Manoj K. Shukla

Tillage Effects On Physical And Hydrological Properties Of A Typic Argiaquoll In Central Ohio

No-till management is generally preferred over conventional tillage, especially in fine-textured soils where tillage can increase soil compaction, disrupt the natural structure formation process, and have long lasting effects on soil quality. The objective of this project was to quantify the interactive and residual effects of different tillage systems on the water transmission and structural properties of Kokomo silty clay loam (fine, mixed, superactive, mesic Typic Argiaquoll). Soil physical properties were assessed at the Don Scott experimental farm of the Ohio State University, Columbus, Ohio, 9 years after initiating the study and 20 months after the last tillage operation. Three tillage treatments were replicated four times: moldboard plow (MB), chisel plow (CP), and no-till (NT). Tillage operations took place during the fall of each year between 1993 and 2000, and soil samples for physical property assessment were obtained during summer 2002 for 0–10- and 10–20-cm depths. The water infiltration tests conducted on each of the 12 experimental plot showed that the highest cumulative infiltration (I, 90 cm) and steady state infiltration (ic, 27 cm h−1) were for the NT treatment and varied in the order NT > CP ∼ MB. Soil bulk density (&rgr;b) varied in the order MB > NT ∼ CP, available water capacity (AWC) and air filled porosity (fa) NT > MB ∼ CP. The water stable aggregation (WSA) (943 g kg−1) and the volume of transmission (TrP) (0.10 cm3cm−3) and storage pores (StP) (0.31 cm3cm−3) were the highest for the NT plots for 0–10-cm depth. For the 10–20-cm depth, the WSA and MWD were in the order NT > MB ∼ CP; AWC-NT (2.00 cm) ∼ CP (1.71 cm) > MB (1.36 cm). Tillage effects on soil properties between MB and CP seemed to diminish at the end of the growing season, and the infiltration rate after 5 min, ic, I, WSA, and soil &rgr;b values were similar. Canonical correlation analysis indicated strong association between volumes of StP and I, ic and soil &rgr;b, and SOC and soil &rgr;b.

Principal component analysis for predicting corn biomass and grain yields

Soil variability, a rule rather than an exception, necessitates site-specific management for optimizing the efficient use of inputs. Biomass and grain yields depend on complex interactions among spatially variable physical and chemical properties of soil. The objectives of this study were to determine (i) the variability in soil properties using coefficient of variation (CV) and range as indicators and (ii) the relationships between principal components (PCs) derived from measured soil attributes and corn (Zea mays)biomass and grain yields. Soil physical and chemical properties were determined for four treatments: no-till corn without manure (Field 1), no-till corn with manure (Field 2), no-till corn-soybean (Glycine max) rotation (Field 3), and conventional tillage corn (Field 4). The CV for saturated hydraulic conductivity (Ks) (0.59 to 1.43) and infiltration rate at 5 min (i5) (0.38 to 0.86) was classified as most variable; for 3-h infiltration (ic) (0.30 to 0.97) and cumulative infiltration (I) (0.27 to 0.76) as moderate to most variable; for SOC (0.21 to 0.02) and MWD (0.12 to 0.23) as moderate to least variable; and the CV for WSA (0.03 to 0.12), pH (0.1 to 0.2), and soil bulk density (ρb) (0.05 to 0.11) as least variable. The highest CV overall was obtained for soil properties in the conventional till treatment (Field 4), although mean values of Ks, i5, and I for this field were the smallest. The biomass and grain yields were also the lowest for Field 4. The principal component (PC) analysis showed that four PCs with eigenvalues greater than one explained more than 78% of the variability in soil physical and chemical properties. The stepwise regression analysis showed that the grain yield (Yg) was linearly correlated with PCs as Yg = 8.77 + 0.81 PC1 (r2 = 0.19; P< 0.02) and biomass yield (Yb) as Yb = 4.85 + 0.41 PC1 + 0.32 PC2 (r2= 0.36; P < 0.003). The coefficients on PC1 were positive and were the highest for both Yg and Yb. Therefore, PC1 was the most dominant yield determinant.

