Effects of Secondary Sewage and Fertilization on Forest Ecosystems

1. Effects of Secondary Sewage and Fertilization on Forest Ecosystems

2. I. Biosolid Wastes i. Introduction • U.S. pulp and paper industry produces: 5.3 million tons of paper mill waste 2.5 million tons of boiler ash • U.S. wood products industry produces an additional 1.3 million tons of boiler ash • 72% of the ash and 51% of the paper mill waste are disposed in landfills • U.S. produces 5.3 million tons of municipal sewage waste: 16% is incinerated, 38% is placed in landfills, 36% is spread on to lands, and the balance is “lost”

3. II. Biosolid Wastes • Introduction continued Advantages of applying biosolid waste to forests • Land fills are expensive to build and use valuable land. • Many of the biosolids contain heavy metals, carcinogenic organic compounds, and pathogens that should not get back into the human food chain - forest are better than agriculture soils. • Can improve tree growth. • Mixed with other material (I.e. sawdust) it can improve physical properties of soils.

4. II. Biosolid Wastes Types of Biosolid Wastes Secondary sewage sludge: waste material from municipal sewage treatment plants. Typically have high concentrations of N, P, and other essential elements. Also can contain heavy metals, and pathogens. Concentration of all these can vary dramatically - depending on what gets dumped into sewage system by humans Paper mill sludge: residue from paper making process that contains residue organic matter, modest concentrations of N, usually higher concentrations of base cations. Past concern was dioxin.

5. I. Biosolids Wood-fired boiler ash Wood-fired boiler ash is the residue remaining after woody biomass is burned for energy. Recall the fire lecture and volatilization temperatures for different elements - N is readily volatilized while the divalent cations have very high volatilization temperatures. As a result, wood-fired boiler ash is very low in N, and high in base cation concentrations. • wood-fired boiler as may have modest amounts of heavy metals • Wood-fired boiler ash does not contain pathogens

6. Potential adverse effects of biosolid applications on forests • Secondary sewage may cause: N leaching, heavy metal contamination, pathogens harmful to humans (i.e. Salmonella, Coliform), nutrient imbalance. Beneficial because contains high concentration of N and P. • Paper mill sludge may cause: heavy metal contamination, dioxin, nutrient imbalance. Beneficial because it adds organic matter and N. • Boiler ash has little or no environmental concerns. High in base cations. No N.

7. Effects of secondary sewage and boiler ash on ANPP of aspen and sugar maple stands.

8. Treatments

9. Effects of biosolids on wood net primary production (WNPP) and aboveground net primary production (ANPP). All units are t/ha/yr

10. Application and recovery of N from secondary sewage

13. II. Fertilization i. Introduction Use of commercial fertilization of forest began in the early 1970’s and has rapidly become one of the most important silviculture management practices in some regions (southeast and Pacific Northwest).  Significantly increases forest growth, thereby significantly reducing rotation length… $$$$  In extreme cases correcting nutrient deficiency/imbalance can mean plantation survival versus failure  Increase forest vigor  Fertilization is expensive, hence there is a real economic incentive to understand which stands will respond to fertilization (quantity, fertilizer type, frequency, etc.)

14. North Carolina State Forest Nutrition Cooperative Field Trials

15. I. Fertilization ii. Regional Nutrient Limitations Based on our knowledge of general soil order distribution and effects of parent material on soil fertility, it is possible to make educated guesses as to what nutrients are likely to be limiting.

16. Gelisols, Aridisols, Vertisols, Andisols, Entisols, Inceptisols, Alfisols, Mollisols, Histisols, Spodosols, Ultisols, Oxisols a. Major Soil Orders. There are eleven major soil orders. Soil order is the coarsest level of classification. Even this level of classification provides valuable insight into general fertility characteristics.

17. I. Fertilization iii. Physiological Responses of Tree Growth to Fertilization • Increased photosynthetic rate (leaf level) • Increased LAI (canopy level) • Biomass allocation shifts (tree level) Leaf:root Stem NPP Ps LAI Available N

18. I. Fertilization iv. Efficiency of fertilizers The application of fertilizers to forests (and lawns!!) is not very efficient. That is too say, only a small fraction actually gets taken up by the target plant. Other fates of fertilizers are: • immobilized (temporarily) by microbes • complexed with organic matter • leached • volatilized to the atmosphere

19. Percent of total fertilizer applied that is actually taken up by the crop trees

20. I. Fertilization v. Duration of fertilization effects • Soil nutrient concentration of fertilized forest soils returns to unfertilized forest soil nutrient concentrations very quickly (< 1 year). • Beneficial effect on growth of the nutrient amendment can last for 4 - 10 years. • Why????

21. Control plots

23. III. Nitrogen Saturation • Human activities have doubled the cycling of nitrogen in the earth's system. • Four-fifths of nitric oxide emissions worldwide now come from human activities such as the combustion of fossil fuels, cultivation of certain crops, and especially the manufacture of nitrogen-rich fertilizers. • The amount of industrially-fixed nitrogen applied to crops during the decade from 1980 to 1990 more than equals all that applied previously in human history (Pearce, 1997a).

24. Results from a long-term ecosystem study that compared the N cycle and chemical properties of soils beneath a Douglas-fir and Douglas-fir + red alder

25. Hypothesized effects of chronic N deposition to soil fertility Chronic N addition (in the form of atmospheric deposition, fertilization, or N fixation) will eventually exceed the biological demand by microbes and vegetation, resulting in significant NO3 (and base cation) leaching.

26. Hypothesized effects of N saturation on foliar chemistry and NPP (Aber 1998)

27. Hypothesized effects of N saturation on forest biogeochemical cycles (Aber 1998)