Environmental Engineering Reference
In-Depth Information
TABLE 24.1
The Key 21 Fossil Natural Resources for Food
Production
Primary Inputs
Macronutrients
Micronutrients
Freshwater
Nitrogen—N
Magnesium—Mg
Fertile soil
Phosphorus—P
Boron—B
Fossil fuels
Potassium—K
Copper—Cu
Fine seeds
Calcium—Ca
Chorine—Cl
Carbon—C
Iron—Fe
Oxygen—O
Molybdenum—Mo
Hydrogen—H
Manganese—Mn
Sulfur—S
Nickel—Ni
Zinc—Zn
production has dropped 20% over the last 3 years forcing phosphorus imports from
Morocco.
Peak phosphorus use will occur before 2040, which will drive up prices dramatically on
remaining stocks.
21
Economically recoverable reserves for several other plant nutrients are
seriously constrained. Armin Reller has been investigating world supplies of metals and
estimates that the world will run out of copper in 25 years and zinc in 20-30 years.
22
Plants
need zinc to propagate which is critical for people and animals that depend on the seeds
of plants (the fruit of the vine), for food.
Inorganic soil nutrients dissolve quickly in water which makes them ideal for plant
absorption through the roots. The downside of high solubility is that these nutrients
are easily rinsed out of topsoil by rain or irrigation water. Therefore, farmers must add
substantial additional fertilizer every year which drives up costs. The high solubility also
means these agricultural chemicals find their way into well water, wetlands, and estuaries.
Soil degradation and nutrient loss reduces yields for years before the land must
be abandoned. Global grain production continues to increase but yield increases are
decreasing each decade (Figure 24.3), largely due to soil degradation.*
2.8
2.6
Global grain yields
2.4
2.2
Annual percent increase by decade
2
1.8
1.6
1.4
1.2
1
1950s
1960s
1970s
1980s
1990s
2000s
2010s
FIGURE 24.3
Increase by decade global grain yields—annual percent.
*
http://www.who.int/whr/2004/annex/topic/en.annex_2_en.pdf (accessed October 1, 2004).
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