Linking hydropedology and ecosystem services: differential controls of surface field saturated hydraulic conductivity in a volcanic setting in central Mexico

In this study the variation of field saturated soil hydraulic conductivity (Kfs) as key control variable and descriptor of infiltration was examined by means of a constant head single ring infiltrometer. The study took place in five coverage types and land uses in a volcanic setting in central Mexico. The tested hypothesis was that there exist a 5 positive relationship between plant cover and surface Kfs for the study area. The examined coverage types included; Second growth pine-oak forest, pasture land, fallow land, gully and Cupresus afforestation. Results indicate that Kfs did not depend exclusively of plant cover; it was related to surface horizontal expression of the unburied soil horizons and linked to land use history. Therefore the Kfs measured at a certain 10 location did not depend exclusively of the actual land use, it was also influenced by soil bioturbation linked to plant succession patterns and land use management practices history. The hypothesis accounts partially the variation between sites. Kfs under dense plant cover at the Cupresus afforestation was statistically equal to that measured at the fallow land or the gully sites, while second growth pine-oak forest Kfs figures were over 15 an order of magnitude higher than the rest of the coverage types. The results suggest the relevance of unburied soil horizons in the soil hydrologic response when present at the surface. Under these conditions loosing surface soil horizons due to erosion, not only fertility is lost, but environmental services generation potential. A conceptual model within the hydropedological approach is proposed. It explains the possible con20 trols of Kfs, for this volcanic setting. Land use history driven erosion plays a decisive role in subsurface horizon presence at the surface and soil matrix characteristic determination, while plant succession patterns seem to be strongly linked to soil bioturbation and preferential flow channel formation.

positive relationship between plant cover and surface Kfs for the study area. The examined coverage types included; Second growth pine-oak forest, pasture land, fallow land, gully and Cupresus afforestation. Results indicate that Kfs did not depend exclusively of plant cover; it was related to surface horizontal expression of the unburied soil horizons and linked to land use history. Therefore the Kfs measured at a certain 10 location did not depend exclusively of the actual land use, it was also influenced by soil bioturbation linked to plant succession patterns and land use management practices history. The hypothesis accounts partially the variation between sites. Kfs under dense plant cover at the Cupresus afforestation was statistically equal to that measured at the fallow land or the gully sites, while second growth pine-oak forest Kfs figures were over 15 an order of magnitude higher than the rest of the coverage types. The results suggest the relevance of unburied soil horizons in the soil hydrologic response when present at the surface. Under these conditions loosing surface soil horizons due to erosion, not only fertility is lost, but environmental services generation potential. A conceptual model within the hydropedological approach is proposed. It explains the possible con-

