Forest Soil Management: A Mexican Experience

Forests improve the livelihoods and resilience of communities in diverse ways. In particular, soils provide important environmental services for communities in addition to performing many essential ecological functions in forest ecosystems, such as nutrient uptake, organic matter decomposition, water storage, and provision of anchorage for plant growth. The sound management of forest soils, although often disregarded, is a key element of sustainable forest management. From 2002 to 2016 the Forest Soil Conservation and Restoration Sub-Program was designed and implemented by the National Forest Commission (CONAFOR) in Mexico. Forests in Mexico have high biological diversity and are often owned, governed, and managed by communities or, in some cases, community forestry is practiced. Despite the importance of periodic monitoring to ensure that policies are both effective and suitable for diverse conditions and decision making, the policies implemented by this program were not evaluated during its years of operation. Therefore, in the present study, we aimed to identify the deficiencies of this policy as well as opportunities based on a review of the official information available on the Forest Soil Conservation and Restoration Sub-Program of CONAFOR during the 2002-2016 period and interviews with key informants. In addition, we aimed to highlight experiences that may be useful for similar soil conservation policies in tropical forest regions. The identified limitations ranged from conceptual problems such as policy weakness and lack of understanding of local drivers of soil degradation to an overly rigid implementation of soil conservation measures across diverse forest ecosystems


Introduction
Forests provide many essential goods and environmental services that contribute to local well-being and livelihoods, such as food, firewood, shelter, fodder fiber, income, and employment in addition to sheltering biodiversity, sequestering carbon, and regulating the water cycle. For these reasons, forests are essential for the communities that live within and near them and for fostering ecosystem resilience at both the global and local level [1].
Soils are the foundation of forest ecosystems: they help to regulate important ecosystem processes, such as nutrient uptake, organic matter decomposition, and water storage in addition to providing anchorage for trees. The sound management of forest soil is thus a key element of forest conservation and sustainable forest management [2].
Soil conservation practices are classified as vegetative or mechanical. Both can reduce overland flow velocity and thereby slow sediment transport, resulting in sediment deposition [3] [4]. Vegetative practices function by adding organic matter to soils in order to improve their quality [5]. In contrast, mechanical practices are also commonly implemented but can also have some negative effects. For example, terracing can increase soil erosion and contribute to the formation of gullies, and the construction of ditches can lead to the deterioration of soil quality [6]. A combination of both types of practices adapted to local conditions is often best in order to effectively retain sediments and ensure the sustainability of soil conservation [3] [5].
Policy monitoring and assessment are key elements of adaptative policy management that are particularly important in the field of environmental and natural resources [7]. Despite their importance, almost all forest protection and restoration policies in Mexico up to date lack systematic monitoring, thereby missing important opportunities to learn from experience [8] [9]. From 2002 to 2016, the Forest Soil Conservation and Restoration Sub-Program (FSCRSP) of CONAFOR 1 operated as the most important soil conservation initiative in the history of Mexico, actively implementing different measures in most of Mexico's forest regions. Despite its potential, it was canceled in 2017.
Therefore, in the present paper, we aimed to evaluate the performance of the FSCRSP. Specifically, we aimed 1) to evaluate the coherence of soil conservation practices and budget allocation with the actual soil degradation problems and restoration needs of different regions, focusing on the transparency of resource use and concentration of administrative capacities; 2) to assess the program's 1 The Forest Soil Conservation and Restoration Sub-Program forms part of the ProÁrbol program under which other sub-programs exist, including several oriented toward the control of forest pests and fires, planning, payments for environmental services, community forestry, and reforestation. Open Journal of Soil Science flexibility and capacity to adapt to the diverse conditions of Mexico's forest regions and to contemplate the diverse drivers of deterioration; and, finally, 3) to highlight some critical lessons learned from this initiative that would be useful for improving forest soil conservation and restoration practices.

