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Cover crops (CCs) are known to influence water infiltration just prior to termination, but their effects on water infiltration over time are less known. This study investigated the influence of CCs on in situ water infiltration just prior to CC termination (during April) and again 2 mo after CC termination (during June). The multi‐species mixture of CCs used included hairy vetch (Vicia villosa Roth.), crimson clover (Trifolium incarnatum L.), winter wheat (Triticum aestivum L.), winter peas (Lathyrus hirsutus L.), oats (Avena sativa L.), triticale (Triticale hexaploide Lart.), barley (Hordeum vulgare L.), and flax (Linum usitatissimum L.). Infiltration rates were measured using double‐ring infiltrometers during April and June. The physically based Parlange and Green‐Ampt models were fitted to measured infiltration data. Cumulative infiltration was 52% higher in April and 68% higher in June under CC compared with no cover crop (NC) management. During April, the Parlange model–estimated saturated hydraulic conductivity parameter (Kdr) was 245% higher under CC compared with NC management. During the same sample period, the Green‐Ampt–estimated Kdr parameter was 383% higher under CC compared with NC management. The higher sorptivity parameter and lower antecedent water content under CC compared with NC management during both measurement periods suggest that CCs can significantly improve water infiltration into the soil, and this effect can last for up to 2 mo after CC termination. Core Ideas: Cover crop reduced antecedent water content before and after termination.Parlange and Green‐Ampt models provided good fits for measured infiltration data.Cover crop increased quasi‐steady infiltration rate 2 mo after termination.Cover crop increased in situ measured saturated hydraulic conductivity.Cover crop management can improve water infiltration 2 mo after termination. [ABSTRACT FROM AUTHOR]

Soil hydraulic properties influence water and nutrient availability as well as environmental sustainability, and these properties vary across several landscape positions. This study investigated the spatial variability and fractal characterization of soil hydraulic properties across five slope positions: summit, shoulder, back, foot, and toe slopes. Triplicate soil samples (0–18 cm) were collected from each slope position from a pasture field planted to tall fescue [Festuca arundinacea Schreb., syn. schendonorus arundinaceus (Schreb.) Dumort., nom. cons.]. Soil bulk density (ρb); saturated hydraulic conductivity (Ksat); water retention at 0, −33, and −1,500 kPa soil water matric potentials; soil organic carbon (SOC); and various pore sizes (macropores [>1,000 μm], mesopores [10–1,000 μm], and micropores [<10 μm]) were analyzed. Results show that SOC was 26% higher, while ρb was 10% lower at the toe slope compared with the summit. Similarly, Ksat values were 3, 9, 16, and 2% greater at the toe slope compared with the summit, shoulder, back, and foot slopes, respectively. Semivariogram analysis showed that the gaussian isotropic model provided the best fit (R2 >.99) for hydraulic properties across all slope positions. The range of spatial variability of soil hydraulic properties was between 5.60 and 123.00 m at all slope positions. The fractal dimensions of soil hydraulic properties across all slope positions ranged from 0.784 to 1.966. Soil hydraulic properties were similar at the foot and toe slopes, which might favor improved crop productivity at these slope positions. Core Ideas: Soil hydraulic properties vary spatially along a catena.Range of spatial variability was different for hydraulic properties along a catena.Saturated hydraulic conductivity was highest at the toe slope compared with other positions.Spatial autocorrelation of hydraulic properties depends on intrinsic soil properties.As the soil dries, most soil hydraulic properties tend to be less self‐similar. [ABSTRACT FROM AUTHOR]

