Purpose

Peatlands have an important role in methane cycling in the natural environment. Methane emissions as a result of methanogenesis and methanotrophy in soil are affected by several environmental factors such as temperature, oxygen and groundwater level. The objective of this study was to analyse methane cycling as a function of soil depth.

Materials and methods

In this study, methane cycling and soil organic matter mineralization were investigated in a drained fen grassland area of Ljubljana marsh, Slovenia that has been subjected to reclamation strategies for several centuries. Potential mineralization, methane production and methane oxidation rates were measured in slurry incubation experiments with soil samples from 10 sampling depths of a 1-m profile. In addition, the extent of iron reduction in the soil was determined.

Results and discussion

The potential for methane production was low in the investigated soil profile, even in constantly flooded layers below the water table fluctuations. During anaerobic incubations, the highest accumulated concentrations and production rates of methane were observed in the upper 10-cm layer and the lowest in deeper soil layers, indicating that plant exudates are the main source of energy for heterotrophic soil microbes and that methanogenesis in deeper layers is limited by the availability of appropriate organic substrates. Methane oxidation was on the other hand active throughout the soil profile, suggesting that the potentially active methane oxidizing community is present despite low methane production. The highest abundance and activity of methanotrophs was detected in the water table fluctuation layers.

Conclusions

Together, these findings have implications for understanding the biogeochemical function of drained peat soils and emphasize the influence of drainage on quality of soil organic matter and consequently on methane production even in flooded soils.

Purpose

A longtime monitoring (2003–2013) of groundwater levels and soil moisture was done in a plain tract surrounded by deposits from the Saale glacial stage in northern Germany. The purpose was to document the changes in the soil water regime over time in relation to changes in management of groundwater extraction and to evaluate if the hitherto management has been suitable for plant water supply for the local grassland production.

Materials and methods

Groundwater wells in the surface aquifer were monitored at 11 survey sites, and soil matric potentials were measured with tensiometers at five depths per site. Soil analyses also were done. This report contains the results from three of the 11 survey sites, which best represent the variability of the soils in the area.

Results and discussion

The monitoring showed that groundwater extraction from deep aquifers via individual wells altered the groundwater levels in the surface aquifer, even though there was a distance of several meters depth and a geological parting between the two aquifers. The impact of the groundwater extraction was shown by significant correlations between groundwater levels in the surveyed soils and groundwater extraction rates of individual wells. Climatic factors only affected groundwater levels in individual years. The management of the groundwater extraction from 1977 to 2006 severely lowered the groundwater level in the surface aquifer. Due to a limitation of the groundwater extraction rates and a shift in the degree of capacity utilization of the individual wells from 2006 onward, groundwater levels in the area are recovering. Correspondingly, the contribution of capillary rise to plant water supply has increased within the monitoring period.

Conclusions

The monitoring proves that the present management of groundwater extraction is more suitable for the groundwater situation than past management. However, groundwater levels have not yet obtained a new equilibrium, so continual monitoring is needed.

Purpose

The study aimed at comparing the effects of different water managements on soil Cd immobilization using palygorskite, which was significant for the selection of reasonable water condition.

Materials and methods

Field experiment was taken to discuss the in situ remediation effects of palygorskite on Cd-polluted paddy soils, under different water managements, using a series of variables, including pH and extractable Cd in soils, plant Cd, enzyme activity, and microorganism number in soils.

Results and discussion

In control group, the pH in continuous flooding was the highest under three water conditions, and compared to conventional irrigation, continuous flooding reduced brown rice Cd by 37.9%, and brown rice Cd in wetting irrigation increased by 31.0%. In palygorskite treated soils, at concentrations of 5, 10, and 15 g kg^?1, brown rice Cd reduced by 16.7, 44.4, and 55.6%; 13.8, 34.5, and 44.8%; and 13.1, 36.8, and 47.3% under continuous flooding, conventional irrigation, and wetting irrigation (p < 0.05), respectively. The enzyme activity and microbial number increased after applying palygorskite to paddy soils.

Conclusions

Continuous flooding was a good candidate as water management for soil Cd stabilization using palygorskite. Rise in soil enzyme activity and microbial number proved that ecological function regained after palygorskite application.

