Tools & How to Measure Soil Health

There are many tools available that can help us understand what’s going on inside the soil. Each tool has its own usage and limitations, and none can give us a full picture of what’s going on inside the soil and crops. It requires the collective wisdom of farmers, soil experts and TAPs to decipher the information gathered and use those insights to implement regenerative practices successfully.

Here are a few tools that we find very useful in local vegetable farms:

1. Soil moisture probe measures soil moisture level. Excessively high moisture levels for a prolonged period may block the influx of air into the soil, creating an anaerobic condition that would harm crops’ roots. This isn’t uncommon and should be minimized especially in the coming wet season.

2. Penetrometer is a pointed metal rod with a pressure gauge to be pressed down the soil vertically. Resistance pressure exceeding 300 psi indicates severe compaction where no roots can grow. The ideal case is the whole rod being pressed down without reaching 300 psi. Otherwise, the depth where 300 psi is reached would be the depth available to plant roots, and the presence of compaction may imply anaerobic zones where water can’t drain properly.

3. Electrical conductivity (EC) probe measures the level of “salts” and temperature in the soil at the same time. EC would jump if the soil is over-fertilized and soils that are not properly mulched or planted can be “baked” by direct sunlight. Most vegetables grow well only 1.0 dS/m and under 25℃. The probe allows us to see if these conditions are met.

4. 24hr soil respiration test kit measures the activity of microbes in soil. By the amount of carbon dioxide the soil “breathes out”, we can know how active the soil microbes are. Optimally active soil microbes cycle nutrients for crops and produce soil organic matter to build healthy soil!