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(NAS Colloquium) Plants and Population Is There Time? (1999) / Chapter Skim
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Ecological intensification of cereal production systems: Yield potential, soil quality, and precision agriculture
Pages 5952-5959

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From page 5952...
... Hence, average farm yields must reach 70-80% of the yield potential ceiling within 30 years in each of these major cereal systems. Achieving consistent production at these high levels without causing environmental damage requires improvements in soil quality and precise management of all production factors in time and space.
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From page 5953...
... Similar tendencies in relation to natural resource endowments are seen in the yield trends of wheat and maize. Modern crop management practices have had the greatest impact on yields in irrigated systems, such as the high-production rice and wheat systems in Asia, and in rain-fed environments where both climate and soil quality are favorable for crop growth, such as the wheat systems of northwest and central Europe and maize-based systems in North America.
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From page 5954...
... or at yield potential levels (minimal stress) Rate of genetic yield gain, annual percentage rate With stress Minimal stress Crop and region Period Oldest Newest Oldest Newest Bread wheat, 1962-88 2.6 NW Mexico Tropical rice, Philippines 1966-95 Temperate maize Iowa, USA Nebraska, USA 1.6 1.0 0.8 1.0 0.8 O O 1967-91 1.2 0.9 1983-97 0 o Rates of gain are linear in relation to year of release and therefore are computed separately in relation to the yield levels of the oldest and most recent (newest)
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From page 5955...
... These soil properties include: physical attributes such as the size and continuity of pores, aggregate stability, impedance, and texture, which together determine soil structure; chemical properties such as organic matter content and composition, nutrient stocks and availability, mineralogy, and the amount of elements and compounds that are deleterious to plant growth; biological attributes such as the quantity, activity, and diversity of microbial biomass and soil fauna. A reduction in soil quality as a result of human activities can be defined as soil degradation.
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From page 5956...
... Subtle changes in soil properties and subsequent effects on yield and input requirements illustrate the complexity of the relationships between soil quality and cropping system performance. It is postulated that subtle forms of soil degradation are occurring in some of the most important cereal production systems in the world.
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From page 5957...
... Precision Agriculture The gap between average farm yields and the yield potential ceiling must shrink during the next 30 years because the yield potential of tropical rice and maize appears to be stagnant and wheat yield potential is increasing more slowly than the expected increase in demand (Tables 1 and 2~. Hence, achieving consistent cereal yields that exceed 70~o of the yield potential barrier depends on sophisticated management of soil and water resources and applied inputs.
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From page 5958...
... It is argued that the present state of knowledge is far from sufficient to answer these questions despite the need for answers and widespread application of this knowledge within a relatively short timeline. It is concluded that global food security 30 years hence will depend on rapid scientific advances in understanding the physiological basis of crop yield potential, the processes governing the relationship between soil quality and crop productivity, and plant ecology related to the many interacting environmental factors that determine crop yields.
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From page 5959...
... (1996) Methods forAssessing Soil Quality (Soil Sci.
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Key Terms

  • soil quality
  • soil degradation
  • cereal production
  • organic matter
  • soil organic

  • food security
  • soil properties
  • potential ceiling
  • genetic gain
  • global food

  • farm yields
  • average farm
  • yield trends
  • major cereal
  • input requirements

  • genetic yield
  • control measures
  • yield levels
  • rice yields
  • yield increases

  • food demand
  • crop management
  • rice production
  • rice yield
  • food production

  • stress resistance
  • solar radiation
  • temperate maize
  • subtle forms
  • precision agriculture


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