Geography 2011A/B Lecture Notes - Lecture 20: Soil Salinity, Urban Agriculture, Sustainable Agriculture
5 May 2018
School
Department
Course
Professor
Organic Agriculture
Green Revolution
- Allowed us to increase food production to feed our growing population, BUT:
- fertilizer runoffs lead to algal blooms and pose threat to human health
- irrigation can lead to waterlogging and soil salinization
- pesticides can affect non-target organisms and human health
No-Till Agriculture
Sustainable Agriculture Low-Input Agriculture
- Production of agricultural products that doest
deplete the soil or pollute the environment to Locally Supported Agriculture
retain soil to grow crops in the future (ex. community-supported agriculture,
urban agriculture)
Organic Agriculture
No-Till Agriculture
- depth and frequency of ploughing and tilling (mechanical turn over of soil) are kept to a minimum
- avoids mechanical manipulation of the topsoil so as to leave it covered with crop residues (from the
time of harvesting one crop to planting the next crop)
- no-till agriculture is increasing over time
- benefits protects soil moisture, prevents soil compaction, prevents soil erosion
- Conventional Tillage mechanical manipulation of topsoil that leaves no more than 15% of the
ground covered w/crop residues
- Benefits
- reduces weeds
- softes the soil ad akes it easier to plat e rop
- allows the soil to warm more quickly
- Drawbacks
- major contributor to soil erosion (tillage soften soils = soil can be blown away by wind, washed
away by rain).
Low-Input Agriculture
- uses less pesticide, fertilizers, growth hormones, water, and fossil fuel energy than industrial
agriculture.
find more resources at oneclass.com
find more resources at oneclass.com
Local Agriculture
- minimizing distance between food production and food consumption
- examples:
1) Community-Supported Agriculture consumers pay farmers in advance for a share of their
yield (and during the year, consumer gets produce); consumers share risk w/farmer
2) Urban Agriculture taken parkland and converted it into small farm that produces food
Organic Agriculture
- no synthetic fertilizers or pesticides (can be inorganic though)
- relies on biological approaches to provide soil nutrients (ex. composting, manure, nitrogen-fixing
legumes) and pest control (ex. mechanical weeding, biological control)
- like the other forms of sustainable agriculture, organic agriculture is on the rise (market for organic
food has increased 20% annually, more than 500,000 ha are used to grow organic products in Canada)
- Why is Organic Agriculture increasing?
- Consumers concerns about pesticide effects on human health, desire to improve
environment quality
- Farmers lower input costs, enhanced income from higher-value products, reduced chemical
costs and pollution
- Benefits
Rodale Institute Farming Systems Trials
- 1981-2002; Kutztown, Pennsylvania
- compared organic and conventional grain-based farming systems
- 3 cropping systems
1. Conventional synthetic fertilizer and herbicides used...also no cover crops grown during
non-growing seasons (leae field ept he or ad stuff aret groig
2. Animal-Based Organic no synthetic fertilizers and herbicides used...cow-manure and
nitrogen-fixing legumes used as fertilizers.
3. Legume-Based Organic no synthetic fertilizers and herbicides used...nitrogen-fixing
legumes used as fertilizers.
- not much of a difference in soil chemistry
- increase in soil structure, soil invertebrates, and soil microbial activity,
indicating better soil health in organic systems
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Allowed us to increase food production to feed our growing population, but: Fertilizer runoffs lead to algal blooms and pose threat to human health. Irrigation can lead to waterlogging and soil salinization. Pesticides can affect non-target organisms and human health. Production of agricultural products that does(cid:374)(cid:859)t deplete the soil or pollute the environment to locally supported agriculture retain soil to grow crops in the future. Depth and frequency of ploughing and tilling (mechanical turn over of soil) are kept to a minimum. Avoids mechanical manipulation of the topsoil so as to leave it covered with crop residues (from the time of harvesting one crop to planting the next crop) Benefits protects soil moisture, prevents soil compaction, prevents soil erosion. Conventional tillage mechanical manipulation of topsoil that leaves no more than 15% of the ground covered w/crop residues. (cid:862)softe(cid:374)s(cid:863) the soil a(cid:374)d (cid:373)akes it easier to pla(cid:374)t (cid:374)e(cid:449) (cid:272)rop. Allows the soil to warm more quickly.
