Silty Clay Loam Soil Research Articles

Effects of Biochar‐Straw on Soil Aggregation, Organic Carbon Distribution, and Wheat Growth

Exogenous C application can improve the physicochemical properties and fertility of soil. This study was conducted to determine whether the application of biochar (BC) was better than straw for improving soil structure and crop growth. The short‐term effects of exogenous C application on the size distribution of water‐stable aggregates, organic C sequestration, and grain yield of winter wheat (Triticum aestivum L.) were investigated on a silty clay loam soil in the Guanzhong Plain, Northwest China. Biochar and straw were applied at equal C rates: 1, 3, and 10% in straw treatments (Str1.0, Str3.0, and Str10.0, respectively) and 0.8, 2.4, and 8% in BC treatments (BC0.8, BC2.4, and BC8.0, respectively). No‐C treatment (CK) was used as the control. The mass proportion of macroaggregates (>0.25 mm) was increased by 16.9% in BC2.4 and 45.8% in BC8.0, and soil organic carbon (SOC) was increased by 13.2 to 155.1% on average in the BC treatments when compared with CK. A small quantity of BC (0.8 and 2.4%) increased microbial biomass C content but decreased dissolved organic C content, while a large quantity of BC (8%) had the reverse effects. Wheat yields were increased by 14.9 and 19.1% in BC0.8 and BC2.4, respectively, while they were decreased by 37.3 and 90.1% in Str3.0 and Str10.0, respectively, when compared with CK. Moderately heavy soil BC amendment (e.g., applied rate, 2.4%) is beneficial to soil structure improvement and wheat growth and effective for harmless disposal of excess plant residues in the Guanzhong Plain, Northwest China.Core Ideas Biochar addition enhanced macroaggregate formation and microaggregate agglomeration. Biochar particles mostly existed in the macroaggregate (>0.25 mm) fractions. Low and moderate biochar application at 0.8% and 2.4% increased microbial biomass C and wheat yield. Heavy straw application at 3% and 10% inhibited wheat growth and yield increase.

Corn Response as Affected by Planting Distance from the Center of Strip-Till Fertilized Rows.

Strip-till has been used at a large scale in east central Kansas as an alternative to earlier planting dates under a no-till system. To determine the effects of planting corn (Zea mays) under previously established strip-tilled fertilized rows, experiments were conducted on an Osage silty clay loam soil in 2006 and 2008 and on a Woodson silt loam soil in 2009, 2010, and 2011 using three different planting distances from the strip-tilled fertilized rows (0, 10, 20, and 38 cm) with a strip-till operation performed between 1 and 73 days before planting. The depth of the strip-till fertilizer application was 13–15 cm below the soil surface. Corn that was planted 10 cm from the fertilized row showed greater early season growth, higher plant population, and grain yield. Planting 20 and 38 cm from the center of the fertilized rows showed none of the benefits that are typically associated with strip-tillage system. Enough time should be allowed between the strip-till operation and planting to reach satisfactory soil conditions (e.g., moist and firm seedbed). Our results suggest that the best location for planting strip-tilled fertilized corn vary depending on soil and climatic conditions as well as the time between fertilizer application with the strip-till operation and planting. With fewer number of days, planting directly on the center of fertilized strip-till resulted in decreased plant population and lower grain yield. However, the greatest yield benefit across different planting conditions was attained when planting within 10 cm of the strip.

Effect of biochar amendment on nitrate retention in a silty clay loam soil

Biochar incorporation into agricultural soils has been proposed as a strategy to decrease nutrient leaching. The present study was designed to assess the effect of biochar on nitrate retention in a silty clay loam soil. Biochar obtained from the pyrogasification of fir wood chips was applied to soil and tested in a range of laboratory sorption experiments. Four soil treatments were considered: soil only (control), soil with 2, 4 and 8% of biochar by mass. The Freundlich sorption isotherm model was used to fit the adsorbed amount of nitrate in the soil-biochar mixtures. The model performed very well in interpreting the experimental data according to a general linear regression (analysis of co-variance) statistical approach. Nitrate retention in the soilbiochar mixtures was always higher than control, regardless the NO3 – concentration in the range of 0-400 mg L–1. Different sorption capacities and intensities were detected depending on the biochar application rate. The highest adsorption capacity was observed in the soils added with 2 and 4% of biochar, respectively. From the results obtained is possible to infer that nitrate retention is higher at lower biochar addition rate to soil (2 and 4%) and at lower nitrate concentration in the soil water solution. These preliminary laboratory results suggest that biochar addition to a typical Mediterranean agricultural soil could be an effective management option to mitigate nitrate leaching.

