Class Notes (837,191)
Canada (510,160)
POL469H1 (23)
M.Isaac (22)

IDSB02 Readings Nutrient Imbalances in Agricultural Development.docx

2 Pages
Unlock Document

Political Science

IDSB02 Readings – Nutrient Imbalances in Agricultural Development P.M. Vitousek - 2009  Nitrogen and phosphorous are necessary for high crop yields but downwind and downstream losses of them diminish environmental quality and human well being  Agricultural nutrient imbalances differ with economic development o Ex. Sub-Saharan Africa inputs are inadequate to maintain soil fertility  National and regional policies contribute to patterns of nutrient use and consequences in these situations  Solutions to these nutrient challenges (excess/limiting) can be informed from analyses of trajectories of change within and across agricultural systems  Harvesting crops removes nitrogen and phosphorous & other nutrients  Require replenishing either through biological processes like nitrogen fixation/addition of animal wastes or mineral fertilizer  fertilizer main pathway of nutrient addition its doubled quantities of N&P in terrestrial biospheres  this has helped keep crop production ahead of population growth and can enhance rural economic development but has costs of nutrient pollution (downstream water quality, eutrophication, photochemical smog, increases of GHG nitrous oxide)  in sub-Saharan Africa crop yields have not increased substantially – unlike most other places in the world ->nutrient additions don’t replenish soil nutrients that are extracted from crop harvest  this is seen in Kenya  system persists by drawing down the nutrient capital of what was once high-fertility soil  China: agricultural production increased dramatically since 1975  Policy driven increases in fertilizer use contributed to rising crop yields as they strived for food security  The fertilizer additions far exceeded the amounts used in Europe and USA -> lots lost to the environment degrading the air and water quality  N&P fertilizers in the US contributed to rising crop yields since the 1940s 
More Less

Related notes for POL469H1

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.