Silt Loam Research Articles

Hydraulic and pore functions of differently textured soils modified by biochar from different parts of the mango plant

Studies that elucidate the likely differential impact of biochar produced from different parts of the same plant on soil functions and structure are scanty. Therefore, in this study, biochar made from 2 feedstocks: Mango Twig (B1) and Mango Branch (B2) were pyrolyzed at 550 ○C, and mixed with 2 differently textured substrates (silt loam – S and sandy loam –SD) at application rates of 0%, 3%, 4.5% and 6%, and uniformly prepared to a bulk density (BD) of 1.4 g cm−3. The substrates were subsequently subjected to standard procedures to characterize the affected water retention properties, air permeability, and saturated hydraulic conductivity (Ks). The results indicate marked differences in the impact of biochar types on the available water and water retention capacity, depending on soil texture. The significant main effect of the biochar type on Ks in silty loam and the plant available water capacity in sandy loam highlights the relevance of the selected part of the feedstock pyrolyzed. The optimum amount of biochar required to achieve a significant increase in soil water content was about 3% in both substrates, while air permeability and pore continuity were significantly altered at about 6% biochar amendment rate. Moreover, significant (P < 0.05) improvements in the saturated hydraulic conductivity were observed in the biochar-amended soil compared to the control. Air permeability decreased as the added biochar increased, while the air-filled pores increased at defined matric potential in all treatments. The improvement in soil functions was mostly due to the modification of soil structure parameters (pore size distribution (PSD) and pore continuity), due to increased meso pores concomitant with biochar additions; and greater changes were obtained with B1. The varied impact of the biochar types especially on the soil water retention, available water capacity, pore continuity, and hydraulic properties for the different soil textures showed that even the selected plant part affects the options to improve soil functions.

Thermal Conductivity of Frozen and Unfrozen Gas-Saturated Soils

Arctic permafrost often contains gas-saturated horizons. The gas component in freezing and frozen soils can exist under different pressures, which are expected to affect their properties and behavior. The effect of pore gas pressure on the thermal conductivity of frozen and unfrozen silt loam saturated with methane or carbon dioxide at pressures below the hydrate formation conditions is observed in the current study. The variable gas pressure and temperature conditions are simulated in a specially designed pressure cell, which allows thermal conductivity measuring in pressurized samples at positive and negative temperatures. The experiments using natural samples collected near the gas emission crater (Yamal Peninsula) show that thermal conductivity is sensitive to pore gas pressure even at high moisture contents. The thermal conductivity of methane-saturated soil becomes 4% and 6% higher in frozen and unfrozen samples, respectively, as the gas pressure increases from 0.1 MPa to 2 MPa. In the case of CO2 saturation, the respective thermal conductivity increase in frozen and unfrozen samples reaches 25% and 15% upon pressure change from 0.1 to 0.9 MPa. The results stimulate further special studies of the effects of gas type and pressure on the thermal properties of closed gas-saturated taliks, of which the pore pressure is increasing during freezing up.

Long-Term Effects of Single Application of Biochar on Physical and Hydrological Properties of Crosby Silt Loam Soil in Central Ohio, USA

Long-Term Effects of Single Application of Biochar on Physical and Hydrological Properties of Crosby Silt Loam Soil in Central Ohio, USA

Effectiveness of preemergence- and postemergence-applied oxyfluorfen in rice compared to current standards