Introduction
Ecosystem services can be defined as "the capacity of natural processes and components to provide goods and services that satisfy human needs, directly or indirectly", in this perspective ecosystem services are part of ecosystem structure and processes which in turn are the result of diverse and complex interactions between abiotic and biotic components of ecosystems linked trough matter and energy fluxes (De Groot, 1992). Even when 1970s' researchers addressed the importance of economic value of ecosystem functions and services, e.g. Odum and Odum (1972), it was not until recently that ecosystem services got into public and government concern worldwide. The actual environmental crisis had lead to a revaluation of the natural and transformed 10 ecosystems as sources of ecosystem services and goods (Maass et al., 2005).
The hydropedological approach embrace a link between soil sciences and hydrologic sciences building a bridge between classical disciplines such as soil physics, pedology and hydrology studying the critical zone its functioning at different spatial and temporal scales (Lin, 2004;Lin et al., 2008Lin et al., , 2004Lin and Zhou, 2008). Regulation ecosystem functions and the related ecosystem services such as water regulation and water supply are strongly dependent of the vado zone functioning, therefore the hydropedological approach may be adequate to address and study the physical processes that control this ecosystem service's performance, at least partially. The hydropedological approach can provide conceptual and methodological elements to ecosystem service 20 quantification which in turn could improve the understanding of their functioning and dependence of the natural components and the effect of human activities on them.
Water infiltration is a key process for water regulation ecosystem functions. It is a complex process that under field conditions and natural precipitation varies for each event due to it's dependency of soil moisture content (Wit, 2001;Cerdà, 1995). Sev-25 eral authors have addressed the relationship between soil cover and infiltration (Zimmermann et al., 2006;Wit, 2001;Cichota et al., 2003). The importance of plant cover to infiltration has been reported in different environmental settings, from arid and semi-2501 arid to humid forests, and a link between plant cover and soil physical properties had been addressed (Zimmermann et al., 2006;Li and Shao, 2006). Differential effects of vegetation have been reported between vegetated and non vegetated areas (Cerdà, 1997a, b;Lyford, 1969;Álvarez-Yépiz et al., 2008). It is known that vegetation characteristics such as composition or management have a strong influence in infiltration 5 rates, specially in areas under livestock grazing (Descroix et al., 2001;Prause and Gallardo-Lancho, 2000;Mwendera and Saleem, 1997;Singleton et al., 2000;Tobón et al., 2004).
An extensive literature review indicate that for Mexico there are few studies about hydrophysical properties in soils under non agricultural cover, and none including the 10 hydropedological approach. The actual federal government Ecosystem Services Program (Programa de Servicios Ambientales), driven by the CONAFOR (which stands for National Forest Commission in Spanish) and claimed to be the largest worldwide (CONAFOR, 2008), establishes that payments should be done according to predefined rates (CONAFOR, 2004), in which the only evaluating criteria is vegetation type. Pérez-Maqueo et al. (2005) criticised this and mention that outlines of this federal program is based in not verified generalizations or empirical approaches regarding land use, land cover and hydrologic ecosystem services. Therefore there is a need of hard data studies relating hydrophysical properties to ecosystem services, because ecosystem service programs need to be evaluated and their intended effectiveness assessed 20 (Cotler and Ortega-Larrocea, 2006;Perevochtchikova et al., 2005;Pérez-Maqueo et al., 2005).
On the other hand, land cover and land use change severely affects Mexico. Deforestation national rates are among the highest in the world, about 0.5% annually (Carabias, 1990;Jardel, 1990). However recent studies had demonstrated that de-25 forestation and land use change has regional and local peculiarities. In Cuitzeo Lake basin in central Mexico López et al. (2006) found a positive relationship between farmer migration and plant cover recovery . The main changes occurred in abandoned marginal croplands, where shrub vegetation is recovering.
