Soil Management- The Basics

Soil science is infinitely complex, but the basics of managing soil fertility can be boiled down to a few simple guidelines:

  • Maintain high organic matter through composting, cover cropping & mulch.  Organic matter is the engine that drives a fertile, healthy soil.  Organic matter retains water, improves soil structure, stimulates biological activity thereby releasing nutrients and buffers soil pH.  The single most important and effective thing you can do for your soil is to add and maintain organic matter.  Ideally soil organic matter should be between 3- 10%.
  • Stimulate biological activity Not all organic matter is created equal.  The best methods for increasing organic matter and stimulating biological activity are cover cropping, composting and mulching.  It's important to understand the carbon to nitrogen (C:N) ratio of organic matter.  Adding organic matter with a high C:N ratio such as sawdust will consume nutrients such as Nitrogen, making it unavailable for plants.
  • Maintain soil pH between 6.5-6.8 - Soil pH effects the availability of nutrients (see graph).  When a soil becomes too acidic (low pH), Phosphorous, Sulfur, Potassium and Magnesium become unavailable, while some micronutrients become unavailable in an alkaline soil (high pH).  The effects of pH below or above this range can be moderated by high organic matter.  The best way to determine pH is through laboratory analysis (see below).soil-ph.jpg 
  • Have your soil tested by a lab.  A complete nutrient analysis of your soil costs between $30 - $40 and is an excellent investment if you plan to farm or garden for more than one season.   A good soil analysis will include soil pH, soil texture, complete nutrient analysis, cation exchange capacity, and organic matter content.  A&L Labs is a reputable laboratory that offers a comprehensive soil fertility analysis for a reasonable price.  This booklet, offered by Peaceful Valley Farm Supply, is an excellent guide to interpreting your soil fertility analysis results from this lab.
  • Amendments- It's best to amend your soil based on lab results, but without a soil analysis you can use the following as a guide for amending soils in the Mid Klamath region:
    • Add Calcium and Phosphorous every 2-4 years.  Many soils of the Mid Klamath region are deficient in Calcium and Phosphorous (see Ultramafic Soils).  If you add these amendments in a mineral rather than chemical form there is no danger of burning crops or damaging the soil.  The best forms of mineral Calcium are oyster shell flour and mined limestone, apply 2-5 LB per 100 square feet , or 1,000 - 2,000 LB/acre.   The best form of mineral phosphorous is colloidal soft rock phosphate - be sure to use colloidal form for best availability.  Apply 2-3 LB/ 100 square feet, or  500-1,000 LB/acre.
    • Organic matter - add high quality organic matter ever year in the form of compost, cover crops and/ or mulch.
    • Nitrogen is a highly mobile plant nutrient that requires continual replenishment via compost, cover cropping, often supplemented with a concentrated form such as bloodmeal, fish meal, cottonseed meal, alfalfa meal, or feather meal. 


A Rough Guide for Amending Soils in the Klamath-Trinity Region

Add every 2-5 years:




LB/ 100 ft2

LB/ acre


Mined limestone or oyster shell flour

2-5 LB

1,000 - 2,000 LB


soft rock colloidal phosphate

2-3 LB

500 - 1,000 LB

Add every year (choose one, or combine):



Nitrogen, choose one:


4 LB

500-1,000 LB


6 LB

750 - 1,000 LB

cottonseed meal

8 LB

1,000 - 2000 LB

alfalfa meal

5 LB

500 - 1,000 LB

composted chicken manure

25 LB

10 yards/ acre

Organic Matter

compost, cover cropping, mulching


Soil Links & References