Soil organic matter
Soil salinity, EC
Link to UC ANR Healthy Soils
> SOM Calculation
How much Residue or Compost do I need to increase my Soil Organic Matter levels?
Converting crop residue and compost to Soil Organic Matter (SOM). It ain't easy!
These are estimates only!
Part 1: What's our weight of soil and of new SOM needed?
1. Enter the depth of soil to consider (inches):
(most organic matter is in the top 6-8")
2. What is the Bulk density of the soil ? :
(Common values: Sand 1.4; Loam 1.2; Clay 1.1 g/cm3)
3. How much do you want to increase SOM by? (%)? :
(note that a 1% increase can take 10 years)
4. What is your garden size in sq ft? :
5. What's the density of your fertilizer (Oz/cup) :
(approx: 2.5 for compost up to 5 or 6 for urea and powdered sulfur to 9.5 for ammonium sulfate)
6. Is there Phosphorus in your fertilizer? Percent? :
(e.g., 0 in urea, 11% in 11:11:11- check the label)
7. Is there Potassium in your fertilizer? Percent? :
(e.g., 0 in urea, 37% in Potassium nitrate - check the label)
Click here to
What's the volume of soil in 1 acre to the depth you said?:
What's the (approx) weight of soil in that volume?:
lbs/acre (based on bulk density)
What's the weight of SOM that we need to increase it by:
By the way how much other nutrients were added (lbs/acre)?
The rate of Fertilizer is:
Given the Fertilizer Use Efficiency you entered, the (approx) amount of Fertilizer N reaching the plant is:
lbs/acre (based on the fertilizer use efficiency)
The (approx) amount of fertilizer N gone elsewhere (leached, lost as gas, or in organic matter):
More than likely many gardeners over-fertilize their gardens. You can change SOM, but not texture
Fertilize responsibly, build Soil Organic Matter.
A good way to build soil health.
Created March 2010