Comparative research on tillable properties of diatomite-improved soils in the Yangtze River Delta region, China

To improve soil texture and structure, techniques associated with physical, biological or chemical aspects are generally adopted, among which diatomite is an important soil conditioner. However, few studies have been conducted to investigate the physical, hydraulic and tillage performance of diatomite-improved soils. Consistency limits and compaction properties were investigated in this study, and several performance indicators were compared, such as the liquid limit, plastic limit and compactability, of silt, silt loam and silty-clay loam soils to which diatomite was added at volumetric ratios of 0%, 10%, 20%, and 30%. The results showed that diatomite significantly (p<0.05) improved the consistency limits, with the most preferred effects in the silt soil. The liquid limits were increased by 53.9%, 27.3%, and 14.7%, in the silt, silt loam and silty-clay loam soils, respectively, when the volumetric ratio was 30%. While diatomite lowered the maximum dry bulk density (MBD) of the classified soils, the optimum moisture content (OMC) was increased overall. The trend was consistent with the proportion of diatomite, and MBD decreased by 8.7%, 10.3%, and 13.2% in the silt, silt loam and silty-clay loam soils when 30% diatomite was mixed, whereas OMC increased by 28.7%, 22.4%, and 25.3%, respectively. Additionally, aggregate stability was negatively correlated with MBD but positively correlated with OMC. Diatomite exerts positive effects on soil mechanical strength, suggesting that soils from sludge farms are more tillable with a larger stabilized and workable matrix.

The Effect of addition different levels of organic matter for soil in some infiltration standards

The experiment was conducted during spring season 2016 in two type's soils textures, the first one was held in college of agriculture-Baghdad University (abu-Grhaib) which is silty clay loam, The second texture of soil was silty loam. The purpose is to study the effect addition for different levels of organic matter in some infiltration rate and basic infiltration rate, the experiment includes two factors; first factor includes two levels for organic matter, addition 20 tan. ha-1 L1, 40tan. ha.-1 L2 and control treatment L0 (without organic matter), the other factor includes two texture of soil , Silty clay loam T1 and silty loam T2, these levels of organic matter was mixed of the surface soil until the depth 0.75m before measuring the infiltration. The results showed that values of accumulative infiltration were increased at 18.80, 23.00% by addition of highest levels of organic matter to the silty clay loam soil and silty loam soil, respectively. The values of infiltration rate were increased up to 31.97, 34.74% for the two texture of soil silty clay loam and silty loam, respectively. The values of basic infiltration rate were increased up to 18.00, 31.82% by addition of the highest level of organic matter to the two textures of soils silty clay loam and silty loam, respectively.

Development and evaluation of a draft force calculator for moldboard plow using the laws of classical mechanics

The moldboard plow is the most common primary tillage implement in the world; therefore, it is valuable to consider this plow from an engineering viewpoint. Since the required draft force and power are among the most important engineering specifications of a moldboard plow, in this paper, a model was developed to calculate them. In this model, the effect of soil cutting, soil displacement, and soil-metal friction on the plow specific draft was considered. Soil parameters, plow parameters, and working condition parameters were considered as the model inputs. To simplify the required calculations, the derived equations were entered in the Excel software, and the finalized spreadsheet was utilized as the moldboard plow draft force and power calculator. To verify the model, comparison of the model outputs with the corresponding results of other studies was carried out. Furthermore, the output of the model and the measured draft force of plowing on a silty clay loam soil was compared. According to the results of this study, the developed model produced acceptable specific draft forces that were within the overall range of the moldboard plow specific draft. Furthermore, draft force and power requirements of a three-bottom moldboard plow working on a silty clay loam soil with the forward velocity of 7kmh−1 were 17.9kN, and 34.8kW, respectively, that were about 8% higher than the results obtained by the developed model (16.64kN, and 32.28kW). Therefore, the developed model can be used to calculate the draft force and power of the moldboard plow with reasonable accuracy.

