- - AGRICULTURE CORE CURRICULUM - - (CLF3000) Advanced Core Cluster: ANIMAL SCIENCE (CLF3550) Unit Title: WASTE MANAGEMENT ____________________________________________________________________________ (CLF3551) Topic: ANIMAL WASTE Time Year(s) 2 hours 3 / 4 ____________________________________________________________________________ Topic Objectives: Upon completion of this lesson, the student will be able to: Learning Outcome #: (J-1) - Identify the three main types of agricultural (animal) wastes. (J-2) - Describe two ways to recycle manure where it can be utilized by livestock. Special Materials and Equipment: References: Bath, Donald L. (1978). DAIRY CATTLE: PRINCIPLES, PRACTICES, PROBLEMS, PROFITS (2nd ed.). Ensminger, M.E. (1983). ANIMAL SCIENCE (8th ed.). Ensminger, M.E. (1983). THE STOCKMAN'S HANDBOOK (6th ed.). Evaluation: Quiz by instructor. TOPIC PRESENTATION: ANIMAL WASTES A. Waste Production 1. In California, most livestock waste is either flushed out immediately from the cattle pens through drainage troughs, or eventually scraped out of the pens and piled elsewhere for further drying. a. For flushed manure: 1) the moisture content can be as high as 98-99%. 2) it is often placed in a lagoon for storage. 3) it is usually used in furrow irrigation. b. Dry manure: 1) moisture content is normally between 50-75%. 2) is often allowed to set for several weeks to dry out before it is finally used. 2. Waste classifications a. SOLID manure refers to a mixture of animal excrements consisting of undigested feeds plus certain body wastes and bedding. b. LIQUID manure includes urine, and waste water from flush systems. c. GASES generated from manure include methane, ammonia, hydrogen sulfide, and carbon dioxide. Gasses can kill animals and people by asphyxiation (e.g., methane and carbon dioxide displace oxygen in the body). 3. The table below indicates liquid and solid manure production by species: ==================================================================== animal tons excreted per year fertilizer per 1000 pounds live weight value/ton ($) ____________________________________________________________________ Cow 12 tons $4.92 Steer 8.5 tons $6.42 Sheep 6 tons $11.32 Swine 16 tons $4.69 Poultry 4.5 tons $12.32 ==================================================================== 4. The table below describes the effects of the above mentioned gases: ==================================================================== gas physiologic other effect properties ____________________________________________________________________ methane anesthetic odorless, explosive ammonia irritant strong odor, corrosive hydrogen poisonous rotten-egg odor, sulfide corrosive carbon asphyxiant odorless, mildly dioxide corrosive 5. Moisture content: a. is important in determining weight and value of excretement. b. can be tested when the manure is fresh or after drying. c. determination helps identify how the waste can be used most effectively. B. Uses of Waste 1. As fertilizer a. Applications: 1) 5 - 20 tons of animal manure can be applied per acre per year to fields. a. The maximum rate at which manure can be applied varies according to soil type, rainfall, and temperature. b. State regulations differ in limiting the rate of manure application. b. Disadvantages of using manure as fertilizer: 1) An excess of 20 tons per acre may cause a build-up of salt or nitrate. 2) Excess nitrate from manure can pollute streams, groundwater, and result in toxic levels of nitrate in food crops. 3) Weed seeds in manure can eventually overrun or at least compete with planted crops. 4) Potential plant disease spores maybe stored in manure. 5) Potential spontaneous combustion of stored manure piles can occur. c. Advantages of using manure as a fertilizer: 1) It is available with little or no cost, except for pick up and delivery, and it is most often sold where organic farming is popular. 2) It is rich in organic matter which almost all soils need. 3) It produces long-lasting benefits: a) about 1/2 of the plant nutrients in manure are available to and effective upon the crops in the immediate cycle of rotation to which the application is made. b) of the unused (by the plants) remainder, about 1/2 is used by the next crop and 1/2 by the crop following that. Figure this one: 50% of 50% of 50% = 12 1/2% unused after a period of three years. 2. As feed a. Feedlot manure: 1) Is high in undigested grain and can be: a) incorporated into a grower ration, or b) fed to range cattle when range supplementation is necessary. b. Poultry manure: 1) is high in nitrogen in the form of urea which can be altered by rumen bacteria and utilized to make protein (it can used in ruminants' feed). 2) must be sterilized and processed before being used as a feed. 3) is very unpalatable alone and must be mixed with some other feed. 3. As energy a. Methane is a gas produced by bacteria while they ferment manure. 1) If harnessed, it can be utilized like any other natural gas to run generators. 2) The capture and utilization of this gas is already taking place on some dairies in California. b. Cattle manure can be burned through a process called fluidized bed combustion. a) Air is injected into the burning of dry manure (25% moisture content) so there is little or no slag accumulation (ash). This use is normally seen in dry desert areas. b) If regular dry manure is burned, there is a large residue of dirt and ash left in the furnace. 4. As bedding manure is dried, sterilized, and then used as bedding in free stalls or open lots on dairies. 5. The other available by-product is the ash, from the combustion process. It can be used as a) a soil fertilizers, b) an acid soil neutralizer, c) a soil conditioning agent to prevent erosion along hardening roadways, d) an environmental clean up agent for of hazardous wastes, and e) a component of plastic polymers. 5/4/90sg #%&C