromass is vital for the storage of subsoil C after deep injection of compost	33
Aggregate pore structure, stability characteristics, and biochemical properties induced by different cultivation durations in the Mollisol region of Northeast China	33
Linking soil phosphorus fractions to associated microbial functional profiles under crop rotation on the Loess Plateau of China	33
Integration of Sentinel-1/2 and topographic attributes to predict the spatial distribution of soil texture fractions in some agricultural soils of western Iran	33
Impacts of straw return coupled with tillage practices on soil organic carbon stock in upland wheat and maize croplands in China: A meta-analysis	33
50 years of continuous no-tillage, stubble retention and nitrogen fertilization enhanced macro-aggregate formation and stabilisation in a Vertisol	33
Temperature sensitivity of soil respiration to elevated temperature and nitrogen availability	32
Long-term Conservation Agriculture increases sulfur pools in soils together with increased soil organic carbon compared to conventional practices	32
Spatiotemporal variation of soil water potential and its significance to water balance for a desert shrub area	32
Effects of crop residue on wind erosion due to dust storms in Hotan Prefecture, Xinjiang, China	32
Modeling soil texture and residue management effects on conservation agriculture productivity in Nepal	31
Effects of land use types and environmental factors on spatial distribution of soil total nitrogen in a coalfield on the Loess Plateau, China	31
Winter cover crops favor cereal crop in N competition against creeping thistle Cirsium arvense (L.) Scop	31
Enhanced microplastic retrieval efficiency from cultivated soil samples through optimized pre-treatment in density-based extraction	31
Depth-driven responses of soil organic carbon fractions to orchard cover crops across China: A meta-analysis	31
Does direct-seeded rice performance improve upon lime and phosphogypsum use?	31
Soil organic carbon, total nitrogen, available nutrients, and yield under different straw returning methods	31
A mathematical model for predicting the draft force of shank-type tillage tine in a compacted sandy loam	30
Assessment of soil water retention characteristics based on VNIR/SWIR hyperspectral imaging of soil surface	30
Combined measurement of roots, δ18O and δ2H, and a Bayesian mixed model capture the soil profiles of wheat water uptake in a deep loamy soil	30
Evaluation of bentleg and straight narrow point openers in cohesive soil	30
Fusion of Gamma-rays and portable X-ray fluorescence spectral data to measure extractable potassium in soils	30
Rotational horse grazing and dry weather maximize infiltration into soil macropores	30
Zeolite application coupled with film mulched drip irrigation enhances crop yield with less N2O emissions in peanut field	30
Physical, topological and hydraulic properties of an Oxisol under conservation practices: X-ray tomography imaging and pore-network simulation	29
Soil surface properties and infiltration response to crust forming of a sandy loam and silt loam	29
Effects of vibration parameters on the interfacial adhesion system between soil and metal surface	29
Prediction of water retention properties of French soils using the in situ volumetric water content at field capacity as single input data	29
Soil and management effects on aggregation and organic matter dynamics in vineyards	29
No-till farming and greenhouse gas fluxes: Insights from literature and experimental data	29
Effects of freeze-thaw cycles on consistency limits of soils amended with diatomite	29
Possibility of exogenous organic carbon input to increase global soil nitrogen supply potential: A meta-analysis	29
Does the duration of no-till implementation influence depth distribution of soil organic carbon, hydro-physical properties, and computed tomography-derived macropore characteristics?	29
Responses of freeze-thaw process and hydrothermal variations within soil profiles to the cultivation of forest and grassland in Northeast China	29
Short-term dynamic responses of soil properties and soil fauna under contrasting tillage systems	28
Short-term response on microstructure and soil organic matter characteristics after fertilization change in an Andic Anthrosol	28
Responses of soil aggregation and aggregate-associated carbon and nitrogen in black soil to different long-term fertilization regimes	28
Performance evaluation of a biomimetically designed disc for dense-straw mulched conservation tillage	28
The effects of no-tillage and conventional tillage on greenhouse gas emissions from paddy fields with various rice varieties	28
Spatial-temporal variation of soil organic matter decomposition potential in China	28