A new method to estimate soil water infiltration based on a modified Green–Ampt model

Water infiltration is an important component of overland hydrology, closely related to the amount of water that penetrates into soil, overland flow, soil erosion, and chemical transport. The Green–Ampt infiltration equation is one of the most widely used infiltration equations in hydrological and erosion models. The piston assumption in the model simplify the soil moisture distribution and overestimated the values at the mean time. A new model for predicting the soil water content distribution along a horizontal soil column and a related algorithm for soil water infiltration rate estimation are presented. Two linear functions were used to replace the even distribution of soil water content in the vadose zone and the wetting front, as traditionally used in the Green–Ampt infiltration model. The new algorithm for soil water infiltration rate estimation was based on a new soil water content distribution model. Laboratory experiments were conducted with three soils (sandy loam, silt loam, and silty clay loam) to illustrate the infiltration estimations experimentally. The relative errors of the method calculated based on the water/mass balance principle were 2.05%, 4.75%, and 1.92% for sandy loam, silt loam, and silty clay loam soil, respectively. Changes in the relative errors over time were also analyzed. This new, highly precise method can be applied to infiltration and groundwater modeling studies, as well as irrigation and drainage management.

Development and assessment of a draft force calculator for disk plow using the laws of classical mechanics

Estimation of the draft requirement of tillage implements is important from machine design, and tractor selection viewpoints. In this study, a model was developed to calculate the draft force and power of a disk plow. In this model, the effects of soil cutting, soil displacement, and soil-metal friction processes on the specific draft force of a disk plow were considered. Model inputs consisted of the soil parameters, the plow parameters, and the working condition parameters. To simplify the required calculations, the derived equations were entered in the Excel software, and the finalized spreadsheet was utilized as the disk plow draft force and power calculator. One of the advantages of the developed model was that the required calculations did not depend upon the dimensionless N-factors. Model verification was carried out by comparing the model outputs with the corresponding results of other studies. Moreover, the output of the model and the measured draft force of plowing on a silty clay loam soil were compared. According to the results of this study, the form of equation developed in this paper and the Hendrick's formula regarding the specific draft force, were compatible, since both equations were polynomials of order 2 with respect to the forward velocity of the plow. On the other hand, the developed model overestimated the required draft force of a disk blade in comparison with the Godwin⿿s model; however, the average value of overestimation was only 18%. Moreover, draft force and power requirements of a three-blade disk plow working on a silty clay loam soil with the forward velocity of 7kmh⿿1, were 11.3kN, and 22kW, respectively, that were about 5% lower than the results obtained by the developed model (11.8kN, and 22.95kW). Therefore, the developed model can be used to calculate the disk plow draft force and power with reasonable accuracy.

Growth and fatty acid composition of sesame (Sesamum indicum L.) genotypes as influence by planting dates and nitrogen fertilization in semiarid region of Northwest, Pakistan

A field experiment was conducted on silty clay loam soil in the years 2011–2012. Two sesame (Sesamum indicum L.) cultivars (Local Black and Local White) were evaluated using various 3 different sowing dates (20th June, 10th and 30th July) and four agrotechnical level (0, 40, 80 and 120 kg N ha–1) at New Developmental Farm The University of Agriculture, Peshawar, Pakistan. The objective of this study was to evaluate the effects of sowing dates on growth, yield and oil fatty acid composition of two sesame cultivars grown under different nitrogen fertilization. Results showed that cv. Local Black was characterized by significantly higher content of oil (47%), seed yield (696 kg ha–1) and oil yield (335 kg ha–1) while cv. Local White had higher palmitic acid (8%) and linoleic acid (38.7%). Yield and its main components were positively affected by the earlier sowing date. With regard to fatty acid composition, a decrease in oleic and stearic acid and an increase in linoleic and palmitic acid were observed. At early sowing, oleic and palmitic acid decreased whereas linoleic and stearic acid increased. The decrease in the oleic/linoleic acid ratio observed at early sowing, suggests a possible role of temperature on the activity of oleate desaturase in the developing seeds. Intensive technology of cultivation (120 kg N ha–1), compared to the economical technology (40 kg N ha–1), significantly increased the seed yield of both sesame cultivars. This was due to higher number of branches, Capsules m–2, capsules plant–1, seeds capsule–1 and 1000 seed weight (g). The intensive technology of cultivation had a beneficial effect on the content of palmitic acid, linolenic acid and oleic acid in sesame seed.

