Production, arable land

Biomass potentials are mainly determined by agricultural productivity and the amount of land accessible for energy crop production. The total area under energy crops in the EU was around 1.6 million hectares in 2004 (estimate for 2005 2.5 million hectares), which represents nearly 3% of the total arable land. AEBIOM (2007) estimated a total biomass supply of 220 MtOE for the year 2020, while 23 MtOE are covered by wood-based bioenergy (direct from forests) and 88 MtOE by agriculture-based energy crops (by-products not considered). The Commission has estimated that about 15% of the EU s arable land (17.5 million hectares) would be used to reach the targets for 2020. 

Declining amounts of arable land, increasing world populations, and increasing costs of fertilizer and food and energy needs will make it increasingly difficult to maintain our soil resources. A key component for sustaining soil productivity is the maintenance of soil organic carbon (SOC). SOC maintenance requires the amount of carbon added to the system to equal the amount of relic carbon mineralized... 

Where arable land is high cost, high value, or in scarce supply the production potential of protein becomes an especially important factor. Fruits and leaves from wild, undomesticated plants provide attractive sources of protein in the diet because of their natural acceptability by local inhabitants and their wide-spread accessibility due to native growth. However, for domesticated and commercialized situations the production of protein per unit area of arable land is an important factor. 

Even in a country with much arable land such as the U.S., a large part of the agricultural land would be needed for biomass production for it to serve as a major source of fuel. A good fraction of arable land in the United States (and the world) would be needed for biomass-to-hydrogen production sufficient to displace a significant fraction of gasoline which may not be a practical or politically feasible approach. The United States uses about 350 million acres for crops and about 10% of this is cropland idled by federal programs. 

One can estimate that there is a fair good correlation between N produced in animal manure and the ammonia emission. As the production of cattle slurry is linked with grassland and in many regions the main part of the manure from pigs and poultry is spread on arable land, there is a risk for underestimating the ammonia emissions from cattle slurry. In table II an estimate is made of the total production of mineral N in animal manure in the Netherlands. 

It is estimated that there will be an additional 3 billion people to feed in the world by 2025 and, by 2050, the population is expected to exceed 11 billion, more than twice today s population.8 This means that within the next 50 years it will be necessary to produce more than twice as much food as is currently being produced.3 It must always be remembered that if the population increases, the land available for agricultural production will fall as these new people will have to live somewhere. Today, the amount of arable land available for the production of food per person is down from the half-a-hectare figure of the 1960s to about one-third of a hectare.9 Each available hectare must support more and more people as world population continues to increase at a rate of 1.7% per year (90 million more people to feed and clothe each year), whilst the rate of expansion of world cropland is less than one tenth of this rate (0.15% per year or 50 to 60 million new hectares of cropland by 2010).9 In less than twenty years each person will have to be supported by only 0.2 hectares. 

Given projected levels of population growth, world food production must more than triple in the next 50 years to adequately feed 9.6 billion people. A long-term solution may turn on increasing crop productivity on the arable land affected by aluminum toxicity, and citric acid may play an important role in achieving this goal. 

The growing world population and a constant area of arable land call for additional growth in agricultural production. Agribusiness has an important contribution to make here both now and in the future, through crop protection chemicals and also improved seeds which improve yields and enhance food quality. 

From a different (but related) environmental perspective, provision of adequate supplies of food, shelter, medicines and resources of energy and raw materials already constitute serious global challenges. Superimposed over the issues of safety and the environment introduced above are difficult and long-term problems involving sustainability. The current population of planet earth, approximately 6 billion, has tripled since 1938. Various projections indicate that by 2050 it will be about 11 billion, nearly twice the present level. Innovative methods for greater food production from diminishing tracts of available arable land and increased and efficient utilization of renewable resources will be essential. 

Waste biomass, such as peanut shells or bagasse (the residue from sugarcane), tends to be the most cost-effective source, but the ultimate supply is limited. Even in a country with as much arable land as the United States, a large fraction of agricultural land would need to be devoted to biomass production if that were to serve as the major source of transportation fuel. 

What fraction of arable land in the United States (and the world) would be needed for biomass-to-hydrogen production sufficient to displace a significant fraction of gasoline—and is that a practical or politically feasible approach ... 

The regions where all factors of climate and soil are favorable are generally where food will have to be produced (Table 1.2). There are about 8 billion acres of potentially arable land in the world, but we are cultivating less than 4 billion acres. Most of these areas are already in production, so in most places there is little room... 

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