Mechanism of microbial inhibition of rainfall erosion in black soil area, as a soil structure builder	28
Optimization design and performance study of a subsoiler underlying the tea garden subsoiling mechanism based on bionics and EDEM	28
Assessment of soil vulnerability to erosion in different land surface configurations and management practices under semi-arid monsoon climate	28
Undecomposed litter mixed in the soil can increase interrill erosion on hillslopes: A laboratory study	28
Editorial Board	27
Response of soil microbial properties in the life cycle of potatoes to organic substitution regimes in North China	27
Assessing the effects of agricultural management practices and land-use changes on soil organic carbon stocks	27
Modeling compaction effects on hydraulic properties of soils using limited information	27
Effects of road- vs. field-recommended tyre inflation pressures and small variations in soil moisture content on traffic-induced soil compaction during seedbed preparation	27
Mechanical and biological chiseling impacts on soil organic C stocks, root growth, and crop yield in a long-term no-till system	27
Fate of atrazine in soybean (Glycine max L.) and corn (Zea mays L.) succession in Brazilian subtropical conditions	27
Investigating the relationships between soil and sugarcane attributes under different row spacing configurations and crop cycles using the state-space approach	27
Ratio of physical model parameters can retrieve aggregate size from different types of soil in cultivated regions	27
Carbon farming practices for European cropland: A review on the effect on soil organic carbon	27
Straw incorporation helps inhibit nitrogen leaching in maize season to increase yield and efficiency in the Loess Plateau of China	27
Editorial Board	27
Coupling of Hofmeister effect, electrolyte concentration, and mechanical composition in soil loss: Runoff simulation study	27
Adaptive regulation of microbial community characteristics in response to nutrient limitations under mulching practices across distinct climate zones	26
Potential of no-till agriculture as a nature-based solution for climate-change mitigation in Brazil	26
Identifying the best tillage system to maintain soil properties and crop yields after Conservation Reserve Program grassland conversion	26
Relative role of soil nutrients vs. carbon availability on soil carbon mineralization in grassland receiving long-term N addition	26

Glyphosate and AMPA dynamics during the transition towards conservation agriculture: Drivers under shallow groundwater conditions	25
Paddock-scale carbon and greenhouse gas budgets in the first year following the renewal of an intensively grazed perennial pasture	25
Soil potassium regulation by changes in potassium balance and iron and aluminum oxides in paddy soils subjected to long-term fertilization regimes	25
Optimizing drip irrigation with alternate use of fresh and brackish waters by analyzing salt stress: The experimental and simulation approaches	25
Macroscopic mechanical behavior and microstructural evolution of compacted loess in the Chinese Loess Plateau	25
Vertical distribution of soil water repellency in ortsteinic soils in relation to land use	25
Effects of subsoiling rotational patterns with residue return systems on soil properties, water use and maize yield on the semiarid Loess Plateau	25
Soil compaction in a new light: Know the cost of doing nothing – A cotton case study	25
Controlling enhanced surface runoff components as a result of a freezing-thawing cycle by inoculating soil bacteria and cyanobacteria	25
Winter wheat cover crop increased subsoil organic carbon in a long-term cotton cropping system in Tennessee	25
Best Management Practices to Alleviate Deep-Seated Compaction in Asparagus (Asparagus officinalis) Interrows (UK)	25
Soil organic carbon content and mineralization controlled by the composition, origin and molecular diversity of organic matter: A study in tropical alpine grasslands	25
Long-term effects of contrasting tillage systems on soil C and N pools and on main microbial groups differ by crop sequence	25
Spatial correlation of nutrients in a typical soil-hickory system of southeastern China and its implication for site-specific fertilizer application	25
Long-term mulched drip irrigation enhances the stability of soil aggregates by increasing organic carbon stock and reducing salinity	24
Crop residue management challenges, opportunities and way forward for sustainable food-energy security in India: A review	24
A systematic review of strategies for identifying and stabilizing dispersive clay soils for sustainable infrastructure	24
Effects of different tillage on morpho-physiological traits of dryland chickpea (Cicer arietinum L.)	24
Short-term morphological evolution of an ephemeral gully in the Dry-hot Valley of Southwest China	24