Evaluating the relative air permeability of porous media from their water retention curves

AbstractAccurate modeling of water and air flow in porous media requires the definition of the relevant hydraulic properties, namely, the water retention curve (WRC) and the relative hydraulic conductivity function (RHC), as well as the definition of the relative air permeability function (RAP). Capitalizing on the approach developed previously to represent the RHC, a new model allowing the prediction of RAP based on information resulting from the WRC is proposed. The power value ηa in the model is a decreasing exponential function of the coefficient of variation, ɛ, characterizing the pore size distribution of the porous medium, and derived from its WRC. The model was calibrated using data from 22 disturbed and undisturbed soil samples and was validated using data from eight soil types ranging from quartz sand to silty clay loam. The proposed model provided accurate prediction of the soil RAP and performed in some cases (sandy loam and silty clay loam soils) better than available alternative models.

EFFECT OF APPLICATION TREAEED WATER AND DRY SLUDGE ON SIIL CONTAMINATION WITH PATHOGENIC BACTREIA

Research was conducted to assess the effect of treated waste water and dry sludge application on soil contamination by some pathogenic bacteria such as Pseudomonas aeruginosa , Fecal coliform and Fecal streptococci, which used as an indicator organisms for soil contamination by bathogenic bacteria. Composting sludge (T2) and non composting dry sludge (T1) applied to soil to assess the effect of compost of sludge on the number of pathogenic bacteria and soil contamination . Research consisted to identification and enumeration. The three pathogenic bacteria were examined at the mid and end of cultivation season. Factorial experiment with three replicate, using waste water treatment (W2) as a source of irrigation water, compared with tap water (W1).Composting sludge(T2) and non-composting sludge (T1), added and mixed with soil in three different levels 0, 30 , 60 ton .ha-1 .Pancium milicine was cultivated in pots weighted 10 Kg of silty clay loam soil. Results showed that the number of pathogenic bacteria Pseudomonas aeruginosa, Fecal coliform and Fecal streptococci. Were increased significantly with soil irrigated with waste water treatment, giving 5.88, 5.48 and 5.37 log cfu g-1dry soil respectively,compared with tap water 4.45, 4.29 and 2.97 log cfu g-1dry soil respectively. Results showed also significantly increment in the number of pathogenic bacteria with increase rate of dry sludge utilized to soil. The rate 60 ton.ha-1 was the highest number of pathogenic bacteria in soil 6.21, 5.78 and 5.24 log cfu g-1dry soil respectively. Results showed reduced in the number of pathogenic bacteria in composting sludge compared with non-composting sludge, with reduced proportion of 9.78 , 6.67 and 8.50 % respectively.

Calcium application mitigates salt stress in Date Palm (Phoenix dactylifera L.( offshoots cultivars of Berhi and Sayer

The effectiveness of exogenous application of calcium in ameliorating the adverse effects of salt stress (15.9 dS m-1) on date palm offshoots (Phoenix dactylifera L. cultivars of Berhi and Sayer) was investigated. Ca-fertilisers Polixal and Rexene were applied either as soil amendments or foliar spray. The results showed that Polixal at 30 ml offshoot-1 significantly increased plant height, leaf area, total chlorophyll content, RWC, proline concentration, peroxidase activity, IAA content, K+ and K+/Na+ ratio in leaves of Berhi cultivar, whereas catalase activity, ABA and Cl- content were decreased. Also Berhi cultivar responded to soil amendments more than to foliar spray. However, Ca-fertilisers mitigated salt stress in the two cultivars and Berhi cultivar was more salt stress tolerant than Sayer cultivar by maintaining the high ratio of K+/Na+ and regulating levels of IAA to ABA, in silty clay loam soil. These results suggest that calcium application can improve the defense system under salt stress conditions.

