Effects Of Subsoil Compaction Research Articles

Subsoil compaction caused by heavy sugarbeet harvesters in southern Sweden: I. Soil physical properties and crop yield in six field experiments

The introduction of six-row sugarbeet harvesters, with total loads of approximately 35 Mg on two axles, caused major concern among Swedish sugarbeet ( Beta vulgaris L.) growers regarding the risk for subsoil compaction. A project was started in 1995, which included six long-term field experiments in southern Sweden. The objective was to study effects of heavy axle load traffic during harvest of sugarbeets on penetration resistance, saturated hydraulic conductivity, bulk density and crop yield. Three of the field sites were loams (Eutric Cambisols), two were sandy loams (Eutric Cambisols) and one was sand (Haplic Arenosol). The treatments were: no traffic, four passes by a three-row harvester towed by a tractor (approximately 18 Mg total load on four axles, tyre inflation pressure of tractors 100–150, and 200–250 kPa for the harvester) and one and four passes by a self-propelled six-row harvester (approximately 35 Mg total load on two axles, tyre inflation pressure 200–240 kPa). Traffic was applied late in the autumn at a soil moisture content close to field capacity, but the treatment with four passes with a six-row harvester was also carried out under drier conditions earlier in the autumn. In the spring after traffic, no significant changes in penetration resistance were found. When measured 2–4 years after traffic, significant changes between treatments were found to 0.5 m depth on three sites. Differences between years are possibly an effect of age-hardening. Saturated hydraulic conductivity at 0.3 and 0.5 m depth, measured on cores sampled in the spring after traffic, was in several cases reduced by about 90% after four passes with a six-row harvester. As an average for all sites, this traffic significantly reduced saturated hydraulic conductivity and increased bulk density at 0.5 m depth. At two sites, measurements were repeated 4 years after traffic and differences in saturated hydraulic conductivity between treatments were approximately the same as on the first sampling occasion. Despite the great effects on soil physical properties, differences in yield between treatments were mainly small and insignificant. The data concerning saturated hydraulic conductivity may be useful for modelling the effects of subsoil compaction, for example on erosion and denitrification, since little such data is available in the literature. The results clearly demonstrate to farmers that heavy traffic during harvest of sugarbeet implies a major risk for compaction of the subsoil, which can be seen as a long-term threat to soil productivity.

Subsoil compaction effects on crops in Punjab, Pakistan: I. Soil physical properties and crop yield

Traffic on agricultural land, inappropriate tillage, and poor timing of field operations cause subsoil compaction, which decreases soil productivity and crop yields. A field experiment was conducted during 1997–1998 and 1998–1999 on a sandy clay loam (fine-loamy, mixed, hyperthermic Typic Haplargids, USDA; Luvic Yermosol, FAO) to study subsoil compaction effects on soil physical properties, and yield of wheat ( Triticum aestivum L.) and sorghum ( Sorghum bicolor L. Moench). Soil compaction was artificially created once at the start of the study. The 0.15 m top soil layer was manually removed with a spade. The exposed layer was compacted with a mechanical compactor to a bulk density of 1.93 Mg m −3. The topsoil was then again replaced above the compacted subsoil and levelled. Both compacted and control plots were hoed manually and levelled. This soil compaction treatment resulted in a 38% decrease in grain yield of wheat during 1997–1998 and 8% during 1998–1999. In contrast, straw yield decreased by up to 12% in 1997–1998 and was not affected in 1998–1999. The number of fertile tillers was significantly lower during 1997–1998 in the compacted treatment than in control. However, plant height and 1000-grain weight were unaffected by compaction. In accord with bulk density, penetration resistance increased and total porosity and air-filled porosity decreased significantly due to subsoil compaction. Subsoil compaction reduced both the water and nutrient use efficiencies of wheat by about 38% in the first year and 9% in the second year. Soil compaction also reduced fodder yield, and water and nutrient use efficiencies of sorghum by 22% in 1998 and 14% in 1999. After three crops, soil bulk density and penetration resistance decreased in the compacted zone, indicating the ameliorating effect of cropping on soil physical properties. The subsoil compaction effects on soil properties and yield, however, persisted for 2 years. Results showed that subsoil compaction adversely affected soil physical properties, which decreased yields as well as water and nutrient use efficiencies by crops. Therefore, appropriate measures such as periodic deep ploughing, controlled traffic, conservation tillage, and incorporating of crops with deep tap root system in rotation cycle is necessary to minimize the risks of subsoil compaction.

