Editing Geography of Paraguay (section)

===The Western Region: Chaco===
[[Image:Chaco Paraguay cattleranch2.JPG|thumb|right|[[Cattle ranch]], [[Presidente Hayes Department]], Chaco]]  
{{main|Gran Chaco}}

Separated from the Eastern region by the Paraguay River, the Chaco region is a vast plain with elevations reaching no higher than {{convert|300|m|ft|sigfig=2|abbr=on}} and averaging {{convert|125|m|ft|-2|abbr=on}}. Covering more than 60 percent of Paraguay's total land area, the Chaco plain slopes gently eastward to the Río Paraguay.

The Paraguayan Chaco is subdivided into two parts. The ''Alto Chaco'' (Upper Chaco), also called ''Chaco Seco'' (Dry Chaco) is the western three-quarters of the region, bordering on Bolivia, while the ''Bajo Chaco'' (Lower Chaco) or ''Chaco Húmedo'' ([[Humid Chaco]]) borders on the Paraguay River. The low hills in the northwestern part of the Alto Chaco are the highest parts in the Gran Chaco. One prominent [[wetland]] of the Bajo Chaco is the Estero Patiño, which at {{convert|1500|km²|sqmi|sigfig=2|abbr=on}} forms the largest [[swamp]] in the country.

The Paraguay Chaco's western two-thirds belong to the [[Semi-arid climate|semi-arid]] tropics with annual precipitations between {{convert|550|and|1000|mm|in|-1|abbr=on}}, vegetation being dry low scrub in the west to higher growth [[Xerophyte|xerophytic]] (semi-arid impenetrable [[Thorns, spines, and prickles|thorn]]) forest towards the east. The eastern third belongs to the semi-humid tropics, with rainfall between {{convert|1000|and|1300|mm|in|-1|abbr=on}}, taller vegetation, and tropical semi-humid forest. A belt about {{convert|50|km|mi|-1|abbr=on}} in length along the Paraguay River again has a different [[evergreen]] vegetation of wetlands and [[Arecaceae|palm tree]] forests (''Bajo Chaco'').

Annual evaporation is around {{convert|1500|mm|in|-1|abbr=on}}. The very pronounced dry season lasts from May to October, and a wet season occurs from November to April, when the vegetation turns green and abundant.

The soils of the Chaco are very deep [[sediment]]ary [[soil]]s rich in nutrients, including [[luvisol]]s, [[cambisols]], and [[regosols]], and are in general very fertile and apt for agriculture and pasture (always presuming responsible and sustainable techniques), more so than most of the world's semi-arid tropics.<ref name= fao>{{cite news | first= Dr. Fernando | last= Riveros | title= The Gran Chaco | publisher= FAO | url= http://www.fao.org/ag/AGP/agpc/doc/Bulletin/GranChaco.htm | access-date= 2009-01-09 | archive-date= 2011-10-02 | archive-url= https://web.archive.org/web/20111002213811/http://www.fao.org/ag/AGP/AGPC/doc/Bulletin/Granchaco.htm | url-status= dead }}</ref> Limiting factors include a lack of ground freshwater in most of the Paraguay's Chaco, except in the north and the west. The lowlands facing the Paraguay River have insufficient drainage and seasonal flooding (which again increases soil fertility) as a constraint.

The western region has a population of 220,805 and an area of 246,925&nbsp;km<sup>2</sup>, the population density is 0.89/km<sup>2</sup>.