Abstract Control of barnyardgrass is becoming increasingly difficult as plants evolve resistance to herbicides. ROXY oxyfluorfen-resistant rice (ROXY® Rice Production System) has been developed to provide an alternative mode of action for controlling barnyardgrass and other weeds. In 2021 and 2022, field trials were conducted at the Pine Tree Research Station near Colt, AR; the Northeast Research and Extension Center in Keiser, AR; and the University of Arkansas Pine Bluff Small Farm Research Center near Lonoke, AR, to determine the level of weed control and crop tolerance following oxyfluorfen applied preemergence (PRE) or postemergence (POST) relative to herbicides currently labeled for use in rice crops. When applied post-plant PRE on silt loam soil, oxyfluorfen alone at 1,120 and 1,680 g ai ha−1 resulted in barnyardgrass control comparable to that of clomazone applied alone at 336 g ha−1. Still, injury to rice was often greater than with clomazone, ranging from 20% to 45%. On clay soil, oxyfluorfen applied at 1,680 g ha−1 resulted in barnyardgrass control that was comparable to that of clomazone alone in both site-years at 3 wk after emergence but caused up to 18% injury to rice. When oxyfluorfen was applied at 560 to 1,680 g ha−1 at the 2-leaf rice growth stage, barnyardgrass control was ≥85% in three of four site-years 1 wk after treatment. However, injury to rice ranged from 38% to 73% for the rates evaluated. Propanil caused the greatest injury by a herbicide currently labeled for use in rice at 34%. Oxyfluorfen should be used as a post-plant PRE herbicide rather than a POST herbicide due to the injury that occurred after a POST application. The data indicate that if used as a PRE herbicide, oxyfluorfen should be applied at 560 g ha−1 to reduce the injury that occurred on silt loam and clay soils.

Soil health, microbial communities, and annual ryegrass yield under contrasting management practices

AbstractBiological indicators are often used to evaluate the effect of management practices on soil health. However, determining which indicators can detect changes in soil health after implementation of conservation practices and how these indicators relate to plant growth in grass seed production systems remains unclear. The goal of this study was to explore the relationships between management practice history, soil health metrics, plant growth, and soil microbial communities in annual ryegrass grown under greenhouse conditions. Soils were collected from 12 annual ryegrass [Lolium multiflorum (L.) Husnot] fields managed under conventional (till/bale) or conservation (no‐till/full straw) management practices, with three silt loams and three silty clay loams collected for each practice. Annual ryegrass was grown for 5 months on each of the 12 soils in a greenhouse. Soils with a history of conservation management improved the majority of the carbon cycling‐related metrics for the silt loam soils. Management practices had no effect on seed yield, however, conservation management significantly improved aboveground biomass in silty clay loam soils. Contrasting management practices resulted in distinct microbial communities, making them sensitive indicators of changes in soil conditions. Soil health and plant metrics were positively associated with the microbial communities in soils under conservation management. Total C and organic matter were positively correlated to plant parameters in silt loams, while few indicators were correlated to plant metrics in silty clay loams. These results highlight the complex interplay between microbial communities, soil health, and plant growth and the importance of considering inherent soil properties like texture.

Effect on Yield, Attribute Character and Economics of Various Treatment in Wheat (Triticum aestivum L.) Crop

A field experiment was conducted at Agronomy Research Farm of Narendra Deva University of Agriculture &amp; Technology, Narendra Nagar (Kumarganj), Faizabad (U.P.) during Rabi season of 2014-15 to study the response of late sown wheat varieties to doses of nitrogen application. Eighteen treatment consisted of six doses of nitrogen (0, 40, 80, 120, 160 and 200 kg N ha-1) and three varieties of wheat (PBW-373, HD-2327, and NW-1014). The experiment was carried out in Randomized Block Design R.B.D. (factorial) with three replications on silt loam having low organic carbon (0.37%), nitrogen (194.25 kg ha-1), medium in phosphorus (15.25 kg ha-1) and potassium (250.25 kg ha-1). All the growth and yield parameters increased significantly with increasing nitrogen doses up to 200 kg ha-1. The maximum net return (Rs. 40712ha-1) was obtained at 160 kg N ha-1 with NW-1014 and B:C ratio 1.19 followed by same variety at 120 kg N ha-1. Thus it may be concluded that application of 160 kg N ha-1 proved appropriate levels of nitrogen for exploration of the yield potential of the late sown wheat varieties. Among the varieties NW-1014 was found the most suitable for cultivation under late sown condition for Northern East Plain zone.

Sugarcane mill mud-induced putative host (soybean (Glycine max))-rhizobia symbiosis in sandy loam soil.

