2-18 - Today The birth of Scientific Agriculture late 18th...

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Today The birth of “Scientific Agriculture” The Fertilizer Revolution late 18th thru early 20th century The “Green Revolution” late 1950s to today Early Greek on plant nutrition and soils Democritus of Abdera (ca 460-360 BCE) “But that which come from earth must return to earth and that which came from air to air” “Death however, does not destroy matter but only breaks up the union of its elements which are then recombined into other forms” Early ideas – humus & N Aristotle (384-322 BCE) Argued that plants assimilated organic matter from the roots Beginning of humus theory of plant nutrition Pliny (23-79 CE) “It is universally agreed by all writers that there is nothing more beneficial than to turn up a crop of lupines [nitrogen fixers], before they have podded, either with the plough or the fork, or else to cut them and bury them in heaps at the roots of trees and vines” Early ideas - manure Bernard Palissy (1510 –1589) “Manure is carried to the field for the purpose of restoring to the latter a part of what had been removed… Proceeding thus you will restore to the soil the same substances that have been removed by previous crops and which following crops will regain to their advantage” European AG revolution of late 1700s – early 1800s Use legumes (e.g., clover) in rotations to increase N (did not know how it worked but it did) Real AG revolution that made agriculture science
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Increased output helped cope with (cause?) early pop boom Pre-legume yields were 2-3 x volume sown By 1850s European grain yields 3x pre-legume era (i.e., 6-9 x volume sown) All this stoked desire to understand the new science of soil and ag chemistry Important early advances Late 1700s: discovery of nitrogen in air (Lavoisier, et al.) Late 1780s Berthollet shows nitrogen in all living substances Von Liebig - early 1800s “law of the minimum” – growth limited by nutrient in shortest supply Also conceptualized the re-cycling of nutrients Also theorized about mineral nutrients (stuff other than organic) Important early advances II Lawes & Gilbert - 1830s: application of nitrogen fertilizers (e.g., dung) => best growth Boussingault 1830s: Value of fertilizers is dependent on nitrogen content; 1838 proved that legumes restore nitrogen to soils 1888: Hellriegel & Wilfarth show how nitrogen fixation occurs Nutrition “crisis” 1850 to 1900 population in NW Europe and N America grew from 300 to 500 million (about 1% per year) Add rapid urbanization and increasing wealth => demand for food
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This note was uploaded on 03/31/2008 for the course GEOG 232 taught by Professor Whitmore during the Spring '08 term at UNC.

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2-18 - Today The birth of Scientific Agriculture late 18th...

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