Soil physics : an introduction

Introduction to Soil Physics Importance of Soil Physics Interactions of Soil Physics with Other Disciplines Soil Physics, Soil and Environmental Quality, and Quality of Life Soil Physics and Climate Change Soil Physics Curriculum Problems References Units and Dimensions Introduction Definitions of Unit and Dimension Systems of Units Nondimensional Quantities Deriving Units of Physical Quantities Use of Units and Dimensions Unit Conversions Problems References Characteristics of Soils of the Vadose Zone Introduction Soil Formation Soil Profile Soil Texture Soil Separates Methods for Particle Size Measurement Particle Shapes Properties of Clay Particles Physical Properties of Soil K14069_C000.indb 5 7/17/2013 6:35:20 PMvi Contents3.10 Soil Structure Problems References Sampling Concepts and Designs Introduction Representative Elementary Volume Sample Size Sampling Designs Practical Aspects of Soil Sampling Problems References Spatial Variability of Vadose Zone Properties Introduction Sources of Variability Scale of Variability Statistical Evaluations Influence of Sample Support Influence of Measurement Device Influence of Land Use Statistical Analysis Geostatistical Analysis Semivariogram Functions Problems References Fundamentals of Hydrology Introduction Hydrologic Cycle Components of Hydrologic Cycle Water Balance Rainfall Runoff Relationships References Properties of Water Introduction Properties of Water Forces on Water Molecules Contact Angle Capillarity Empirical Approach Importance of Capillarity Problems References Water in the Vadose Zone Introduction Soil-Water Content Soil-Water Content Measurement Methods Direct Methods Indirect Methods Energy State of Soil Water Definitions and Components of Soil-Water Potential Soil-Water Potential Measurement Devices Total Soil-Water Potential under Different Conditions Soil-Water Retention Soil-Water Retention Models Hysteresis Phenomenon Problems References Flow through the Vadose Zone Introduction Laws Governing Flow through Saturated Porous Media Saturated Hydraulic Conductivity Permeability Laws Governing Flow through Unsaturated Porous Media Unsaturated Hydraulic Conductivity Measurement Soil Water Diffusivity Measurement Flow through Layered System Models for Simulating Flow through Soil System References Water Infiltration into the Vadose Zone Introduction Process of Infiltration Measurement of Infiltration Factors Affecting Infiltration Rate 1Infiltration Models 1Water Redistribution Problems References Energy Flow through the Vadose Zone Introduction Energy Balance of Soil Factors Affecting Energy Balance Heat Flow Processes Heat Flux through Soil Heat Conservation Equation 1Measurement of Thermal Properties Soil Temperature Effects of Soil Temperature Soil Temperature Variations Mathematical Representation Management of Soil Temperature Problems References Evaporation from Soil Introduction Evaporation from Different Water Bodies Evaporation Processes Stages of Evaporation Steady-State Evaporation Transient-State Evaporation Soil Water Redistribution during Evaporation Vapor Flow through Soil Control of Evaporation Transpiration Measurement of Evapotranspiration Problems References Root Water Uptake Introduction Root Water Uptake Models Microscopic Root Water Uptake Model Macroscopic Type I Root Water Uptake Model Macroscopic Type II Root Water Uptake Model References Airflow through the Vadose Zone Introduction Soil Gas Content Factors Affecting Soil Air Composition Air Flow through Soil Air Flow Mechanisms through Soil Air-Filled Porosity Measurement through Soil Air Permeability Problems References Chemical Transport through the Vadose Zone Introduction Types of Solutes Related Terminology Pore Water Velocity Solute Conservation Equation Solute Transport Processes Ficks Law Solute Movement Solute Breakthrough Curve Interpretations from Breakthrough Curves Equilibrium Convective Dispersion Equation Solute Transport Equation under Physical Nonequilibrium Solute Transport Equation under Chemical Nonequilibrium Effect of Pore Water Velocity on Solute Transport Parameters Parameter Estimation Transport of Reactive Solutes Problems References Modeling Flow through the Vadose Zone Using HYDRUS-1DModel Introduction Installation of the HYDRUS-1D HYDRUS-1D Tutorial References Flow through the Vadose Zone Using RZWQM Introduction Installation of the RZWQM2 Model RZWQM2 Tutorial Working with the RZWQM2 Project Working with the RZWQM2 Scenario Scenario Comparisons References Index

Soil quality indicators for the North Appalachian Experimental Watersheds in Coshocton Ohio

Identification of soil quality indicators (SQI) is important to sustainable management of natural resources. The objective of this project was to develop a technique for identifying SQIs for agricultural land use. Soil structure, water retention and transmission properties, and pH and electrical conductivity (EC) were measured and related to agronomic productivity for five land use and soil management treatments at the experimental farm of the North Appalachian Experimental Watersheds, Coshocton, Ohio. The five treatments were no-till corn without manure (NTWM), no-till corn with manure (NTM), no-till corn (Zea mays)-soybean (Glycine max) rotation (NTCSR), conventional tillage corn (CT), and meadow (M). Soil properties measured were bulk density (ρb), drainable porosity (fa), available water capacity (AWC), steady state infiltration rate (ic), saturated hydraulic conductivity (Ks), soil organic carbon (SOC) concentration, water stable aggregation (WSA), mean weight diameter of aggregates (MWD), and texture. The correlation analysis on the measured soil attributes reduced the number of key variables from 17 to 11. A rating index on a 1 to 5 scale was obtained for each of the key soil properties. The linear regression analysis was first performed with key soil attributes as independent variables and biomass or grain yields as dependent variables, with the rating factor later assigned to each measured key soil attribute. The multiple regression analysis showed that SOC and WSA explained more than 35% of variability in biomass and 33% in grain yields, respectively, and were identified as the major SQIs. Other important SQIs were ρb, AWC, MWD, pH, and EC. The cumulative sustainability ratings (CR) for each land use showed that NTM was the most sustainable soil management treatment (CR = 20) and CT the least sustainable (CR = 30). The CR was also correlated significantly with grain yield (R2 = 0.31, P < 0.002). The CR for different land uses suggests that soil management with NTM is the most sustainable and CT the least.

