Cone Index Values Research Articles

Evaluation of an empirical traction equation for forestry tires

Variable load test data were used to evaluate the applicability of an existing forestry tire traction model for a new forestry tire and a worn tire of the same size with and without tire chains in a range of soil conditions. The clay and sandy soils ranged in moisture content from 17 to 28%. Soil bulk density varied between 1.1 and 1.4g cm −3 with cone index values between 297 and 1418 kPa for a depth of 140 mm. Two of the clay soils had surface cover or vegetation, the other clay soil and the sandy soil had no surface cover. Tractive performance data were collected in soil bins using a single tire test vehicle with the tire running at 20% slip. A non-linear curve fitting technique was used to optimize the model by fitting it to collected input torque data by modifying the coefficients of the traction model equations. Generally, this procedure resulted in improved prediction of input torque, gross traction ratio and net traction ratio. The predicted tractive performance using the optimized coefficients showed that the model worked reasonably well on bare, uniform soils with the new tire. The model was flexible and could be modified to predict tractive performance of the worn tire with and without chains on the bare homogeneous soils. The model was not adequate for predicting tractive performance on less uniform soils with a surface cover for any of the tire treatments.

Tillage and residue effects on root growth and yields of grain sorghum following wheat

Crop production in the Southern Great Plains of TX (USA) is limited by insufficient precipitation. Furrow diking and residue management systems in water deficit regions can influence water infiltration, root growth and water extraction and, consequently, plant growth and yield. Field studies were conducted on a clay loam soil in unfertilized rotation systems to determine the influence of tillage and residue management practices on grain sorghum [ Sorghum bicolor (L.) Moench] rooting depth and changes in soil water content and cone index (CI). Treatments imposed on a wheat-sorghum-fallow (WSF) rotation system included furrow diking (FD), conventional tillage (CT), no-tillage with wheat ( Triticum aestivum) residue maintained on the field (NT+), and no-tillage with wheat residue removed from the field (NT−). Furrow diking and NT+ management systems increased sorghum grain yields 19 and 15%, respectively, compared to CT. Grain yields from the NT− system were not significantly different from the CT system. The FD system decreased CI and increased depth of rooting, profile water use and grain yield. Conventional tillage and NT− adversely affected these variables. Tillage operations loosened the soil and reduced the CI of the tilled layer. A decrease in CI values in the NT+ treatment was related to increased root development and penetration of roots to deeper soil layers. Root length in the 40 to 60 cm depth of FD and NT+ treatments was 30 to 85% greater compared to the CT and NT− treatments. Greater rooting densities, at all three growth stages (30, 60 and 90 days after emergence of sorghum), under FD and NT+ were associated with higher soil profile water contents. Data from this study show that profile water content, root development and sorghum grain yield can be significantly increased in semiarid regions with limited rainfall by incorporating furrow diking or surface residues into the management system.

AREA FOLIAR, LONGITUD DE RAICES Y PRODUCCION DE GRANO DE Amaranthus hypocondriacus L. EN UN SUELO COMPACTADO

A highly compacted soil layer was detected in an amaranth field in Tulyehualco, Mexico. The purpose of the present work was to analyze the effect of soil compaction on the crop of amaranth. Two plots with superficial (S) (10-15 cm) and intermediate (I) (20-25 cm) levels of compaction were compared. Several crop physiology parameters were studied and soil resistance was measured with a digital penetrometer. The cone Index values of both compacted soil layers were > 3 MPa. Amaranth plants from the S plot had 46% smaller leaf area (p<0.01) and were 12% shorter (p<0.01) than those from the I plot. The grain yield was significantly higher in plants from I compared to plants from S (68 vs 38 g/plant, p< 0.03). Concerning the root growth, the main roots of plants from S were 34% shorter than those from I (p<0.01). The adventitious roots emerging from the stem base were very prolific in both plots (non statistical differences were appreciated). Adventitious roots were 4-4.8 times longer than main of plants from either plot. In summary, our results show that the depth of compacted soil layer has a direct effect on the amaranth crop. Superficial soil compaction rendered short plants with lower grain yield whereas intermediate compaction resulted in taller plants with higher grain yield.