Domestic production of controlled-release, compost-based, and microbe-enhanced fertilizers is being expanded in the U.S. as a part of rural development. Sugarcane mill mud is a sterilized (≈90°C) agricultural byproduct in surplus that has received interests as a soil amendment in several Southern states, because of its high phosphorus and organic carbon contents. Addition of mill mud to sandy loam significantly increased the nodule formation compared to fertilized and unfertilized controls. Mill mud addition also resulted in pod yields similar to the fertilized control. Though not found in mill mud itself, mill mud additions correlated with an increase in soil Rhizobia as determined by deep 16S rRNA gene sequencing. We hypothesize that Firmicutes in sterilized mill mud induced Rhizobia that in turn enhanced soybean (Glycine max) growth. Collectively, mill mud enhanced the plant growth promoting bacteria when applied to a silt loam, although the relative influence of mill mud-derived bacteria, organic carbon, and nutrients is yet to be determined.

Model of Soil Particles to Investigate Shear Stress and Deformation in Silt Loam and Silt Clay Soil Using Finite Element Method

Model of Soil Particles to Investigate Shear Stress and Deformation in Silt Loam and Silt Clay Soil Using Finite Element Method

Effects of conservation practices on rainfed maize yield, furrow water infiltration, and soil moisture for surface sealing loam soils in the Yazoo‐Mississippi Delta

AbstractDecades of intense tillage have created the problem of surface sealing in loam soils across the Mid‐South United States and beyond. These soils exhibit low organic matter, poor aggregate stability, and ultimately low infiltration rates that decrease rainfed crop productivity and increase irrigation water demand. This research quantified the effects of soil management practices on rainfed maize (Zea mays L.) yield, furrow water infiltration, and soil moisture in Commerce very fine sandy loam and silt loam near Stoneville, MS. The six treatments included conventional tillage (CT), cereal rye (CR; Secale cereale L.), furrow diking (FD), no‐till (NT), polyacrylamide (PAM), and subsoiling (SS). No other treatment achieved a significantly higher maize grain yield than the CT control treatment in both years consistently. Single‐ring infiltrometer results indicated no significant differences among CT, CR, PAM, and SS in 2022 and between CT and NT in 2021. Neutron attenuation found that total soil water within the top 1 m was not significantly different among CT, FD, and SS on any of the eight measurement dates throughout the 2022 maize reproductive period. However, soil moisture was numerically lower for FD in the late reproductive stages. These findings suggest that environmental factors and other agronomic operations may counteract conservation practices, limiting their effectiveness at reducing irrigation requirements to mitigate groundwater depletion in the Mississippi River Valley Alluvial Aquifer.

Sustainable ecosystem management based on optimal water allocation and equity measures

Abstract Allocation of water resources is an interesting research topic and one of the main challenges of arid regions. From the point of view of agriculture, this issue is closely related to ecological balance, economic development and social stability. Therefore, fair, efficient and sustainable allocation of water resources for users and decision-making is essential. This paper presents a dynamic stochastic programming model that predicts soil moisture content in a growing season based on data collected from an experimental farm. The model included three types of loam soil, silt loam and clay loam with three treatments of irrigation intervals of 3, 7, 10 and 14 days and three amounts of water allocation with three replications. The proposed framework was evaluated with two criteria of spatial and temporal equity, and the optimal water allocation was analyzed based on this criterion. The results showed that the criterion of temporal equity for loam soil with 7-day irrigation intervals is more than twice that of 14-day irrigation intervals. In addition, the depth of irrigation has had the greatest impact on the fluctuations of the criterion of equity in water allocation in the growing season.

Effect of varying sand percentage in sheath of nature-based capillary barriers composite on water storage capacity and okra growth in arid climate

