Soil–water content and air-filled porosity affect height growth of Scots pine in afforested arable land in Finland
Introduction
Tree growth requires adequate availability of water and oxygen from the soil as well as a sufficient supply of nutrients, light, and heat. The availability of oxygen to the roots depends on the rate of influx of oxygen into and the efflux of carbon dioxide out of the soil to the atmosphere (i.e. soil aeration). Soil aeration is positively related to air-filled porosity (AFP) and negatively to soil–water content (SWC) (Glinski and Stepniewski, 1985). AFP is defined as a measure of the relative air content of the soil (Hillel, 1982). The results of poor soil aeration include reduction of growth or ultimately the death of trees (Kozlowski, 1986). Poor aeration may also result in a shallow rooting pattern and consequently in instability and propensity of trees to windthrow (Armstrong et al., 1976).
AFP is usually measured at a fixed matric potential value representing the upper limit of plant available water content (field capacity), which has been reported to vary from −5 kPa to −33 kPa (McKeague et al., 1984). The field capacity is defined as the presumed SWC at which internal drainage allegedly ceases (Hillel, 1982). In general, AFP is higher in coarse-textured than in fine-textured soils, and decreases with increasing bulk density (BD) of the soil (Heinonen, 1954, Archer and Smith, 1972, Reeve et al., 1973). Decreased AFP and impeded aeration can result from the mechanical compaction of the soil, the dumping of fill material, poor drainage and water logging, and heavy soil texture (Ruark et al., 1982).
Although there may not be a single critical value for soil aeration (Cook and Knight, 2003), usually the AFP value of 10% is presented as the minimum limit for gaseous diffusion and for plant root respiration and growth (Päivänen, 1973, Theodorou et al., 1991, Xu et al., 1992). Wall and Heiskanen (2003a) showed a curvilinear relationship between AFP and growth of Norway spruce seedlings in soils with high organic matter content (OMC) and the most suitable range of AFP for seedling growth to be 20–40%.
In recent decades, afforestation of arable land has been an important land use change in all over the world. In the case of Finland, over 240 000 ha of arable land, corresponding to 1% of the area of forest land, has been afforested (Anon., 2006). Afforested arable land range from mineral soils to peat soils, in the latter the surface soil being composed of peat and mineral soil mixed together in various proportions as a result of agricultural practices (Wall, 2005). Thus, afforested soils may vary considerably in OMC, SWC, and AFP, which can also affect the plantation performance and tree growth.
In the case of afforested arable land in Finland, the high water table levels associated with the predomination of small pores in the soil pore space means that there is a potential risk of impeded aeration and reduced tree growth (Wall and Heiskanen, 1998, Wall and Heiskanen, 2003b). However, the prevailing SWC and AFP values of afforested former arable land in situ are poorly known, and thus information about these soil properties is needed. In afforested arable land in Finland, the former agricultural land use has increased the nutrient pools in the soil due to use of organic amendments and inorganic fertilizers (Wall and Westman, 2006). We hypothesized that in afforested arable land, the supply of nutrients from the soil is sufficient for tree growth and that AFP is related to tree growth as a limiting factor. This hypothesis was tested by relating the SWC values, measured in situ using time domain reflectometry (TDR), and AFP, estimated from SWC and total porosity of soil, with the growth of Scots pine growing on afforested arable land in Finland. The studied sites are especially suitable for examining the relationship between SWC and AFP and tree growth because the relationship is not confounded by topography as the studied sites are situated on level ground.
Section snippets
Material and methods
The study material consists of 34 stands chosen randomly from among former arable land afforested with Scots pine (Pinus sylvestris L.) in 1973–1974 or 1981–1982 (Hytönen and Ekola, 1993). The sites are located in western Finland and scattered over an area of 5500 km2. The study region emerged from the sea some 7000 years ago due to land uplift and the plantations are all situated on level ground. The mean effective temperature sum (threshold +5 °C) of the study region is 1000° days, the mean
Results
Of the soil nutrients, the content of total N was significantly smaller (p < 0.001) and the contents of extractable P (p < 0.015) and K (p < 0.001) were significantly greater in mineral soils than the nutrient content of organic soils (Table 3). As regards the other soil nutrients and pH, there were no statistically significant differences between the soil types.
Of the foliar nutrients, the concentration of K, Ca and Zn were significantly greater in mineral soils than the nutrient concentration of
Discussion
Many environmental factors such as latitude, elevation, aspect, and soil physical and chemical properties have been shown to have an impact on forest site productivity (e.g., Tamminen, 1993, Wang and Klinka, 1996, Chen et al., 1998, Szwaluk and Strong, 2003). On the studied sites here, there was a narrow range in climate, topography and elevation. In addition, due to former agricultural land use, the level of nutrient availability in soil was high and did not limit tree growth as was indicated
Conclusions
The present results suggest that afforested former arable land in Finland on mineral soils possess adequate aeration conditions, while the aeration conditions of organic soils are commonly limiting tree growth. Therefore, to maintain favourable aeration for tree growth on afforested former arable land with high OMC values, effective drainage is needed. The results indicated that OMC and BD are not good indicators for soil aeration in the present data, although they are related to SWC. Thus,
References (46)
- et al.
