Forest Soils & Site Productivity Nutrition Management: Fertilization 1

Nutrient Limitations Amount of Nutrients? Input (additions)? – Natural ppt & wind deposition OM decomposition & mineral weathering manure (deposition & decomposition) fire (OM & ash) biological N fixation (eg, legumes, lichens) Output (losses) –Erosion –Leaching –Fire –?? 2

Nutrient Limitations Amount of Nutrients? Input (additions)? – Natural….. – Management fire (OM & ash) biological N fixation Crop rotation/alley cropping fertilizer – natural…. – synthetic 3

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Soil Textures Soil pHSandLoamClay Pounds of Lime needed to raise soil pH to 6.5 (lbs/1000ft 2 ) 7

Fertilizer Growth Response due to? (Besides the fertilizer amount and type) Stand – species – age – size – stocking – vigor Patterns of functions, eg, N immobilization/mineralization Availability of other nutrients & water 8

Forest Soils & Site Productivity Nutrition Management: Biological N-Fixation 9

assimilation 10

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ALGAE DiatomsCyanobacteria – N fixing Lichens (fungi+algae) 12

Nitrogen-fixing Bacteria Nodules formed where Rhizobium bacteria infected soybean roots. 13

Actinomycetes –Bacterial cells –Grow like fungal hyphae –e.g. Non-legume root nodules having Frankia in Alnus 14

Red Alder nodules – actinomycete fixing atmospheric nitrogen, plant accessing N which limits growth 15

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(Huxley 1999) 17

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Forest Soils & Site Productivity Forest Soil Management 21

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Multiple States of an Ecosystem 23

Resistance and Resiliency 24

Low Resistance but High Resiliency 25

High Resistance but Low Resiliency 26

Forest Management (Disturbances via Tree Planting - Intensive Plantation Forestry) Tree planting is used in: Afforestation – open sites w/o trees for some time Reforestation – cleared and replanted (genetically improved?) Conversion from one forest type to another type (in sites still supporting considerable forest cover) 27

Forest Management and Soil Disturbances MORELESS Wheeled vehiclesTrack vehicles Steep slopesLevel slopes Clayey textureSandy texture Wet soilDry soil 28

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North coast of Papua New Guinea in the Vanimo Timber Area. Creek provided drinking water to the Amoi village but can no longer be used by the villagers! 36

Decommissioning and restoration of logging roads For water erosion, keep soil infiltration high, control overland flow using vegetation, ditches, contour plowing etc. 37

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Good Forest Management should also be Good Forest Soil Management Planning Harvesting? –BD (aeration, percolation,… –OM –Equipment oil spills, ? Soil prep - scarification, bedding (temp, H 2 O table), fertilizer, herbicide Planting - species, soil types, … 40

Forest Soils & Site Productivity Long Term Soil Productivity 41

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Communal Property and the Tragedy of the Commons Tragedy of the Commons Open access systems - have no rules to manage resource use (1968, Garret Hardin) Commonly held resources are degraded and destroyed by self-interest 43

Tragedy of the Commons Garrett Hardin (biologist)

Tragedy of the Commons Garrett Hardin (biologist)

Tragedy of the Commons Garrett Hardin (biologist)

Tragedy of the Commons Garrett Hardin (biologist)

Long-Term Soil Productivity?? Sustainability? (yield) –The condition of being able to harvest biomass from a system in perpetuity (several human generations?) so that the ability of the system to renew itself (or be renewed) is not compromised 48

the minimization of the number and activity of soilborne plant disease organisms and soilborne insect pests. (narrow definition?) Soil health is the capacity of soil to function as a vital living system with ecosystem and land- use boundaries to: – sustain plant and animal productivity, – maintain or enhance water and air quality, and – promote plant and animal health. (Doran and Zeiss, 2000, Applied Soil Ecology 15:3-11) Soil Health? 49

Soil Quality Soil Quality – capacity of the soil : –to sustain plant and biological productivity, –to maintain environmental quality, and –to promote plant and animal health –AND support human health and habitation. Soil Health? – some suggest it is the evaluation of soil quality over time??? 50

Sensitive indicators of Soil Quality Indicators? – Physical – Chemical – Biological 51

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Management Practices expressed: locally regionally, &? Management affected by ?: locally, regionally, globally Need to THINK and ACT LONG-TERM 54

Sustainability? Silvicultural (or ecological) but also Economic Socio-political Hard to quantify!!! So use term Good Forest Management 55

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Forest management will affect soil forming factors 57

Long-Term Soil Productivity Short-Term Use? Still need to consider: Long-Term Productivity (crops & SOIL) 58