Soil Classification

What is purpose of classification? “Chaos was the rule of nature; order was the dream of man”. Henry Adams Adams 19th century historian

How would you go about classifying soil? Organize knowledge; soring and retrieving information; communication; mapping; land valuation

Ethnopedology Study of folk soil knowledge Many ways of knowing “folk”, “traditional”, “indigenous”, “local” Soil knowledge held by people who have occupied land for a long time Many ways of knowing Western science looked down on local soil knowledge as unscientific. Folk soil knowledge uses spatial and time scales much more relevant to sustainable agriculture.

Local soil knowledge Time-tested Strategies that have been tried over centuries (or millennia) compared to < 100 yrs of industrial agriculture Provides insights about human responses to change (climate change, soil erosion) Many properties used (taste!, texture, color, etc) but all are about function of soil in land use (need for water, nutrients, aeration, support) Does not imply that indigenous groups have not substantially altered land or caused environmental degradation problems; can learn from mistakes, too

Region Maya occupied 2000 BC to 1500 AD

Maya occupation of Yucatan peninsula 1200 BC to AD 1300 How did the Maya manage to feed millions of people for thousands of years in an area that is today sparsely populated and agriculturally poor?

Maya Lowlands Highlands relatively small area is composed of n intricate mosaic of widely varied micro-environments

Climates of Maya Lowlands: BS semi-arid steppe Aw tropical savanna Am tropical wet-dry Af tropical rainforest

roughly north-south transect showing (400 – 500 miles) Eocene limestone platform changes in veg. assemblages, structural geology, relief, and access to groundwater one of the great mysteries about Maya is how they were able to feed millions of people for 1000s of years in ag poor sparsely pop region

Agricultural adaptive regions in the Maya lowlands Gave rise to a vast array of of agricultural intensification techniques; crazy quilt; managed mosaic; very valuable for region as a whole,

Lari, Peru 1500 yrs agriculture Terraces Compared to uncultivated: thicker A, lower bulk density, higher organic carbon, higher N and P; Impressive management suggests a substantial body of soil knowledge

50 unique soil types in a 4 tiered hierarchy; most names are in Quechua, some borrowed from Spanish

FAO/UNESCO International system, adopted for purposes of creating a global map Has been replaced by World Reference Base Uses some classes from other systems Food and Agriculture organization The United Nations Educational, Scientific and Cultural Organization

USDA Soil Taxonomy system Seventh Approximation Originally 10 Great Orders Have added two more (Andisols, Gelisols) Many include another order “ Anthrosols” Hierarchical system

ORDER SUBORDER SUBORDER SUBORDER SUBORDER GREAT GROUP SUBGROUP FAMILY SERIES

Hierarchical categories Order Suborder Great group Subgroup Family Series Alfisol Udalfs Hapludalfs Typic hapludalfs Fine,loamy,mixed,superactive,frigid Nebish Fine-loamy, mixed, superactive, frigid Typic Hapludalfs