Agricultural development in many arid countries including Oman is limited due to water scarcity which is currently exacerbated with increasing demand due to rapid population growth, economic development, and mismanagement of water resources. Impact of climate change is expected to adversely impact the water resources. Therefore, finding new efficient, environmentally friendly, and affordable water-saving techniques in agronomy is a necessity for achieving agricultural sustainability. Irrigation water can be saved by creating capillary barriers (CB) to unsaturated moisture flow. In this study, a “nature-inspired capillary barrier design” called hereafter as Smart Capillary Barrier (SCB) (mosaic of fine textured blocks, made of silt loam, and sandy sheath surrounding the blocks) was tested in series of field experiments with soil columns and pots. We investigated the effect of the percentage of sand of the sheath on water storage capacity of the SCB blocks and growth of okra (Abelmoschus esculentus L.) under deficit irrigation. Three proportions of sand to silt loam (sand%:silt loam%) in the sheaths were used in this study, SCB-25 (25:75%), SCB-50 (50:50%) and SCB-75 (75:25%). Our results show that increasing the percentage of sand in the designed and constructed SCB composite reduces evaporative and drainage water losses and therefore increases the water storage capacity of the blocks. Our SCB-75 attains 1.7–1.3 smaller drying rate than that for SCB-25 and SCB-50, respectively. Therefore, this composite had higher water saving capacity than a homogeneous soil (no capillary barrier) and a soil with a standard sand mulch (coarse soil overlies fine soil). The study found that using SCB composite did not consistently have a clear effect on the growth of okra plants at all stages of their development. However, during the development stage, using SCB-75 resulted in significantly higher dry biomass of the plants compared to using a homogeneous soil (the control). Additionally, during the initial stage of fruit yield, using SCB-75 also resulted in significantly higher fruit yield compared to using a homogeneous soil. Application of our SCB composite is a promising approach for saving water in desertic farming.

Validating coupled flow theory for bare‐soil evaporation under different boundary conditions

AbstractEvaporation from bare soil is an important hydrological process and part of the water and energy balance of terrestrial systems. Modeling bare‐soil evaporation is challenging, mainly due to nonlinear couplings among liquid water, water vapor, and heat fluxes. Model concepts of varying complexity have been proposed for predicting evaporative water and energy fluxes. Our aim was to test a standard model of coupled water, vapor, and heat flow in the soil using data from laboratory evaporation experiments under different boundary conditions. We conducted evaporation experiments with a sand and a silt loam soil and with three different atmospheric boundary conditions: (i) wind, (ii) wind and short‐wave radiation, and (iii) wind and intermittent short‐wave radiation. The packed soil columns were closed at the bottom (no water flux) and instrumented with temperature sensors, tensiometers, and relative humidity probes. We simulated the evaporation experiments with a coupled water, vapor, and heat flow model, which solves the surface energy balance and predicts the evaporation rate. The evaporation dynamics were predicted very well, in particular the onset of stage‐two evaporation and the evaporation rates during the stage. A continuous slow decrease of the measured evaporation rate during stage‐one could not be described with a constant aerodynamic resistance. Adding established soil resistance parametrizations to the model significantly degraded model performance. The use of a boundary‐layer resistance, which takes into account the effect of point sources of moisture, improved the prediction of evaporation rates for the sandy soil, but not for the silt loam.

Enhancing Density Prediction of Agricultural Land Soil through Void Area Curve Analysis

Thresholding is a digital image analysis method used to distinguish objects from the background in images and it is mainly used for void and density analysis in soil. It is important to select an appropriate thresholding method because the accuracy of void analysis can vary significantly depending on the threshold value; however, there is currently no standard for soil density analysis. Therefore, this study proposes an image analysis method for soil density prediction. The experimental process involved collecting soil samples from agricultural lands, encompassing various soil textures including sandy loam, loam, silt loam, and silty clay loam. These samples were then meticulously prepared under controlled conditions, ensuring a comprehensive range of dry densities and water content levels. Digital images of the soil samples were acquired using a Canon EOS100d camera, employing a high-resolution setup that provided precise imaging capabilities. The porosity of the soil image is calculated by various thresholding methods. Based on the analysis results, we propose a void area curve, a new approach that can be applied to the soil density prediction. The void area curve is the relationship curve between the threshold value and porosity of the soil image. The standard deviation of the void area curve showed a high correlation with the dry density of the soil. The standard deviation of the void area curve was used to predict the dry density under various soil texture and water content conditions, and the RMSE was 0.037 t/m3. The method of estimating soil density with the standard deviation of the void area curve can be used more generally than the existing analysis method because there is no need to select a specific threshold value.

