In recent decades due to the negligence of groundwater management, the resources are degrading rapidly and have resulted in soil water stress. Owing to the role of climate change, now most of the environmental variables undergo variations in their dynamics and magnitude, and above all, arid zones suffer the greatest loss due to evapotranspiration and soil water stress. In order to understand the nutritional future of the most important agricultural regions in Mexico, this scientific contribution aims to analyze the trend of soil water stress in the Northern Mexico. The work emphasizes on the relationship between the energetic movement of groundwater and soil water stress which also includes the process of crop absorption that is affected by the changes in soil surface temperature and the geography of the region. The results reveal a positive trend that gradually leads to soil water stress and intensities associated with conditions of interdependence of unique variables in each valley. Global withdrawals of ground water tripled in the last 50 years with unequal volumes in arid zone that will definitely lead to instabilities, where sustainable management will be the basis of conservation to adapt to the new facies of climate change.
- climate change
- water stress
- risk and agricultural valleys
Worldwide, in many countries, the concerns of the productive sector on issues related to global warming and the consequences that current climate change could cause, especially the effects due to the changes in the average surface temperature of the world, will be discussed in this chapter. Soil and environmental temperature can significantly affect economic activities that are mainly related to the agricultural sector where soil is the main source of supply for food sustainability which is at risk due to water stress. The situation strongly affects the developing countries because of scarce economic resources that make their population vulnerable and poor resilience when it comes to facing the phenomena related to climate change. Decades ago, simple observations permitted mankind to realize the changes experienced by the environment, preferably by the increase in the frequency of occurrence of extreme weather events and environmental changes. Likewise, global environmental events associated with global warming caused the initiation of relevant investigations that would implement different methodologies to evaluate the vulnerability of climate change and henceforth to bring in awareness among the people. The book “Training methodology to assess vulnerability to climate change” is a typical example of this action. Undoubtedly, the frequency of occurrence and extreme meteorological phenomena of the past, present, and future and the fundamental cause is largely due to the increases and/or decreases in the regime of precipitation and potential evapotranspiration resulting in droughts and heavy rainfall regimes. Several research papers have documented the disparities and influences of climate change, whereas this work presents the thematic behavior of the temporal variation of soil water stress in the agricultural zones of North Mexico. In the present investigation, climate modifying factors in reduced spaces are analyzed in an integrated manner which could permit the scientific community to focus on general concepts such as heat islands and heat waves [1, 2] as in the past, which is actually related to augmented temperature rise .
There are many documented evidences regarding the economic losses caused by extreme meteorological events due to climate change, for example, Colombia witnessed 1970–2000 landslides and floods from 1970 to 2000 that caused heavy economic losses up to US $ 2.227 million that the National Planning Department (NPD) of that country was only 2.66% of the National Gross Domestic Product (GDP) for the year 2000 . Perilous phenomenon in Mexico that could cause economic losses in the future, such as those caused in other regions of the country, is the excessive accumulation of cloud systems around the great mountains in the south of the country, preferably over the southern mountain ranges of Oaxaca and Chiapas, and also in the Northwest on the eastern and western Sierra Madre Oriental and Occidental. Several satellite images have also represented an increase in the spatial and temporal distribution of cloud systems (mostly clusters) that can reach up to size of a cyclone. The cloud accumulations before the presence of sufficient humid air initiate their route toward their distinct stages resulting in precipitation. However, irregular precipitations due to climate change can be considered to be the vital reasons that could increase the ambient and soil surface temperatures.