Purpose

The potential heat load and stormwater reduction of the anthropogenic, lightweight soil systems, such as green roofs, are valuable to heat island effect mitigation and to urban water management. Benefits of extensive green roofs, as widely used vegetated roof system with very thin soil layer, could be threatened by temporal changes of the soil structure.

Materials and methods

Green roof raised beds filled with two different anthropogenic soils (artificially constructed stripped topsoil with admixed crushed bricks and a commercial mixture of a technogenic substrate) were built to investigate the benefits of such systems in a temperate climate. These two soils were chosen with the intent to compare their thermal and water regime. One soil is expected to be favorable for hydrological functioning, whereas the other one for the thermal performance. Temperature and water balance measurements complemented with meteorological observations and knowledge of physical properties of the soil substrates provide the basis for detailed analysis of a thermal and hydrological regime in green roof raised beds. Moreover, the state of pedogenesis was studied on undisturbed soil samples by means of X-ray computed tomography.

Results and discussion

The water balance of green roof raised beds was calculated for a whole vegetation season and individual rainfall events. Runoff from raised beds was 38 and 63 % of received rainfall. On the basis of a detailed analysis of individual rainfall events, rainfall-runoff dependency was found for both raised beds. The difference between measured actual evapotranspiration and calculated potential evapotranspiration was discussed on the period with contrasting conditions in terms of moisture stress. Thermal characteristics of soil substrates result in a highly contrasting diurnal variation of soil temperatures. Analysis of X-ray computed tomography-derived macroporosity profiles reveals significant temporal changes in the soil comprised of the stripped topsoil with admixed crushed bricks.

Conclusions

Both green roof systems were able to reduce heat load of roof construction when comparing with the concrete roof construction. Similarly, received rainfall was significantly reduced. The extent of rainfall reduction mainly depends on soil, vegetation status, and experienced weather patterns. Methods used for non-invasive imaging proved to be beneficial for studying of soil structure changes.

Purpose

Soil water retention plays a crucial role in regulating soil moisture dynamics, water circulation, plant growth, contaminant transport, and permafrost stability, and it is an issue of concern in water-limited ecosystems. However, our understanding of the relationship between plant roots and soil water retention is still relatively poor in the alpine grasslands of permafrost regions. To addresses this, our study evaluated the effect of plants on the soil water retention in permafrost regions of the Qinghai-Tibet Plateau.

Materials and methods

Three alpine grassland sites were identified and characterized as alpine wet meadow (AWM), alpine meadow (AM), and alpine steppe (AS). Root biomass, soil water retention, and soil physico-chemical properties were examined in the top 0–50 cm of active layer in the three experimental sites in the hinterland of the Qinghai-Tibet Plateau (QTP). Pedotransfer functions (PTFs) and Retention Curve program (RETC) were employed to illustrate how the plant roots affect soil water retention.

Results and discussion

Approximately 80, 65, and 60% of root biomass was distributed in the top 0–20 cm in the AWM, AM, and AS soil, respectively. Soil water retention was enhanced with the presence of plant roots; thereinto, the highest values of field capacity were found in AWM soil: on average, about 0.45 cm³ cm^?3. Field capacity of AWM soil was almost twice as high as that of AM soil, and triple higher than that of AS soil. Correlation and regression analysis showed that root-induced changes to soil water retention were caused by altering the soil organic matter and soil structure. In addition, we evaluated the Retention Curve (RETC) program’s performance and found that the program underestimated soil water retention if the effects of plant roots were not considered.

Conclusions

A lack of alpine plants is associated with a decline in soil physical conditions and soil water retention in permafrost regions, and the function of plant roots should be considered when predicting hydrological processes.

Purpose

Increasing data have shown that biochar amendment can improve soil fertility and crop production, but there is little knowledge about whether biochar amendment can improve water infiltration in saline soils. We hypothesized that biochar amendment could promote water infiltration in saline soil. The aims of this study were to evaluate the effects of biochar amendment on water infiltration and find the suitable amendment rate and particle size of biochar as a saline soil conditioner.

Materials and methods

We measured water infiltration parameters in a coastal saline soil (silty loam) amended with non-sieved biochar at different rates (0.5, 1, 2, 5, and 10%, w/w) or sieved biochar of different particle sizes (≤?0.25 mm, 0.25–1 mm, and 1–2 mm) at 1 and 10% (w/w).

