Carrington Research Extension Center


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2021 Soil Fertility Trials at the Carrington REC


We have several soil fertility projects underway this season at the CREC. Let’s look at a few of them:

Comparative impact of biodegradable polymer-coated urea fertilizers on corn
Only a few effective slow-release nitrogen fertilizers (SRNFs) such as ESN (Environmentally Smart Nitrogen) exist on the market. ESN, however, sometimes releases N too slowly, missing synchronization of available N with crop needs. ESN polymer coating that protects urea granules from N loss usually persists in the soil for prolonged periods and is of some environmental concern. Field trials are testing the impact on corn performance of newly-developed soy-based coatings on SRNFs by Renuvix (Renuvix, LLC Fargo, ND).  

Assess the impact of seed applied SRNFs during planting
Some farmers apply a blend of ESN and urea with seed during planting. This study tests what rates and formulation of the Renuvix SRNF can safely be applied simultaneously, compared with ESN, on dryland and irrigated wheat.

Assess the effectiveness of three nitrogen extender products that contain urease inhibitors
Urea fertilizers treated with NBPT (N-(n-butyl)thiophosphoric triamide) urease inhibitors like Agrotain, SuperU and ANVOL have been shown to reduce N loss from surface-applied urea fertilizer. Farmers have different preferences for these nitrogen extenders, and request them without knowing which particular product is being used. Because these treated fertilizers are more expensive than conventional urea, and they impact yields positively under specific environmental conditions, it is imperative to determine the most effective types. This trial compares products in wheat and corn.

Fertilizer coatings come in various colorsFertilizer coatings in several colors.

Jump starting mycorrhizal colonization in corn following non-host crop
Corn roots are hosts of beneficial mycorrhizal fungi upon which the crop depends to maximize nutrient uptake. Because the fungi population drops following non-host crops like canola or sugarbeet, field studies compare the impact of a host cover crop like rye, and seed-applied vesicular arbuscular mycorrhiza inoculant on corn yield and on the mycorrhizal fungi population following non-host crops.

Optimizing nitrogen and sulfur application strategies to improve canola production
High levels of available N in the soil can negatively impact canola yields if sulfur was deficient. Depending upon N levels, 15 lbs S can produce similar yields to 25 lbs S. Some research in Europe suggests that a onetime S application at bolting can be effective for increasing canola yields. Field trials will compare yield and quality with a single pre-plant application of S versus a single top-dress application at start of bolting. The trials also assess how yields vary with low and high N rates combined with low and high S rates.    

Verifying corn response to mid-season N application based on crop canopy spectral reflectance
Current N fertilizer prices are over 50% higher than a year ago. Split application of N has been advocated as a means to improve N efficiency in corn production. Field studies will estimate the N needs of corn using crop spectral reflectance from light using the normalized difference vegetation index (NDVI). Plant height will be used in conjunction with NDVI to assess plant health.  

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If you have any questions about these projects or other soil matters, please contact me.

Jasper Teboh, Ph. D.
Soil Scientist

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