Soil thermal properties can influence several soil processes important for crop productivity. This study was conducted to evaluate the influence of cover crops on selected soil physical and thermal properties. The field site was set up using a randomized complete block design with two levels of cover crops (cover crops versus no cover crops). The soil thermal properties measured included thermal conductivity, volumetric heat capacity, and thermal diffusivity. The physical properties of the soil studied included bulk density, volumetric water content, total pore spaces, water-filled pore spaces, air-filled pore spaces, gas diffusion coefficient, and soil pore tortuosity factor. Soil organic carbon was also measured. The results showed that soil organic carbon was 26% higher under cover crops management compared to no cover crops management. Thermal conductivity and thermal diffusivity were positively correlated with soil bulk density and these properties (soil thermal conductivity and soil thermal diffusivity) were higher under no cover crops management compared with cover crops management probably due to the proximity between soil particles. The volumetric heat capacity was positively correlated with soil organic carbon, with soil organic carbon being higher under cover crops management compared with no cover crops management. Results from the current study show that cover crops can improve soil physical and thermal properties which may benefit crop productivity as corroborated via laboratory measurements. [ABSTRACT FROM AUTHOR]

Soil thermal properties play an important role in crop productivity, but the influence of a multi-species cover crops (CCs) on these properties are not well understood. This study evaluated the effects of no-till CCs (winter wheat [ Triticum aestivum L.], crimson clover [ Trifolium incarnatum L.], triticale [ Triticale hexaploide Lart], hairy vetch [ Vicia villosa ], oats [ Avena sativa ], and cereal rye [ Secale cereale L.]) on soil physical (bulk density [BD], and volumetric water content [ϴ] at 0, −33, and −100 kPa soil water pressures) and thermal properties (thermal conductivity [λ], volumetric heat capacity [ C V ], and thermal diffusivity [ D ]). Soil samples were collected just before CC termination at 0–10, 10–20, and 20–30 cm depths from CC and no cover crop (NC) plots during 2021 and 2022. Results showed that, after 2 years, CCs reduced BD by 17% and increased ϴ at 0, − 33, and − 100 kPa soil water pressures by 23%, 25%, and 28%, respectively relative to NC management. Thus, λ under NC was 16%, 19%, and 20% higher at 0, − 33, and − 100 kPa soil water pressures, respectively, compared with CC management. Conversely, C V was 17%, 14%, and 15% higher under CC compared with NC management at 0, − 33, and − 100 kPa soil water pressures. Regression analysis further demonstrated that while plant root was the most important factor influencing λ at saturation, ϴ played the greatest role in λ at other soil water pressures. Expectedly, ϴ was the most important factor influencing C V at all measured soil water pressures. Conclusively, no-till CCs can improve laboratory measured soil thermal properties by moderating heat transfer. • CCs reduced BD and increased ϴ at measured soil water pressures relative to NC. • NC management significantly increased λ, while CC management improved C V. • At saturation, plant roots determined λ, while ϴ influenced λ at lower soil water pressures. • ϴ was the most important factor influencing C V at soil water pressures measured. • Multi-specie CCs can reduce extreme heat transport in a changing global climate. [ABSTRACT FROM AUTHOR]

Heat transport is an important factor that can influence the soil environment. The objective of this study was to determine if perennial biofuel and cover crops could alter soil thermal properties. Experimental treatments included two levels of cover crops (cover crops [CC] vs. no cover crops) [NC], collectively called row crops (RC) and two biofuel crop treatments. Cover crops used included cereal rye (Secale cereale L.), hairy vetch (Vicia villosa subsp. villosa) and Austrian winter pea [Pisum sativum subsp. arvense (L.) Asch. & Graebn]. The two biofuel treatments included perennial biofuel crops (PB): giant miscanthus (Miscanthus x giganteus J.M. Greef & Deuter ex Hodkinson & Renvoize) and switchgrass (Panicum virgatum L.). Soil samples were collected at 10-cm depth increments from the soil surface to a depth of 30 cm. Soil thermal properties (thermal conductivity [λ], volumetric heat capacity [CV], thermal diffusivity [D]) and volumetric water content (θ) were determined at 0, -33, -100 and -300 kPa soil water matric potentials. Additionally, bulk density and soil organic C (SOC) were determined. Results showed that PB had 11% higher CV at saturation, probably because they had significantly higher θ and SOC than RC management. Cover crops had 13% higher CV at saturation probably because they had significantly higher θ and SOC than no cover crop management. Row crops had significantly higher λ and D than PB. The results from the current study imply that CC and PB can change soil thermal properties by reducing λ and D and increasing CV under laboratory conditions. [ABSTRACT FROM AUTHOR]