Incorporation of tracers and dazomet by rotary tillers and a spading machine

Soil fumigant efficacy in forest-tree and ornamental nurseries depends on the tillage tool used for incorporation. Maximum depth and uniformity of incorporation of surface applied materials by three rotary tillers and a spading machine were compared in a loamy sand nursery using ceramic-sphere tracers (1–3 mm diameter) and dazomet (tetrahydro-3,5,dimethyl-2H-1,3,5-thiadiazone-2-thione) micro-granules. Depth of incorporation in the top 30 cm of soil was evaluated by (1) recovery of incorporated spheres in 2 cm increments, (2) biocidal activity in 6 cm increments, and (3) cone resistance by 1.5 cm increments to 45 cm. Uniformity of incorporation was evaluated by sphere recovery and biocidal activity. Depths above which more than 95% of the spheres were recovered for the four implements were: 12.5 cm, Kuhn and Fobro rotary tillers; 17 cm, Northwest rotary tiller; 21 cm, Gramegna spading machine. The spading machine produced a distribution of spheres through the soil profile closest to a uniform distribution compared with that produced by the three rotary tillers. Lettuce seed ( Lactuca sativa L.) germination was inhibited in the upper 12 cm in low and high dazomet rate treatments, indicating that all four implements effectively incorporated dazomet into that zone. Maximum depth (24 cm) for total inhibition of germination was observed for the spading machine regardless of chemical rate. Cone index values showed the following maximum penetration: 14 cm, Fobro rotary tiller; 22 cm, Kuhn and Northwest rotary tillers; 27 cm, spading machine. All three measures of depth show a distinct superiority of the spading machine when the chemical fumigant must reach depths greater than 18 cm. Within transects across the width of the implement, variations of sphere counts among 5 cm 3 volumes were much larger for the rotary tillers than for the spade machine.

EFEITO DA PATINAGEM DA RODA MOTRIZ DE UM TRATOR AGRÍCOLA NA COMPACTAÇÃO DO SOLO

O rodado dos veículos que trafegam sobre uma área cultivada tornou-se um dos principais agentes de compactação dos solos agrícolas. O tipo de rodado, suas dimensões, velocidade de deslocamento, número de vezes que trafega sobre o mesmo local e carga suportada, por exemplo, são fatores que provocam maior ou menor compactação do solo. O objetivo do presente trabalho foi determinar, em condições de campo, a influência da patinagem da roda motriz de um trator agrícola na compactação de um solo de textura franca. Desenvolveu-se o experimento em blocos ao acaso, com quatro níveis de patinagem, 0, 10, 20 e 30%, e cinco repetições, com delineamento estatístico em parcelas subdivi-didas. Avaliou-se a compactação do solo pelo índice de cone, realizando-se trinta determinações, metade na linha de centro do rasto da roda motriz, metade no terreno ao lado, não compactado pela roda. A cada determinação, realizaram-se leituras de índice de cone para seis profundidades, a saber: 25; 50; 75; 100; 125 e 150 mm. Constatou-se que houve diferença significativa sobre o índice de cone apenas para os níveis 0 e 30% de patinagem. Os aumentos percentuais do índice de cone foram 19,2; 22,0 e 31,9%, quando se passou de 0 para 10, 20 e 30% de patinagem, respectivamente, embora não tenha havido diferença significativa na faixa de 10 a 20%. Constatou-se, também, que a maior influência da patinagem ocorreu até a profundidade de 50 mm.

Subsoiling and surface tillage effects on soil physical properties and forage oat stand and yield

