Least limiting water range: a potential indicator of physical quality of forest soils

Soil Research ◽  
2000 ◽  
Vol 38 (5) ◽  
pp. 947 ◽  
Author(s):  
C. Zou ◽  
R. Sands ◽  
G. Buchan ◽  
I. Hudson
Keyword(s):  
Forest Management ◽  
Plant Growth ◽  
Water Content ◽  
Forest Soils ◽  
Soil Compaction ◽  
Soil Strength ◽  
Matric Potential ◽  
Potential Indicator ◽  
Least Limiting Water Range ◽  
Water Contents

The interactions of the 4 basic soil physical properties—volumetric water content, matric potential, soil strength, and air-filled porosity—were investigated over a range of contrasting textures and for 3 compaction levels of 4 forest soils in New Zealand, using linear and non-linear regression methods. Relationships among these properties depended on texture and bulk density. Soil compaction increased volumetric water contents at field capacity, at wilting point, and at the water contents associated with restraining soil strength values, but decreased the water content when air-filled porosity was limiting. The integrated effect of matric potential, air-filled porosity, and soil strength on plant growth was described by the single parameter, least limiting water range (LLWR). LLWR defines a range in soil water content within which plant growth is least likely to be limited by the availability of water and air in soil and the soil strength. Soil compaction narrowed or decreased LLWR in most cases. In coarse sandy soil, initial compaction increased LLWR, but further compaction decreased LLWR. LLWR is sensitive to variations in forest management practices and is a potential indicator of soil physical condition for sustainable forest management.

scholarly journals Soil resistance to penetration and least limiting water range for soybean yield in a haplustox from Brazil

2005 ◽  
Vol 48 (6) ◽  
pp. 863-871 ◽  
Author(s):  
Amauri Nelson Beutler ◽  
José Frederico Centurion ◽  
Alvaro Pires da Silva
Keyword(s):  
Water Content ◽  
Soil Compaction ◽  
Dry Matter ◽  
Field Capacity ◽  
Soil Resistance ◽  
Soybean Yield ◽  
Randomized Experimental Design ◽  
Least Limiting Water Range ◽  
Dry Matter Weight ◽  
Resistance To Penetration

The objective of this study was determine the resistance to penetration (PR), least limiting water range (LLWR) and critical bulk density (Db-crit) for soybean yield in a medium-textured oxisol (Haplustox). The treatments represented the soil compaction by passing a tractor over the site 0, 1, 2, 4, and 6 times, with 4 replications in a randomized experimental design. Samples were collected from 0.02-0.05, 0.07-0.10 and 0.15-0.18 m depths. Soybean (Glycine max cv. Embrapa 48) was sowed in December 2002. Plant height, number of pods, aerial dry matter, weight of 100 seeds, and the yield in 3.6 m² plots were recorded. Soybean yield started reduction at the PR of 0.85 MPa and Db of 1.48 Mg m-3. The LLWR was limited in highest part by water content at field capacity (0.01 MPa tension) and in lowest part by water content at PRcrit, achieved the Db-crit to yield at 1.48 Mg m-3.

scholarly journals Soil Compaction Due to Increased Machinery Intensity in Agricultural Production: Its Main Causes, Effects and Management

2021 ◽  
Author(s):  
Songül Gürsoy
Keyword(s):  
Plant Growth ◽  
Soil Properties ◽  
Soil Compaction ◽  
Soil Bulk Density ◽  
Soil Strength ◽  
Environmental Consequences ◽  
Modern Agriculture ◽  
Environmental Events ◽  
Agricultural Areas ◽  
Number Of Passes

In modern agriculture, most of the field operations from sowing to harvesting are done mechanically by using heavy agriculture machines. However, the loads from these heavy machines may induce stresses exceeding soil strength causing soil compaction. Nowadays, soil compaction is considered as a serious form of soil degradation, which may have serious economics and environmental consequences in world agriculture because of its effects on soil structure, plant growth and environmental events. Vehicle load, inflation pressure, number of passes, stress on the soil, and soil properties (e.g. soil water content, soil texture, soil strength, soil bulk density) play an important role on soil compaction. This chapter reviews the works related to soil compaction in agricultural areas. Also, it discusses the nature and causes of soil compaction, the effects of the compaction on soil properties, environment and plant growth, and the possible solutions suggested in the literature.

scholarly journals Modelling soil moisture – soil strength relationship of fine-grained upland forest soils

