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Soil Methods

Sample Amount: Submit 300-500 g of dried and ground sample. Five (5) mL per element is required for samples submitted in extract form. N & C require one (1) gram of finely powdered soil (to pass through a 60 mesh sieve).

Soil Preparation: Air or oven-dry soil at 35-55°C (the Lab oven dries at 40°C). Grind to pass through a 2 mm sieve. Analysis for N, C, TKN and "total" metal analysis require grinding to pass through a 60 mesh screen.

Containers: Submit samples in pint-size plastic containers or in bags (plastic or paper).

Notes:

Sodium Adsorption Ratio and Exchangeable Sodium Percent are calculations derived from analysis of Ca, Mg and Na.

For N and C by combustion (Carlo-Erba), 1 gram of sample material needs to be finely ground to pass through a 60 mesh sieve.

To determine available N-P-K on California soils, we normally analyze for NO3-N, Olsen-P and Exchangeable K.

Method Summaries

Soil Salinity

  • 200 — Saturated Paste and Saturation Percentage
  • 205 — Soil pH
  • 210 — pH of a 1 + 10 Soil Suspension
  • 215 — Estimated Soluble Salts (ECe)
  • 220 — Bicarbonate and Carbonate in Saturated Paste Extract
  • 227 — Chloride in Saturated Paste Extract - Flow Injection Analyzer Method
  • 235 — Potassium, Sodium, Calcium, Magnesium, Boron and Sulfate-Sulfur in Saturated Paste Extract
  • 240 — SAR (Sodium Adsorption Ratio) and ESP (Exchangeable Sodium Percentage)

Soil Fertility

  • 312 — Soil Nitrate and Extractable Ammonium-Flow Injection Analyzer Method
  • 315 — Total Kjeldahl Nitrogen (TKN)
  • 320 — Total Nitrogen and Carbon - Combustion Method
  • 322 — Total Organic Carbon - Combustion Method
  • 330 — Sulfate - Sulfur
  • 340 — Extractable Phosphorus - Olsen Method
  • 355 — Extractable Phosphorus - Bray Method
  • 360 — Exchangeable Potassium, Calcium, Magnesium, Sodium and Estimated Cation       Exchange Capacity
  • 370 — Potassium -Sulfuric Acid Extraction
  • 380 — Extractable Micronutrients using DTPA Extraction - Zinc, Manganese, Copper, and Iron
  • 390 — Total Elements (includes Phosphorus, Zinc, Manganese, Iron, Copper, Molybdenum, Cadmium, Chromium, Lead and Nickel)
  • 392 — KCL Extractable Aluminum
  • 394 — Selenium
  • 396 — Arsenic

Physio-Chemical

  • 410 — Organic Matter - Walkley-Black Method
  • 415 — Organic Matter - Loss On Ignition Method
  • 420 — Gypsum Content
  • 430 — Cation Exchange Capacity
  • 440 — Calcium Carbonate and Calcium Carbonate Equivalent
  • 450 — Lime Requirement
  • 460 — Moisture Retention
  • 470 — Particle Size Analysis
  • 480 — Bulk Density