Researchers assessed the spatial distribution of soil chemical properties and nutrients at four depths in a clay loam soil cropped to corn and soybean at Freeman farm of Lincoln University. Soil samples were taken at depths of 0–10, 10–20, 20–40, and 40–60 cm in a 4.05-ha field and analyzed for acidity or basicity (pH), cation exchange capacity (CEC), total carbon (TC), organic matter (OM), base saturations on the CEC, ammonium (NH4+), nitrate (NO3−), phosphorus (P), potassium (K), calcium (Ca), sulfur (S), magnesium (Mg), sodium (Na), manganese (Mn), copper (Cu), iron (Fe), and zinc (Zn). Results showed that coefficients of variation (CV) ranged between 5 and 30%, except for TC, NO3−, and Zn, which had greater CVs. Soil chemical properties and nutrients responded to exponential, linear, Gaussian, and spherical variogram models with nugget-to-sill ratios ≤ 1.0 and effective ranges from 4 to 56 m. Fractal analysis showed that CEC in all depths belonged to the 1.99 ≥ D3 ≥ 1.90 group, which suggests great disorder and antipersistence in the spatial structure. [ABSTRACT FROM PUBLISHER]

We assessed the spatial variability of soil physical properties in a clay-loam soil cropped to corn and soybean. The study was conducted at Lincoln University in Jefferson City, Missouri. Soil samples were taken at four depths: 0-10 cm, 10-20, 20-40, and 40-60 cm and were oven dried at 105°C for 72 hours. Bulk density (BDY), volumetric (VWC) and gravimetric (GWC) water contents, volumetric air content (VAC), total pore space (TPS), air-filled (AFPS) and water-filled (WFPS) pore space, the relative gas diffusion coefficient (DIFF), and the pore tortuosity factor (TORT) were calculated. Results showed that, in comparison to depth 1,means for AFPS, Diff, TPS, and VAC decreased in Depth 2. Opposingly, BDY, Tort, VWC, and WFPS increased in depth 2. Semivariogram analysis showed that GWC, VWC, BDY, and TPS in depth 2 fitted to an exponential variogram model. The range of spatial variability (A0) for BDY, TPS, VAC, WFPS, AFPS, DIFF, and TORT was the same (25.77 m) in depths 1 and 4, suggesting that these soil properties can be sampled together at the same distance. The analysis also showed the presence of a strong (⩽25%) to weak (>75%) spatial dependence for soil physical properties. [ABSTRACT FROM AUTHOR]

• Spatial variability of soil nutrients ranged from 5.8 to 71.0 m across the catena. • Soil nutrient elements tend to become self-similar at sampling distances greater than 71 m. • Autocorrelation tendency of nutrient elements ranged between 2.9 and 35.5 m. • Fractal analysis reveal the dependence of soil nutrients on dynamic soil properties. Soil nutrient elements influence crop productivity and environmental sustainability and they vary across several slope positions. The objective of the current study was to evaluate the spatial and fractal variability of selected soil macro- and micronutrient elements across five slope positions: summit, shoulder, back, foot, and toe slopes. Triplicate soil samples (0–18 cm) were collected from each slope position from a pasture field planted to tall fescue (Festuca arundinacea syn. schendonorus arundinaceus). Soil nutrient elements analyzed include phosphorus (P), potassium (K), nitrate N (NO 3 -N), iron (Fe), and manganese (Mn). Additionally, soil pH, bulk density (BD), and soil organic carbon (SOC) were determined. Results show that SOC was 26% higher, while BD was 10% lower at the toe slope compared with the summit. Similarly, NO 3 -N was 15, 16, 18, and 1% higher at the toe slope position compared with the summit, shoulder, back and foot slopes probably due to nutrient mobility with water flow. Semivariogram analysis showed that the gaussian isotropic model provided be best fit (R2 > 0.97) for all nutrient elements across all slope positions. The range of spatial variability (A 0) of nutrient elements was between 5.8 (K at the backslope position) and 71.0 m (P and Fe at the shoulder and back slope positions, respectively). The fractal dimensions of soil nutrient elements across all slope positions ranged from 0.216 to 1.949 suggesting that as the sampling distance exceeds half the A 0 , soil nutrient elements tend to become self-similar. The variability in soil nutrient elements from the current study can serve as a useful nutrient application recommendation tool for precision agriculture across five slope positions. [ABSTRACT FROM AUTHOR]

