Week 1 Exam 4 notes
Week 1 Exam 4 notes ESS 210 001
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This 2 page Class Notes was uploaded by Michaela Humby on Wednesday March 23, 2016. The Class Notes belongs to ESS 210 001 at University of Tennessee - Knoxville taught by Andrew Conrad Sherfy (P) in Fall 2015. Since its upload, it has received 17 views. For similar materials see Intro to Soil Science in Environmental Science at University of Tennessee - Knoxville.
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Date Created: 03/23/16
Soil Science exam 4 Week 1 Role of P The energy currency in the cell ◦ ATP -- adenosine triphosphate ◦ DNA--deoxyribonucleic acid ◦ RNA--ribonucleic acid enhances many aspects of plant physiology ◦ photosynthesis, maturation ◦ N-fixation, flowering, fruiting, seed production P Deficiency Hard to recognize but: ◦ stunted, thin-stemmed, spindly ◦ dark, bluish green foliage P is mobile in the plant, moves from older plant parts to newer, younger plant parts Why is Phosphorus Unavailable? Most soils naturally low in available P, additional P added turns into insoluble forms quickly. Highly weathered soils in warm, humid and subhumid regions ◦ Little capacity to supply P for plant growth ◦ Why? Extensive losses during intense weathering Undisturbed ecosystems contain enough P in plant biomass and organic matter ◦ If undisturbed, sufficient P levels How Does Eutrophication Occur? Low soil P levels means greater application rates ◦ Fertilizer P bound in unavailable forms ◦ Therefore higher rates are needed Manures & biosolids ◦ Applied at N rate ◦ Overapplication of P Erosion must be minimized or excessive aquatic P levels will occur Practical control of P availability Saturate the P-fixing capacity ◦ If done at once, erosion must be kept in check ◦ Once saturated, fertilizer P will be available allowing lower application rates Placement of fertilizer P ◦ If placed as starter, more will be available and less lost to erosion Phosphorus Availability 2 Combine ammonium and P fertilizers ◦ At higher pH ammonium will increase availability of P Choose P efficient plants Soil Science exam 4 Week 1 ◦ Mycorrhizal uptake ◦ Plant efficiency ◦ Increase cycling of organic P ◦ Crop residues ◦ Cycling provides constant availability ◦ Control soil pH ◦ |b| pH 6-7 is best ◦ Will promote P availability ◦