Finite analytic method based on mixed-form Richards’ equation for simulating water flow in vadose zone

Summary In this paper, we develop a finite analytic method (FAMM), which combines flexibility of numerical methods and advantages of analytical solutions, to solve the mixed-form Richards’ equation. This new approach minimizes mass balance errors and truncation errors associated with most numerical approaches. We use numerical experiments to demonstrate that FAMM can obtain more accurate numerical solutions and control the global mass balance better than modified Picard finite difference method (MPFD) as compared with analytical solutions. In addition, FAMM is superior to the finite analytic method based on head-based Richards’ equation (FAMH). Besides, FAMM solutions are compared to analytical solutions for wetting and drying processes in Brindabella Silty Clay Loam and Yolo Light Clay soils. Finally, we demonstrate that FAMM yields comparable results with those from MPFD and Hydrus-1D for simulating infiltration into other different soils under wet and dry conditions. These numerical experiments further confirm the fact that as long as a hydraulic constitutive model captures general behaviors of other models, it can be used to yield flow fields comparable to those based on other models.

Mineralization of carbon, nitrogen, phosphorus and sulphur from different organic wastes in silty clay loam soils

Mineralization of carbon, nitrogen, phosphorus and suphur was studied by incubating soil samples for 90 days at 30°C temperature with four different organic materials viz. Press mud, sugarcane trash, paper mill bagasse and pine needle. The results showed that the carbon mineralization in soil was significantly higher from sugarcane trash followed by press mud as compared to control. The cumulative percent of carbon mineralization increased with incubation period and maximum mineralization was recorded at 90 DOI (days after incubation). The maximum cumulative percent N-mineralization (16.88%) in soil was shown by paper mill bagasse followed by sugarcane trash and pine needle. The percent N-mineralization from all added organic amendments increased incubation period up to 45days of incubation DOI (days after incubation) after then it gradually declined, while the pine needles showed maximum cumulative P-mineralization in soil followed by sugarcane trash while minimum was recorded from press mud. The paper mill bagasse showed highest cumulative S-mineralization in soil followed by sugarcane trash. Irrespective of organic wastes, cumulative S-mineralization significantly increased after 15 days of incubation up to 45 days later on it showed declined trend. Among the organic wastes, sugarcane trash showed maximum Cmineralization in soil exhibited fast decomposition in comparison to other wastes. So, it can be used for composting.The paper mill bagasse showed more N and S mineralization while maximum mineralization of P was found in pine needle. The press mud and sugarcane trash showed potential for short duration enriched compost.

Fertilizer placement to maximize nitrogen use by fescue

ABSTRACTThe method of fertilizer nitrogen (N) application can affect N uptake in tall fescue and therefore its yield and quality. Subsurface-banding (knife) of fertilizer maximizes fescue N uptake in the poorly-drained clay-pan soils of southeastern Kansas. This study was conducted to determine if knifed N results in greater N uptake than the conventional top-dress application method in a deep, well-drained soil of east-central Kansas. The experiment, conducted in a Smolan silty clay loam soil, was a split-plot with fertilizer nitrogen rates 0, 140 and 280 kg N ha−1 applied as urea-ammonium nitrate (UAN, 28% N), knifed or top-dressed. Soil inorganic N [ammonium (NH4)- and nitrate (NO3–N)] and N in roots and plant tops were measured at various times during the growing season. At final harvest, most of the knifed N (99.7%) was accounted for in plant tissue (roots and tops) and soil, with more than half of the knifed N remaining as soil inorganic N. With the top-dressed method, 27% was unaccounted for and presumed lost in gaseous form. Knifing fertilizer N in fescue fields of east-central Kansas will maximize the availability of N, reduce potential N losses, and increase forage quality.

Transport of manure-borne testosterone in soils affected by artificial rainfall events

Information is very limited on fate and transport of steroidal hormones in soils. In this study, the rainfall simulation tests were conducted with a soil slab reactor to investigate the transport of manure-borne testosterone in a silty-clay loam soil under six controllable operation conditions (i.e., three rainfall intensities and two tillage practices). The properties [e.g., rainwater volume, particle size distribution (PSD)] of the slurry samples collected in runoff and leachate at different time intervals were measured; their correlation with the distribution of testosterone among runoff, leachate and soil matrix was analyzed. The results indicated that more than 88% of the testosterone was held by the applied manure and/or soil matrix even under the rainfall intensity of 100-year return frequency. The runoff facilitated testosterone transport through both dissolved and particle-associated phases, with the corresponding mass ratio being ∼7 to 3. Soil particles collected through runoff were mainly silt-sized aggregates (STA) and clays, indicating the necessity of using partially-dispersed soil particles as testing materials to conduct batch tests (e.g., sorption/desorption). No testosterone was detected at the soil depth >20 cm or in the leachate samples, indicating that transport of testosterone through the soil is very slow when there is no preferential flow. Tillage practice could impede the transport of testosterone in runoff. For the first time, results and the methodologies of this study allow one to quantify the hormone distribution among runoff, leachate and soil matrix at the same time and to obtain a comprehensive picture of the F/T of manure-borne testosterone in soil-water environments.