Soil hydraulic and physical properties can be influenced by various land management practices, and they determine water movement and storage within the vadose zone, with both agronomic and environmental effects. The objective of this study was to evaluate the effects of two such practices (no‐till [NT] and cover crops [CCs]) on soil hydraulic (e.g., saturated hydraulic conductivity [Ksat], and water retention) and physical (e.g., bulk density [BD], pore size distribution, air‐filled pore spaces [AFPSs], and water‐filled pore spaces [WFPSs]) properties. The CCs used included crimson clover (Trifolium incarnatum L.), hairy vetch (Vicia villosa Roth.), winter peas (Lathyrus hirsutus L.), oats (Avena sativa), winter wheat (Triticum aestivum L.), triticale (Triticale hexaploide Lart.), flax (Linum usitassimum L.), and barley (Hordeum vulgare L.). Soil samples were collected and analyzed during 2021 and 2022 right before CC termination at 0‐ to 10‐cm, 10‐ to 20‐cm, and 20‐ to 30‐cm depths. Results showed that, during 2021 and 2022, BD was 18% and 14% higher, respectively, under NC compared with CC management, while Ksat was 2.2 and 1.9 times higher, respectively, under CC compared with NC management. Further, the non‐capillary pores were significantly (p ≥ 0.05) higher under CC compared with NC management during both years of study. As a result, the majority of the total pores under CCs were filled with air, while the majority of total pores under NC management were filled with water. Therefore, this CC mix may be useful in lengthening the growing period during wet seasons by increasing air‐filled pore spaces. Core Ideas: NT cover crops (CCs) significantly lowered BD and increased saturated hydraulic conductivity compared with no cover crop management.During 2 years, the van Genuchten α and n parameters were higher under CC management.CCs improved the proportion of capillary and non‐capillary pores.CCs increased the proportion of total pores filled with air.Under CC management alone, most soil properties were similar during 2 years. [ABSTRACT FROM AUTHOR]

Simple Summary: The demand for poultry products is increasing at the same time as the prices of raw materials and other ingredients used in feed manufacturing, leading to the implementation of strategies to improve nutrient utilization in broiler diets and reduce feeding costs. One strategy used in broiler production is the dietary supplementation of phytase, an enzyme that assists in phytate degradation. Phytate is the primary storage form of phosphorus (P) in seeds and it accounts for two-thirds of the P in vegetable feedstuffs. Dietary phytase supplementation has become a common practice because the activity of endogenous phytase in broilers does not allow for the adequate utilization of phytate-bound P. Consequently, the effects of phytase have been widely studied and the beneficial effects on broiler growth performance and reduced P excretion into the environment have been previously described. In the present study, broilers were fed a diet with a combination of two phytase forms (coated and uncoated) to assess the effects on broiler performance, tibia characteristics, and residual fecal phytate P. The results indicated no distinct advantage of combining phytase forms, but this information may be useful for the direction of future research. The present study evaluated the individual and combined effects of coated and uncoated phytase on broiler performance, tibia characteristics, and residual phytate phosphorus (P) in manure. Two repeated studies were conducted using 240-day-old Cobb 500 by-product male broilers per trial. For each trial, birds were assigned to four treatments with four replicate battery cages per treatment (60 birds/trt) and grown for 21 days. Treatments included: (1) negative control (NC), (2) NC + 1000 phytase units (FTU) coated phytase (C), (3) NC + 1000 FTU uncoated phytase (U), and (4) NC + 500 FTU coated + 500 FTU uncoated phytase (CU). Data were analyzed with a one-way ANOVA and means were separated using Tukey's HSD. In the pooled data for both trials, all treatments with dietary phytase had a higher body weight (BW) and feed consumption (FC) than the NC on day 21 (p < 0.05). Similarly, a six-point reduction was observed for day 1 to 21 feed conversion (FCR) for U and CU (p < 0.05). All treatments with phytase inclusion differed from the NC in every evaluated parameter for bone mineralization (p < 0.05) and had significantly lower fecal phytate P concentrations compared to the NC (p < 0.05). Overall, bird performance was essentially unaffected by phytase form, indicating that combining phytase forms does not appear to offer any advantage to the evaluated parameters from day 1 to 21. [ABSTRACT FROM AUTHOR]