Coupled Liquid Water, Water Vapor, and Heat Transport Simulations in an Unsaturated Zone of a Sandy Loam Field

Information on the coupled liquid water, water vapor, and heat transport under arable field conditions is still limited, particularly for unsaturated soils of semi-arid and arid regions such as New Mexico. HYDRUS-1D model was applied to evaluate various transport mechanisms associated with temporal variations in water content and soil temperature in the unsaturated zone of a sandy loam furrow-irrigated field located at Leyendecker Plant Science Research Center, Las Cruces, New Mexico. The model was calibrated using measured soil water content and soil temperature at 5-, 10-, 20-, and 50-cm depths during a 19-day period (day of the year [DOY] 85 to DOY 103, 2009) and validated for a 31-day period (DOY 104 to DOY 134, 2009). Measured and optimized soil hydraulic and thermal properties and hourly meteorological data were used in model simulations. HYDRUS-1D simulated water contents and soil temperatures correlated well with the measured data at each depth. The total liquid water flux, composed of isothermal and thermal liquid water flux, dominated the soil water movement during early periods after irrigation, whereas the contribution of total water vapor flux, composed of primarily thermal and much smaller isothermal water vapor flux, increased with increasing soil drying. During the soil drying process, the total liquid flux within 15-cm depth eventually changed to water vapor flux near the surface. The upward total liquid and vapor fluxes decreased from 5 cm, indicating that vapor flux was much higher in the layer near the soil surface. The total vapor flux in this unsaturated soil layer was approximately 10.4% of the total liquid and vapor fluxes during the simulation period.

Evaluation of Spatial and Temporal Root Water Uptake Patterns of a Flood-Irrigated Pecan Tree Using the HYDRUS (2D/3D) Model

AbstractQuantitative information about the spatial and temporal patterns of compensatory root water uptake (RWU) in flood-irrigated pecan orchard is limited. We evaluated spatio-temporal compensated and uncompensated RWU patterns of mature pecan tree in a silty clay loam orchard using the HYDRUS (2D/3D) model. HYDRUS (2D/3D) simulations, which agreed well with measured water contents and temperatures at different soil depths and horizontal distances from the tree trunk, suggested that while both compensated and uncompensated RWU varied with soil depth they did not do so laterally because of similar spatial vertical distributions of root length density (RLD) for the under-canopy and the tree canopy dripline locations. Considering compensated RWU resulted in an increase in actual transpiration by 8%, and a decrease in evaporation and drainage by 5% and 50%, respectively, during a growing season. Simulated transpiration and relative transpiration (a ratio between actual and potential transpiration) values we...

Deep Percolation and its Effects on Shallow Groundwater Level Rise Following Flood Irrigation

Deep percolation (DP) from irrigation may be important for groundwater recharge in irrigated agricultural river corridors of arid regions, yet few studies of this physiographic setting have characterized both percolation and its direct effects on groundwater levels. The objectives of our study in a sandy loam, flood-irrigated, alfalfa-grass field in northern New Mexico were to (1) compare DP below the 1 m effective root zone based on water balance method (WBM) and Root Zone Water Quality Model (RZWQM) simulations, and (2) characterize effects of DP on shallow groundwater levels. Irrigation water applications were metered, and automated instrumentation measured soil water content and climate data for WBM calculations and RZWQM simulations. Groundwater response was characterized by recorded below-field water levels in four experimental wells. DP varied with initial soil water content and water application amount, ranging from 5 to 18 cm (mean 11.2 ±4.1 SD) with the WBM and from 6 to 17 cm (10.6 ±3.8 SD) with RZWQM (using 0.0005 cm3 cm-3 macroporosity). Across irrigation events, there was high correlation (r = 0.90) between WBM and RZWQM DP. Peak water level response (up to 38 cm) varied from 8 to 16 h after irrigation onset depending on well location and water application amount. Study results show that flood irrigation is a significant source of shallow groundwater recharge. The high correlation between calculated and simulated deep percolation without iterative model calibration indicates that RZWQM can be a useful tool to estimate DP and extend localized field studies to larger spatial scales.