Specifically, in the mountain ranges of Sierra Madre Occidental and Oriental, the cloud clusters begin to group and tend to grow vertically to reach their mature state during the afternoons and later they begin to propagate throughout the region, but when crossing the great mountain ranges of the Sierra Madre, they form storms with intense lightning and up to the possible presence of hail. During the propagation, the clusters are conglomerated in large cloud systems of extensive oval shapes that can be observed by infrared satellite images. Likewise, the similar type of occurrences on August 23, 2010 caused heavy rains in the Papaloapan River Basin situated in the southeast part of Veracruz State, Mexico was observed, which eventually resulted in the accumulation of large oval cumulus systems during the same time period causing electrical storms that by the end of August ensued large floods in the Tlacopalcan community of the same state. Given the damage caused, there is no doubt about the importance of continuous monitoring of meteorological phenomena by means of available resources, and that the evolution and trajectory of the meteorological events must be tracked, in order to anticipate possible damage and take right decisions immediately. However, current meteorological studies do not reach such magnitudes of tracking, but with state-of-the-art technology developed in Mexico, satellite imageries and high-end monitoring techniques can provide early alerts and prevent risks from fires, severe storms, hurricanes, and also infrared satellite images can track the trajectory of a tropical storm in real time . It is important to highlight that there are many scenarios in Mexico where the historical levels of diverse phenomena related to extreme meteorological events are surpassed; and most of them occur in regions which have experienced the rainiest periods in their histories leading to massive floods in the agricultural areas affecting the economy. Otherwise, the phenomenon can also occur in regions with absence of precipitation face drought scenarios such as those found in the northwest of the country facing Gulf of California. Regardless of the conditions caused by climate change, increase in the frequency of extreme meteorological activities always affects the economy and GDP of a country as climatic variability in great proportions distresses different productive sectors. Several studies at the regional level indicate that agriculture and rural development are severely affected, especially during the presence of the El Niño and La Niña phases; that increase or decrease in the climatic anomalies in large proportions bring floods, landslides in cultivated lands, proliferation of diverse pests, expansion of diseases, changes in the vegetative cycles of crops that are commonly enabled to the repeated ways of practicing agriculture, the seasonality of crops and production. Agriculture largely depends on the rainfall regime, soil surface and ambient temperature, and the soil conditions.
Therefore, it is logical to think that in places where climate change effects are observed, it can be inferred by the presence of environmental damages, so this would be the areas where the responses of soil due to climate change have to be defined, considering that soil, air, and temperature are in equilibrium. The large coastal plains of Northwest Mexico located along the Gulf of California encompassing the states of Sonora, Sinaloa, and Nayarit are the regions in which changes have been observed and reported for a long time due to the increased occurrences of extreme meteorological events. In the present work, the abovementioned regions are considered to be regions where geography intervenes to the formation of meteorological events. So, in this work, it is assumed that the environmental interventions due to climate change are directly proportional to the local geographical conditions that aid the formation of extreme meteorological events described above. That is the reason why we selected a coastal region of the state of Sinaloa to raise the objective of determining the change in water stress with respect to time [in the soil of the valley of Guasave better known as “The agricultural heart of Mexico.” The region is predominantly agricultural in which the subsoil has undergone agricultural pressure continuously since the 1960s due to the growing technologies and ideals set by the “Green Revolution.”
In order to achieve the objective, data available from CONAGUA and the Environmental Engineering research group of CIIDIR-IPN-Sinaloa were analyzed and processed; in relation to the intrinsic variables of the agricultural land possibly affected by extreme meteorological events. The temporal space variation of was measured based on the criteria of Medrano et al.  and conditioned to the methodological approaches of Sánchez . The results can significantly measure over effects that could cause changes in the internal structure of the soil subjected to local climatic changes that could significantly affect the ways in which various crops exploit the H2O resource for its development in the area possessing climatic conditions ranging from arid to semi/arid.
The investigation is justified by the mere fact of the latent presence of the meteorological phenomenon that currently occurs in both Sierra Madre Occidental and Oriental that causing rare meteorological events and forcing to carry out agriculture unceasingly under high risk.
Among the three states of the Northwest Mexico (Sonora, Sinaloa, and Nayarit), a coastal agricultural region of Sinaloa State, Guasave, was selected for the present study. Located in the Northwest part of Sinaloa State, the region elucidates a long history of agricultural practices even from the period of “Green Revolution” (Figure 1). Due to its agricultural history, high productivity, and high-end technology, the area represents the incursion of large foreign currency into the Mexican economy, which have been the fundamental bases to be called “The agricultural heart of Mexico.” The region consists of soils with diverse granulometric extents originated by the geological processes derived from different episodes that date from the Late Oligocene, the Middle Miocene (25–15 million years ago), and late Pliocene (<5 million years ago) and the current Quaternary . The region also characterizes intermountain relief and coastal valleys.
