Lecture 13: Agriculture and Food PDF

Lecture 13: Agriculture and Food Dr. Mansoor Hamed AlJahdhami [email protected]  Review question ❑ What is the relationship between Agroecosystem and ecological succession? A. Agroecosystem keeps the land in a late successional stage. B. Agroecos...

Lecture 13: Agriculture and Food Dr. Mansoor Hamed AlJahdhami [email protected]  Review question ❑ What is the relationship between Agroecosystem and ecological succession? A. Agroecosystem keeps the land in a late successional stage. B. Agroecosystem keeps the land in an early successional stage. C. Agroecosystem promotes the change to late successional stage D. Agroecosystem reduces the land in a middle successional stage. E. Unlike natural ecosystems, agroecosystem has no relationship with ecological succession. 2  Reading materials CHAPTER 7 Food and Agriculture 7.4 Living soil is a precious resource 7.5 Agricultural inputs 📄 Pages: 163 ‒ 171 3  Learning outcomes Realize that soil is the foundation of food production Describe the six components of soil Understand why water and wind are dominant erosive forces for soil loss 4  How much food do we need? More production doesn’t necessarily reduce hunger Overabundance of food supplies but hunger has not eliminated. Why? ❑ Not because of lack of food production in developing countries ❑ It is the better use and even distribution of food supply ✔ Global food waste/loss account for 30% of all food production ❖ Every year, 1.3 billion tons spoiled during storage, transit, used inefficiently or thrown away after preparation 5  How much food do we need? Biofuels have boosted commodity prices Why? ❑ Biomass, supposed to be used as food items (e.g. soybean, corn, palm oil and sugar cane), used for In USA, federal ethanol subsidies led to a doubling of corn prices in 2007 6 bio-ethanol production  How much food do we need? Do we have enough farmland? Probably, we do have enough farmland to feed more people than currently live on earth Could we expand production further by creating new farmlands? World’s uncultivated land could potentially be converted to cropland, but this land currently provides essential ecological services on which farmers depend ❑ Examples? 7  How much food do we need? Think about essential ecological services (e.g. pollination)! 8  How much food do we need? Think about essential ecological services (e.g. pollination)! 2017 9  What do we eat? 500000 plant species known ~3000 agricultural crops 150 species cultivated on large scale 14 crop species provide most of world’s food 6 species provide 80% of the Copyright © 2014 by John Wiley & Sons, Inc. 10  What do we eat? Only a few edible plants and animals in the world provide most of our food In USA, corn and soybeans have become primary staple foods Wheat and rice are also important to many 11  What do we eat? Production of food has increased over the last 50 years (consumption varies greatly!) Meat is a concentrated, high-value source of protein, iron, fats, and other nutrients Meat is a good indicator of wealth Number of kg of grain required to produce 1kg of bread or 1 kg of live weight gain 12  What do we eat? CAFO increases food production Confined animal feeding operation (CAFO) ❑ One of the most important technological and breeding innovations ❑ Thousands of animals are housed in giant enclosures and fed—mainly soy and corn—for rapid growth ❑ Dominant livestock raising in the USA , Europe, and increasingly in China and other countries 13  What do we eat? CAFO increases food production CAFO have expanded the global market for corn and soybeans, consequently making soybean as the dominant agricultural product of Brazil. 14  What do we eat? Seafood-both wild and farmed depends on wild-source inputs Seafood provides about 15% of all animal protein eaten by humans Seafood is the main animal protein source for about 1 billion people in developing countries Due to declined marine fisheries or overfishing, aquaculture is providing an increasing share of the world’s seafood 15  What do we eat? Aquaculture is providing an increasing share of the world’s seafood Fish can be grown in farm ponds that take relatively little space but are highly productive 16  What do we eat? Biohazards arise in industrial food production Bacteria or other pathogens can escape into the environment ❑ From manure in the feedlots, or liquid wastes Constant use of antibiotics may be producing antibiotic-resistant diseases ❑ Slowly rendering our standard 17 antibiotics useless for human  Living soil is a precious resource Croplands (for growing plant crops) Both dependent on healthy soil Rangelands (for grazing animal livestock) Soil is a marvelous substance and a living resource of astonishing complexity and frailty Mineral grains weathered from rocks Partially decomposed organic molecules A host of living organisms Soil can be considered a living ecosystem by itself. Why? 18  Living soil is a precious resource When carefully managed, soil is a renewable resource Building a few millimeters of soil can take anything from a few years to a few thousand years With careful husbandry that prevents erosion and adds organic material, soil can be replenished and renewed 19  Living soil is a precious resource Healthy soil fauna can determine soil fertility Complex mixture of 6 components ❑ Sand and gravel (mineral particles from bedrock) ❑ Silts and clays (extremely small mineral particles) 20  Living soil is a precious resource Healthy soil fauna can determine soil fertility Complex mixture of 6 components ❑ Sand and gravel (mineral particles from bedrock) ❑ Silts and clays (extremely small mineral particles) © Nature Education. All rights reserved. ✔ Other differences? 21  Living soil is a precious resource Healthy soil fauna can determine soil fertility Complex mixture of 6 components ❑ Sand and gravel (mineral particles from bedrock) ❑ Silts and clays (extremely © 2005 Pearson Education, Inc., Publishing as Benjamin Cummings small mineral particles) 22  Living soil is a precious resource Healthy soil fauna can determine soil fertility Complex mixture of 6 components ❑ Sand and gravel (mineral particles from bedrock) ❑ Silts and clays (extremely small mineral particles) ❑ Dead organic material (decaying plant matter and other biomass) ❑ Soil fauna and flora (living organisms) ❑ Water (moisture from rainfall or groundwater) ❑ Air (tiny pockets of air) 23  Living soil is a precious resource Healthy soil fauna can determine soil fertility 24  Living soil is a precious resource Healthy soil fauna can © 2014 Rodale Inc. determine soil fertility In soil, complex feeding relationships contribute to formation of humus during decaying of biomass ❑ Humus contributes to nutritional value and fertility of soil ✔ Soils with higher humus content hold moisture better and are more 25  Living soil is a Most important? precious resource Idealized soil profile? Soils are arranged in layers or horizons Soils vary greatly in composition and thickness of layers between different biomes ❑ Examples? 26  Living soil is a precious resource Your food comes mostly from the A horizon Ideal farming soils have a thick, organic-rich A horizon ❑ Black A horizon that can reach over 2.0 meters in fertile soil ✔ Example: fertile farm belt of the USA Midwest Great Plains → support of large-scale corn fields ❑ Most soils have less than 0.5 meter of A horizon ❑ Desert soils, might have almost no 27  Living soil is a precious resource Soils vary dramatically among different climate areas Classification of soil types based on A horizon Mollisols: thick, soft, organic-rich Aridsols: little or no organic matter A horizon or A horizon Alfisols: a slightly thinner A horizon, with slightly less organic matter 28  Living soil is a precious resource Soils vary dramatically among different climate areas Classification of thousands Color of different soil types based on several factors ❑ What are these? © 2005 Pearson Education, Inc., Publishing as Benjamin Cummings 29 Living soil is a precious resource Particle size 30  Living soil is a precious resource Soils vary dramatically among different climate areas Classification of soil types based on soil texture Loam, an even mix of these three types is the best for plant growth ❑ What is the soil texture of © 2005 Pearson Education, Inc., Publishing as Benjamin Cummings Soil texture triangle soil sample of 40% sand, 31 Questions? 32