Tillage homogenizes soil bacterial communities in microaggregate fractions by facilitating dispersal

Soil aggregation physically protects soil organic matter and promotes soil carbon persistence through microaggregate formation and organo-mineral associations. Tillage is a ubiquitous disturbance to arable soil that disrupts aggregation, thus affecting microbial resource availability, soil microhabitat conditions, and microbial interactions. We investigated how tillage affects bacterial community composition of soil microaggregate fractions (53–250 μm), specifically the free microaggregate fraction in bulk soil and the occluded microaggregate fraction within macroaggregates, using two long-term tillage vs. no-tillage experiments in southern WI, U.S., that represent two different silt loam soils (Alfisol and Mollisol). We applied 16S rRNA gene amplicon sequencing to characterize the effects of tillage on microaggregate bacterial communities by relating compositional changes and ecological community assembly patterns to various tillage-driven changes in the soil environment, including aggregate size distribution and carbon content. Tillage homogenized soil bacterial communities, as quantified by increased compositional similarity at both within-plot and between-plot scales, and community assembly was increasingly influenced by homogenizing dispersal with tillage. We did not identify major distinctions between bacterial communities of the free and occluded microaggregate fractions, thus highlighting how soil microaggregates readily shift between these operationally defined fractions in temperate annual cropping systems, where the soil environment is subject to drastic seasonal changes that are exacerbated by tillage. By identifying influential community assembly processes and analyzing communities in microaggregate fractions, we improve our understanding of the microbial response to soil disturbance, and thus the potential mechanisms through which disturbances like tillage affect soil carbon persistence.

Unlocking Agricultural Potential: Soil Structure and Analysis in a Limestone Mining Site Using Artificial Intelligence and USDA Classification

This study aimed to investigate the soil structure and agricultural potential of a research area located within a limestone mining site. The sampling process was conducted using sieve analysis and hydrometer tests on soil samples collected from six points within a 1-hectare area. The results revealed that the soil structure was Silt Loam, with 48%-64% consisting of Silt, 30%-50% sand, and 1%-6% clay. The data were then classified using USDA classification to identify the potential agricultural uses of the soil. Additionally, artificial intelligence was used through ArcGIS software to prepare a regional map and analyze soil properties. The study findings can serve as a valuable reference for agro-industry activities and land-use planning in the area.

Determination of Physicochemical Properties of Spent Engine Oil Polluted Soils Sites in Bali and its Environs, Taraba State, Nigeria

The present study aimed to investigate the physicochemical properties of spent engine oil polluted soil sites in Bali and its Environs, Taraba State, Nigeria. The result revealed the particle size distribution show that polluted soils were categorized by relatively high sand content ranging from 30.2 – 80.2 %, and an average mean 58.08 %; silt 15.3-65.1 % (34.88 %) and clay 3.0-11.6 % (7.04 %). The textural descriptions of soils from the study sites were mostly sandy loam. The soil samples from Bali 1, Bali 2, Maihula, Garba Chede and Gazabu were of varying texture; sandy loam, loamy sand, sandy loam, silt loam and loamy respectively. The physicochemical properties of the soil samples show the temperature ranges from 31.33 - 31.58 0C with Garba Chede and Bali 2 having the lowest and highest respectively. The pH range between 5.6 - 6.2 with Bali 1 and Bali 2 having the lowest and highest respectively. The result shows that the soil samples are all slightly acidic. Samples from Bali 2 and Bali 1 were discovered to be the highest with 69.5% and least with 68.1% respectively for humidity. The electrical conductivity of the soil range is 1027.25 µs/cm and 474.0 µs/cm with Garba Chede and Gazabu having the highest and lowest respectively. The amount of total dissolved solid range is 14.5 – 30.0 mg/L making Gazabu have the highest lowest and Garba Chede the highest. Bali 1 and Bali 2 have the Cu range values of 3.500 and 1.080 ppm, showing the highest and lowest respectively. Pb and Cr were not detected in the samples.