The variation in the present-day relief started approximately in the altitudinal elevation of 1800 m, in the eastern limit of the Sierra Madre Occidental (natural barrier that protected Mexico against the dangerous tropical hurricane Patricia in mid-October 2015, formed by a tropical disturbance south of the Gulf of Tehuantepec). A transition towards the high plateau is characterized by a steep decline governed by an abrupt slope tending toward the Gulf of California and the Pacific Ocean until reaching the coasts at a regular altitude varying between 14 and 40 m above sea level. Specifically, to the North of the Sierra Madre Occidental, geological processes have resulted in an average altitude of 1400 m above mean sea level . Henceforth, the area is made up of extensive agricultural coastal plains, and precisely the valley of Guasave constitutes slow and continuous flows of River Sinaloa streams of Ocoroni, Cabrera, and San Rafael; where the last three streams discharge into the Gulf of California. According to recent studies on the interpretation of geophysical data of geo-electric type , as a hydrogeological unit, the system is sometimes treated as a free aquifer that is commonly exploited and represents the regional geology which could be observed in varying depths where the hydraulic works are drilled .
Due to the changes in the environmental temperature, the increase and/or decrease of the precipitation regime, the presence of global warming and the consequences of climate change, some of the considerations of the criteria of Medrano et al.  were taken into account in order to justify this investigation related to the ways in which a soil is stimulated ∆
Since each continuous system fills every space it occupies, the magnitude of the variables that described
The following is a brief description of the variables that intervene in the previous criteria and justifies the reason why they were taken into account in the definition of
In the first criterion, the variables that intervene in the physical, chemical, and physiological processes inside and outside the plants are addressed and correspond to the variables that integrally give an ideal representation of the mechanisms that govern the water fluids. Therefore, it was considered that these variables define the availability of water resources, the humidity of both the soil and the environment. The variables considered were the depth at which the groundwater table is located in the aquifer as this distance is defined according to the internal and porous structure of the subsoil by 80% in the presence of the surface moisture of the soil and the moisture of the environment.
Regardless of the fact that a change in the precipitation regime is the one that can largely define the presence and/or absence of both surface and groundwater resources, this process does not result in a significant change in the internal structure of the subsoil at great depths and influences the physicochemical properties that would occur only in the structure of the superficial parts of the soil. Henceforth, within the aquifer, there are no significant changes in the ways in which advection processes can occur simply because no changes occur in the internal structure that defines the properties in which the advection occurs, to mention a few; storage coefficient, porosity, transitivity, hydraulic conductivity, among others; which will be discussed in the following criteria. Nevertheless, the foregoing, significant changes may occur due to the intensity and long periods of rain affecting the surface soils and within the aquifer, the changes would occur in relation to the magnitude of the intensity of the flows and quantities of existing fluids during the transportation processes in the porous medium. Therefore, it was taken into account that the magnitude of the following variables is those that contribute greatly to the existence of water flows and directly related to the temporal space variation of the depth of the static level of a region.
In the second criterion, the soil scenarios in which the crops are grown are also directly related with the internal structure of the soil and/or with the potential of each soil to exercise agriculture. Texture is one of the main variables that define the granulometric variation of each soil, degree of characterizing its structure type from thin to thick; that allow plants with the facility to extend their roots to the length of the subsurface horizons and are associated with the potentiality of crop development. Other variables that develop a crop into plant and aid in water storage are porosity (
The third criterion was selected because it indirectly contemplates for its occurrence which includes the effects of the amount of radiation, humidity (absolute and relative), environmental temperature, and wind speed, which can be altered due to global warming, changes in the rainfall, and climate regime of a region. Regarding the modification produced by climate change, the criteria of Sánchez  were taken into account to select the factors that have enormous consequences on any climatic parameter and that depend on geography and that the literature considers them as the main regional climate modifiers. The modifying factors in a closed system that favor climate change were observed to be absolute height (
From the physical point of view, the basic hypothesis to formulate this investigation was “The balance of the extensive properties in the theory of the systems of the continuous flows and of the variables that interact with the matter, as a whole converge to define an integrated manner both in closed and open systems the effects produced by climate change” whose numerical analysis will be established through the type of system (closed and/or open) and its mass balance can be obtained through the premise “any variation of the extensive property caused by the changes in matter due to climate change is the result of what is generated or destroyed within the body or mass and of what enters or leaves through its borders.” Given that the effects caused by climate change depend on the main geographic factors that regulate the climate of each region, precipitation, and environmental temperature, their respective magnitudes were concentrated in a database to position the variables according to the three criteria of Medrano et al.  and according to the territorial extension. To perform the measurements of the variables involved in the description of
During the field trips, the locations of the wells in both the networks were estimated using differential GPS. The temporal variation of the solar radiation was also measured using a pyrometer. Although a good number of variables were measured to understand the dynamics of
3. Results and discussion
To meet the first criterion of Medrano et al.  for the presence and/or absence of surface humidity in the soil and in the environment, indistinctly of precipitation, the results of the spatial variation of the phreatic depth are discussed. The phreatic depth variation from the measures of central tendency presented an irregular spatial behavior along the valley with respect to the average value obtained from the dataset in the network constituted by 660 wells from the coast to the mountain areas. The central tendency measurements marked somewhat similar values for and equivalent to 5.88 and 5.61 m; measures of central tendency did not provide an adequate description of the set of measurements that defined the spatial distribution of phreatic depth in the Valley, and could not give an exact description of the variation of this parameter; however, because the phreatic depth values turned out to be superficial, it can be regarded as a potential indicator of the evidence of type saturation in most of the soils of the study area. The values of were 0.94 and 16.17 m, respectively, whereas the variability or dispersion of the variance was observed to be = 10.34 m and = 3.21 m with 0.03, which was relatively low.