Results and discussion

Compared with the control, amending non-sieved biochar at 10% significantly decreased water infiltration into the saline soil (P?<?0.05). In contrast, sieved biochar of ≤?0.25 mm significantly improved water infiltration capacity, irrespective of the amendment rate. Sieved biochar of 1–2 mm was less effective to improve soil porosity and when amended at 10%, it even reduced the water infiltration capacity. The Philip model (R²?=?0.983–0.999) had a better goodness-of-fit than the Green-Ampt model (R²?=?0.506–0.923) for simulation of cumulative infiltration.

Conclusions

Amending biochar sieved to a small particle size improved water infiltration capacity of the coastal saline soil compared with non-sieved biochar irrespective of the amendment rate. This study contributes toward improving the hydrological property of coastal saline soil and rationally applying biochar in the field.

Purpose

Field portable X-ray fluorescence (FPXRF) technology can offer a rapid and cost-effective determination of the total elemental concentrations in soils. The aims of this study were (i) to test the capability of FPXRF to predict the element concentrations of a very large soil sample set and (ii) to assess the influence of soil moisture, known to strongly affect the quality of FPXRF analyses.

Materials and methods

A large set of 215 soil samples were analysed for Ba, Ca, Cr, Cu, Fe, Mn, Pb, Rb, Sn, Sr and Zn by inductively coupled plasma atomic emission spectroscopy (ICPAES) after aqua regia digestion and with a FPXRF analyser using a short acquisition time. Soil samples were then saturated with ultrapure water to test the influence of soil water content on FPXRF signal.

Results and discussion

For all of the elements, the total concentrations obtained with ICPAES and FPXRF showed a very high degree of linearity, indicating that FPXRF can effectively predict element concentrations in soils. A Lambert-Beer law was successfully used to describe the decrease in the FPXRF concentrations with increasing soil moisture. The attenuation coefficient obtained for each element allowed us to satisfactorily predict the FPXRF concentrations of samples for water contents as high as 136.8 %.

Conclusions

These results show that the effect of water on signal attenuation can be corrected and that FPXRF may gradually replace chemical methods for the analysis of environmental samples.

Purpose

Understanding how archaeal communities are affected by water-table drawdown is essential for predicting soil functional responses to future climate change and the consequences of the responses on the soil carbon cycle.

Material and methods

We investigated the effect of water-table drawdown, warming, drought, and combinations thereof on archaeal communities using terminal restriction fragment length polymorphism (T-RFLP) and quantitative PCR.

Results and discussion

Methanosarcinales, Methanosaeta, Methanomicrobiales, Methanobacteriales, uncultured Rice Cluster II (RC-II), and uncultured Crenarchaeota were detected. Water-table drawdown and drought exhibited significant effects on the archaeal communities. When the water table was at or above 10 cm, the archaeal abundance at 10 cm remained high (approximately 10⁹ cells per gram dry soil), whereas the archaeal abundance at 10 cm was reduced to approximately 10⁸ cells per gram dry soil where the water table was lowered to 20 cm or below. When the water table kept constant, warming caused a significant reduction in the archaeal abundance, whereas drought only caused a decrease in archaeal abundance when the water table was higher than ?20 cm.

Conclusions

Results suggest that changes in water table may directly impact archaeal community abundance and assemblage which can in turn influence methane emissions, potentially on a large scale. Our results also indicate that archaeal communities response to water-table drawdowns that are dependent on the initial ecohydrology.

Purpose

Nanoparticles (NPs) have received increased attention in recent past due to their unique distinct properties. Metal-based NPs are widely used in chemical and allied sector. Most of the research is directed to study the efficiency of NPs in medicine and agriculture. The aim of this review is to explore the possible threats posed by toxicity of various NPs on plants and microbial diversity.

Materials and methods

First, major sources of NPs to the environment were analyzed. The effects of metal-based NPs on the microbiota and plants are presented in this review. The results obtained by the authors during last 12 years of research are used.

Results and discussion

The exposure of soil to nanoparticles causes a decrease in soil microbial biomass and enzymatic activity, which impacts microbial community composition including yeasts, bacteria, fungi, and biological diversity. The effects of NPs on plants result in various types of abnormalities. Nanoparticles can also pose risks to human health.

Conclusions

Increased applications of NPs pose a threat to beneficial microbial communities as well as crops and soils. Thus, it is important to explore whether NPs could compromise crop yield, soil properties, soil organisms, and functional activities of soil.