Influence of a compacted loam subsoil layer on growth and yield of irrigated cotton in Southern Spain

Subsoil compaction, which may occur naturally or be a consequence of machinery traffic, causes reductions in crop yields. The aim of this work was to characterize the effects of subsoil compaction on growth and yield of cotton ( Gossypium hirsutum L.) under field conditions. Two field experiments were carried out in Córdoba, Spain, on an Eutric Fluvisol with loam texture. A treatment with a compacted layer (bulk density of 1.6–1.7 Mg m −3) at 0.2–0.4 m depth was compared with a control treatment with maximum bulk density of about 1.4 Mg m −3. Soil resistance to penetration was related to soil bulk density and water content. The compaction provoked reductions in root length (40% in 1996 and 33% in 1997), leaf area index (26% in 1996 and 12% in 1997), evapotranspiration (12% in 1996 and 7% in 1997) and seed cotton yield (28% in 1996 and 10% in 1997). Average resistance to penetration in the compacted layer was above 3 MPa (a threshold for cotton root growth according to the literature) but root growth was observed below this layer. It was speculated that spatial variation of soil bulk density and resistance and temporal variation of soil water content allowed the roots to find weaker path-ways to cross the compacted layer. The effect of the subsoil compaction on the soil characteristics and the root growth remained during the second experimental year but it was less pronounced on the above ground plant growth, development and yield. It was concluded that subsoil compaction influences significantly growth and yield of cotton, but successive cropping may alleviate the effects of the compaction.

Subsoil compaction due to wheel traffic.

The article reviews those major soil properties and traffic factors, which together influence subsoil compaction resulting from the passage of agricultural vehicles. Likewise, the effects of subsoil compaction on soil properties, processes and crop growth are discussed on several levels, from methods of measuring to the persistence of compaction effects. The risk of subsoil compaction exists whenever moist soils are loaded with heavy axle load and moderate to high ground contact stress. Subsoil compaction tends to be highly persistent. To avoid the risk of long-term deterioration, limits for the induction of mechanical stresses in the subsoil should be established through international teamwork.;

Root and shoot response of field-grown lettuce and broccoli to a compact subsoil

The direct effect of subsoil compaction on the root and shoot growth of lettuce (Lactuca sativa ‘Classic’) and broccoli (Brassica oleracea L. Italica ‘Bushido’) was investigated in field experiments. Possible secondary effects of the compact subsoil were minimised through careful supply of water and nutrients to the soil. Roots were sampled at 3 times to determine the timing and extent of root growth into the compact subsoil. The compact treatment had a distinct layer of high strength soil at 0·17-0·35 m, maximum soil strength of 3·1 MPa at 0·27 m. In the loosened treatment, deep ripping reduced the maximum subsoil strength to 1·9 MPa at 0·35 m. The roots of both crops penetrated the compact subsoil approximately half-way through the vegetative growth phase of the shoots. Root growth was restricted by the compact subsoil, with root length densities 60-75% lower than in the loosened subsoil. As a result, only 6-13% of the total root system was present in the compact subsoil. The reduced root length in the subsoil was compensated for by increased root growth in the topsoil, for the broccoli crop only. The compact subsoil had no effect on the shoot growth or yield of either vegetable crop when water and nutrientswere well supplied. This may have been due to the small proportion of roots growing in compact soil and/or the advanced vegetative growth stage of the shoots when the roots grew into the compact subsoil. Consequently, under dield conditions, a compact subsoil had no direct effect on vegetable crop shoot growth or yield.