Much of New Zealand's agriculture integrates animal and crop production on poorly drained, easily compacted soils. We hypothesized that soil properties affecting forage oat ( Avena sativa, cv Awapuni) establishment on land compacted by 15 years of conventional cropping might be influenced by various subsoiling and surface tillage combinations. Plots on a Moutoa silty clay (Typic Haplaquoll) were paraplowed (P), deep subsoiled (V), shallow subsoiled (S), or were left as non-subsoiled controls (C). Subsequently, the surface 15 cm was surface-tilled (T) using a power rotary-tiller and firmed with a Cambridge roller or were not tilled (N). Oats were then sown with a cross-slot drill. Subsoiling greatly reduced soil strength. Cone indices showed disruption to 40 cm with P, 36 cm for V, and 30 cm for S. Approximately 60% of profile cone indices to a depth of 0.5 m from subsoiled treatments were less than 1.5 MPa, compared to approximately 30% for C. T slightly improved strength distribution in non-subsoiled controls but had little effect in subsoiled treatments. Subsoiling without T continued to show improved profile cone index cumulative frequency 233 days after subsoiling. Subsoiling after T in this high rainfall climate eliminated most of the separation in cumulative frequency of soil profile cone index values by two weeks after T. T reduced emergence from 142 to 113 plants per square meter and reduced yield from 5318 to 3679 kg ha −1. Forage yield increased from 3974 to 4674 kg ha −1 with subsoiling. Soil porosity, saturated and slightly unsaturated hydraulic conductivities ( K SAT and K −40) and air permeability were highly variable but generally increased with subsoiling. Oxygen diffusion rate (ODR) (using Pt microelectrodes) was also variable, but N and C treatments had consistently lower ODRs than T or subsoiled treatments. Generally, subsoiling without T produced better soil conditions and oat crop performance than the prevailing New Zealand practice of T without subsoiling.

Normalizing Cone Resistance Values by Covariance Analysis

Measured cone index values were adjusted for soil water content and bulk density by normalizing their effects using a covariance analysis as described by Christensen et al. (1989). Cone indices adjusted by covariance analysis allowed the testing of tillage differences at a given depth and across depths. The procedure showed that double disking a Sharpsburg silty clay loam soil reduced the cone penetration resistance to 152 mm depth. The penetration resistance was similar in the deeper undisturbed zones. Unadjusted field measured cone indices showed differences in the deeper zones though no tillage was performed.

DROUGHT CONDITION ENERGY REQUIREMENT AND SUBSOILING EFFECTIVENESS FOR SELECTED DEEP TILLAGE IMPLEMENTS

ABSTRACT Draft requirement, fuel consumption, wheel slip, engine speed, and forward speed were measured for two-row Brown-Harden SuperSeeder, BushHog RoTill, Tye ParaTill, and Kelley (KMC) In-Row Tillage System on a Norfolk loamy sand (fme-loamy, siliceous, thermic Typic Paleudult) near Florence, SC. Cone index was measured with a recording penetrometer before and after tillage to evaluate soil disruption pattems. Cone index values before tillage showed that non-disked plots on which com had been grown the previous year had higher soil resistance at all depths than disked (conventional tillage) plots. The non-disked tillage plots had a lower initial soil water content because winter weeds had depleted soil moisture by evapotranspiration to greater depths than had been depleted by evaporation in the disked plots. Higher soil resistance and lower water content in non-disked tillage plots resulted in a wider pattern of soil disturbance for all implements, except the KMC, when compared to the disked plots; however, volume of soil disturbed was greater in the disked plots because subsoiler penetration was greater. Implement draft, wheel slip, and drawbar power were also signifi-cantly greater in non-disked plots. Among implements, there were significant differences (P = 0.05) for all measured parameters except engine speed. This study shows that when water is limited, the primary benefit of disking prior to deep tillage is for weed control. Weed control eliminates transpiration of soil water and thus reduces soil resistance and the energy required for subsequent deep tillage.

SOIL COMPACTION AND CROP RESPONSE TO WHEAT/SOYBEAN INTERSEEDING

ABSTRACT Tests were conducted in Coastal Plain soils for three years to determine proper fall primary tillage for a system that supports interseeding soybean into standing wheat. The residual effects of various tillage systems and controlled traffic on soybean yield, crop response, and hardpan formation were determined. Use of a Paratill greatly reduced soil compaction, especially in the E horizon. For each tillage system, there were no significant differences in cone index values measured two and eight months after tillage in non-traffic rows. A good correlation between average soil cone index in the E horizon and soybean root length was demonstrated. Deep tillage significantly increased wheat and soybean yields. Interseeded soybean consistently yielded more than double-cropped soybean planted after wheat harvest at irrigated and non-irrigated locations. Due to controlled traffic patterns associated with the interseeding system, only one deep tillage operation before small grain seeding is required for the wheat/soybean double-cropping system. The residual effect of deep tillage operations will extend for one additional year when interseeding is practiced in costal plain soils.