Perennial systems, such as switchgrass have been shown to improve soil hydraulic properties on degraded soils relative to annual cropping systems; however, studies of the effects on thermal properties are limited. Therefore, the objectives of this study were to determine the effects of topsoil thickness on soil thermal properties under switchgrass (Panicum virgatum L.) and row crop production systems. The experiment was carried out at the University of Missouri South Farm Research Center (38°54′ N, 92°16′ W). Research plots were re-established in 2009 with selected topsoil thickness categorized into two treatments (shallow [4 cm] and deep [36 cm]) on a Mexico silt loam (Vertic Epiaqualfs). Plots were planted to either switchgrass or a corn (Zea mays L.)-soybean (Glycine max (L.) Merr.) rotation with four replicates. Undisturbed soil cores (7.6 by 7.6 cm) and bulk soil were collected from two depths (10 cm increments) to determine thermal properties. Thermal conductivity (λ), volumetric heat capacity (C v), and thermal diffusivity (D) were measured at 0, −33, −100 and − 300 kPa soil water pressures. In addition, soil organic carbon (SOC), bulk density (D b) and water content (θ) were also determined. The results showed that the switchgrass treatment had 23% higher SOC, 5–8% greater θ, and 11% lower D b than the row crop treatment. In turn, switchgrass plot exhibited a 5–7% reduction in λ, an 8–9% reduction in D, and a 2–3% increase in C v. Shallow topsoil thickness demonstrated increased thermal properties (λ, D and C v) relative to the deep topsoil thickness, likely due to higher clay content in the surface soil horizon and associated higher θ. This study contributes to a better understanding of the impact of topsoil loss and perennial vegetation on the thermal properties of soils in degraded landscapes. • Switchgrass reduced soil thermal conductivity but increased heat capacity. • Switchgrass has the potential to buffer heat transport within the soil profile. • Management that influences bulk density also affects soil thermal conductivity. [ABSTRACT FROM AUTHOR]

Understanding the effects of cropping practices on soil pore characteristics is important for determining soil productivity and ecosystem services. Objectives of the study were to compare differences in computed tomography (CT) measured soil pore parameters (number of macropores, macroporosity, area of the largest pore, circularity and fractal dimension) among cover crops (CC), no-cover crops (NCC), and biofuel crops [Miscanthus (M): Miscanthus x giganteus and switchgrass (SG): Panicum virgatum ] and examine relationships between CT-measured pore parameters and soil hydraulic and thermal properties. Cover crops were Cereal rye ( Secale cereale L.), Hairy vetch ( Vicia villosa ) and Austrian winter pea ( Pisum sativum subsp. arvense ). Three replicates each of undisturbed soil cores were collected at two soil depths (0–10 and 10–20 cm) from each treatment using plexiglass cores measuring 76.2 mm diameter by 76.2 mm long. Ten scan images from each core were acquired using an X-ray CT scanner with 0.19 by 0.19 mm pixel resolution with 0.5 mm slice thickness and analyzed with Image - J . Soil under CC, NCC, M, and SG on average had 21, 14, 17, and 12 macropores on a 2500 mm 2 area across all the depths. Soil under miscanthus had significantly greater macroporosity (0.049 m 2 m − 2 ) and area for the largest pore (89.70 mm 2 ) than other treatments. The cover crop treatment had approximately 50%, 28%, and 75% greater number of macropores than NCC, M, and SG treatments. Bulk density (D b ) of soil was 13% lower in M than the NCC. Saturated hydraulic conductivity (K sat ) values were positively correlated with most CT-measured pore parameters. In contrast, D b was negatively correlated with most CT-measured pore parameters (circularity and fractal dimension were positively correlated). While the circularity values were correlated positively with D b and thermal conductivity ( λ ), the fractal dimension was correlated positively with volumetric heat capacity ( C v ). The study illustrates that M and CC treatments can improve soil pore parameters. [ABSTRACT FROM AUTHOR]

