Biochar Update: Soil Sampling

Since my last update on the Biochar Student Mentoring and Participatory Learning project, we’ve made a lot of progress.  First, we planted the Year 1 crop of Red Norland potatoes on Thursday, May 14.

After planting, Sarah used the tilther to weed the paths between the potatoes. (Fun fact on the tilther: We also use this tool to incorporate compost or other soil amendments just below the soil, to a depth of about 2 inches.)

Once the potato plants were large enough, we hilled the plants, this time with the aid of a couple helpers.

But what I really want to focus on is soil sampling.  Professor Tamara Benjamin from Purdue  joined us last week Friday, June 19, to work with Sarah on taking soil samples, one sample from each of the plots in the randomized block design (review: 4 of the plots have a low rate of biochar, 4 have a high rate of biochar, and 4 have no biochar).  They used a soil probe to take the samples.

These samples will be sent to A&L Great Lakes Laboratory in Fort Wayne, where they’ll be analyzed for soil nitrates, or nitrogen.  We’re looking at nitrogen for two reasons: 1) to make sure there’s enough nitrogen in the soil for the potatoes 2) to see how the different rates of biochar affect how much nitrogren is plant available.  

This round of soil nitrate test results will offer useful information, but not enough.  However, by taking a number of soil samples over the three years of the project from each of the six Hoosier farms spread out over the state, and by testing for a variety of nutrients, we’re hoping to get reliable data that will offer clear insights about biochar’s value to soil and plant health.

Photography: Julie Oudman Perkins