Gypsum as an ameliorant for subsoil hardpans

In many highly weathered soils, subsoil penetration by roots is severely limited by chemical and physical barriers such as Al toxicity, hardpans and dense textural B horizons. Previous work has demonstrated the efficiency of surface applied gypsum in ameliorating such chemical and physical barriers after sufficient time has elapsed to allow the gypsum to leach into the subsoil. Cone index (CI) was measured using a tractor-mounted computerized penetrometer on plots which had received gypsum 2 to 4 years prior to measurement. Water stable aggregates were measured by the wet sieving method. In all cases, surface gypsum application reduced CI values for the subsoil hardpan layers when the crops used were alfalfa, peaches and cotton. The gypsum treatments resulted in significantly improved rooting in the subsoil hardpans. The proportion of large water-stable aggregates in the dense B horizon was also increased. Under laboratory conditions, both CI and gravimetric moisture contens at high matric potential were higher then the soil was wetted with deionized water than saturated gypsum solution.These improvements in subsoil physical condition appear to be due to both a root effect and a direct effect of the gypsum on flocculation and aggregation.

Tillage Effects on Some Soil Physical and Corn Physiological Characteristics

AbstractTillage systems influence soil temperature and available soil water, which can influence photosynthetic rates and growth of corn (Zea mays L.). Field experiments were conducted in 1987 and 1988 in New York on a tile‐drained silt loam soil (fine‐loamy, mixed, nonacid, mesic Aeric Haplaquept) to determine to what extent conventional tillage (CT), no‐till (NT), and ridge tillage (RT) systems influence soil temperature and soil water conditions, thereby influencing CO2 exchange rates (CER) and growth of corn. Soil temperature at the 0.1‐m depth under NT averaged about 1 °C lower than CT and RT during the first 50 d after emergence (DAE). In 1987, when water stress was not a factor, the lower soil temperature under NT resulted in lower leaf, stem, and total phytomass throughout the vegetative period. Kernel growth rates, however, did not differ between tillage treatments (33.2, 30.9, and 31.4 g m−2 d−1 for CT, NT, and RT, respectively) which resulted in no differences in kernel phytomass at physiological maturity (1125, 1000, and 1030 g m−2 under CT, NT, and RT, respectively). During the hot and dry 1988 growing season, soil water pressure under CT at the 0.25‐m‐soil depth decreased to −0.1 MPa at 44 DAE, 13 d earlier than under NT anti RT. Cone index values were higher under NT and RT from the 0.07‐ to 0.22‐m‐soil depth which indicates increased soil mechanical resistance under NT and RT. The CER were significantly lower under NT or RT compared to CT on 8 of 10 measurement dates during a dry period in 1988 (34‐54 DAE) which was reflected in lower leaf, stem, and total phytomass during the vegetative period. Likewise, NT had a lower kernel growth rate (19.6 compared to 27.4 and 23.4 g m−2 d−1 under CT and RT, respectively), which resulted in lower kernel phytomass at physiological maturity. The data suggest that increased soil mechanical resistance can develop under a continuous NT and RT system which can decrease soil water uptake, CER and growth of corn when dry conditions occur during vegetative development.

Soil Strength Properties Under Four Tillage Systems at Three Long‐Term Study Sites in Indiana