Effects of soil physical and chemical properties on phosphorus adsorption-desorption in fluvo-aquic soil under conservation tillage	24
Trade-offs between high yields and soil CO2 emissions in semi-humid maize cropland in northern China	24
Net field global warming potential and greenhouse gas intensity in typical arid cropping systems of China: A 3-year field measurement from long-term fertilizer experiments	24
Diverse feedstock’s biochars as supplementary K fertilizer improves maize productivity, soil organic C and KUE under semiarid climate	24
Variability in mollic epipedon thickness in response to soil erosion–deposition rates along slopes in Northeast China	24
Modeling soil erodibility and critical shear stress parameters for soil loss estimation	23
Low efficacy of different crop residue management on C and N stocks after five decades	23
Microbial attributes as structural quality index for physical health of an Oxisol under compaction levels	23
The PROMETHEE-GAIA: A multi-criteria decision-making method for identifying best conservation agricultural practices	23
Anisotropy of soil hydraulic properties induced by repeated machinery traffic in a Typic Argiudoll of the Argentinean Pampas Region	23
Evaluation analysis of the saturated paste method for determining typical coastal saline soil salinity	23
Evolution of the transport properties of soil aggregates and their relationship with soil organic carbon following land use changes	23
Effect of crop rotation diversity and windrow burning of residue on soil chemical composition under long-term no-tillage	23
Influence of inorganic and organic fertilizers on the performance of water-absorbing polymer amended soils from the perspective of sustainable water use efficiency	23
Structure liming reduces draught requirement on clay soil	23
Estimating the permeability of soils under different tillage practices and cropping systems: Roles of the three percolating pore radii derived from X-ray CT	23
Biochar rather than organic fertilizer mitigated the global warming potential in a saline-alkali farmland	23
Soil water, nutrient distribution and use efficiencies under different water and fertilizer coupling in an apple–maize alley cropping system in the Loess Plateau, China	23
Effects of long-term monocropping, rotation cropping, and fertilization on energy and fuel requirements for fall moldboard plowing in a clay-loam soil	22
Mapping the soil C:N ratio at the European scale by combining multi-year Sentinel radar and optical data via cloud computing	22
Soil gas diffusivity and pore continuity dynamics under different tillage and crop sequences in an irrigated Mediterranean area	22
Blended controlled-release nitrogen fertilizer with straw returning improved soil nitrogen availability, soil microbial community, and root morphology of wheat	22
Effects of long-term manure substitution regimes on soil organic carbon composition in a red paddy soil of southern China	22
Five years of conservation tillage and weed management in a rice-chickpea rotation of northern Gangetic Plains of India: Weed growth, yield benefits and economic profitability	22
Linkage between aggregate stability of granitic soils and the permanent gully erosion in subtropical China	22
Using nitrogen-loaded biochar for soil improvement to decrease applied nitrogen and stabilize rice yield under alternate wet-dry irrigation	22
Constraints on mineral-associated and particulate organic carbon response to regenerative management: carbon inputs and saturation deficit	22
Long-term gully dynamics over cropland in the black soil area of China based on systematic sampling	22
Divergent responses of phoD- and pqqC-harbouring bacterial communities across soil aggregates to long fertilization practices	22
Contrasting effects of different straw return modes on net ecosystem carbon budget and carbon footprint in saline-alkali arid farmland	22
Biochar application enhances microbial interactions in mega-aggregates of farmland black soil	22
A bionic profiling-energy storage device based on MBD-DEM coupled simulation optimization reducing the energy consumption of deep loosening	22
Improved soil organic matter monitoring by using cumulative crop residue indices derived from time-series remote sensing images in the central black soil region of China	22
Results of cone and piston pull-out tests for evaluation of clay-soil adhesion	22
Effect of soil supplementation with mineral-organic mixtures on the amount of maize biomass and the mobility of trace elements in soil	22
Effects of rainfall characteristics and contour tillage on ephemeral gully development in a field in Northeastern China	21
Comparing WEPP with USLE based models: The role of bare fallow runoff and soil loss plots	21
