Descriptions of two shallow soils overlying limestone bedrock (oolite) in SW Miami-Dade County Wayne Worthley SWS 5716c Dr. Harris Krome ‘R’ Biscayne (marl) 2R

Sat. image of S FL – (from US Dept. of Int. Geol. Survey – 1993) [online image] Available at Wikipedia, 15 Mar 2010 (file name too long to list) Sat. image of SW Miami-Dade and location of two sites: Krome soil (1) and Biscayne marl (2) [online image] Available County-FL/2964_rid/ , , , _rect/11_zm/, 15 Mar 2010 Krome soil ‘upland’ site on rock ridge at UF-TREC Biscayne (marl) ‘lowland’ site in East Everglades near Homestead-Miami Speedway Distance between sites = 4.1 miles

[online image] Available FL/5201_rid/ , , , _rect/18_zm/, 15 Mar 2010 Biscayne (marl) site [online image] Available , , _rect/16_zm/, 15 Mar 2010 Krome sites – UF-TREC undisturbed native area rock-plowed ag. land

Krome soil formed from rock-plowing pine rockland habitat in Miami-Dade undisturbed pine rockland [online image] Available mgrefurl, 16 Mar 2010

Krome soil - undisturbed limestone at surface 10 cm OA layer

Krome (rock plowed) Ap - 10 YR 4/4 sl-vgr Ap-R (42cm) 5 YR 4/6 sicl conc. redox conc. >50% course aggregates 5 YR 4/6 sicl

Krome (disturbed) description: 107 cm pedon depth high infiltration & hydraulic conductivity, very low avail. water ~ 1cm, water table in R >150 cm severe limitations for septic tanks, basements, and roads (shallow depth to ‘R’ layer is only factor causing any limitations – not sure why a problem?? ) upland soil of marine material (calcareous precipitate) with nearly level slope and very slow surface runoff and low erosion potential Krome is an Entisol with an Ochric epipedon and lacking a subsurface horizon classification site characteristics Soil properties and interpretations soil morphology

Biscayne (marl) – coastal flat Homestead-Miami Speedway [on-line image] Available content/uploads/2008/11/homestead-miami-motor-speedway-small.jpg&imgrefurl, 16 Mar 2010 Limestone exposed between berms ~32cm Ap ‘berms’

mechanism for marl formation marl is CaCO3 but ‘lithologically discontinued’ from bedrock (2R) Ca HCO 3 CaCO 3 + CO 2 + H 2 O enters into photosynthesis limestone bedrock CaCO3 MARL! CO2 (from microbial respiration) + H2O… 1 …knocks off calcium cations and bicarbonate to feed this reaction 2

32cm Ap only redoxomorphic differences Krome ‘R’ Biscayne ‘2R’ low chroma (gleyed) in Biscayne (right) Krome (two on left) 5YR 4/6 10YR 4/4 10YR 5/2 Biscayne (marl) 10YR 5/2 silt loam moderate structure – sbk

Biscayne (marl) description: 32 cm pedon depth (to ‘2R’ layer) moderate infiltration & hydraulic conductivity, very low avail. water ~ 6.4cm, water table <25 cm water table is above surface of epipedon during wet months (this particular area is drained) severe limitations for septic tanks, basements, and roads coastal marine terrace flat of chemical (not physical/lithological but organic) calcareous precipitate with nearly level slope and very slow surface runoff & very slow erosion potential Biscayne marl is an Entisol with an Ochric epipedon and lacking a subsurface horizon classification site characteristics Soil properties and interpretations soil morphology

observations -pedogenesis of red ‘pockets’ & redox features in Krome ‘R’ horizon (from where, how?) -why does USDA limit the use of Krome soil for basements, septic, and roads? (most homes in area have septic systems and paved roads nearly every 8 blocks) -several of my findings not consistent with USDA surveys (Ap layer depth, texture, and CEC of Krome; absence of Cg layers in Biscayne) Biscayne - severe limitations for roads, how does the speedway accommodate 160,000 people for a weekend every year? The BURNING question: Is that Biscayne marl ‘sustainable’? Does accumulation exceed depletion? (it appears that a few cubit feet go out with each extracted palm tree) *have researchers observed and reported the rates of accumulation of that soil?