The values of were accepted to be less than the values for and , situation observed by the symmetry of the phreatic distribution along the valley with the magnitude of 2.54 presented the distribution of . showed a less value, so in general terms, the data collected were considered adequate for the information process. The spatial variation of the phreatic depth is presented in Figure 3 and the lesser values of the phreatic depth ranged from 1 to 5 m with parallel alignments to the coast line and in the preferential direction of NW-SE revealing the protuberances of the Sierra Madre Occidental. These conditions of low depth represent the presence of a high environmental humidity; however, it is also indicative of high saturation states in the internal structure of the soil and in turn the presence of in which the soils by proximity to the sea in the presence of an intrusion phenomenon are no longer apt for practicing agriculture. In turn, the spatial configuration of the phreatic zone allows us to observe soils in transition to the presence of and that could be considered as a future risk. Nonetheless, the foregoing, before the most important factors that modify the climatic conditions of a closed environment, it is important to take into account the superficial granulometric variation of the soil that may constitute its full conservation or its ease of destruction, and which is defined respectively by the magnitudes of and
There are evidences that at the depth at which the phreatic zone is located, a very specific humidity condition will be defined in the environment that is directly proportional to its depth, i.e., there is a linear and direct relationship with soil moisture. Due to the above conditions, increases and decreases in the water table of a zone like those observed in Figure 2 can represent a direct relation to the period of time without precipitation, where and
In Figure 3(A), the spatial distribution 660 wells where the measurements of the depth of the water table (
The reason why a wide network of 660 wells was selected was due to the fact that it was considered to have a greater control in the phreatic depth of the aquifer due to the fact that most of the water is concentrated throughout the year, and it is with respect to the phreatic depth. This network constitutes a constant and important source of water volumes that intervene in the content of the environmental and soil humidity, as well as large volumes of water for the ETP processes occurring between the plant and the soil.
Figure 3(C) and (D) represents the spatial behavior of the equipotential curves for the values of
According to the values of (Figure 3(D)), a heterogeneity will be exhibited due to the high values of K allowing the soil to reach scenarios of of high water saturation or low values of with low values that tend to be completely dry. Therefore, correlations between intensive and expansive processes in the gradual scenarios of can be represented through the following multiple and interdependent correlations . It is also important to mention that the porous medium and its changes with respect to its internal structure are made in a slow way and are minimal changes that may occur over long periods of time; however, in the presence of extreme meteorological events, soils present erratic portrayals.
Despite the slowness with which the internal structure of the soil occurs, a scenario of drought or saturation of its internal structure is highly conditioned to the availability of water resources, and the aforementioned multiple interdependent correlation would be dominated exclusively by a scenario of drought or saturation, with all the intrinsic parameters of the soil to be defined under the availability of water resources. In the map of , in Figure 2(C), an alignment in the direction NE-SW parallel to the flow of river sediments with the tendency of belonging to sandy soils can be observed, also the similar scenario is repeated in the area located to the NW and in some areas of the coastal zone. The clayey soils are observed to be distributed concentrically along the valley, which indicates isolated basin lines where the water is concentrated to drain quickly toward the tributaries of the area, not allowing the soils a strong interaction with the water resource which also puts them at risk of being dry. The region is partially covered by alluvial materials and fluvial deposits of the Quaternary, which occupy the subsoil of the entire region with variable thicknesses, heterogeneous in terms of lithology, degree of cementation, and hydraulic characteristics.