Purpose

The use of composted sewage sludge and limestone outcrop residue in land rehabilitation, soil improvement, and technosol making can influence the mobility of nitrogen compounds in groundwater.

Materials and methods

This experiment analyzed this source of possible pollution under an experimental design based on the use of columns (0–30 cm) formed by both wastes and a heavy irrigation regime. Two waters of different quality (saline and non-saline) were used for irrigation. The presence of nitrate, nitrite, and ammonium in the leachates was checked.

Results and discussion

The environmental risk due to the presence of nitrogen species associated with the use of these materials was very low in general, although nitrate was the most important compound affected by the use of sewage sludge compost and saline water.

Conclusions

The combination of saline water for irrigation with the compost has to be seriously considered as a source of pollution for surface and ground waters, and the use of both resources may be a key factor to be studied (low-quality water and sewage sludge compost).

Purpose

Occlusion of carbon (C) within phytoliths, biogenic silica deposited in plant tissues and returned to the soil, is an important mechanism for long-term terrestrial biogeochemical C sequestration and might play a significant role in mitigating climate change.

Materials and methods

Subtropical and tropical soil profiles (to 100 cm depth) developed on granite and basalt were sampled using a mass-balance approach to explore the influence of climate and lithology on soil phytolith-occluded carbon (PhytOC) accumulation.

Results and discussion

Soil PhytOC storage in the subtropics was significantly greater than in the tropics, with the soil profiles developed on granite storing greater PhytOC than soils derived on basalt. Phytolith and PhytOC content decreased with depth in all soil profiles. Phytolith content showed a positive correlation with the soil bio-available silicon in the soil profiles developed on basalt, while a negative correlation was observed in soil profiles developed on granite.

Conclusions

Climate and lithology have a significant impact on soil PhytOC sequestration. The management of forests (e.g., afforestation and reforestation) and external silicon amendments (e.g., basalt powder amendment) in soils, especially those developed on granite, have the potential to enhance PhytOC accumulation in forest ecosystems.

Purpose

Soil water is a critical variable for hydrological and biological processes in arid and semi-arid ecosystems. Information on regional spatial pattern of soil water storage (SWS) and its relationship with environmental factors is important for optimal water management and vegetation restoration in China’s Loess Plateau (CLP) region. State-space approach and artificial neural network (ANN) were used to analyze spatial variability of SWS in the CLP region.

Materials and methods

SWS in the 0–1, 1–2, 2–3, 3–4, and 4–5 m soil layers was measured during the period from June 2013 to September 2015 at 86 locations along a 860 km long south–north transect of CLP.

Results and discussion

The analysis showed that SWS in the 5 m soil profile generally decreased with increasing latitude, driven by decreasing precipitation and soil–water holding capacity. Using various combinations of variables, the state-space model gave a better spatial pattern of SWS than the ANN approach. The best state-space approach, which included clay content, mean annual precipitation, and slope gradient, explained 96.0% of the total variation in SWS. Then, the best ANN approach explained only 76.2% of the variation. Clay content, mean annual precipitation, and slope gradient was the most effective combination for large-scale estimation of SWS under the state-space approach.

Conclusions

The state-space model was recommended as an effective method for analyzing large-scale spatial patterns of soil water using soil, climatic, and topographic properties in the CLP region.

Purpose

Studying the rate of chelant degradation is important to select environmental friendly compounds to assist phytoextraction. The objective of the present study was to evaluate degradation rate of complexes formed between synthetic or organic chelants and Pb aiming to increase the efficiency of phytoextraction while reducing adverse effects resulting from the Pb leaching.

Materials and methods

The following six chelating agents were tested: citric acid P.A., commercial citric acid, glutamic acid P.A., monosodium glutamate, nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA), besides a control treatment (no addition of chelating agent); they were applied at a concentration of 10 mmol dm^?3 in pots containing 1 dm³ of Pb-contaminated soil.

Results and discussion

The results of this study showed that commercial citric acid adequately solubilized Pb to levels suitable for plant uptake and showed relatively rapid biodegradation in soil. Therefore, this commercial product may be a highly promising alternative for phytoextraction studies in the field. EDTA and NTA demonstrated high Pb solubilization ability but degraded comparatively slowly; therefore, they are not recommended for use in phytoextraction due to environmental risks regarding metal leaching.

