Agriculture: Part 2 Increasing food production

© Brooks/Cole Publishing Company / ITP Green Revolutions: increasing crop yields per unit area First Green Revolution Developed countries 1950s- 1970s Increased the intensity and frequency of cropping Widespread mechanization Used large amounts of fertilizers, pesticides, and water Second Green Revolution Started in the late 1960s Spread industrialized farming to developing nations Selective breeding and later genetic engineering led to faster growing varieties of rice and wheat that could thrive in tropical climates

Fig. 15–3 1st Green Revolution in 1950s- 1970s 2nd Green Revolution after 1967 © Brooks/Cole Publishing Company / ITP Green Revolution

increase and change inputs of water, fertilizer, & pesticides -eventually these additions produce no additional increase in crop yields. © Brooks/Cole Publishing Company / ITP Increasing Crop Yields

breeding (artificial selection) genetic engineering -increase proportion of photosynthesis going to food; -develop strains of plants that are resistant to disease, cold, pests, toxins, insects, & drought. -Ex. Corn, cotton, soybeans, canola, squash, and papaya. © Brooks/Cole Publishing Company / ITP The Gene Revolution: Increasing Crop Yields

Mixing Genes Genetic engineering involves splicing a gene from one species and transplanting the DNA into another species. Advantages: Need less fertilizers, water, pesticides Less spoilage and damage Tolerate higher levels of herbicides Higher yields per acre Disadvantages: Unpredictable genetic & ecological effects New allergens or toxins in food Lower genetic diversity Can harm beneficial insects

Golden Rice Golden rice is a new genetically engineered strain of rice containing beta-carotene. Can inexpensively supply vitamin A to malnourished and prevent childhood blindness. But… Figure 13-1

Increasing meat production From meat production increased from 52 billion kg to 240 billion kg More and more countries are moving towards a “Western” diet 70% of corn harvest in US goes to animal feed 80% of world soybean harvest goes to animal feed Further increasing meat production would put a strain on world grain resources and world fisheries (1/3 of catch is used for animal and farm fish feed) What will this mean for land use? How will meat production keep up with demand?

Animal Feedlots AdvantagesDisadvantages Increased meat production Need large inputs of grain, fish meal, water, and fossil fuels Higher profits Concentrate animal wastes that can pollute water Less land use Reduced overgrazing Reduced soil erosion Antibiotics can increase genetic resistance to microbes in humans Factory farming will likely expand

Aquaculture: Aquatic Feedlots Raising large numbers of fish and shellfish in ponds and cages is world’s fastest growing type of food production. Fish farming involves cultivating fish in a controlled environment and harvesting them in captivity. –Fish on fish farms must be fed 5 pounds of wild-caught fish to produce one pound of farmed fish flesh (Robbins 2004) Fish ranching involves holding anadromous species that live part of their lives in freshwater and part in saltwater. –Fish are held for the first few years, released, and then harvested when they return to spawn. © NOAA