The effects of organic matter and particle size on the water-retention properties of some soils in the west Midlands of England
Geoderma
(1977) - et al.
Soil quality assessment in domesticated forests - a southern pine example
For. Ecol. Manage.
(1999) - et al.
Seasonal and yearly variations of fine-root biomass and necromass in a Scots pine (Pinus sylvestris L.) stand
For. Ecol. Manage.
(1998) - et al.
Late-summer soil water content on clear-cut reforestation areas two decades after site preparation in Finnish Lapland
For. Ecol. Manage.
(2004) - et al.
Tentative assessment of soil survey approaches to the characterization and interpretation of air-water properties of soils
Geoderma
(1984) - et al.
Effect of development and cultivation on physical properties of peat soils in New Zealand
Geoderma
(1992) - et al.
Near-surface soil characteristics and understorey plants as predictors of Pinus contorta site index in southwestern Alberta, Canada
For. Ecol. Manage
(2003) - et al.
Water-retention characteristics and related physical properties of soil on afforested agricultural land in Finland
For. Ecol. Manage.
(2003) - et al.
Use of synoptic variables in predicting white spruce site index
For. Ecol. Manage.
(1996) Finnish Statistical Yearbook of Forestry 2006. SVT. Agriculture, Forestry and Fishery
(2006)
The relation between bulk density, available water capacity, and air capacity of soils
J. Soil Sci.
The relationship between soil aeration, stability and growth of Sitka spruce (Picea sitchensis (Bong.) Carr.) on upland peaty gleys
J. Appl. Ecol.
Site index, site quality, and foliar nutrients of trembling aspen: relationships and predictions
Can. J. For. Res.
Oxygen transport to plant roots: modelling for physical understanding of soil aeration
Soil Sci. Soc. Am. J.
Skattning av höjdboniteten i unga tall- och granbestånd. (Summary: Estimating site index in young stands of Scots pine and Norway spruce in Sweden)
Rapporter och Uppsatser, Institutionen för Skogsproduction
Evaluation of forest site productivity
For. Abstr.
Nutrient analysis methods
Metsäntutkimuslaitoksen tiedonantoja
Favourable water and aeration conditions for growth media used in containerized tree seedling production: a review
Scand. J. For. Res.
Introduction to Soil Physics
Cited by (20)
Variation of branched tetraethers with soil depth in relation to non-temperature factors: Implications for paleoclimate reconstruction
2021, Chemical GeologyCitation Excerpt :For example, climate warming may increase the water stratification and dysoxia of lakes (Yan et al., 2017; Woolway and Merchant, 2019). More precipitation may substantially increase soil moisture (Yang et al., 2020), which in turn reduces soil aeration (Moldrup et al., 2000; Wall and Heiskanen, 2009). As shown in the three SPs, the oxygen level may significantly affect the brGDGT-derived proxies and thus it is necessary to assess how these proxies are biased in paleo-reconstructions.
Effects of moisture and salinity on soil dissolved organic matter and ecological risk of coastal wetland
2020, Environmental ResearchCitation Excerpt :This may be because substitutions of H+ and Al3+ on the soil surface are greater than that of OH− after adding soluble salt (An et al., 2019). Wall and Heiskanen (2009) have reported that the soil structure and agglomerate porosity are affected by the variation of salinity. As a result, BD decreases with soil salinity increase in this work.
Factors controlling nitrous oxide emissions from managed northern peat soils with low carbon to nitrogen ratio
2018, Soil Biology and BiochemistryCitation Excerpt :Nitrous oxide production is also limited if the soil water content is too low because microbial activities and substrate diffusion are restricted under low soil water content conditions (Stark and Firestone, 1995; Bateman and Baggs, 2005). In Finland, afforested former arable land on mineral soils is usually well drained and aerated whereas on organic soils the drainage system may not work adequately and often tree growth on organic soils is limited due to the bad aeration (Wall and Heiskanen, 2009). The optimum WFPS for N2O production in boreal peat soils varies from 50 to 90% (Regina et al., 1998a).
A study on the effect of compaction on transport properties of soil gas and water I: Relative gas diffusivity, air permeability, and saturated hydraulic conductivity
2014, Soil and Tillage ResearchCitation Excerpt :The transport properties of soil gases may be used to describe aeration (Glinski and Stepniewski, 1985; Taylor, 1949; Yoshikawa and Hasegawa, 2000), which is important for allowing O2 intake and CO2 discharge by plant roots (Hillel, 1998). With better aeration, plant growth may be improved (Jackson, 1962; Liang et al., 1996), while conversely, reduced aeration may reduce plant growth (Wall and Heiskanen, 2009). Other than requiring air for respiration, plants require water, which plays a central role as a major metabolic agent for growth that is a source of H atoms for photosynthesis (Hillel, 1998).
Effect of Soil Moisture Distribution under Subsurface Drip Irrigation on Soil CH<inf>4</inf> Flux in Facility Farmland
2023, Research of Environmental Sciences