Introduction and context: global biomass resources - Biomass as Energy Source: Resources, Systems and Applications - page 6

Table 1.5. Agriculture and food production as a function of economic categories.

Fertilizer Fertilizer Cereal yield

consumption consumption [kg/ha] Agriculture

% of production [kg/ha] tractors

2008 2008 1970 2009 2002

Low income 207 16.5 1296 1952 121409

Middle income 104 138.6 1515 3202 9268485

High income 73.2 109.3 2766 5448 14210537

World wide 95 119.3 1829 3513 25486834

track distributing the residual 2/3 the soil could take up all nitrogen with very few emission
to the air, as well as to the small river downstream. As this was administered when the cereal
(wheat) was approximately 10 cm high, all could be utilized and thus the production could be
sustained but with half the dosage of ammonia/nitrate per hectare! This of course saved energy,
cost and the environment! (Odlare, 2010). Larsson et al . (2009) have presented the concept ERA,
Environmental RecyclingAgriculture. The focus for this concept is to recycle nutrients like N and
P from animals in such an amount that what is produced in a country should be distributed evenly.
Not more than one animal unit ( = corresponding to manure from one cow) should be fed per
ha to avoid eutrophication. The primary target was the Baltic Sea and the countries around this.
To get a balance we should reduce the consumption of meat by some 60-70%, as the production
of crops will be reduced, but by doing this we will still get the food needed.
The most important crops from a human food perspective are cereals. It should be noticed that
generally we get at least the same amount of biomass from waste from the food crops as we get
grains used for food. As we increase the yield for these crops, we simultaneously also increase
the production of hydrocarbons that can be used for energy purpose. Some specific important
crops will be covered in the following section.

1.2 CROPS USED PRIMARILY FOR FOOD

There are some crops which are more important than others for the human population of earth.
In this section, a number of these are presented more in detail.

1.2.1 Soybean
Soybean is a very popular crop for production of very good protein. The beans contain 40% with
a very good distribution between amino acids making it good as a replacement for animal protein.
In 2009 the world production was 222 million tonne (FAO statistical database 2009). If we would
distribute to all the population in the world it would be 13 kg per capita or almost 100 g protein
per day. This could replace all animal and fish protein we eat today. Still, only a little more than
10% is used as direct human food (www.soyatech.com/soy_facts.htm, 2010). The rest is used to
feed 18.6 billion chicken and hen, 1.4 billion cows and bulls and 940 million pigs worldwide
annually.

1.2.2 Rice
Rice is a crop for tropical and subtropical countries. The global average production is 3.9 tonnes
per ha, but the yields may be much higher where there is intensive irrigation like in Australia
with 9.5 tonnes/ha per y and Egypt with 8.7 tonnes/ha per y. Some countries having “traditional”
methods like the Republic of Congo on the other hand have production as low as 0.75 tonnes/ha