Silva Fennica ◽  
2019 ◽  
Vol 53 (1) ◽  
Author(s):  
Jori Uusitalo ◽  
Jari Ala-Ilomäki ◽  
Harri Lindeman ◽  
Jenny Toivio ◽  
Matti Siren
Keyword(s):  
Water Content ◽  
Forest Soils ◽  
Model Performance ◽  
Rolling Resistance ◽  
Absolute Error ◽  
Field Studies ◽  
Soil Bulk Density ◽  
Soil Strength ◽  
Fine Grained ◽  
Strength Models

The strength of soil is known to be dependent on water content but the relationship is strongly affected by the type of soil. Accurate moisture content – soil strength models will provide forest managers with the improved ability to reduce soil disturbances and increase annual forest machine utilization rates. The aim of this study was to examine soil strength and how it is connected to the physical properties of fine-grained forest soils; and develop models that could be applied in practical forestry to make predictions on rutting induced by forest machines. Field studies were conducted on two separate forests in Southern Finland. The data consisted of parallel measurements of dry soil bulk density (BD), volumetric water content (VWC) and penetration resistance (PR). The model performance was logical, and the results were in harmony with earlier findings. The accuracy of the models created was tested with independent data. The models may be regarded rather trustworthy, since no significant bias was found. Mean absolute error of roughly 20% was found which may be regarded as acceptable taken into account the character of the penetrometer tool. The models can be linked with mobility models predicting either risks of rutting, compaction or rolling resistance.

scholarly journals Physical and Hydraulic Properties of Baked Ceramic Aggregates Used for Plant Growth Medium

2005 ◽  
Vol 130 (5) ◽  
pp. 767-774 ◽  
Author(s):  
Susan L. Steinberg ◽  
Gerard J. Kluitenberg ◽  
Scott B. Jones ◽  
Nihad E. Daidzic ◽  
Lakshmi N. Reddi ◽  
...  
Keyword(s):  
Plant Growth ◽  
Water Content ◽  
Hydraulic Properties ◽  
Root Zone ◽  
Pore Space ◽  
Large Change ◽  
Total Porosity ◽  
Volumetric Water Content ◽  
Matric Potential ◽  
Order Of Magnitude

Baked ceramic aggregates (fritted clay, arcillite) have been used for plant research both on the ground and in microgravity. Optimal control of water and air within the root zone in any gravity environment depends on physical and hydraulic properties of the aggregate, which were evaluated for 0.25-1-mm and 1-2-mm particle size distributions. The maximum bulk densities obtained by any packing technique were 0.68 and 0.64 g·cm-3 for 0.25-1-mm and 1-2-mm particles, respectively. Wettable porosity obtained by infiltration with water was ≈65%, substantially lower than total porosity of ≈74%. Aggregate of both particle sizes exhibited a bimodal pore size distribution consisting of inter-aggregate macropores and intra-aggregate micropores, with the transition from macro- to microporosity beginning at volumetric water content of ≈36% to 39%. For inter-aggregate water contents that support optimal plant growth there is 45% change in water content that occurs over a relatively small matric suction range of 0-20 cm H2O for 0.25-1-mm and 0 to -10 cm H2O for 1-2-mm aggregate. Hysteresis is substantial between draining and wetting aggregate, which results in as much as a ≈10% to 20% difference in volumetric water content for a given matric potential. Hydraulic conductivity was approximately an order of magnitude higher for 1-2-mm than for 0.25-1-mm aggregate until significant drainage of the inter-aggregate pore space occurred. The large change in water content for a relatively small change in matric potential suggests that significant differences in water retention may be observed in microgravity as compared to earth.

scholarly journals Least limiting water range in assessing compaction in a Brazilian Cerrado latosol growing sugarcane

2014 ◽  
Vol 38 (2) ◽  
pp. 432-443 ◽  
Author(s):  
Wainer Gomes Gonçalves ◽  
Eduardo da Costa Severiano ◽  
Fabiano Guimarães Silva ◽  
Kátia Aparecida de Pinho Costa ◽  
Wellingthon da Silva Guimarães-Junnyor ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Compaction ◽  
Structural Changes ◽  
High Water Content ◽  
Soil Conditions ◽  
Ratoon Crop ◽  
Industrial Processing ◽  
South Central ◽  
Four Levels ◽  
Least Limiting Water Range

