It is right to say that the region of El Chaco shows critical desertification processes, specifically in the most populated areas of the Central Chaco. Desertification happens because of the soil damages and also because of the salt increases. Specifically in the Central Chaco area, the transition zone between high Chaco (dry) and low Chaco (sub humid) is affected by the salt increases on the soil, due to the fact that the salt layers come to the surface or are located very near from it. Another desertification thread takes place at Northwest, where the annual precipitation is only about 400 mm and there are very aggressive blizzards during almost the whole year. It is possible to find sandbanks that are already present in the near forest in the shape of tongues. Deforestation is the main thread of desertification; it facilitates the soil degradation because of wind erosion and salt increases. During the last years, deforestation as a tool for pastures implementations without agro-forestry systems has become popular. 

Zone	Characteristics
María Auxiliadora	Semi-arid zone, this is a new settlement with high agro-forestry potential. Farming exploitation is practiced in there and it is based on the reduction of wooded areas; it includes tree felling, burnings, agricultural crops and pastures. The good level of precipitations (1000 – 1200 mm) makes this zone a hybrid between semi-arid and sub-humid. The lands are flat and the erosion is low, due to the fact that the weather allows the vegetal cover growing.
Sierra León	Semi-arid zone with an annual precipitation level of 600 – 800 mm. 80% of the lands are flat with a high proportion of sandy soils very susceptible to degradation caused by the effects of water and wind erosion.
San José Obrero	Semi-arid zone with an annual precipitation level of 800 – 1000 mm. The lands are flat and the soils are over-used and exposed to degradation, caused by wind erosion and cutting ants attacks. This is a zone where the agro-forestry practices are becoming more and more popular.

For Paraguay, specifically the Chaco region, they have identified three forestry-pasture systems.

 

In the humid Chaco (eastern part) is covered by sub-humid sub tropical forest and extensive palm savannas. The most common system is native grasslands with palm trees, until this time with very low, but increasing, changes of the natural landscape. This forestry-pasture system of palm trees and sometimes algarrobo trees as well plus native pasture in natural regeneration causes a low impact in the natural system. This system provides constant food for the livestock, it is of low maintenance cost; little manpower demand and they obtain a diversity of products.

 

In the Central Chaco the main part is covert by subtropical dry forest (xerophytic forest) and just a few small areas with native grassland.  For pasture purpose, cleared areas there are forestry-pasture systems composed of native trees (algarrobo or karandá both Prosopis spp.) + pasture (gaton panic). These are systems of natural regeneration and need of maintenance. The trees grow naturally but must be maintained by hand labor.  The implementation costs are relatively low and show good adaptation to loamy soils. Further there is availability of additional energy forage from the fruit of the trees during dry season; fixation of atmospheric N; and even to obtain earnings from the wood in the local market.

 

The third forestry-pasture system identified is of Leucaena with pasture that allows to recover degraded areas, increase the quality and quantity of forages, increase the meat production per  hectare; availability of additional green forage during dry season and fixation of atmospheric N, among other. The implementation and maintenance costs of this system are high and a negative aspect is that the animals have to be inoculated with a specific bacterium to reduce the toxic effects of “mimosina” caused by Leucaena.

1. WATERHOLE

• Waterhole: Consists in digging a hole with a machine (tractor or digger) in a lower part of the terrain where naturally accumulates water. The most appropriate thing is that the clay – soil, that makes the hole waterproof so that the accumulated water cannot drain easy into the soil. The size of the waterhole depends on how much extended is the surface of the soil with appropriate conditions. Generally the waterholes are about 40 x 60 meters and some are more than a hectare. If the clayish layers are deep enough, it’s convenient that the waterhole is deeper than 3 meters, what allows store water for a longer period (seven month without rainfalls). In some places it’s possible to dig the waterhole (water reservoir) up to 8 meters deep. For a good water reservoir it’s important to take into account the characteristics of the soil (impermeable clay) and the surface in relation to the depth.  Water reservoirs can be built in a dry riverbed as well. It allows water to flow during rain season and keeps water for the dry season, rather than by building a dam they can be destroyed during heavy rainfalls. 
• Australian tank: To built an Australian tank the use the dirt from digging the waterhole. First thing is to construct a floor about one meter high. Above of this floor the dirt is elevated in form of a circle, leaving in the middle a hole. On the bottom of the hole they put a pipe that goes through the dam (circle) and is connected to the drinking trough. The stored water from the waterhole is pumped into the Australian tank by windmill or using a pump with an engine. 
• “Encamellado” (like the back of a camel): This word is used for a part of land prepared to harvest water. Generally the surface is between one and five hectares. For this purpose they use a grader to construct parallel running “ditches and dams” (30 cm deep and 1 m wide). This system of channels conducts to a main channel (ditch) at the end of the smaller parallel running ditches. The main ditch brings the water to the waterhole, where the collected water finally flows into. In natural soil conditions rain water starts to run from 40 mm of rainfall or more, but on the surface built in form as “encamellado” the water can be gathered already from 7 mm of precipitation. This is important, because more than 60% of all rainfalls in the Chaco are less than 40 mm in once.

2. CISTERN

• Cistern: To construct a cistern it’s necessary to dig a round hole, mostly 3 to 4 meters deep and also with a diameter from 3 to 4 meters (the volume of a cistern is between 30.000 and 50.000 liters). On the bottom of the hole they built a floor with bricks or concrete (without iron bars) and than construct the circle walls elevating the bricks in form as a spiral. The inside of the wall is covered with a mix of cement and glue to make them waterproof. Before the wall reaches the level of the surrounding surface, the wall becomes tighter, so that the opening on top is no more than one meter. On top of the opening there is made a box from bricks (1 x 1 m) covered with a wooden or metal sheet. In this plate on top of the box they leave an opening with a diameter of 20 cm where the pipe from the roof goes in. From the cistern the water is pumped in to a tank (capacity 500 liters) placed on top of a 6 to 8 meter high pedestal (tower).
• Channels: Along the edge of the roof from the house is placed a channel (half pipe) to catch up the water that runs from the roof. Trough the half pipe the water flows to the pipe that runs into the cistern.
• Roof: It’s common to use metal plates for the roof, rather than tiles or other material, which absorbs too much water. The first 15 to 20 mm of rainfall brings down all the dirt and dust from the roof and that’s why it is drained  beside the cistern for drinking water, frequently in a second cistern where they collect water for irrigation use.