Conclusions

The results of this study showed that commercial citric acid adequately solubilized Pb to levels suitable for plant uptake and showed relatively rapid biodegradation in soil, which is associated with a low risk of groundwater contamination. Therefore, this environmental friendly and low-cost product may be a highly promising alternative for inducing Pb phytoextraction.

Purpose

We investigated the effect that ashes may have on the soil microbial activity. Our hypothesis is that different wood ashes and different proportions of them could have beneficial or detrimental effects depending on the applied dose.

Materials and methods

Dehydrogenase activity and soil oxygen consumption were used to evaluate the potential improvement of soil conditions through the application of two different wood ashes coming from industrial waste. Different ash proportions and time dependence have been used to make comparisons. The respiration curves obtained through a closed-jar incubation experiment were well fitted by a sigmoidal function, the derivative of which yields the time evolution of the consumption rate.

Results and discussion

The results indicate that the dehydrogenase activity and soil oxygen consumption are very sensitive to the presence of ashes in the soil, and the reached values of both are linked to the applied dose of them. In our research, soil oxygen consumption is time and rate dependent of ash application. The curves show that parameter was affected by the ashes in different way, raising the respiration rate, and stretching the biological activity period.

Conclusions

Dehydrogenase activity and soil oxygen consumption are very sensitive to the presence of ashes and can be used to assess their potential use as amendments. The results of this paper can contribute to the required knowledge in order to use ashes in a sustainable way. Ashes coming from olive marc and vine shoots may affect positively the soil respiration and, therefore, the soil fertility, if they are applied in moderate amounts.

Purpose

An analytical database containing XRF chemical analyses and real density measurements of unconsolidated sediments of the Padania Plain (Northern Italy) has been used to understand the relationship that exists between the soil particle density (ρ_s) and their bulk chemical composition.

Materials and methods

Using a linear regression, we built an equation able to link the particle density with the soil elemental composition.

Results and discussion

Positive correlations were found between ρ_s and SiO₂, MgO, CaO and Na₂O and negative correlations with K₂O, TiO₂, Al₂O₃, Fe₂O₃ and LOI, reflecting the presence in the soils of quartz and feldspars/mineral clays respectively.

Conclusions

Our equation is very useful because it helps to know the density properties of a soil when it is not possible to measure ρ_s with a pycnometer. On the other hand, by knowing the ρ_s, it is possible to have a quite precise knowledge about the chemistry of the studied soils.

Purpose

The study aimed at comparing organic matter decomposition in two semi-natural agrobiocenozes, namely fallows and meadows, with similar plant biomass but differing in plant community composition and diversity and in succession stage.

Materials and methods

The decomposition rate of a standard material (cellulose) was measured in soils from six fallows and six meadows spanning a few kilometres apart. The mathematical model was fitted to the data.

Results and discussion

The model showed a significantly longer lag-time in cellulose decomposition in the meadows. Despite the delayed start of decomposition in the meadows, the estimated decomposition rates were similar in both ecosystem types, once the decay started.

Conclusions

The faster start of decomposition in fallows seems to be promoted by higher contents of nitrates and phosphates in the fallow soils. The fallows, as younger ecosystems, may have faster C turnover than older grasslands due to remains of fertilisers on these ex-arable fields.

Purpose

Topography-soil relationships usually vary with climate, vegetation type, degree of human disturbance, type of parent material, and the scale being studied. In this paper, we studied the topography-soil relationship in a hilly forest in subtropical China.

Materials and methods

The influence of topography on soil properties (soil moisture, organic carbon (C), total nitrogen (N) and total phosphorus contents, C:N ratio, and pH) was evaluated using a recursive partitioning conditional inference tree (CIT) as well as a multiple linear regression (MLR) method.

Results and discussion

The CIT models generally performed better than MLR in describing the topography-soil relationships. Topographic parameters chosen by the CIT models, which indicate the mechanisms at play for the spatial variation of the soil properties, varied with the soil property of concern. The soil moisture, organic C, and total N models contained only primary terrain attributes, the soil C:N ratio and pH models contained both primary and secondary terrain attributes, while the total phosphorus model contained mostly secondary terrain attributes.