Effect of Subsoil Compaction and Three Densities of Simulated Root Channels in the Subsoil on Growth, Carbon Gain and Water Uptake of Pinus radiata

The experiment investigates effects of subsoil compaction, of three densities of simulated root channels through the compacted layer, and of fertiliser addition on growth, carbon gain and water relations of Pinus radiata. Treatments were designed to simulate subsoil compaction produced by a previous tree crop and access to depth through the compacted layer via old root channels. Comparisons were also made of diurnal carbon assimilation, micro-climate, water potential, and mineral nutrition of well-exposed foliage. Subsoil compaction was negatively associated with growth, plant water potential, foliar nutrient concentration, water uptake and diurnal carbon gain per unit foliage area. All treatments with compacted subsoil grew more slowly than controls, and an interaction between root access to depth and nutrition is indicated. Diurnal carbon gain per unit foliage area of trees growing on unperforated, compacted subsoil was about 0.78 that of controls, while stem growth was about 0.56 that of controls. Root growth of trees on compacted subsoil with the largest number of root channels showed an effect of fertilisation on growth. Fertilised trees in this compaction treatment had a significantly greater fine root biomass in the upper 0.3 m of the profile, greater access to water at depth, higher plant water potential, higher soil water content below the compacted subsoil layer, and greater growth than unfertilised trees in the same soil compaction treatment.

Effects of compaction and simulated root channels in the subsoil on root development, water uptake and growth of radiata pine.

Effects of subsoil compaction and simulated root channels (perforations) through the compacted layer on root growth, water uptake, foliar nutrient concentration and growth of radiata pine (Pinus radiata D. Don) were studied in a field experiment where a range of treatments were applied in reconstituted soil profiles. Subsoil compaction adversely affected root penetration in deeper parts of the soil and consequently caused greater water stress in trees. However, the effect of compaction was largely overcome when the subsoil was perforated to render 0.2% of the soil volume into vertical channels. Roots showed a remarkable ability to reach the points of low penetration strength and to travel through them to deeper parts of the profile. Perforations through compacted soil layers at a relatively low frequency may be a practical solution to allow root development into deeper parts of the soil and allow greater soil water exploration by roots.

A model for estimating crop yield losses caused by soil compaction

A computerized empirical model for estimating the crop yield losses caused by machinery-induced soil compaction and the value of various countermeasures is presented, along with some examples of estimations made with it. The model is based mainly on results of Swedish field trials, and predicts the effects of compaction in a tillage system that includes mouldboard ploughing. It is designed for use at farm level and predicts four categories of effects: (1) Effects of recompaction after ploughing. The calculations are based on the wheel track distribution in the field and the relationship between “degree of compactness” of the plough layer and crop yield. (2) Effects of plough layer compaction persisting after ploughing. Crop yield losses are estimated from traffic intensity in Mgkm ha −1 (Mgkm = the product of the weight of a machine and the distance driven), soil moisture content, tyre inflation pressure and clay content. (3) Effects of subsoil compaction. The calculations are similar to those presented under point (2), but only vehicles with high axle load are considered. These effects are the most persistent. (4) Effects of traffic in ley crops. The estimations are based on wheel track distribution, soil moisture content and several other factors.

Influence of subsoil compaction on the uptake of 45Ca from the soil profile and on maize yield

The effect of subsoil compaction on maize dry matter content and green tops yield was investigated in a lysimeter experiment. After labelling several layers of the soil profile with 45Ca the uptake of this isotope was determined. Maize green tops yield increased and dry matter content decreased with increasing subsoil bulk density. Total uptake of 45Ca had a minimum at 1.55 g cm −3 and was not different for 1.45 and 1.70 g cm −3. The concentration of 45Ca in the dry matter was higher at 1.70 g cm −3 than at 1.55 and 1.45 g cm −3, where it was similar.

