(Summarized from an
article in a National No-Till magazine publication)
Researchers have found that regardless of the practice,
Phosphorus is leaving the fields and getting into the water sources. This
ultimately impacts Lake Erie and waters leading to and going from The Lake. So,
the big question right now is, what can farmers do to help this issue? Here are
some tips that researchers are recommending farmers use or at least consider.
11.)
Soil Testing
Soil testing is crucial for any
field, the results let the farmer know what they need and don’t need in their
fields when it comes to fertilizer application. Phosphorus is our main concern,
and the soil test will show if any is needed in the field or not. According to
the Tri-State Fertilizer recommendation it says that the maintenance range for
P is 46 ppm, so farmers won’t see much of a response from P if they are
applying it to their field if their soil test is at or around that number. The
Tri-State also says that the critical range is 26 ppm, farmers should expect to
see a response from P if their soil test is below that level.
Some researchers believe that
there is too much P being applied. They are recommending that farmers do strip
trials; farmers should turn off their P application for 100 yards two or three
different times within the field and then use a yield monitor during harvest to
see if there is any difference between the areas.
22.)
Timing
Timing is everything when it comes
to fertilizer placement. The recommended time to fertilize fields is right
after wheat harvest, at least that is when researchers are seeing the lowest
amount of runoff. Kevin King, a USDA Ag. Research Engineer, is very concerned
about when farmers are placing fertilizer on their fields. King says that many
farmers are applying fertilizer on frozen ground, there might be a growing
cover crop but it does not mean that it is ok to be applying during those conditions.
The risk for runoff is at the greatest when the ground is frozen, everything
that is applied cannot be adequately adsorbed and in turn, runs off the fields
and into the water sources. King said, “A cover crop’s not a free pass. If we
put anything out on frozen ground and we get rainfall, it’s going to move…”.
33.)
Take Things Deeper
Tillage is not recommended, but
researchers have found that in some cases that tillage has helped in P runoff.
Nutrients that are placed onto a field need to go below the soil surface;
subsurface placement is crucial. When poorly structured soils receive
nutrients, they sit on the top and sometimes fall into the cracks, when a rain
occurs both the water and fertilizer run into the cracks and eventually run off
the field whether it’s on the surface or through tile. Toolbars are available
that allow producers to apply solid fertilizer 3-6 inches deep and at speeds of
6-8 mph.
44.)
Control the Flow
Nutrients move when water moves,
end of story. Therefore, farmers should consider implementing drainage water
management, this is where the farmer can raise the elevation of the outlet tile.
Drainage is only a concern a few times a year, when the farmer needs to get
into the field or to bring the water level down to avoid root damage. If water
in a farmer’s field can be controlled, then the issues that Lake Erie is facing
could potentially be controlled. Researchers have found that during the winter
and during a drought, nutrient runoff amounts decrease dramatically, and this
is due to the reduction of water movement.
Blind inlets are another option
for no-tillers, inlet drains are cut off and are filled with gravel or
something similar. Gravel has proved to help with the drainage and filtering
processing according to Kevin King. He says that a 60% reduction in P has been observed,
if sediments are given enough time to drop out then P is staying in the field
and out of water sources.
55.)
Gypsum Application
Gypsum improves the structure of
soil, this in turn allows more water to move through the soil and then into the
tile. The nice thing about gypsum is that when the water moves through the soil
it doesn’t take P with it! Increased water-use efficiency of crops is extremely
important during a drought. The key to helping crops survive a drought is to
capture all the water you can when it does rain. Better soil structure allows
all the positive benefits of soil-water relations to occur and gypsum helps to
create and support good soil structure properties.
6
66.)
Cover Your Soils
Cover crops are no longer a thing
of the past (or a passing fad) and many have gotten wrapped up in this new
trend. One thing farmers need to remember is to use the right kind of cover
crop for their field. Radishes are one cover crop that researchers are keeping
a close eye on. The concentration of P around radishes is five times greater
than the bulk of P in the soil, when the crop winterkills a pore is left that
has elevated levels of P around it. Cover crops are very important, they build
organic matter, and they build carbon. The greater the organic matter in the
soil the higher content of water it can hold, therefore if the soils organic
matter could be built up by about 2-3% then more water could be stored in the
fields and in turn the amount of runoff could decrease!
Climate change is happening, whether we like it or not.
Researchers have taken note of the amounts of rainfall over the last few
decades and the intensity of those rainfalls. History shows that precipitation
has increased in the fall, this is causing fertilizer application to take place
in the spring. This time change in fertilizer application has changed the time
period when P moves into Lake Erie and could be some of the reasoning for Lake
Erie’s issues. As long as farmers continue to be proactive and willing to try
new things we should see improvement in the Western Lake Erie Basin (W.L.E.B.).