In this central part of Mexico main agricultural practices include the traditional rainfed slash-burn year-turn (roza-quema año y vez) and the burn year-turn (año y vez) of the milpa local variant. The system is similar to the highly documented Mayan milpa (Turner and Brush, 1987;Barrera-Basols and Toledo, 2005) in which forest is removed (clear-cut) then burned and after that corn (maize) is grown for a short period usually 5 2 to 4 years. Then the area is left to recover and revegetate for a longer period 10-30 years (Mariaca-Méndez et al., 2007). Nevertheless, in recent times due to different causes recovery times had been shortened, reducing the effective vegetation recovery (Mariaca-Méndez et al., 2007). This produced the regional and local variant of milpa, in which forest slashing is nowadays seldom used and the fields are left in fallow for 1 to 3 10 years. Burning is still highly used in order to eliminate weeds and pests when needed. The local system includes maize (Zea mays L.), beans (Phaseolus vulgaris L.), and different species and subspecies of Cucurbita genus, like squash and pumpkin. The crops are grown simultaneously during the rainy season (June to October) and harvest is done by hand during fall. Usually the system is maximized and during the months 15 following the harvest, cattle is left to graze on leftover stubble. As mentioned earlier cropland abandonment and vegetation recovery had been documented in the study area as a consequence of peasant emigration (Lopez et al., 2006), abandoned land are incorporated as regular grazing areas for cattle. This activities may produce soil compaction, modify soil structure, porosity and thus hydrophysical properties (Newman 20 et al., 1999;Singleton et al., 2000;Descroix et al., 2008).
In such a context, plant cover recovery can be described as a qualitative gradient represented by a series of sites with different level of degradation that follow different ecological recovery paths as a response of the ecosystem natural dynamic (Hilderbrand et al., 2005). Even when it is difficult to define the order and level of perturba-25 tion, plant structure suggest distinctive successional stages that may affect hydrological processes such as infiltration due to changes in soil hydraulic conductivity. The latter relationship had been reported by Li and Shao for the Loess Plateau in China (2006).
Due to infiltration dependency of antecedent soil moisture, some researchers have 2503 recently used saturated hydraulic conductivity or field saturated hydraulic conductivity (Kfs from here on) as a descriptor of infiltration because it provides a homogeneous conceptual and practical framework, allowing comparison between sites with different characteristics. Besides Kfs is a variable particularly sensitive to soil disturbance and can be used as indicative of land use practices impact on the soil (Perkins et al., 2007;5 Schoenholtz et al., 2000;Berli et al., 2004). In this study the actual postulates of the Hydrologic Environmental Services Payment Program (Programa de Pago por Servicios Ambienteles Hidrológicos of CONAFOR) part of the National Ecosystem Services Program are put to the test. And at the same time learn about the spatial variation and specific controls of field saturated hydraulic 10 conductivity as a descriptor of the infiltration process. Thus the driving hypothesis of this work was "Land cover type conditions the spatial patterns of variation of hydraulic conductivity such that land cover with higher plant coverage should have higher hydraulic conductivities than those with less or no plant coverage".  (Fig. 1). This location can be considered a microcosm of the Cuitzeo basin because many of the processes addressed earlier by Lopez et al. (2006) are known to be present. The Mexican National Institute of Statistics, Geography and Informatics (Instituto Nacional de Estadística Geografía e Informática, INEGI) which is in charge of national cartography including that of soil reports Orthic Acrisols (following the FAO 1970 5 nomenclature) (INEGI, 1979), nevertheless detailed studies indicate the presence of polygenetic soil profiles with sandy-loam (Chromic cambisols) with andic properties on top of clayely (Humic lixisols) soils according to FAO (2006), both from volcanic origin Gómez-Tagle (2008). Seveney and Prat (2003) mention that buried soils of this kind are common within this region of the Trans-Mexican Volcanic Belt. Lithology is ex-10 trusive basic, with ignimbritic materials (Bigioggero et al., 2004;Gómez-Tagle, 2008). The geoform corresponds to volcanic lava flow hills smoothed by volcanic ash deposits (Gómez-Tagle, 2008), slope ranges are between 0 and 20 degrees.
According to Garcia (2004), climate is temperate sub humid with rainy season during the summer and annual average temperature of 16.7 • C and mean annual precipitation 15 of 850 mm.