Rapid quantitative analysis of multi-components in Andrographis paniculata using UPLC-QqQLIT-MS/MS: Application to soil sodicity and organic farming

An ultra performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry method in multiple-reaction monitoring mode was developed for the rapid determination of 12 bioactive compounds in the leaf and stem of Andrographis paniculata (A. paniculata). Different soil conditions i.e., soil sodicity and use of organic manure was manually prepared and its effect on the extractive yield and quantity of bioactive phytoconstituents was studied. A good linear regression relationship (r2, 0.9988–0.9999), intra-day precision (RSD, 0.17–3.22%), inter-day precision (RSD, 0.31–3.44%), stability (RSD, 1.19–3.09%), and recovery (RSD, 1.03–3.20%) were obtained for all the analytes. The results showed significant differences in the content of diterpenoids, flavonoids, phenolics and triterpenoid compounds. Major markers i.e., andrographolide and neoandrographolide (187.5mg/g and 109.0mg/g, respectively) were detected highest in silty clay loam soil with addition of 3.5% organic manure in leaf of A. paniculata. This study was designed to benefit the cultivators by suggesting them about the suitability of soil and manure conditions to enhance the quantity of major bioactive compounds from A. paniculata. The present work described a highly specific, sensitive and rapid determination method of 12 bioactive compounds.

Effect of Conservation Tillage on the Physical and Mechanical Properties of Silty-Clay Loam Soil

Effect of Conservation Tillage on the Physical and Mechanical Properties of Silty-Clay Loam Soil

Residue Harvest Effects on Irrigated, No‐Till Corn Yield and Nitrogen Response

Crop residue harvest occurs on about 40% of Nebraska's 3,700,000 ha of corn (Zea mays L.) land, primarily for feeding of beef cattle. Immobilization of applied N is expected to be less with residue harvest due to reduced microbial activity for digestion of high C/N ratio organic material. Residue reduction may affect subsequent crop yield and response to applied N. Field research was conducted at three locations over 2 yr in eastern Nebraska for irrigated, no‐till corn following corn to determine residue harvest effects on yield and the economically optimal nitrogen rate (EONR). Study sites had deep silt loam or silty clay loam soil with good water infiltration and plant‐available water holding capacity. Mean aboveground biomass N content, applied N recovery efficiency, and grain yield were 22, 43, and 20% higher with &gt;75% residue removal compared with no residue removal. Agronomic efficiency of applied N use was not consistently affected. The residue removal effects were often greater in the third compared with second year of continuous corn. The residue removal effect on EONR was not consistent over site‐years, and the mean reduction in EONR with residue removal was between 10 and 20 kg ha−1.While removal of some corn residue is expected to result in higher yield of the following corn crop, reduction in applied N need cannot be well predicted before planting.

Herbicide combinations for control of complex weed flora in garden pea

A field experiment was carried out with twelve weed control treatments during the winter season of 2012–13 and 2013–14 on a silty clay loam soil to evolve an effective herbicide combination to control the complex weed flora in garden pea. Phalaris minor (28.8%), Alopecurus myosuroides (21.3%), Avena ludoviciana (15.8%), Lolium temulentum (12.1%) and Vicia sativa (16.7%) were found major weeds in experimental area. Pendimethalin 1000 g/ha supplemented with one HW at 45 DAS being statically at par to the application of pendimethalin 1000 g/ha (pre)fb imazethapyr + imazamox 60 g/ha (post) significantly reduced the density of major weeds. In general, the efficacy of the formulated mixtures whether as double knock or as a sole application was found better than the sole application of herbicides. Pendimethalin 1000 g/hafb one HW and pendimethalin 1000 g/ha fb imazethapyr + imazamox 60 g/ha being statistically alike with weed free resulted in significantly higher number of nodules, green pod yield and straw yield.