Contrasted effects of biochar application on interrill erosion depending on age, application rate and soil type

Besides its carbon sequestration potential, biochar can mitigate soil erosion through improved soil structure. However, the short-term erosion mitigation potential of biochar remains debated, while it is unknown in the long-term. The aim of this study was therefore to determine the impact of biochar application on soil interrill erosion parameters, and to assess whether this impact depends on biochar age and application rate for two different soils. To assess the short-term impact, experiments were performed with topsoil from cultivated silt loam and sandy loam soils enriched with fresh biochar at rates of 1% w/w (13.5 T ha−1) and 2% w/w (27 T ha−1). In the same fields, soil from former kiln sites containing 19th century-old biochar was used to assess the long-term impact. Aggregate stability was measured according to Le Bissonnais (1996). Runoff and soil loss were measured in a flume under simulated rainfall. On the sandy loam soil, old biochar and 2% fresh biochar improved aggregate resistance to slaking. For the same soil, old biochar increased the time to runoff by 55%. For both study sites together, old biochar reduced the final runoff rate by 48%, whereas 2% fresh biochar reduced the final soil loss rate by 39%. Overall, the positive impact of biochar on interrill erosion was clearly more pronounced for the sandy loam soil compared to the silt loam soil. These contrasted results call for further studies across a wider variety of soil types.

Plot Layout Method of Field Experiment for Wheat with Border Irrigation Based on Soil Water Content Heterogeneity

The objective of this research was to improve the accuracy and representativeness of experimental plot studies by determining the optimum plot area and replication number for winter wheat with border irrigation. Considering the spatial distribution of soil water content, the border effect in relation to crop growth, and the lateral seepage of soil water, we sought to study and optimize the area and specifications of irrigation experiment plots with different levels and replicates. The results show that the experimental irrigation plot consisted of two parts—the core area and the guard area. The most suitable area for the experiment plot core area, with a single level and without replicates, was 60–80 m2. The core experimental area can be arranged with two replicates per 40 m2, with differences in soil moisture content between the treatments reaching more than 15% at the two experiment levels. Each plot comprised two replicates, or if they were 20 m2, then they contained three replicates; when the soil moisture contents differed between 10% and 15%, the area of each replicate plot was 80 m2, comprising two replicates, or 30 m2 with three replicates. When the difference in soil moisture content between the treatments exceeded 15% with the three experimental levels, the area of each plot was 30 m2 and they contained two replicates, or 20 m2 containing three replicates; at differences of 10% to 15%, each replicate plot was 50 m2 containing two replicates, or 30 m2 with three replicates. The experimental plots were rectangular, with irrigation furrows dug lengthwise; therefore, the plots had aspect ratios between 7:1 and 5:1. The width of the buffer area was over 60 cm. The effect of the border on plant height and LAI for winter wheat primarily emerged with one to three rows (20–60 cm) at the jointing stage, while the effect on grain yield and biomass in winter wheat mainly emerged with one to two rows (20–40 cm). The conclusions of this research will inform the development of surface irrigation methods for silt loam in northern Henan, as a reference for optimizing experiment plots employing border irrigation with different soil textures.

A modified approach to model the hydrological effects of living moss and fallen leaves on carbonate-derived laterite in karst forests

Due to recent vegetation restoration projects in karst mountainous areas of China, the living moss and litter layer play important roles in controlling soil water dynamics in karst forests. However, the underlying mechanisms of the effects of moss and the litter layer on soil water dynamics are still controversial. To explore the underlying mechanisms, we employ the CoreKarHydro model, capturing soil water content dynamics driven by evapotranspiration and influenced by living moss and fallen leaves. This model integrates surface changes' impact on evapotranspiration, categorizing the domain into: no cover (S), moss (SM), pine needles (SP), and both (SMP). Model validation employs the MOCOM-UA method, using diverse metrics (RMSE, R2, ACC, ED, KGE and SA) against lysimeter data with 4 moss biomass levels and 3 pine needle biomass levels. The results indicated: 1) The CoreKarHydro model exhibited reliable performance in simulating the soil water content curves, with an RMSE ranging from 1.49% to 4.21% and an R2 value ranging from 0.60 to 0.77. 2) Among the factors that influenced evaporation processes, soil hydraulic properties emerged as the most sensitive parameters, whereas the properties of the moss and pine needles played a relatively lesser role. 3) The impact of moss cover on evaporation processes varied depending on the soil texture and the stage of evaporation. Moss cover reduced evaporation loss in 8 out of 12 soil textures (loamy sand, loam, silt, silt loam, sandy clay loam, silty clay loam, sandy clay, and silty clay). On the other hand, moss cover increased evaporation loss in 4 out of 12 soil textures (sand, sandy loam, clay loam, and clay). This study contributes to the understanding of the mechanisms of coupled soil-moss(litter)-hydrological processes in karst areas.