Editorial Board	21
Effects on soil nitrogen and plant production from land applying three types of biosolids to an agricultural field for three consecutive years	21
Effects of fallow and chemical fertilizer applications on soil carbon and nitrogen pools in North China Plain: Medium-term and long-term trends	21
Evaluation of the gully erosion susceptibility by using UAV and hybrid models based on machine learning	21
Effect of long-term tillage and cropping system on portion of fungal and bacterial necromass carbon in soil organic carbon	21
Supplemental irrigation in the humid Pampean region: Effects on soil salinity, physical properties, nutrients and organic carbon	21
Dynamics and composition of soil organic carbon in response to 15 years of straw return in a Mollisol	21
The effect of soil salt content and ionic composition on nitrification in a Fluvisol of the Yellow River Delta	21
High soil bacterial diversity increases the stability of the community under grazing and nitrogen	21
Editorial Board	21
Variability in soil characteristics in the field–bund transition area increases water loss potential in paddy fields	21
Fifteen-years of continuous application of organic materials improve the soil aggregation, organic carbon status and sustain the productivity of the basmati rice-wheat system	21
Assessing the impacts of climate change on crop yields, soil organic carbon sequestration and N2O emissions in wheat–maize rotation systems	20
Towards rapid analysis with XRF sensor for assessing soil fertility attributes: Effects of dwell time reduction	20
Soil depth mapping and its linkage to gully erosion rate prediction in granite areas of southern China	20
Soil organic matter pools response to perennial grain cropping and nitrogen fertilizer	20
No-till annual wheat increases plant productivity, soil microbial biomass, and soil carbon stabilization relative to intermediate wheatgrass in a Mediterranean climate	20
Soil profile carbon sequestration and nutrient responses varied with cover crops in irrigated forage rotations	20
Deep vertical rotary tillage mitigates salinization hazards and shifts microbial community structure in salt-affected anthropogenic-alluvial soil	20
Long-term land use and tillage influence on phosphorus species in Brazilian Oxisols: A multi-technique assessment by chemical P fractionation, 31P NMR and P K-edge XANES spectroscopies	20
Approximate analytical solution to equation for two-dimensional soil-water movement in ponding infiltration based on numerical simulation	20
The potential of crop residue recycling for sustainable phosphorus management in non-flooded rice-lentil system in alkaline soil	20
Spatial pattern and controlling factors of soil organic carbon density in a typical karst province, China	20
Soil-dwelling springtails as indicators of the efficiency of No-till technologies with different amounts of mineral fertilizers in the crop rotation on chernozem soils	20
Predicting and mapping soil magnetic susceptibility in an agro-pastoral transitional zone: Influencing factors and implications	20
From science to practice: The AGSUS protocol for monitoring and certification of sustainable soil management and carbon sequestration	20
Current limitations and future research needs for predicting soil precompression stress: A synthesis of available data	20
Soil mechanical reinforcement by the fibrous roots of selected rangeland plants using a large soil-root shear apparatus	20
Improvement in dryland crop performance and soil properties with multiple annual applications of lignite-derived humic amendment	20
Long-term green manuring enhances crop N uptake and reduces N losses in rice production system	19
Landslide-impacted soils recover faster biologically than chemically or physically, though recovery also varies with forest type in subtropical China	19
Mechanical and microscopic properties of soil according to the rate of increase in pore water pressure	19
An ice correction model for dielectric sensor to improve accuracy of soil water potential measurement in frozen soils	19
Remediation and mitigation measures to counteract orchard soil degradation by treated wastewater irrigation	19
Exploring biochar addition impacts on soil erosion under natural rainfall: A study based on four years of field observations on the Loess Plateau	19
High-molecular-weight dissolved organic matter enhanced phosphorus availability in paddy soils: Evidence from field and microcosm experiments	19
Dual-platform micromechanical characterization of soils: Oscillation shear rheometry and spherical indentation	19
Soil transportation due to harvesting of ginger and turmeric under tillage management practices	19
Response to “Geometric standard errors are multiplicative not additive” and erratum	19