AbstractThere is increasing concern that long‐term continuous conservation tillage may cause increased surface soil strength and compaction detrimental to root growth and crop yield. The objective of this study was to characterize distribution of cone index (CI) and vane shear strength (VS) values at three row positions: in row (R), non‐wheeltrack interrow (NW), and wheeltrack interrow (WT), under four tillage systems: conventional moldboard plow (PL), chisel plow (CH), ridge‐till‐plant (RT), and no‐till (NT), on three long‐term tillage studies on silty soils in Indiana. The Mollisol and Alfisols studied had been under the continuous tillage treatments for 13, 8, and 4 yr, respectively. Maximum cone index (CImax) averaged over three row positions was in the order RT &gt; CH, NT &gt; PL. As less tillage was performed, the zone of maximum strength was closer to the soil surface. Depth of CImax was in the order PL &gt; CH &gt; NT, RT. On the two Alfisols, soil strength in the non‐trafficked positions (NW and R) tended to be lower in no‐till than in the other tillage treatments, especially in the lower portion (below 15 cm) of the formerly tilled zone. High‐strength layers were recorded at 23 to 40 cm and 15 to 22 cm on the PL and CH treatments, respectively. Wheeltrack compaction was more severe under RT and NT than on PL and CH. Vane shear data generally verified the tillage and row position effects found with the cone penetrometer.

Cone Index Values Diagnostic of Where Subsoiling Can Increase Corn Root Growth

AbstractTo identify root restrictive layers in a field using a penetrometer, a diagnostic cone index (CI) value indicative of restricted root growth must be known for the particular soil and crop. This investigation identified diagnostic CI values indicative of where corn (Zea mays L.) root abundance could be increased by subsoiling. Two tillage treatments were evaluated in seven Typic and Arenic Paleudults from 1985 through 1987. Penetrometer readings were made weekly in the plant row of both tillage treatments to a depth of 0.4 m. Roots were described primarily between 77 and 90 d after planting (DAP). Root observations were expressed on a proportional basis and were termed relative root abundance. Regression analyses showed that relative root abundance in the chiseled treatment was related to mean CI, depth, and clay percentage (R2 = 0.85). By 77 to 90 DAP, subsoiling significantly (P&gt; 0.10) reduced mean CI as compared to the chiseled treatment at depths below 0.1 m, while significant increases in relative root abundance as a result of subsoiling were found primarily at 0.3 to 0.4 m. Diagnostic CI values for the chiseled treatment were identified where relative root abundance could be increased by subsoiling. Diagnostic CI values decreased with soil depth and increased with clay percentage. For a depth of 0.35 m, subsoiling was estimated to increase root abundance where the mean CI over a 3‐ to 5‐wk period was greater than approximately 1.5, 3.0, and 4.5 MPa for soil layers having clay percentages of 4, 12, and 20%, respectively.

Traction prediction equations for radial ply tyres

Three radial tyres (16.9R38, 18.4R38 and 24.5R32) were tested in two different soil types (Capay clay and Yolo loam), five different soil treatments (conditions) in each of the two soils, at three different axle loads and two different inflation pressures to obtain traction prediction equations for radial tyres. The field data were analysed to obtain traction prediction equations under varying soil and loading (vertical load, inflation pressure) conditions for radial ply tyres. Simulation studies were conducted to determine the effect of soil conditions, dynamic load on the axle and inflation pressure on the tractive performance of radial ply tyres. The results indicate that (i) changes in soil conditions influence tyre performance much more than changes in tyre loading and dimensions; (ii) in a given soil condition the 24.5R32 tyre appears to perform better than the other two tyres; (iii) the performance of the 18.4R38 tyre was similar to that of the 16.9R38 tyre, although at lower soil cone index values, the 18.4R38 tyre performed slightly better than the 16.9R38 tyre.

Bulk Density Values Diagnostic of Restricted Root Growth in Coarse‐textured Soils