In the south-central region of Brazil, there is a trend toward reducing the sugarcane inter-harvest period and increasing traffic of heavy harvesting machinery on soil with high water content, which may intensify the compaction process. In this study, we assessed the structural changes of a distroferric Red Latosol (Oxisol) by monitoring soil water content as a function of the Least Limiting Water Range (LLWR) and quantified its effects on the crop yield and industrial quality of the first ratoon crop of sugarcane cultivars with different maturation cycles. Three cultivars (RB 83-5054, RB 84-5210 and RB 86-7515) were subjected to four levels of soil compaction brought about by a differing number of passes of a farm tractor (T0 = soil not trafficked, T2 = 2 passes, T10 = 10 passes, and T20 = 20 passes of the tractor in the same place) in a 3 × 4 factorial arrangement with three replications. The deleterious effects on the soil structure from the farm machinery traffic were limited to the surface layer (0-10 cm) of the inter-row area of the ratoon crop. The LLWR dropped to nearly zero after 20 tractor passes between the cane rows. We detected differences among the cultivars studied; cultivar RB 86-7515 stood out for its industrial processing quality, regardless of the level of soil compaction. Monitoring of soil moisture in the crop showed exposure to water stress conditions, although soil compaction did not affect the production variables of the sugarcane cultivars. We thus conclude that the absence of traffic on the plant row maintained suitable soil conditions for plant development and may have offset the harmful effects of soil compaction shown by the high values for bulk density between the rows of the sugarcane cultivars.

scholarly journals Soil compaction and water content as factors affecting the growth of lodgepole pine seedlings on sandy clay loam soil

2005 ◽  
Vol 85 (5) ◽  
pp. 667-679 ◽  
Author(s):  
C. E. Bulmer ◽  
D. G. Simpson
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Compaction ◽  
Mechanical Resistance ◽  
Clay Loam Soil ◽  
Soil Water Regime ◽  
Loam Soil ◽  
Collar Diameter ◽  
Least Limiting Water Range ◽  
Root Collar

The response of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelman.) seedlings to three levels of soil compaction and water content was evaluated in raised beds filled with a sandy clay loam soil. In compacted soils, seedling survival, height, root collar diameter and root growth were reduced. Soil water regime was adjusted with irrigation to levels associated with plant moisture stress (near wilting point) and limiting soil aeration (near 0.10 m3 m-3 air-filled porosity). Soil water regime affected seedling performance, with higher survival, root collar diameter and root growth observed on treatments with higher water content. Compaction had detrimental effects on growth at all levels of soil water availability. Compaction and water content had strong effects on soil mechanical resistance. Limitations to seedling growth and survival were at least partly explained through their relationships with soil water content and soil mechanical resistance, and combinations of these factors as described by the least limiting water range concept. Key words: Soil compaction; soil physical properties; water availability; plant growth response; least limiting water range

scholarly journals Comportement mécanique d’un sol argileux. Effets de la taille des agrégats, de la teneur en eau et de la pression appliquée

1994 ◽  
Vol 74 (2) ◽  
pp. 185-191 ◽  
Author(s):  
H. Derdour ◽  
M. R. Laverdière ◽  
D. A. Angers
Keyword(s):  
Tensile Strength ◽  
Water Content ◽  
Soil Compaction ◽  
Applied Load ◽  
Aggregate Size ◽  
Sensitivity Threshold ◽  
Compaction Process ◽  
Teneur En Eau ◽  
The Subject ◽  
Water Contents

Soil compaction has been the subject of intense research in recent years, but the mechanisms involved in the compaction process remain poorly understood. The objective of this study was to characterize these mechanisms for a Kamouraska clay (Orthic Humic Gleysol) using beds of aggregates (1–2 mm and 2–3.4 mm) compressed into a uniaxial compression device. Changes in structural void ratio were monitored as a function of aggregate size, applied load and soil water content. Measurements of tensile strength and shrinkage were also made on the larger aggregates (2–3.4 mm) to investigate the involvement of the structural units in the soil compaction process. Aggregate size had little effect on the shape of the compression curves. Compression of the aggregate beds was mainly a function of applied load and water content. The compaction sensitivity threshold was about 0.20–0.22 g g−1 at compression loads of less than 200 kPa. This threshold water content corresponds to the air entry point and to the upper limit of the brittle domain of the aggregates during crushing. These results suggest the existence of a threshold water content above which the soil becomes susceptible to compaction even at low applied stress. Key words: Compression, shrinkage, aggregate tensile strength, threshold water contents

Effects of initial water content and soil mechanical strength on the runoff erosion resistance of clay soils