Materials and Methods
Like other cases of evaluations of other programs [7], our research was based on the review of the information gathered and/or produced from several sources by the federal government 2 .
3) Soil Erosion Map of the National Institute of Statistics and Geography (Instituto Nacional de Estadística y Geografía [14], and INEGI's Series V land-use map [15] at a scale of 1:250,000 were reviewed to identify priority areas.

4)
We also performed a budget analysis to examine the continuity and allocation of financial support considering the long time frame required for soil restoration. A period of seven consecutive years was considered as the threshold for continuous funding. Finally, external reviews of the program for 2002-2017 period were also reviewed [16] [17] [18]. These addressed environmental performances, efficiency of subsidies, and changes in soil conservation practices.

5)
The results of the initial assessment of the continuity and allocation of financial support and soil conservation practices were also analyzed within the territorial context, grouping these findings per ecoregion of Mexico. We used the definition of ecoregion from the North American Commission for Environmental Cooperation. An ecoregion is understood as an area containing a geographically distinctive set of natural communities that share species, ecological dynamics, and environmental conditions. Notably, the ecoregional diversity of Mexico includes a broad diversity of soils ( Figure 1 and    Mechanical works require large economic investments, machinery and engineering knowledge. The implementation of this practice tends to be hierarchical placing bureaucrats "in the design chair at the top of the pyramid, and the farmers, who are supposed to adopt these designs at the base" [22]. Extension agents are responsible for technology transfer to communities that do have poor capacities to replicate these practices High cost and low short -term benefits [22].

Vegetative practices
Use of dead plant material as soil cover, living barriers, agroforestry systems, promotion of secondary vegetation ("acahual"), green manure, windbreaks, living fences Reduce runoff rate, reduce overland flow velocity, act as living filters, retain sediments, increase soil organic matter and improve soil fertility and quality [4] [5] [23].
Use of available, local material through practices familiar to farmers [24]. Farmers participate in technology design, adapting it to local context; Medium cost with regard to benefits obtained [22] ecological conditions. Those interviewed were Juan Manuel Torres Rojo, former

Results
CONAFOR, created in 2002, is responsible for promoting sustainable management and conservation practices in Mexico's forests. As a national agency, its rules and guidelines in regard to forest soils are used to guide public investment in different forest regions of the country. To access CONAFOR's resources, forest owners (mostly forest communities) must request them on a yearly basis. In the case of the FSCRSP, after funding was approved, 70% was delivered at the beginning of the intervention and 30% at the end.
Forest soil policy in Mexico was built on the paradigm that the main causes of forest deterioration are deforestation, land-use change, and overgrazing [25].  In the initial selection of municipalities, the program aimed to strengthen forest management capacities without focusing on soil conservation. From the start, a distinction was made between practices oriented toward hillsides and those toward rills control, sediment retention, and water harvesting for reforestation.

Budget
Between forest and soil restoration programs were actually the best funded programs of CONAFOR, with almost 50% of the total budget being allocated to this area [28].
Resources allocated to mechanical practices were much higher than those in-

Forest Soil Conservation Activities
As previously mentioned, the program mainly promoted mechanical practices such as the construction of dams, stone walls, and ditches in the ecoregions where it operated (Table 3; [16] [30]). In the driest regions of Mexico, 85% of the cumulative budget was devoted to mechanical practices. This tendency was strongest in the North American Deserts, where 95% of the total budget was devoted to these practices. Meanwhile, in the Temperate Sierras and Tropical Humid Forests, a lesser but still majority portion of the budget (83% and 63%, respectively), was dedicated to mechanical practices ( Figure 5).
The program's agenda and implementation were strongly centralized and hierarchical. Aside from working with a pre-established set of soil conservation practices for all of Mexico, the CONAFOR headquarters also rigidly defined the payments for the supported activities regardless of differing economic conditions throughout the country [12].

Tropical Dry Forests
Contour bunding, ditches, terraces, stone walls. From 2011, they are used in conjunction with other practices: the use of dead plant material as soil cover and living barriers.

