Lecture 21 Notes

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Department
Biology
Course
BIO220H1
Professor
James Thomson
Semester
Winter

Description
Lecture 21 Issues in Contemporary AgricultureSlide 1There were famines in India Change structures involving population growth or agricultureoBoth were addressedPeople just started to realize the population boom Slide 2Dry land agriculture depends just on precipitation for water Irrigation used for dry land agriculture Longest ecological experiment started by John BennettSlide 3The nutrients can be replaced by natural processes but if you harvest intensively repeatedly the nutrients arent replaced fast enough and soils are exhaustedDraft animals produce a lot of fecal waste dungfibrous organic matterNPKSlide 4John Bennett was interested in the chemistry he found that he got dramatic effects when he used nitrogen Saltpetertwo compounds called this KNO3 NaNO3 both very good agricultural fertilizers Before more technology came around saltpeter was only available from various mineral depositsin the world one of the driest places in the worldAtacama desert there are salt plains that have lots of nitratesCountries went to war for this saltpeter high economic value this was before the HaberBosch process HaberBosch Processway of making nitrogen fertilizers from Nitrogen gas in the airoTakes a lot of power to turn into its first usable form of ammonia need to put a lot of energy into it natural gas is the source and metal catalystoThis is now the way nitrogen fertilizers are produced industrially Slide 5 This was the bad effect in the Atacama desert for being able to chemically produce ammonia
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