Land use and successional stages
The work was conducted in sites representative of five ecological succession stages, the sites were differenced mainly by plant cover, the main characteristics are mentioned further along: herbaceous and shrub species (<10%). This site was part of afforestation government programs during the 1960s which enforced plant cover substitution and afforestation, from annuals under the local milpa system, to tree species in marginal low productivity fields, therefore plough lines were visible in the surface. At the study time eventual light grazing (cattle) took place in all of the sites at least 20 once (one-two days) every two or three weeks, except for the Cupresus Afforestation.

Data acquisition
The sampling took place on the high portion of the geoform (summital surfaces and high hillslope), slopes were in all cases below 5 • , and altitudes between 2190 and 2210 m above sea level. For field soil description a pit was dug on every site. Description was done following the Soil Survey Staff outlines (Soil-Survey-Staff, 1993) and Siebe and Stahr (2006). Form each horizon soil samples were collected and analyzed. Detailed analytical results will be published elsewhere because are out of reach for the present study, at the 5 moment can be consulted in Gómez-Tagle (2008)

Infiltration tests
At each site 49 infiltration tests were conducted. These were distributed using a regular . These devices had been used to estimate Kfs (Prieksat et al., 1992;Wu et al., 1999;Matula, 2003). The device used was similar to that of Prieksat et al. (1992) but the ring is top sealed and connected to the Mariotte reservoir by a water supply tube with a two way valve. This eases the refill process of the Mariotte without affecting the ring insertion in the soil. The applied water head is monitored by 20 means of a water head tube attached to the ring. The increase or reduction of water head height is controlled by rising or lowering bubble tube inside the Mariotte. The applied constant water heads were between 10.0 and 40.0 mm. Water height in the Mariotte reservoir was recorded manually every five minutes until reaching a constant inflow rate indicative of steady-state infiltration phase. Constant inflow rate 25 was recognized when 3 subsequent measurements deviate less than 10% from one another. This usually occurred after 3.0 h of elapsed time. Once the infiltration ex-2507 periment was finished, water was allowed to flow out from inside the ring five minutes and then the ring was removed and a final water content sample was taken (θ 2 ), water content was estimated using the gravimetric method (DOF, 2002).
Estimation of Kfs was performed following the Wu2 method (Wu et al., 1999), generated from axisymetrical scaling of Richards equation (Wu and Pan, 1997). The Wu2 5 method utilizes the slope of the steady-state portion of the cumulative infiltration curve (Wu et al., 1999). The Wu2 methods needs previous estimates or table values of α*, which represents the capilar component of the hydraulic flow in the soil, α* values were taken from Elrick and Reynolds (1992) according to the texture classes.

Statistical analysis
Standard statistic techniques were used to characterize Kfs data from different sites.

20
Previous studies report that several air and water flow related soil properties follow Log-Normal probabilistic distribution (Russo and Bresler, 1981;McIntyre and Tanner, 1959). Therefore probabilistic distribution of Kfs was tested using the W Shapiro-Wilk test (Shapiro and Wilk, 1965). One way Analysis of Variance (ANOVA) was used to test the proposed hypothesis and therefore the existence of Kfs differences between 25 sites. Tukey's Honest Significative Difference test was used to address between which sites there was statistical difference (Crawley, 2002). Multivariate statistical procedures were conducted to explore possible relationships between Kfs and physicochemical 2508 soil properties. Statistical analysis was done using Statistica for Windows version 6.0 (StatSoft Inc., 1998) Further, geostatistical techniques were applied to explore the spatial variation of Kfs within the studied sites. Omnidirectional and directional experimental variograms (Webster and Oliver, 2001) were computed using VarioWin version 2.2 (Pannatier, 5 1996).

Results and discussion
3.1 Soil profile characteristics All sites are located on low slope areas (<5 • ). Soils were formed in situ from pyroclastic deposits. These kind of parent materials evolved to form soils with argilic horizons, the evolutionary paths had been described earlier by Sedov et al. (2003a, b) in similar areas of the Trans-Mexican Volcanic Belt. The soils can be considered as polygenetic with at least two main pedogenetic episodes, the upper horizons (A, A 11 , A 12 , Ap 1 , Ap 2 , AB) corresponds to different forms of a Cambisol with coarser sandy loam to sandy clay loam textures (Gómez-Tagle, 2008) while the subsurface horizons (2 Bt, 15 Bt) correspond to different portions of the argilic horizons of a buried Humic Lixisol (Gómez-Tagle, 2008). The latter is truncated at the G and the CuA sites. Each one of the sites has its own characteristics. A short description is presented (Table 1). In some sites the Cambisol is not clearly recognizable due to erosion, mixing with the underlying calyley horizons by agricultural practices or forming a plough pan.