Tropical Humid Forests
Agroforestry systems, acahuales, living terraces, living barriers, green manure, windbreaks, living fences. In the first years (until 2010-2012), dams and ditches were mainly constructed; they were gradually completed with terraces with a soil cover of dead plants and agroforestry systems.

Temperate Sierras
Dams, ditches, terraces, stone walls and use of dead plant material as soil cover.
In the first years (until 2011), the construction of dams dominated. Then, ditches and stone walls were mostly constructed and used in conjunction with dead plant material as soil cover.

Southern Semi-Arid Highlands
Dams, ditches, terraces, stone walls, contour bunding. In 2011, the construction of dams no longer dominates and is replaced by ditches, stone walls, use of dead plant material as soil cover and, occasionally, subsoiling.
The FSCRSP was designed to be implemented based on the Forest Soil Protection, Restoration, and Conservation manual wherein different practices and activities are described. However, there is no mention of the ecological and social criteria needed to guide the selection of these practices. Four editions of the manual were published: The first three versions proposed the same practices, and only one in five was a vegetative practice. The final edition of the manual introduced some drought mitigation measures, although these were only mechanical, and a new vegetative activity. As mentioned, the construction of dams and ditches largely dominated across all ecoregions.

Soil Conservation: What Time Frame Is Necessary?
Soil conservation and restoration are medium-to long-term processes. In this

Discussion
To address the degradation of forest soils, the FSCRSP focused on the areas of Mexico with the most erosion. However, because of their low productivity, these regions are also the least attractive and least utilized by members of ejidos and communities [30]. Notably, external evaluations found that without the program's support [30], no actions would have been undertaken to protect and/or restore these soils by landowners [17]   Even so, in realm of the soil conservation, no conservation practice is a panacea that can be successfully adopted everywhere [3] [5]. The selection of soil conservation practices should therefore fully consider the particular social, environmental, and institutional conditions of each site [5] [6] in addition to the objectives of landowners, users, and managers. It is necessary to be fully aware of local interests, perceptions, and incentives in addition to the local histories of forest soil management that have led to degradation.
Despite the recommendations of several external evaluations, the program's approach remained rigid [17] [18] [30]. During the last ten years of its operation, the experience gained in each state and ecoregion was rarely incorporated into the program's manual. Another analysis [6] was able to influence the program's operational rules [12], although to only a limited extent 4 . The difficulty of modifying the inappropriate practices of such a program appears to be closely related to overly hierarchical and centralized administration [31].
The restriction of soil conservation activities to the rigid guidelines of a single manual also ignores the rich local knowledge of forest soil conservation, impeding communities' ownership of restoration initiatives. Furthermore, the hierarchical transfer of technology from expert technicians to local forest users characteristic of the FSCRSP largely paralyzed communities' capacity building. The outcomes of such programs appear to have an even greater negative impact on soil conservation in countries with highly biodiverse forests, which are largely owned by local communities [32] [33]. In these forests, local participation and knowledge are critical for sustainability.
Over the fourteen years of the program's operation, forest owners rarely reproduced mechanical soil conservation practices [6] [30]. On the other hand, this approach did initially result in a uniform policy, although slight changes were made later on with respect to the type of soil conservation practices implemented in some ecoregions. Mechanical measures were largely preferred as they are easier to report as an indicator of programmatic performance. However, they can also be a means of diverting resources and, unfortunately, a corrupt use of public funding (interview Juan Manuel Torres Rojo). It is also notable that close and continual advisory to local communities was absent, even though other CONAFOR programs clearly had local technicians working with communities on a permanent basis, particularly in regard to land use planning, which did result in the strengthening of communities' technical and governance capacities (interviews Lucia Madrid, Juan Manuel Frausto).
Also, as previously mentioned, restoration of forest ecosystems is a complex, long-term process rather than a single event or events. Any initial treatments are simply the first steps of this process [8]. Restoration can be a multi-year or even a multi-decade goal requiring the continual improvement of ecological conditions [8]. However, the FSCRSP only granted annual subsidies, a practice in- 4 The discussion of the negative impact of ditches on soil quality was discussed with CONAFOR officials [6] [21]. As a result, the operational rules were modified in 2015, and this practice was prohibited along the Trans-Mexican Volcanic Belt. Open Journal of Soil Science compatible with the long-time objectives of forest soil restoration and conservation. These goals require at least a medium-term vision based on participatory land-use planning. Continuity of funding should not only be based on the diagnosis of the state of ecosystems but also, according to [34] on communities "governance capacities" and "the development of trust and a sense of mutual obligation toward protecting the long-term sustainability of the resource". The duration of a program's financial support should be based on careful and continuous monitoring.
Another disregarded risk was related to the use of economic incentives. As in the case of other government programs that rely on the use of subsidies to promote desired behaviors, farmers may lose interest and abandon conservation practices when incentives end. This is particularly true when the problem, as is often the case with forest soil degradation, is not perceived as a top priority by community members.
Furthermore, the analysis clearly shows that the centralized policies of the Internationally, soil conservation programs contemplating the variability of local contexts have recurred to different methods and strategies such as soil monitoring protocols [36]; the development of distinct intervention strategies for different regions [37]; the definition of general principles to guide restoration Open Journal of Soil Science practices, allowing forest owners to adapt them to local conditions [38]; different approaches for effective monitoring [8]; and the establishment of long-term research sites for producing information to adapt program parameters and report outcomes on a broader scale [2]. These strategies recognize and underline the importance of local approaches that are attentive to site context and markedly contrast with the natural resource management strategies of the Mexican government characterized by strongly centralized and hierarchical decision making.
Policies driven under this approach are opposite to the decentralized, adaptive, bottom-up, and cooperative actions currently evidenced to be effective in ecosystem management [39].

