Carrie Loboski: The wandering element nitrogen
[audio:https://news.cals.wisc.edu/wp-content/uploads/2011/07/carrie_laboski_nitrogen02.mp3|titles=The wandering element nitrogen with Carrie Loboski]
Carrie Laboski
Extension Soil Scientist
Department of Soil Science
UW College of Agricultural and Life Sciences
(608) 263-2795
laboski@wisc.edu
Saving money and helping the environment with soil testing
Time – 3:05 minutes
0:20 – What soil testing is
0:42 – How you take a soil sample on farm scale
1:06 – Soil tests for the home garden
1:36 – What you gain from soil test information
2:08 – Find a soil testing lab
2:38 – How to use the soil test result
2:56 – Lead out
TRANSCRIPT
Sevie Kenyon: Carrie, welcome to our microphone. Carrie, what makes nitrogen so important?
Carrie Laboski: Well, nitrogen is a very essential plant nutrient. It’s needed in large quantity by the plant. It’s used in the manufacture of amino acids, which are the building blocks of protein. It’s what gives the plant its green color, largely.
Sevie Kenyon: Can you describe for us how nitrogen behaves in soil?
Carrie Laboski: So, if we think about the types of nitrogen that are in the soil. First of all we can think about inorganic nitrogen, which would be our ammonium and nitrate. Ammonium is held onto the soil and is available for plants, but ammonium can be converted into nitrates relatively quickly by soil bacteria. And, that nitrate isn’t held so tightly on the soil.
When we have a lot of rain we can have nitrate leeching down into the soil and it can get into the groundwater and that’s a bad thing. And then we have another reaction where nitrate, if it’s in the soil, and the soil is wet… kind of soggy and warm…you get de-nitrification. What that means is that the nitrate is converted to, into gas or nitrous oxide, and nitrous oxide is a greenhouse gas. And, if we think about how we add nitrogen to the system, it can either be through fertilizers, which are directly added as ammonium or nitrates, or if it was organic sources of nutrients such as manure, then we’re also adding not just ammonium nitrate but organic nitrogen as well. And, that organic nitrogen has to then break down into ammonium and then it starts part of the whole cycle again.
Sevie Kenyon: Carrie, what kinds of things can farmers and gardeners do to manage this element?
Carrie Laboski: One thing that farmers really try to do is get the right fertilizer rate. If you have a rate that’s too high, more then what the crop will need, that’s obviously environmentally not very beneficial because it’s just too much. In addition to looking at rate, you could look at timing of the nitrogen application. You might want to put it on, some of it, a little bit before planting and then some throughout the growing season, so you have less opportunity to lose it. So, there are a lot of different things we can do to try and manage it, to minimize our environmental footprint.
Sevie Kenyon: So Carrie, is it possible for a nitrogen element from Wisconsin to make it all the way to the Gulf of Mexico?
Carrie Laboski: It is. It is possible. If it’s in the water here in Wisconsin, and it stays in the water, that water’s going to move all the way down the river and out into the gulf. If we look at the amount of nutrients that are coming out into, into the Gulf of Mexico, they are coming from the whole watershed, even as far north here as Wisconsin or Minnesota.
Sevie Kenyon: We’ve been visiting with Carrie Loboski, Department of Soil Science, University of Wisconsin-Extension in the College of Agricultural and Life Sciences, Madison, Wisconsin…and I’m Sevie Kenyon.