Amino acid, fatty acid, and mineral composition of 24 indigenous plants of Burkina Faso

Global projections for root and tuber crops to the year 2020.

The global population of 6 billion is increasing at the rate of 1.3%or 73 million persons/year.A the present rate of growth,the population will reach 7.5 billion by 2020 and 9.4 billion by 2050.With the projected increase in world population and change in food habits,the future food demand for cereals will increase drastically. Therefore,among principal global concerns of the twenty-.rst century are: (1)food security due to a rapid increase in the world population,(2)soil degradation by land misuse and soil mismanagement;and (3)anthropogenic increases in atmo spheric greenhouse gases.All of these issues are linked to the sustainability of soil quality especially in relation to the soil organic carbon (SOC)pool and its dynamics.

Soil supports terrestrial life through .ve processes:(1)biomass productivity,(2)restoration and resilience of ecosystems,(3)puri .cation of water,(4)detoxication of pollutants,and (5)cycling of C,N,P,S,and H2O.These processes are affected by the quality and quantity of the SOC pool.However,the SOC pool of agricultural soils has been depleted by 30–40 Mg C/ha (Mg =1 metric ton, 1hectare =2 47 acres)due to cultivation and other degradative processes,which has set in motion the downward spiral of soil degradation.

The increase in atmospheric concentration of CO2 is occurring at the rate of 3.4 billion metric tons (Pg)/year.In addition to fossil fuel combustion and cement manufacture,this increase is caused by deforestation,biomass burning,and soil cultivation.Conversion of natural to agricultural ecosystems has resulted in emission of 66–90 Pg of C from world soils.The rate and magnitude of gaseous emissions from world soils are exacerbated by soil degradative processes,that is,decline in soil structure,accelerated erosion,and nutrient imbalance.Until the 1970s,more C was emitted annually from soils and land-use conversion than from fossil fuel combustion.Currently,about 25%of global emissions are from all agricultural activites.Judicious land use and recommended soil management techniques can resequester 60–70% of the historic C loss.

Adoption of recommended agricultural practices or agricultural intensication can improve productivity and resequester C lost from the world soils.In the past 50 years,the number of people fed by a single U.S.farmer has increased from 19 o 129 through adoption of recommended agricultural practices.Such practices include use of conservation tillage,growing cover crops,using biosolids and amendments,enhancing soil fertility through judicious use of fertilizers and adopting precision farming,water conservation and improved methods of irrigation,and use of improved varieties.The global potential of soil C se-questration is estimated at 0.9–1.9 Pg/year through deserti .cation control and about 3 Pg/year through restoration of all degraded soils.Soil carbon sequestration is a win -win strategy based on adoption of improved agricultural practices with potential of 40–70 Pg over a 50-year period.This potential is over and above that in rangeland/pasture soils,forest ecosystem,and biofuel production.In addition,it is important that degraded soils and ecosystems be restored.The soil carbon strategy (1)increases agricultural productivity,(2)improves water and air quality,and (3)reduces the rate of enrichment of atmospheric CO2.

As the world population continues to grow,available farmland shrinks and the emission of gases into the atmosphere increases.Nonetheless,world soils have the capacity to feed the current and future population provided that soils are used,improved,and restored.As has been the case in the past,those holding neo-Malthusian views will again be proven wrong through adoption of recommended agricultural practices for sustainable management of soil resources. Contrary to the misconception,adoption of recommended agricultural practices is a solution to the environmental issues and also to achieving global food security.

Managing world soils for food security and environmental quality

At least since Aristotle, theorists have believed that political dis-content and its consequents—protest, instability, violence, revolution—depend not only on the absolute level of economic well-being, but also on the distribution of wealth. Contemporary political analysts have tried to test this ancient assumption using modern statistical methods. Their results are distressingly confusing. One cross-national investigation finds the commonsensical positive linear relation: the more the inequality, the greater the instability. A second study purports to show the opposite relation in the important case of South Vietnam: the greater the inequality, the less the support for revolution. And a third analysis, also of South Vietnam, detects no relation at all between inequality and rebellion.

Inequality and Discontent: A Nonlinear Hypothesis

China comprises a total land area of 960 million hectares. Approximately 15% is cultivated 20% is forest and woodland grassland covers 35% and more than 22% is covered by sandy or stony desert glaciers and permanent snow and other marginal lands. Cities towns industrial sites rural settlements and infrastructure cover 3.4% of the total land area. Over the next 50 years Chinas population will likely grow by 300 million inhabitants. Rural-to-urban migration urbanization and the growth of the industrial infrastructure will be dominant factors in land-use change especially in the densely settled eastern provinces. Lifestyle changes reflecting growing incomes and changing cultural influences will lead to an increased consumption of animal-based foods demand for larger apartments or suburban homes and a massive expansion in private means of transportation. Private farmland close to urban centers will be converted into residential and commercial sites. These changes may also cause China to become more open to outside influences and more regionally diverse.

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Lester R. Brown

Papers

Rice Bowls and Dust Bowls: Africa, Not China, Faces a Food Crisis

The Agricultural Revolution in Asia