Conclusions
The The present study highlights the unintended outcomes of a centralized soil conservation policy dominated by bureaucratic interests: more than 70% of the total budget was used to implement mechanical measures, such as the construction of dams, stone walls, and ditches, and these solutions were homogeneously implemented across all ecoregions, creating obstacles for the building of local capacities and, ultimately, contributing little to the improvement of forest soil quality in terms of organic matter and [8] [9]. The implementation of mechanical practices often favored rent-seeking practices.
The arbitrary and careless use of public resources is further evident in the pronounced lack of coherence in the allocation of financial resources, for example, 1) the unequal distribution of funding per km 2 in the different ecoregions; 2) the concentration of funding in very few municipalities, specifically in an urban municipality; and 3) the lack of continuity of funding in most areas where the program operated.
Soil conservation is a long-term process with internationally documented experiences of both failures and successes [40] [41]. However, given the severity of Open Journal of Soil Science soil degradation in Mexico and worldwide, it is necessary to shorten the learning curve of public policies through systematic assessments of soil conservation strategies from both environmental and social perspectives. Among the lessons learned from the FSCRSP are the following: First, it is necessary for soil conservation programs to be based on a careful analysis of the underlying drivers of land degradation and strong community governance, with forest owners actively taking part in the design, implementation, and monitoring of interventions in order to successfully achieve adaptive forest management. Second, the best soil management flexibly adapts to local conditions. Also, in this regard, one of the best indicators of the effectiveness of soil conservation practices is their degree of adoption by local communities. Third, to ensure the sustainability of soil, it is important to strengthen vegetative measures and not just mechanical ones.
Third, it is important to establish global or regional monitoring protocols to identify the best forest soil conservation practices and adapt them to the research capabilities and local institutions involved in forest management in particular countries. Monitoring programs are essential for evaluating the efficiency of forest restoration efforts and mitigating the negative effects of poorly planned activities before they have long-term consequences, thereby enabling learning from experience [8].
Although the monitoring and assessment of land degradation has been widely discussed [42], these concepts are rarely included in policy design and implementation [43]. Despite an abundant research body on land degradation control, progress has been hampered by the lack of effective monitoring and assessment, not only of the state of the land but also of the performance and impacts of the interventions.