Statistics and probabilistic distributions of Kfs
A total of 231 infiltration measurements were performed for the five sites. Descriptive statistics are shown in Table 2. The Shapiro-Wilk test (Shapiro and Wilk, 1965), between observed and expected distribution showed that Kfs had a Log-Normal probability distribution behavior in all sites (Table 3). This results agree with previously 25 2509 reported probabilistic functions for soil properties related to water or air flow in soil (Rogowski, 1972;Russo and Bresler, 1981;Regalado, 2005;Mallants et al., 1997). Further analysis were performed using Kfs transformed to lnKfs. The ANOVA indicated statistical difference between sites for lnKfs (F =35.584, p=0.0031), and Tukey SHD test (Crawley, 2002) showed a groupping pattern where sites differentiate and Kfs 5 had the following trend SPOF>PA>FL=G=CuA (Table 4).

Relationships between Kfs and other soil properties
For the whole data set (five sites analyzed) lnKfs showed a positive relationships with the percentage of water stable aggregates for both apparent diameter intervals analyzed (2.0-4.0 and 0.25-2.0 mm), and positive relationship with sand and silt content, 10 but negative relationships with the initial moisture content, clay percentage and bulk density. Nevertheless r values were statistically significative are considered too low to explain the relationship satisfactorily (Table 5).
The analysis of each site indicated a differential relationship between physicochemical soil properties and lnKfs. In SPOF three out of nine correlations were significative 15 (water stable aggregates 2-4 mm, silt percentage and bulk density; Table 5) two positive and one negative. For CuA there were two significative correlations (silt percentage and organic carbon content; Table 5). While for PA there was only a significative correlation; organic carbon ( Table 5). The rest of the sites showed no significative correlations with none of the analyzed properties. This explains partially why the whole 20 data set correletions yielded so low (Table 6). Contrary to expected the only site where lnKfs correlated significatively with bulk density was SPOF (r=0.44, p=0.15). It is important to consider that the samples used to estimate bulk density were not taken exactly from the infiltration test location but from a close location (±0.1 m), therefore it is possible that the latter does not reflect the existing porosity conditions at the soil surface at the exact location of the infiltration test. At SPOF site the three properties related to lnKfs, suggest an important role of maropore and preferential flow paths. The profile descriptions indicate this was the only site that presented in the surface a 2510 horizon with predominance of biogenic structure, furthermore this site was statistically different to the rest of the sites (Table 4). For the Gully site (G) a relationship between sand or clay content with lnKfs was expected, but not detected, this site had the lowest Kfs values of the stuy. Upper Cambisol horizons lost due to erosion and the unburing of the Lixisol argilic horizons (2 Bt) reduce significatively the Kfs for the actual surface 5 soil. The unexpected non relationship between physicochemical properties and hydraulic conductivity at this site is attribuited to macropore presence independent of the physicochemical properties analyzed. In the FL site there were no correlations between lnKfs and the tested properties whereas for the CuA site some relationships were found. This indicate that silt content 10 and soil organic carbon play an important role in Kfs variation control as mentioned by earlier researchers, e.g. Arya et al. (1999); Tietje and Hennings (1996). Further, silt is related to textural class and therefore to pore size and distribution (Fuentes et al., 2004), while soil organic carbon is related to aggregate stability (Porta et al., 1999). This properties had a very conspicious vertical variation pattern. In surface conditions, 15 changes in this properties indicate the presence of subsurface horizons at the surface, due to previous erosion or soil disturbance by historical land management practices.

