OS0607 YWANG what is good soil

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Clay, loess & loam - what is good soil ? : 

Clay, loess & loam - what is good soil ? Yana Wang 17.01.2007

Soil: 

Soil

Soil Science Society of America (SSSA): 

Soil Science Society of America (SSSA) Soil is the unconsolidated mineral material on the immediate surface of the Earth that serves as a natural medium for the growth of land plants.

composition of soil by volume: 

composition of soil by volume Ideal fertile soil Mineral 45% Organic matter 5% Water 25% Air 25% http://jpkc.snnu.edu.cn/geog/webasp/kj/kejian/6%20turangquan.ppt

soil particle: 

soil particle Rock and mineral weathering Parent material Soil formation Soil particle physical chemical biological Primary particle Secondary particle

classification systems of soil : 

classification systems of soil Criterion: equivalent diameter or effective diameter of soil particle Soil texture: gravel >2 mm sand 0.05~2 mm silt 0.002~0.05 mm clay < 0.002 mm

Slide8: 

http://netc.nwsuaf.edu.cn/jingpin/2003/turangxue/ppt/2.1.ppt

soil particle: 

soil particle The larger the particles are, the more SiO2 the soil has, the more barren it is. http://netc.nwsuaf.edu.cn/jingpin/2003/turangxue/ppt/2.1.ppt

Slide10: 

http://netc.nwsuaf.edu.cn/jingpin/2003/turangxue/ppt/2.1.ppt

Slide11: 

http://netc.nwsuaf.edu.cn/jingpin/2003/turangxue/ppt/2.1.ppt

Clay: 

Clay Mineral: Al2[(OH)4Si2O5] · nH2O Al2O3 · 2SiO2 · 2H2O etc. poor aeration and drainage plastic when wet, when dry become firm

Slide15: 

Clay is only good for paddy rice field.

loess: 

loess Mineral: most carbonates small amount of clay minerals good aeration, water-holding ability easy to be transported by river and wind for example: 1935 dust storm in midwest United States

loam: 

loam mixture of clay, silt and sand sandy, plastic when wet easily water contain more nutrients than sandy soils ideal fertile soil

other parameters: 

other parameters organic matter pH value etc.

organic matter: 

organic matter microorganism soil animal organic manure http://netc.nwsuaf.edu.cn/jingpin/2003/turangxue/ppt/3.1.ppt

organic matter: 

organic matter element: 90~95% C、O、H、N、 P、K、Ca、Mg、Fe、Si、 Zn、Cu、B、Mo、Mn etc. soil fertility:

soil pH value: 

soil pH value climate: high temperature and humidity accelerates the weathering microorganism: for example: breath from bacterium environment: acid rain

Slide24: 

The best pH value for plants is 6,5 . soil pH value http://netc.nwsuaf.edu.cn/jingpin/2003/turangxue/ppt/5.1.ppt

Slide25: 

http://netc.nwsuaf.edu.cn/jingpin/2003/turangxue/ppt/5.1.ppt

Slide26: 

Fruit http://netc.nwsuaf.edu.cn/jingpin/2003/turangxue/ppt/5.1.ppt

Slide27: 

Vegetables http://netc.nwsuaf.edu.cn/jingpin/2003/turangxue/ppt/5.1.ppt

Summary: 

Summary Clay: perfect water-holding ability good for paddy rice field Both loess and loam can be tillable soil for most of plants. But loam is better, because of more nutrient. more than 1.5% organic matter pH value by 6.5

Reference: 

Reference C.Y.Huang, Soil Science,1991 J. Bachmann, G. Arye, M. Deurer, S. K. Woche, R. Horton,Y. Chen, J. Plant Nutr. Soil Sci. 2006, 169, 745–753 http://netc.nwsuaf.edu.cn/jingpin/2003/turangxue/html/link.html http://soil.gsfc.nasa.gov/soilform/deposits.htm http://nhjy.hzau.edu.cn/kech/2006/turangxue/dzja.html http://en.wikipedia.org/wiki/Clay http://en.wikipedia.org/wiki/Loess http://en.wikipedia.org/wiki/Loam

Slide30: 

Thank you for your attention!