Temporal Effects of Subsoil Compaction on Soil Strength and Plant Growth

AbstractIn recent years, scientists have become concerned that heavy farm equipment is causing soil compaction below the nominal depth of tillage. Compaction this deep may not be ameliorated after one season's freeze‐thaw and wet‐dry cycles. Experiments were conducted on a Kewaunee (fine, mixed, mesic Typic Hapludalf) and Rozetta (fine‐silty, mixed, mesic Typic Hapludalf) soil to determine the duration and effect of subsoil compaction on soil strength and corn (Zea mays L.) growth. Soil at two sites was compacted with 8 and 12.5 Mg axle loads in the spring of 1983. Cone‐penetration resistance of compacted soil was significantly higher than that of uncompacted soil below the plow zone. Plant heights, at physiological maturity averaged across both sites, were reduced 13 and 26% on the 8‐ and 12.5‐Mg compaction treatments, respectively, compared with the control in 1983. In 1984, average mature plant heights were 2.4, 2.3, and 2.3 m for the control, 8‐, and 12.5‐Mg compaction, respectively. Three years after the compaction was applied (1986), the average mature plant height for the 8‐ and 12.5‐Mg compacted sites were reduced 3.1 and 4.3% compared with the control. Nitrogen and K uptake was reduced by compaction. Iron, Al, and Mn uptake increased with increasing levels of compaction on the Kewaunee soil in 1983. In 1983, yields for the 8‐ and 12.5‐Mg treatments on the Rozetta soil were reduced 4 and 14%, respectively, relative to the control. Similarly, yields for the Kewaunee soil were reduced 14 and 43%. Yields for the Kewaunee soil were not reduced by compaction in 1984, although 5 and 9% reductions were observed at the Rozetta site. Yields were not affected the following 2 yr (1985 and 1986), whereas the resistance to cone penetration was significantly higher in the compacted plots compared with the control.

Corn Growth and Yield as Affected by Surface and Subsoil Compaction

AbstractWheel traffic of harvesting operations on agricultural fields often carries compactive loads in excess of 8 Mg. Consequently, soil physical properties may be affected to depths of 60 cm, and these effects of compaction may persist for a number of years. In addition, smaller compactive forces that affect only the surface layer of soil are applied annually during spring tillage and planting operations. A replicated field study was conducted on a Webster clay loam (fine‐loamy, mixed, mesic Typic Haplaquolls) in southern Minnesota, and two Ves clay loams (fine‐loamy, mixed, mesic Udic Haplustolls) in southwestern Minnesota to assess the effects of surface and subsoil compaction on the growth and yield of corn (Zea mays L.). A total of six compaction treatments was imposed; subsoil compaction of control (no subsoil compaction), 9 Mg per axle, and 18 Mg per axle loads, each with and without annually applied interrow surface compaction of <4.5 Mg per axle. During the first year after high axle loading, 9 and 18 Mg per axle loads significantly decreased final grain yield by 9 and 30%, respectively, on the Webster soil. For the second year, the 18 Mg per axle treatment significantly reduced yield by 12% as compared with the control treatment. Soil water loss data indicated a more shallow rooting depth and/or reduced root activity in the 18 Mg per axle treatment. High axle loads on a dry Ves soil caused little subsoil compaction; grain yield was reduced by only 6% the first year after high axle loading. High axle loads on a relatively wet Ves soil compacted the soil to a depth of 60 cm. However, relatively dry climatic conditions the following year negated any potential adverse effects of subsoil compaction and yields were not affected. Surface layer compaction from annual interrow wheel traffic did not cause a significant yield response consistently at any site.

Vehicle and wheel factors influencing soil compaction and crop response in different traffic regimes

A review is made of effects of machinery traffic on soils and crops, including stress distribution under running gear, soil response to applied stresses, influence of compaction on soil properties and processes, persistence of compaction, and crop response to compaction. The influence of machinery traffic on the crops is divided into several categories: direct damage to growing plants; effects of the state of compactness of the plough layer; residual effects in this layer after re-loosening; effects of subsoil compaction. Traffic intensity and wheel track distribution in different cropping systems are illustrated, and several possibilities for reducing heavy traffic or its negative effects, or to alleviate compaction, are discussed. The present situation in different parts of the world with regard to soil compaction is evaluated, and examples of economic analyses are presented.

Effects of Subsoil Compaction on Corn Yields

ABSTRACT SOIL compactilon has been recognized for several years as having a detrimental effect on plant growth. Since tillage generally loosens the soil in the plowed layer, it was hypothesized that perhaps much of the compaction problem was in the subsoil layer. This compacted layer is often referred to as a plow pan. During the winter of 1979-80 experiments were carried out both in the field and in the laboratory to determine the effect of freeze-thaw cycling on compacted layers. The effects of cycle duration, initial soil moisture, and free water availability were noted. The indications are that the cumulative effects of sub-soil compaction in Indiana can severely reduce corn growth, vigor, and yield. The natural forces of freezing and thawing do not appear to be reliable agents of pan breakup.