Soil porosity and water infiltration as influenced by tillage methods
Introduction
Measurements of pore characteristics are becoming more and more used to characterize soil structure since they influence numerous functions in soils. One important function of soil is transmission of water, which directly affects plant productivity and the environment. Infiltration of water increases water storage for plants and groundwater recharge and reduces erosion. The rate of infiltration is controlled by the pore size distribution and the continuity of pores or pathways (Kutílek, 2004). The role of macro-pores in rapid infiltration under ponded conditions (preferential flow) was stressed in numerous papers (Ehlers, 1975, Lin et al., 1996, Arvidsson, 1997, Guérif et al., 2001). Lin et al. (1996) reported that 10% of macro-pores (>0.5 mm) and meso-pores (0.06–0.5 mm) contributed about 89% of the total water flux. As shown by Ehlers (1975), the maximum infiltrability of conducting channels in untilled soil was more than 1 mm/min, although the volume of these channels amounted to only 0.2 vol.%. The preferential flow has also been observed in an unsaturated soil under non-ponded conditions (Deeks et al., 1999). Therefore, this flow has been increasingly recognised as a major component of water movement in many soils, particularly clays (Armstrong et al., 1999). Incorporating the preferential flow component into models that assume a horizontally homogeneous soil profile improves their performance in predicting water distribution and chemical movement in soil profile (Walczak et al., 1996, Borah and Kalita, 1999, Kumar et al., 1999, Ludwig et al., 1999).
In addition, a soil matrix with macro-pores will offer greater potential for undisturbed root growth because the roots can bypass the zones of high mechanical impedance (Gliński and Lipiec, 1990, Lipiec and Hatano, 2003). The structure and functions of macro-pores can be an effective measure of soil ‘quality’ as they are relatively resistant to vertical compression (Alakukku, 1996). Lin et al. (1999) proposed to incorporate macro-porosity as a criterion of soil structure in the soil morphological system.
Tillage largely influences pore size distribution. Soils under conventional tillage (CT) generally have lower bulk density and associated higher total porosity within the plough layer than under no tillage (NT). The changes in total porosity are related with alterations in pore size distribution. This relation can be different depending on soil type. Schjønning and Rasmussen (2000) reported that under the same site conditions, NT compared to CT resulted in lower volume of macro-pores (>30 μm) on sandy soil and silty loam, whereas the opposite effect was found on sandy loam. Kay and VandenBygaart (2002) reported in their review that converting from CT to NT generally results in an increased volume fraction of pores 100–500 μm and a decreased volume of pores 30–100 μm.
The effect of soil tillage and management on transmission properties is not uniform. The results showed that untilled compared to tilled soil had greater (Freebarin et al., 1986, Arshad et al., 1999, McGarry et al., 2000), similar (Ankeny et al., 1990) or lower infiltration rates (Gantzer and Blake, 1978, Gómez et al., 1999, Rasmussen, 1999). The inconsistencies can be associated with pore functioning. In NT soils, greater infiltration was attributed to greater contribution of flow-active macro-pores made by soil fauna or by roots of preceding crops (Tebrügge and Düring, 1999), whereas in tilled soils with stable structure—to preferential flow through interaggregate pores (Lin et al., 1999). However, the flow-active pores are not frequently quantified combined with infiltration due to the time-consuming measurements.
Understanding the relations between pore structure induced by tillage and infiltration is of crucial importance in predicting flow characteristics of water and solutes in the soil profile. In this study, we assessed the effect of long-term use of various tillage systems on pore size distribution, areal porosity, stained (flow-active) porosity and infiltration of silt loam Eutric Fluvisol.
Section snippets
Soil type and tillage experiment
The experiment was conducted on Eutric Fluvisol by the FAO legend at the experimental field of the Institute of Soil Science and Plant Cultivation in Puławy (51.25°N, 21.58°E), Poland. The soil has 25% clay (<2 μm), 62% silt (2–50 μm) and 13% sand (50–2000 μm) at the depth 0–30 cm. Long-term annual mean temperature and precipitations in the site are 7.7 °C and 588 mm, respectively.