Spatial Variability of Electrical Conductivity of Desert Soil Irrigated with Treated Wastewater: Implications for Irrigation Management

Knowledge of spatial variability is important for management of land affected by various anthropogenic activities. This study was conducted at West Mesa land application site to determine the spatial variability of electrical conductivity (EC1:1) and suggest suitable management strategy. Study area was divided into five classes with EC increasing from class I to V. According to the coefficient of variation (CV), during 2009 and 2010, EC1:1 values for different classes were low to moderately variable at each depth. Semivariogram analysis showed that EC1:1 displayed both short and long range variability. Area coverage of classes I and II were much higher than classes III, IV, and V during 2009. However, during 2010 area coverage decreased from 26% to 14.91% for class II, increased from 12.11% to 22.97%, and 10.95% to 20.55 for classes IV and V, respectively. Overall area under EC1:1≥ 4 dS/m increased during 2009. Soil EC map showed EC classes IV (4.1–5 dS/m) and V (>5.1 dS/m) were concentrated at northwest and southeast and classes I and II were at the middle of the study plot. Thus, higher wastewater should be applied in the center and lower in the northwest and southwest part of the field.

Interleukin 27 (IL-27) Alleviates Bone Loss in Estrogen-deficient Conditions by Induction of Early Growth Response-2 Gene

A growing understanding of the bone remodeling process suggests that inflammation significantly contributes to the pathogenesis of osteoporosis. T cells and various cytokines contribute majorly to the estrogen deficiency-induced bone loss. Recent studies have identified the IL-12 cytokine family as consisting of pro-inflammatory IL-12 and IL-23 and the anti-inflammatory IL-27 and IL-35 cytokines. IL-27 exerts protective effects in autoimmune diseases like experimental autoimmune encephalomyelitis; however, its role in the pathogenesis of osteoporosis remains to be determined. In this report, we study the effect of IL-27 supplementation on ovariectomized estrogen-deficient mice on various immune and skeletal parameters. IL-27 treatment in ovariectomized mice suppressed Th17 cell differentiation by inhibiting transcription factor RORγt. Supplementation of IL-27 activates Egr-2 to induce IL-10 producing Tr1 cells. IL-27 treatment prevented the loss of trabecular micro-architecture and preserved cortical bone parameters. IL-27 also inhibited osteoblast apoptosis through increased Egr-2 expression, which induces anti-apoptotic factors like MCL-1. IL-27 suppressed osteoclastogenesis in an Egr-2-dependent manner that up-regulates Id2, the repressor of the receptor activator of nuclear factor-κB ligand-mediated osteoclastogenesis. Additionally, these results were corroborated in female osteoporotic subjects where we found decreased serum IL-27 levels along with reduced Egr-2 expression. Our study forms a strong basis for using humanized IL-27 toward the treatment of post-menopausal osteoporosis.

Spatial Variability of Soil Properties in an Arid Ecosystem Irrigated With Treated Municipal and Industrial Wastewater

Abstract Information on spatial variability of soil properties is important for designing site-specific management practices for soils affected by human activities. Spatial variability study was conducted at West Mesa near Las Cruces, New Mexico, to identify the areas where remediation is needed and suggest sustainable management strategies to reduce the effect of treated saline and sodic wastewater application on soil environment and existing native vegetations based on the spatial variability of soil physical and chemical properties. Bulk and core soil samples were collected from the center of 54 (50 × 50 m) grid points, and additional 30 samples were collected from smaller grids at 0- to 20- and 20- to 40-cm depth during summer 2010. Geostatistical software (GS+) was used to obtain semivariograms and cross-variograms. Coefficient of variation (CV) indicated that sodium adsorption ratio (SAR), chloride (Cl−), wilting point, saturated hydraulic conductivity (Ks), and nitrate (NO3−) were most variable with CV of greater than 0.35, whereas sand, clay, bulk density, and pH were least variable (CV <0.15). Cross-variogram showed that SAR was spatially correlated with Ks and sand content; Ks, with bulk density; therefore, kriging or cokriging can be used to estimate SAR from Ks. Blocked kriged spatial distribution maps showed positional similarity, and most of the higher chemical properties were concentrated in the northwest and southeast portion and lower near the center of the experimental field. Average SAR concentration in the northwest portion was 22.77, and a southeast portion of the field was 18.12, which were above the threshold limits (>15) for most plants. So, it is necessary to monitor SAR on a regular basis and change the wastewater application pattern, with more wastewater application in the middle and less in the northwest and southeast part of the experimental site.