Soil Research ◽  
1993 ◽  
Vol 31 (5) ◽  
pp. 549 ◽  
Author(s):  
G Govers ◽  
RJ Loch
Keyword(s):  
Water Content ◽  
Water Uptake ◽  
Soil Strength ◽  
Clay Soils ◽  
Initial Water Content ◽  
Simple Relationship ◽  
Initial Water ◽  
Indirect Measure ◽  
Water Contents ◽  
Rill Flow

Effects of antecedent water content and soil strength on the resistance to erosion by overland (rill) flow were tested for two clay soils of the eastern Darling Downs, Queensland. Both shear and unconfined compressive strength of wet soil (for soil wet to saturation immediately prior to application of rill flow) mere higher for soil with initially high water contents than for soil initially air-dry. Rates of runoff erosion did not show a simple relationship with soil strength across the two soils, though for each soil, higher strength was associated with much lower rates of erosion. The results show that variations in initial water content can be associated with large chang;es in soil erodibility. Particularly for the initially wet soils of higher strength, rates of runoff erosion were controlled by rates of detachment of sediment. From size distributions of wet aggregates and of sediment, and from measured water contents of wet soil, it can be suggested that the extent of incipient failure of aggregates on wet;ting was a major factor controlling ease of detachment by rill flow, as it can be inferred that detachment of sediment involved breakdown of aggregates. Consistent with this, rates of runoff erosion across the two soils showed a direct relationship with the amount of water uptake on wetting, which appears to be a useful measure of susceptibility to detachment by rill flow. Water uptake on wetting would be an indirect measure of incipient failure and, hence, of aggregate strength.

scholarly journals Soluble sugars and germination of Annona emarginata (Schltdl.) H. Rainer seeds submitted to immersion in GA3 up to different water contents

2014 ◽  
Vol 36 (spe1) ◽  
pp. 281-287 ◽  
Author(s):  
Juliana Iassia Gimenez ◽  
Gisela Ferreira ◽  
Jaqueline Malagutti Corsato
Keyword(s):  
Seed Germination ◽  
Plant Growth ◽  
Water Content ◽  
Plant Growth Regulator ◽  
Soluble Sugars ◽  
Germination Percentage ◽  
Initial Water Content ◽  
Germination Test ◽  
Initial Water ◽  
Water Contents

The objective of this study was to evaluate the effect of different water contents achieved by Annona emarginata (Schltdl.) H. Rainer seeds during immersion in GA3 solutions, in variation of soluble sugars levels and germination. Seeds with 10% of initial water content were submitted to imbibition in GA3 solutions with concentrations of 0; 250; 500; 750 and 1000 mg L-1 and when they reached the water content of 15%, 20%, 25%, 30% and 35%, the quantification of soluble sugars levels and germination test were performed. Seeds immersed up to they reach 15% of water with GA3 and immersed up to the water acquisition of 20% without GA3, presented higher soluble sugars levels and germination percentage, which were decreased when the seeds reached 30% and 35% of water, independently of the presence of the plant growth regulator. It was conclude that different water contents reached by the seeds in immersion treatments with GA3 affect the soluble sugars levels and germination percentage of Annona emarginata seeds. Thus, in treatments with Annona emarginata, the seeds must remain immersed in water without GA3 up to they reach 20% of water, as higher water contents (35%) reduce the soluble sugars levels and the seed germination percentage.

A sensitivity analysis of the Jackson method of predicting unsaturated hydraulic conductivity

Soil Research ◽  
1992 ◽  
Vol 30 (3) ◽  
pp. 285 ◽  
Author(s):  
HP Cresswell
Keyword(s):  
Sensitivity Analysis ◽  
Hydraulic Conductivity ◽  
Water Content ◽  
Volumetric Water Content ◽  
Small Range ◽  
Matric Potential ◽  
Unsaturated Hydraulic Conductivity ◽  
Moisture Characteristic ◽  
Intended Use ◽  
Water Contents

An assessment is made of the sensitivity of the unsaturated hydraulic conductivity predictions from the Jackson model to changes in the measured moisture characteristic and matching factor hydraulic conductivity inputs. The model is shown to be sensitive to the volumetric water content corresponding to the matching factor hydraulic conductivity as well as to the 0 to -1.0 kPa matric potential section of the moisture characteristic input. The significance of this sensitivity is dependent on intended use of the data. Where accurate conductivity prediction is required over a small range of water contents near saturation, the moisture characteristic input used with this model should include measured points between 0 and 1.0 kPa matric potential.

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