Kfs spatial variation
Geostatistical analysis of data did not yield good results. Even when omnidirectional and directional experimental variograms were estimated, were not able to capture the 20 spatial variation patterns of Kfs. It seems that the sampling grid 3×3 m was either too coarse or too fine to capture the actual spatial variation of the variable. Other researchers using nested small scale sampling schemes had found spatial effective correlation ranges betwen 0.25 and 18.11 m (Sobieraj, 2003;Sobieraj et al., 2004;Zimmermann and Elsenbeer, 2008).  (Pilgrim et al., 1988;Wit, 2001;Cichota et al., 2003;Mills and Fey, 2004;Li and Shao, 2006). This study shows that even with considerably high tree cover, like CuA, low values of Kfs may occur, not being statisticaly different of those 5 in very different sites like a gully (G) or a fallow land (FL). Field observations during infiltration sampling and the later data analysis allow to state that actual plant covarage is related to site's land use history. Figure 2 illustrates the conceptual model that relates land cover, Kfs and surface expression of soil horizons in this particular setting.
As mentioned earlier correlations between lnKfs and soil physicochemical properties 10 is low (<0.5) for most of the variables, which does not allow to conclude strongly. The results presented herewith indicate a plausible differential effect of the cover and vegetation characteristics on field saturated hydraulic conductivity, in such a way that Kfs variation does not depend only and directly of plant cover but the unburing of certain horizons and their dominance within the surface at the site scale, as well bioturbation 15 processes and preferential flow channel formation. Kfs did not depend exclusevly of plant cover and land use as hypotesized.
As mentioned before the local milpa system alternates agricultural and cattle grazing. The results of this work are similar to those of Zimmerman et al. (2006) who mention that the effects cattle grazing on Kfs (13 years of cattle grazing) are strong enough to be 20 perceptible even 10 years after the grazing had stopped and an afforestation (Tectona grandis) had been established. Results refuse partially the idea that a dense plant cover favors infiltration or Kfs increase as the Mexican federal governemt Ecosystem Services Program outlines. Nonetheless the afforestation age suggests that recovery time for Kfs under Cupresus monoculture to pre-agricultural practices values, taking as 25 reference the Kfs at the secondary pine-oak forest (SPOF) may be over 35-40 years in clayley soil in similar subtropical volcanic settings, or never achieved due to substantial edaphic transformation.
The excavated soil profile at the CuA site did not show evidence of bioturbation processes as the SPOF site did. Nor had the loam-clayley or sandy-loam horizons as the SPOF or the PA site soil profiles did. In a landscape perspective, physicochemical data from soil samples acquired during the infiltration tests showed that surface sand content was not statistically different between SPOF and CuA (not shown), while clay 5 content was in deed statisticaly different, indicating the presence at the surface of 2Bt horizons. Similar results trough the whole study area suggest a textural control of Kfs at some level even when the statistical analysis did not reveal significant correlations. The latter agrees with the results of Elsenbeer (2001) and Lin (2004). This kind of relationship between texture class or granulometry distribution had been widely recog- Direct soil profile observations and Kfs data indicate that bioturbation is a key process in preferential flow of water at the studied sites, and that this patterns had been related elsewhere to plant composition (Negrete-Yankelevich et al., 2008) and land use 15 (Shakir and Dindal, 1997), but also land use history (Raty and Huhta, 2004;Callaham et al., 2006;Negrete-Yankelevich et al., 2007). It is important to consider that the soil macroinvertebrate communities are crucial because their modification of physicochemical soil properties, favoring biopores and biotunnel formation, the incorporation of organic matter into the soil matrix and the related aggregate stability (Mboukou-20 Kimbatsa et al., 2007). Macroinvertabretes may also alter soil stratification because they move soil material vertically and horizontally (Eisenhauer et al., 2007), favoring the macropore driven hydraulic connectivity between soil horizons (Pitkanen and Nuutinen, 1998 (Sobieraj, 2003;Zaitlin et al., 2007) from small rodents such as gophers and mice (Matula, 2003;Zaitlin et al., 2007) to armadillos in certain tropical environments (Sobieraj, 2003), as well as root induced turbation (Chisci et al., 2513(Chisci et al., 2001. Several authors had reported earlier that infiltration in the vado zone occurs mainly through preferential flow via macropores (Mohanty et al., 1997(Mohanty et al., , 1988Logsdon and Jaynes, 1993). Preferential flow occurs through macropores which has three main origins; a) biological activity (macro and mesoinvertebrates and tunnel formation due 5 to root activity and decay), b) land use practices and c) natural phennomena such as rock fractures and tube erosion.