First Report of Charcoal Rot Caused by Macrophomina phaseolina on Hemp (Cannabis sativa) in Missouri.

Charcoal rot, caused by Macrophomina phaseolina, is abundantly present in the soil and has been reported as pathogenic to both soybean and corn, as well as numerous other hosts, including hemp grown for fiber, grain, and cannabinoids (Casano et al. 2018; Su et al. 2001). Hemp (Cannabis sativa) production in Missouri was a relatively new addition to the 2021 growing season. Charcoal rot was reported in Reynolds, Knox, and Boone counties in Missouri from commercial and experimental fields. One of the fields in question experienced heavy disease pressure and had an uneven stand loss, but the total loss was estimated at approximately 60% of the field and was attributed to charcoal rot. Charcoal rot signs and symptoms, microsclerotia on the lower stem and root tissue, wilting and stem discoloration, were observed on a majority of the hemp plants received at the University of Missouri Plant Diagnostic Clinic in July and late Fall of 2021, including samples from Bradford Research Farm in Boone County and Greenley Research Center in Knox County. Root and crown tissue from the hemp plants from the Greenley Research Center were cultured onto acidified potato dextrose agar (APDA). Macrophomina phaseolina and other fungi grew from the plated tissue after about three days of incubation at room temperature. Macrophomina phaseolina was confirmed based on the presence of melanized hyphae and microsclerotia (Siddique et al. 2021). The microsclerotia were black, round to ovoid shaped and ranged from about 34-87 µm (average 64 µm) in length and 32-134 µm (average 65 µm) in width (n = 44). A single-hyphae isolation from a putative M. phaseolina isolate was conducted to obtain a pure culture. The M. phaseolina culture from the Greenley Research Center was used to complete Koch's postulates of charcoal rot on four hemp cultivars. Sterilized toothpicks were added to pure cultures of M. phaseolina on APDA and incubated at room temperature for one week to allow for colonization and for use in greenhouse inoculation. Four hemp cultivars (Katani, Grandi, CFX-2, and CRS-1) were grown in a sterilized silt loam for three weeks in a greenhouse. About four plants per cultivar were grown for inoculation and one plant per cultivar was used as a control. The plants were inoculated with the M. phaseolina colonized toothpicks that were gently rubbed onto stem tissue and subsequently inserted into the soil at the stem. For six weeks, the plants were kept in greenhouse conditions of 25°C with a 12-hour light and dark cycle and were watered when soil appeared dry. Plants were kept in a loosely sealed container constructed from wood and vinyl sheeting to minimize cross contamination with other plants grown in the same greenhouse. Plants were monitored weekly for charcoal rot symptoms. Symptoms that resembled charcoal rot, wilting and microsclerotia on the lower stem, were present on inoculated plants after about four weeks and symptoms were not present on the control plants. Isolates resembling M. phaseolina in culture were recovered from symptomatic plants; therefore, Koch's postulates were successfully fulfilled and the fungus was recovered from the inoculated plants. DNA was extracted from the pure cultures of both the initial isolate and the isolate obtained from Koch's postulates using GeneJet Plant Genomic DNA Purification Kit (Thermo Scientific, California, USA) and the internal transcribed spacer (ITS) region of ribosomal DNA including ITS1, 5.8S, and ITS4 regions were amplified using universal primers ITS1 and ITS4 (White et al. 1990). The ITS region was sequenced and compared to reference sequences in GenBank by BLAST analysis. Recovered isolates (GenBank accession no. OQ455934.1) showed closest sequence similarity (100%) to M. phaseolina accession number GU046909.1. Little is known about the life cycle, growth conditions, and possible inoculum buildup in the soil in hemp in Missouri. In addition, M. phaseolina is a known pathogen of corn and soybean and effective management strategies are challenging for these crops as well due to the broad host range of the pathogen. Cultural management practices, such as crop rotations to reduce inoculum in the soil and closely monitoring for symptoms, may help reduce the severity of this disease.