Figure 4 represents the water availability (mm3) in the valley. The statistical measurements in the distribution for the central tendency of the data describing the availability of
Figure 4 presents the North and Northwest part of recharge of the area, as well as the discharge area that is mostly located toward the most important water tributaries; the recharge was observed to be 1600 mm3 and reaches a volume of up to 3200 mm3.
The marked variation in the water availability of the central area of the valley is most probably to the sedimentary terrain of the region. High volumetric imbalance in the storage coefficient can be related to the high demand for groundwater that has always existed in the region due to extensive agriculture practices, livestock, and trade business. It should be noted that these soils, due to their varied granulometric composition, are the soils that are preferred in agricultural activities because they allow diversity in the types of crops of commercial interest whose productivity provides guarantees of having diverse products throughout the year.
Differences in the agricultural activity governed by different types of soils throughout history have been favored by a superficial sedimentary geology in which the water tributaries play an important role in the formation of its granulometric efficiency. In the present study, soils are mostly characterized by a silty-sandy mudstone and silty-clay mudstone, making them suitable for agricultural activities as they permit water content in the pores that have no tendencies toward positive values and extreme negatives of being able to store H2O in its structure and are suitable for any type of crop growth. The variations that exist in the availability are relatively of small gradient (approximately 200–300 mm3 for every 2–3 km), defining the area as high risk tending to the presence of primarily subjected to water availability; however, in a previous year, a scenario with high intensities of precipitation had been presented.
The current increase in temperature and changes in weather conditions had significant impact on the rainfall. The absence/increase of rainfall has possibly been resulted in flooding and/or drought. The soil in these regions has faced different “stress states” depending on the rainfall. So, it is always important to know its current response to the new precipitation regimes, in order to identify the porous internal structure and the current potential to store the water resources. Usually, the development of crops is based on the presence of maximum or minimum H2O retention scenarios and/or absence of the relative and absolute humidity. One of the methods by which they form extreme meteorological events as mentioned in the introductory part, it is directly associated with the formation of cumulus clouds. Occurrence of meteorological events increases when the clouds reach mature stage that causes high cumulus densities to accumulate in the atmosphere by setting the surrounding areas at risk with the continuous manifestation of high rainfall and droughts. It occurs mainly in the presence of humidity in the environment. Continuous accumulation phenomena of cumulus clouds and the saturation of the ground that caused increases in the conditions of depend on the soil moisture condition, the behavior of the water table, surface and subsurface processes of the soil, and the environment. Thus, it is important to know the conditions in which it can develop the magnitude of and are produced to a certain extent by the conditions of antrum factors depending on the activities of each region. The soil protection programs would preferably be aimed at protecting its internal structure through nondeforestation of green areas. Another way is to avoid the production of gases favoring the greenhouse effect, which in turn attributes further changes in global temperature. Understanding the given essentiality of soil in the world, humans must adapt and adjust with respect to climatic stimuli in order to moderate the damages happening in the environment. In addition, it is worthy to identify the beneficial opportunities and possible resources to circumvent the new changes. On the other hand, the current flora and fauna is the result of a continuous evolution by an adaptation to the different environmental conditions, i.e., changes in the temperature on the face of the Earth. We suspect that these new meteorological processes like the one presented here would lead to environmental changes affecting plants. As plants are mostly in contact with soil, water, and air, they are easily amenable for adaptations to environmental temperatures and the availability of the water resources. The governance in tolerance and the way of developing adaptability will allow the plants to define their permanence or disappearance as a species. Apparently, in a given land, fundamental factors like, the dynamics of changes undergone by a land through its history in the different stages of its evolution, and in some of the occasions, external conditions from other planet have been considered to identify the sources causing changes. On this occasion, the evolution dynamics can be conditioned to the high and/or low availability of the water resource and to the environmental conditions in which the soil develops the phenomenon . Currently, many scenarios are changing in relation to the ambient temperature which has forced the plants to develop new tolerance limits and live in the presence or absence of H2O.
An increase or decrease in the ambient temperature, in different regions, will allow the existence of new living conditions experienced by the scenarios that will be conditioned by the presence and/or absence of the superficial or underground H2O depending on the phreatic depth and the water retention capacity of different types of soil. Henceforth, it is recommended in the places where the ambient temperate decreases or increases, studying the availability of water resources from a point of view where the variables are related by the geographical effects allow the development of climatic conditions that are different for both global and closed environment, so the representative function of the change according to each variable will tend to behave differently from the effects caused by the geographical factors but there will always be a function in each environment (representative of the integrated behavior of the system