Final considerations
Even thought neither infiltration nor hydraulic conductivity are ecosystem service per se. They are linked to regulation functions of ecosystems as water regulation and 10 water supply which in turn generate the provision of water for consumptive use as ecosystem service (De Groot et al., 2002). In Mexico's federal government programs, infiltration process is considered as an ecosystem service, and such, it is included in the economical compensation schemes. The results presented herewith support the arguments of Pérez-Maqueo et al. (2005) who criticised the evaluation criteria for 15 the economical compensations of the Ecosystem Services Program of CONAFOR. In this program vegetation cover and type seems to be overestimated while soil role downgraded.
Despite the restricted reach of this research's results. It would be important to consider soil condition in the Ecosystem Services Program schemes, because it is the 20 soil condition and not the vegetation that determines the infiltration. Further, the factors and relationships that define and control water flow through the pedosphere are complex. The ecosystem services approach may need to include the hydropedological perspective in order to better understand these fluxes. This new perspective may help in detailed water source areas definition and key management practices identifi-25 cation which allow the permanence of water sources. Hydropedology may also provide hard data foundation for ecosystem service markets design and development, and to redefine the present economical compensation schemes.
Further research is needed to unveil water flows within the pedosphere and the critical zone, therefore future studies should focus on hydropedological functioning under the ecosystem services approach. It would ease monetary resources flow into a highly specialized and yet demanded field as hydropedology.

Conclusions
The results does not support the conceptual framework used in the Hydrologic Environmental Services Payment Program driven by CONAFOR.
Further the tested hypothesis explains partially the spatial variation of Kfs as a surrogate property of land cover. 10 This study showed that in certain plant cover types and conditions the occurrence of a dense tree canopy is related to Kfs values increase (Secondary Pine-Oak Forest), but in others is not (Cupresus Afforestation). This variation is better explained by the unburing of soil horizons related to land use history.
Infiltration and the field saturated hydraulic conductivity quantified at a specific site 15 or plot in certain time is not the exclusive result of present processes and events; but related and strongly influenced by land use management history as well as natural plant succession patterns. Under dense tree cover such as the Cupresus Afforestation (CuA), Kfs (as lnKfs) was statistically equal to that of the Fallow Land (FL) or the Gully (G), while the Sec-20 ondary Pine-Oak Forest (SPOF) Kfs values were an order of magnitude higher of those present at the Cupresus Afforestation, indicating a relationship of high Kfs with intense soil bioturbation.
The ecosystem services approach may be enriched by hydropedology. The latter may provide methodologies and concepts that would allow a better assessment of 25 ecosystem services programs such as those driven by the federal government in Mexico. Tietje, O. and Hennings, V.: Accuracy of the saturated hydraulic conductivity prediction by pedo-transfer functions compared to the variability within FAO textural classes, Geoderma, 69, 71-84, 1996. Tobón, C., Bruijnzeel, L. A., Frumau, A., and Calvo, J. C.: Changes in soil physical properties after conversion of tropical montane cloud forest to pasture in northern Costa Rica, Second 5 International Symposium Mountains in the Mist, Waimea, Hawaii, 39 pp., 2004. Tsukamoto, J. and Sabang, J.: Soil macro-fauna in an Acacia mangium plantation in comparison to that in a primary mixed dipterocarp forest in the lowlands of Sarawak, Malaysia, Pedobiologia, 49, 69-80, 2005. Wang, D., Lowery, B., Norman, J. M., and McSweeney, K.: Ant burrow effects on water flow 0-5 Weak red (10R 5/2 dry) and dusky red (10R 3/2 moist) sandy clay loam. Angular blocky structure of biogenic origin (10-30 mm) strongly developed, strong macroinvertebrate biological activity. Many biogenic medium and coarse pores, many fine and very fine intertitial and tubular exped pores. Many very fine and fine roots. Soil surface irregular with strong bioturbation features. Clear and smooth boundary. A 12