Warm Weather Delays Fall Fertilizer Application

Nov 07, 2016

The Minnesota Department of Agriculture (MDA) advises farmers and fertilizer applicators to check soil temperatures before fall application of ammonium-based nitrogen fertilizers. Warm weather this season has kept soil temperatures around the state from dropping below 50˚ F, the recommended temperature to apply nitrogen and avoid fertilizer loss.

On average, soil temperatures reach 50˚ F during the first week in October in northern Minnesota and the fourth week of October in southern Minnesota. However, that has not happened this year, with soil temps remaining above 50˚ F in many parts of the state.

To assist tracking soil temperature, the MDA has 48 monitoring stations on its on‑line soil temperature map at: https://app.gisdata.mn.gov/mda-soiltemp/.

Soil temperature is measured at a six‑inch depth; the same depth anhydrous ammonia is typically applied. Station data on the MDA online map is updated every 15 minutes with the help of satellite uplink technology from the Minnesota Department of Natural Resources and the National Weather Service.

Video: Designing a Robotic Berry Picker

Since blackberries must be harvested by hand, the process is time-consuming and labor-intensive. To support a growing blackberry industry in Arkansas, food science associate professor Renee Threlfall is collaborating with mechanical engineering assistant professor Anthony Gunderman to develop a mechanical harvesting system. Most recently, the team designed a device to measure the force needed to pick a blackberry without damaging it. The data from this device will help inform the next stage of development and move the team closer to the goal of a fully autonomous robotic berry picker. The device was developed by Gunderman, with Yue Chen, a former U of A professor now at Georgia Tech, and Jeremy Collins, then a U of A undergraduate engineering student. To determine the force needed to pick blackberries without damage, the engineers worked with Threlfall and Andrea Myers, then a graduate student.