Growing Quality Produce on Difficult Soil

Today we continue the blogs from Luke Freeman who attended the Beginning Farmer Track at the Great Plains Growers Conference in January.

Growing Quality Produce on Difficult Soil presented by Kenny Duzan

Kenny Duzan and his wife Becky grow 3.5 acres of produce in Columbia, Missouri, where they sell at the Columbia Farmers’ Market. Being in his 11th year of production, Duzan knows his soil. He began the session by discussing the various soil types found in Missouri: the sedimentary rocks of the Ozarks, the alluvial and colluvial soils of the river bottoms, the glacial drift of northern Missouri, and the loess deposits surrounding the Missouri River. Duzan farms on central Missouri claypan soil, where drainage is usually the biggest problem.

Duzan stressed the importance of knowing your soil, encouraging growers to take soil tests to know the nutrient composition and pH of their soil. A pH of 6.5 to 7 is best for vegetable production. Duzan also tests the compost or manure he applies to his land for a nutrient analysis. This prevents him from accumulating a buildup of any certain nutrient, like phosphorus, to a toxic level. The standard fertilizer he uses has a 12-12-12 (N-P-K) composition, but different fertilizers would be necessary depending on the farm-specific need. He has also experimented with spent brewers grain as an organic mulch and fertilizer. It has a high protein content (thus a high N content) and is low in carbon content.

The biggest problem he encounters on his farm is poor drainage due to the claypan soils. Poor drainage leads to anoxic conditions causing denitrification, where bacteria convert the plant available nitrate into nitrogen gas, which becomes unavailable to the plants. This problem requires drainage management and nutrient management, applying nitrogen fertilizer to replace the nitrogen lost through denitrification. On any farm, it is vital to stay aware of the nutrient conditions of the soil and adopt practices that minimize nutrient loss and maximize nutrient uptake.
(by Luke Freeman Senior at the University of Missouri, majoring in Sustainable Agriculture.)