Conversion of annual grain crop systems to biofuel production systems can restore soil hydrologic function; however, information on these effects is limited. Hence, the objective of this study was to evaluate the influence of topsoil thickness on water infiltration in claypan soils for grain and switchgrass ( Panicum virgatum L.) production systems. The experiment was performed at the University of Missouri South Farm (38°54′N, 92°16′W) on a Mexico silt loam (Vertic Luvisols) soil. Since 2009, plots were planted with either switchgrass or a corn ( Zea mays L.)-soybean (Glycine max (L.) Merr.) rotation. Infiltration rates were measured using ponded infiltrometers during two years (2014 and 2015) under switchgrass and grain crop management each with two levels of topsoil thickness (0 and 37.5 cm). Physically-based Parlange and Green-Ampt infiltration models were used to estimate saturated hydraulic conductivity ( K s ) and sorptivity ( S ) parameters. Switchgrass planted on degraded soil (shallow topsoil treatment) resulted in greater K s , S , q s (quasi-steady infiltration rate) and K fs (field-saturated hydraulic conductivity) values than with row crop management for both 2014 and 2015 measurement years. Results for selected 24-hour mean frequency (11.8, 14.2, and 16.2 cm) storms showed that switchgrass production systems enhanced estimated water infiltration, reduced estimated runoff, and decreased estimated time from water ponding to end of ponding compared with row crop management. Switchgrass is recommended to be planted on degraded soils especially in claypan landscapes for improved water use. [ABSTRACT FROM AUTHOR]

Loss of productive topsoil by erosion with time can reduce the productive capacity of soil and can significantly affect soil physical and hydraulic properties. This study evaluated the effects of reduced topsoil thickness and perennial switchgrass (Panicum virgatum L.) vs. a corn (Zea mays L.)--soybean [Glycine max (L.) Merr.] rotation on soil bulk density (pb), saturated hydraulic conductivity (K(sat), soil water retention and pore size distributions. The experiment was conducted at the University of Missouri South Farm on a Mexico silt loam (a Vertic Epiaqualf). Plots with the corn--soybean rotation and switchgrass were established in 2009 with four replicates. Twenty-seven years after establishment, plots with selected topsoil thickness were grouped into four treatments (TopA [4 cm], TopB [11 cm], TopC [22 cm] and TopD [36 cm]). Undisturbed soil cores, 76 by 76 mm, were collected by 10- cm depth increments from the surface to the 40-cm depth. Results showed that soil under switchgrass had 53 and 27% higher macroporosity (>1000- mm diameter) and coarse mesoporosity (60--1000-mm diameter), respectively, than row crop management. This led to 73% greater Ksat and 11% higher water content at saturation than row crop management. Thicker topsoil treatments (TopC and TopD) had consistently lower rb and greater Ksat than the shallow topsoil treatments (TopA and TopB) for all sampling depths. These results imply that switchgrass production systems significantly improve soil hydraulic properties, particularly in eroded claypan landscapes. [ABSTRACT FROM AUTHOR]