Irrigated and non-irrigated sands

Key points

General BMPs

Recommended practices for corn and edible beans

• Split-applications of nitrogen (at planting and sidedress).
• Use a nitrification inhibitor with an early sidedress application.

Acceptable practices with risk

• Preplant nitrogen application with an inhibitor.
• Single preplant application of anhydrous ammonia (AA) with an inhibitor. The loss risk depends on how quickly it is converted to nitrate.

Practices not recommended

Nitrogen loss risk is high with these practices and impacts both economic returns and the environment.

• Spring preplant applications without an inhibitor in corn.
• N applied after tasseling with fertigation in corn. Nitrogen needs to be in the soil system by tasseling to be used effectively.
• ESN applications to edible beans after planting.

Nitrogen application guidelines

Rate

• Use the MRTN guidelines for irrigated sandy soils (see Fertilizing corn grown on irrigated sandy soils). You can review how to work with the MRTN guidelines in the Fertilizer N recommendations section.
• Reduce the rate for corn following soybeans
• For non-irrigated sandy soils, see the MRTN guidelines in Fertilizing corn in Minnesota

Timing

• No fall nitrogen applications on coarse-textured soils (irrigated or non-irrigated)

Application method and source

• Use split applications (V2 and V4). In most cases, the two-way split BMP was as good as a 4-way split (V2, V4, V6 & V8) in UMN research.
• N enhancement products applied preplant (ESN, Instinct and SuperU) were not superior to the recommended 2-way split in 8 out of 9 years. These products slow the release or conversion of ammonia to nitrate, but using the 2-way or 4-way split yielded as well or better than the enhanced products.