The experimental design used randomised block with four replicates of micro-plots (1 m × 1.5 m). The treatments were as
Pore size distribution
The derivative presentation of pore size distribution curve (Fig. 1) indicates that the porous system of the studied soil is organized hierarchically with matrix (textural) domain and secondary (structural) domain consisting of two sub-domains. The domains can be separated by the minimum pressure head and the corresponding equivalent pore radii on the pore distribution curve (Kutίlek et al., 2006). The minima between matrix and structural domains in our study are similar among the tillage
Conclusion
Long-term application of various tillage methods (conventional tillage, reduced tillage and no tillage) on silt loam Eutric Fluvisol produced markedly different pore size distribution, areal and stained (flow-active) porosity. As shown by continuous pore size distribution curve, the peaks in matrix domain were most displayed under NT and those in structural domain—under CT. The differences in pore size distribution between the tillage treatments were relatively greater in structural than those
Acknowledgement
This work was funded in part by the Polish State Committee for Scientific Research (Grant No. 3 P06R 001 23).
References (52)
Persistence of soil compaction due to high axle load traffic I. Long-term effects on the properties of fine-textured soils
Soil Till. Res.
(1996)- et al.
Components of surface soil structure under conventional and no-tillage in northwestern Canada
Soil Till. Res.
(1999) - et al.
Quantification of pore size distribution and the movement of solutes through isolated soil blocks
Geoderma
(1999) - et al.
Effects of tillage methods on soil physical properties, infiltration and yield in an olive orchard
Soil Till. Res.
(1999) - et al.
A review of tillage effects on crop residue management, seedbed conditions and seedling establishment
Soil Till. Res.
(2001) - et al.
Evaluation of the effect of morphological features of flow paths on solute transport by using fractal dimensions of methylene blue staining pattern
Geoderma
(1992) - et al.
Conservation tillage and depth stratification of porosity and soil organic matter
Soil Till. Res.
(2002) - et al.
Evaluation of the root zone water quality model for predicting water and NO3-N movement in an Iowa soil
Soil Till. Res.
(1999) Soil hydraulic properties as related to soil structure
Soil Till. Res.
(2004)- et al.
Quantification of compaction effects on soil physical properties and crop growth
Geoderma
(2003)
The fractal dimension of pore distribution patterns in variously-compacted soil
Soil Till. Res.
Effects of soil compaction and tillage systems on uptake and losses of nutrients
Soil Till. Res.
Describing water flow in macroporous field soils using the modified macro model
J. Hydrol.
Spatial analysis of saturated hydraulic conductivity in a soil with macropores
Soil Technol.
Contrasting soil physical properties after zero and traditional tillage of an alluvial soil in the semi-arid subtropics
Soil Till. Res.
Comparison of methods for estimating maximum soil water content for optimum workability
Soil Till. Res.
Soil structure and the effect of management practices
Soil Till. Res.
The theory of infiltration
Adv. Hydrosci.
Impact of ploughless soil tillage on yield and soil quality: a Scandinavian review
Soil Till. Res.
Soil strength and soil pore characteristics for direct drilled and ploughed soils
Soil Till. Res.
Conservation tillage and macropore factors that affect water movement and the fate of chemicals
Soil Till. Res.
The structure of the cultivated horizon of soil compacted by the wheels of agricultural tractors
Soil Till. Res.
Reduced tillage intensity—a review of results from a long-term study in Germany
Soil Till. Res.
Macroporosity to characterize variability of hydraulic conductivity and effects of land management
Soil Sci. Soc. Am. J.
Characterization of tillage effects on unconfined infiltration measurements
Soil Sci. Soc. Am. J.
Measurement of solute fluxes in macroporous soils: techniques, problems and precision
Soil Use Manage.
Cited by (347)
Soil extracellular enzyme activity linkage with soil organic carbon under conservation tillage: A global meta-analysis
2024, European Journal of AgronomyHydrosedimentary behavior of a field combining surface drains and tile drains
2023, Soil and Tillage Research