How to sample

When to Sample

Suggested Sampling Times Through the Year

Time of year and Suggested Sampling Times Through the Year:

The desired food web shifts according to season (Figure 1 - below). Samples should be taken to reflect these changes. Consider what it is you want to know, and what time of year you need to know about.

A soil chemistry report will not change much from early spring into the summer, but the soil foodweb has natural shifts according to season. Winter when soils are cold and wet is not the best time to test for nematodes or active bacteria. These critters are better detected in warmer soils later in the spring. That's OK because the soil foodweb is something you work with and bring into balance over several crop cycles.

Sampling times:

1. Spring: (wet/cold soils) Good time to determine imbalances that need correcting before the plants start growing. Sample early enough that you have two to three weeks for the sample to get back to you, and still have time to do something about imbalances.
2. At planting: Good time to determine whether nutrient cycling can be carried out by organism processing or whether fertilizer applications will be required. Also, assess whether organisms are forming good soil aggregate structure. Compare the effects of different product or management practices with control, or not-treated, samples.
3. Mid-crop: Excellent time to compare the effects of different management practices (different fertilizers, tillage), or the impact of different pesticides or herbicides on soil organisms and their function.
4. Harvest: Good time to determine the impact of the whole cropping cycle on soil health, although if soil is too dry, organisms will have little activity. Also a good time to determine whether significant work needs to be done to improve soil health for the next crop. Add organisms to decompose the residues from harvest.
5. Fall: (Still warm/moist but not frozen soils) Make certain the soil is healthy for the next crop. Good time to manipulate soil organisms to set the stage for optimal plant growth with minimal inputs into the system.