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Introduction to Nutrient Management, Nutrient Cycling and Regional Nutrient Balance Issues Tom Basden Ag. and Natural Resources WVU Extension Service, Morgantown WV 2009 Fundamentals of Nutrient Management Training Course Dec. 16-17
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Introduction Why is Nutrient Management So Important? Changes in Farming Systems and Nutrient Cycling 2 Watersheds with Issues in WV Chesapeake Bay Basin and Mississippi River Basin
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Importance of Nutrient Management Loss of nutrients to the environment Water Quality Impairment
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Why the Concern? Eutrophication Critical problem in impaired fresh waters Critical problem in impaired fresh waters Freshwater eutrophication usually P limited Freshwater eutrophication usually P limited Algal Blooms! Algal Blooms! Fish kills due to hypoxia (“Dead Zone”)Fish kills due to hypoxia (“Dead Zone”) Pfiesteria PiscicidiaPfiesteria Piscicidia acute risk acute risk Chlorination of eutrophic drinking watersChlorination of eutrophic drinking waters carcinogenic risk. carcinogenic risk.
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Eutrophication and Agriculture With 30 years of “point source” control the relative contribution of agricultural non-point sources of P has increased.
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P P P P P P P P The Problem: Changes in the P Cycle Pre 1939 - P cycle occurred within the farm
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P fertilizers have helped to build productive agriculture!
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Manure P Today’s P Cycle is Fragmented P Rock Grain P Manure P
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Cash crop 30 ha 1280 hogs 30 ha 65 Holsteins 40 ha Farming System and P Balance CropDairyPigPoultry - - - - - - kg P/ha/yr - - - - - - 1811 301041690 Input Fertilizer Feed Output161220515 Balance229841175 -- Pennsylvania farms 75,000 birds 12 ha
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N-Based Manure Management results in excess P application P P P P P P P P P P P P P P P P P P P P P P P P P P P P P P PP P P P P P P P P P P N N N N N N N N N N N N:P for crops (7:1-11:1) N:P for manures (2:1-6:1)
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N-Based Manure Management N-Based Manure Management More P is added in manure than needed by the crop! P added in manure Phosphorus (kg/ha) Poultry litter Poultry manure 050100 150 P removed Corn harvest Pig slurry Dairy manure
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Nutrient Cycling
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Nutrient Cycling II
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Nutrient Cycling III
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Chesapeake Bay Basin
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64,000 sq. miles – second largest estuary in the world >15 million people in the basin Easy to pollute – long coastline (7,900 mi.) & shallow depth (~ 21 ft) Major economic resource – 50% of blue crab catch; 90% of soft shell crab Chesapeake Bay Basin (cont’d) Features:
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Health concerns due to pfiesteria outbreak in Md. and Va. rivers Aesthetic, taste, and odor problems Chesapeake Bay Basin (cont’d) Problems: Decline in fisheries -Oysters: 92% decline during 1984-94 - Clam (MD): 95% decline during 1989-92
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Nitrogen: agricultural (60%), atmospheric deposition (25%), & other (15%) -~70,000 tons-N from Potomac (1990-1992), 23% of total Phosphorus – agricultural (30%) & point sources (70%) -~3,750 tons-P from Potomac (1990-1992), 25% of total Sediments Toxics Chesapeake Bay Basin (cont’d) Problem pollutants
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Nutrients move into receiving waters in dissolved and sediment-bound forms Sediments blanket stream floor degrading or destroying aquatic habitat & breeding areas Eutrophication - high inorganic dissolved N and P may result in rapid growth of algae Chesapeake Bay Basin (cont’d) Detrimental effects of nutrients and sediments
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Algae, both alive and dead (during decomposition) consume dissolved oxygen (DO), depriving other aquatic organisms of DO, degrading aquatic habitat Hypoxia – very low DO levels (<2 mg/L) can result in fish kills Healthy DO range for estuaries - 5-8 mg/L Chesapeake Bay Basin (cont’d) Detrimental effects of nutrients and sediments
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Hypoxia
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Gulf of Mexico Basin
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Drains nearly 2 million sq. miles 20% ($) of commercial fishery landings Annual nitrate loading ~1 million tons -75% from agriculture -Ohio River contributes less nitrate compared to discharge Annual orthophosphate loading ~38,600 tons Gulf of Mexico Basin (cont’d)
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~8,600 sq. miles of the Gulf below LA & TX affected in summer 2002 (worst case yet) Excessive nutrient loadings from farmlands suspected as prime factor in hypoxia Hypoxia could occur due to natural causes Gulf of Mexico Basin (cont’d) Hypoxia in the Gulf
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Nutrient Eco-regions WV in Eco-region XI, Central and Eastern Forested Uplands
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Questions Questions ?
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