A cost-effective way to crank up your composite soil samples

The most common soil sampling practice is to collect one composite sample per field. This article will describe a low-cost way to take your composite samples to a new level.

An appropriate composite is based on 12-20 sub-samples or “cores” collected from the most productive areas of a field. (See the sidebar for more specific instructions.) These are usually mid-slopes. For this one primary composite sample, you want to avoid collecting from hill tops, low spots and saline areas. This mid-slope composite will help you select an appropriate fertilizer blend and rate that supports those most productive areas.

However, by avoiding the low-producing areas – the hill tops, the low spots – you may be missing critical insights to boost yield potential in those areas.

You can’t blend samples from low-producing areas into your primary mid-slope composite. The resulting average will produce soil test results that are almost useless. So you need more samples. The extra cost of a second, or third, targeted composite from that field may reveal some interesting issues that could be solved, or at least improved, with localized management.