AbstractBulk density values diagnostic of both moderate and excessive levels of soil compaction have not been conclusively identified. This study estimated diagnostic bulk density values related to conditions where root elongation was virtually stopped due to high mechanical impedance, and also to the less compact condition where root growth was occurring but where subsoiling could be used to increase root growth and yield. Undisturbed cores were collected from Ap, E‐B, and B horizons of 24 Paleudults and Hapludults. Each core was equilibrated to a soil water potential of −0.1 MPa and mechanical impedance was determined and expressed as a cone index (CI). Bulk density and particle size distribution were also measured. A model was developed to estimate CI from bulk density (ρb) and percentages of sand, clay, and very fine sand (0.125‐0.050 mm diam). Using the CI model and previously published soil, tobacco (Nicotiana tabacum L.) root, and tobacco yield data, diagnostic CI values related to zero root growth and significant subsoiling effects on both root growth and yield were estimated. The combinations of ρb and texture that produced the diagnostic CI values were then computed for four textural classes having very fine sand percentages of 0, 10, and 20%. The minimum bulk density values associated with where subsoiling increased both root number and yield over that of a moldboard plow/disk treatment were 1.66, 1.61, 1.60, and 1.58 Mg m−3 for the sand, loamy sand, sandy loam and sandy clay loam textural classes, respectively, having 10% very fine sand. It was estimated that root concentration would be zero at bulk densities of 1.85, 1.82, 1.81, and 1.80 Mg m−3 for these same textural classes.

Cone Index Prediction of Compacted Soils

ABSTRACT THE cone index prediction equation for three soil textures varying in organic matter contents that were subjected to three levels of compaction energy was obtained. The equation is of the form: (CI/Pc) = A (Ts/Qp)^. The functional form of A and n was determined for sandy loam, clay loam and clay for varying moisture contents. The cone indices of the soils estimated with the developed model were in close agreement with measured values. The validation of the model with field measured cone index values showed a high degree of accuracy between measured and predicted values.

Design and Field Evaluation of a Hand-Pushed Digital Soil Penetrometer with Two Cone Materials

ABSTRACT AN experimental electronic hand-pushed soil penetrometer was mated with a commercial data logger to provide a portable penetrometer for determination of soil resistance to penetration in tillage studies. Machine pushing at the ASAE standard rate and at a much slower rate did not improve the performance over hand-pushing at the ASAE standard rate. Stainless steel and Delrin cones produced somewhat different cone index values in two of the three soils tested.

Cone Index of Loamy Sands as Influenced by Pore Size Distribution and Effective Stress

AbstractTillage pans form in coarse textured soil horizons of the Atlantic Coastal Plain and develop high cone index values (soil strengths) which slow root growth and may decrease crop yields. Identification of soil properties that influence cone index may improve field identification of tillage pans and lead to the development of techniques to reduce their detrimental effects. This study examined the influence of pore size distribution, and effective stress on the cone index of loamy sand and loamy fine sand soil materials. Effective stress values were calculated from soil water characteristic curves and compared to cone index values for both natural cores and remolded materials. The remodeled samples of a loamy sand and a loamy fine sand developed different cone index values for relative saturations between 1.00 and 0.10, and these cone index differences were partially related to pore size distribution differences between materials. Pore size distribution influenced cone index by controlling effective stress. In both remolded samples and undisturbed cores of loamy sand, effective stress values ranged from 0 to 33 kPa for soil water potentials between 0.0 and −1500 kPa, respectively. For relative saturation values between 1.00 and 0.10, changes in effective stress closely conformed to changes in cone index for nondispersed soil materials. At a given effective stress, cone index was influenced by bulk density and soil particle characteristics that influence interparticle friction.

Relationships between soil mechanical properties

Soil mechanical properties include basic properties, such as cohesion, and composite properties, such as penetration resistance. Knowledge of the connections between soil mechanical properties is useful in estimating and/or selecting appropriate property values in solving problems in agricultural soil mechanics. Such connections can be found by visualizing the basic properties using the Critical State Soil Mechanics Model and by hypothesizing that, if any two mechanical properties arise from the same physical phenomenon, then they are likely to be connected. Relations are given between uniaxial compression tests and triaxial compression tests, between cohesion and tensile strength, and between unconfined compressive strength and tensile strength. A graph is given to convert index values measured with cone tip angles other than 30° into 30° cone index values.

On the applicability of soil water finite difference models to operational trafficability models

Certain current operational trafficability models (e.g. SMSP) use soil moisture models which are empirically based and have a relatively coarse time increment. It is proposed that the inclusion of a soil water finite difference model may more realistically represent the detailed soil water flux changes that occur near the surface, and thus provide an improved forecasting capability. Results are present which show the important role evaporation can play in its effect upon rating cone index values, emphasizing the need need to have a dynamic soil water model in trafficability modelling.