Conclusions

The CIT method worked well for exploring the topography-soil relationships in the studied undisturbed hilly forest. We conclude that (1) soil moisture, organic C, and total N were strongly affected by location-specific topographic features such as gravitational potential, the amount of precipitation, temperature, and vegetation type; (2) total phosphorus was affected by catchment-related hydrological activities and soil C:N ratio; and (3) pH was affected by location-specific topographic features and catchment-related hydrological activities.

Purpose

The aim of the study was to present variability of content and quality of soil organic matter on the landslide surface. Attempts were made to demonstrate the progress of the process of soil cover restoration 7 years after the landslides and biochemical activity of soil associated with the restoration of soil cover.

Materials and methods

The landslide area was located in southern Poland, in the Sucha Forest District. The soil properties were studied on a regular grid of points, which covered the entire area of the landslide. In soil samples, particle size, soil aggregates content, pH, total carbon and nitrogen content, microbial biomass carbon and nitrogen and the activity of dehydrogenases were determined. Additionally, the fractions of soil organic matter were used in the study as an indicator of soil quality due to the many important interactions of these components in the soil system.

Results and discussion

This study identified the landslide area as characterised by a stronger diversification of physical, chemical, and biological properties. The upper part of the landslide (in the area referred to as the landslide niche) is strongly eroded and characterised by the least advanced soil cover recovery. Additionally, low soil organic matter content was observed in the upper part of the landslide, which restricted biological activity of the studied soils. Soil microbial biomass carbon increased with restoration of landslide soils.

Conclusions

The soil organic matter plays a key role for the initial stage of soil formation on a landslide. The amount of soil organic matter on the studied landslide had a positive effect on the microbial biomasses C and N, dehydrogenases activity. Estimating the soil organic matter fraction can be utilised as an indicator of changes in soil.

Purpose

Irrigation and fertilization can change soil environment, which thereby influence soil microbial metabolic activity (MMA). How to alleviate the adverse effects by taking judicious saline water irrigation and fertilization regimes is mainly concerned in this research.

Materials and methods

Here, we conducted a field orthogonal designed test under different saline water irrigation amount, water salinity, and nitrogen fertilizer application. The metabolic profiles of soil microbial communities were analyzed by using the Biolog method.

Results and discussion

The results demonstrated that irrigation amount and fertilizer application could significantly change MMA while irrigation water salinity had no significant effect on it. Medium irrigation amount (30 mm), least (50 kg ha^?1) or medium (350 kg ha^?1) N fertilizer application, and whatever irrigation water salinity could obtain the optimal MMA. Different utilization rates of carbohydrates, amino acids, carboxylic acids, and polymers by soil microbial communities caused the differences of the effects, and D-galactonic acid γ-lactone, L-arginine, L-asparagine, D-glucosaminic acid, Tween 80, L-threonine, and D-galacturonic acid were the indicator for distinguishing the effects.

Conclusions

The results presented here demonstrated that by regulating irrigation water amount and fertilizer application, the effects of irrigation salinity on MMA could be alleviated, which offered an efficient approach for guiding saline water irrigation.

Purpose

Grassland exclosure is a widely-used option to prevent from grazing in degraded grasslands for restoration. However, the influence of exclosure on soil macropore of grassland remain scarce. The objective of this study was to quantify the pore architecture of grassland soils under exclosure.

Materials and methods

Two treatments, 9E (grassland enclosed for 9 years) and 5E (grassland enclosed for 5 years), were designed, with grazing as a control in the experiment. Nine soil columns (0–50 cm deep) were taken at the three sites with three replicates. At each site, three soil columns were from the grassland, and cores were scanned with a Philips Brilliance ICT Medical Scanner. Numbers of macropores, macroporosity, network density, length density, and node density within the 50-cm soil profile were interpreted from X-ray computed tomography to analyze soil pore architecture.

Results and discussion

The results indicated that exclosure significantly influenced CT-measured soil macroporosity in the Inner Mongolia grassland of northern China. Soils under enclosed grassland had greater macroporosity, length density, total volume, and node density than that of under freely grazed grassland. Macroporosity increased as the enclosure age increased. For soils under enclosed grassland, macropores were concentrated at 0–300-mm soil layers, and macropores were mainly present at 0–100-mm soil depth under freely grazed grassland. The large number of macropores found in soil under enclosed grassland can be attributed to greater root development.

Conclusions

Exclosure increases soil macroporosity and improve soil structure.