Pre Plant Sample
make agreements with the growers on fields to be monitored. Before planting and
soil temperature reaches 50 degrees F, we pull 10" soil samples from
two areas (5-6 cores each) of the field most representative of the rest of the
field. These areas are marked or noted to their location so that we return to
the same areas at each sampling. Samples are tested for NO3 and NH4. The
reason for this early sampling is to see the field before corn is growing to
pick two good areas and to get a baseline of nitrogen levels early to avoid
surprises later. Reports are sent to growers along with recommendations
after all sampling is complete. These reports includes the growers results
with recommendations plus averages of all growers in the program so that each
grower can see how he grades compared to the rest of the program.
take samples at the 4-leaf stage with the soil samples same as the pre
plant, we also take whole plant tissue and test it for TN%, NO3 ppm, P%,
S%, and K%. At this time, growers are usually called with the results and
recommendations so decisions can be made as soon as possible. After all sampling
is complete, a report is sent to growers with the same format and information as
the pre plant report.
sampling is at pollination (a time when vegetative growth has stopped and
reproductive growth is about to start). A soil sample and ear leaf sample
are taken and the same tests conducted as on the 4-leaf sampling.
Reporting is also handled the same way. The corn plant uses at least 1/3 of its
N after this time, and we have found that saving 60 to 80 lbs. of N to be
applied after pollination is very efficient. Our data set is now showing even greater responses to post-pollination fertilizer application. See our graphs.
harvest sample is taken after black layer. A NO3 soil test and a NO3 test on an
8" stalk segment taken 4-6 inches from the ground is all that is done at
this last sampling. This sampling is like our "post-mortem" to tell us how good of
a job we have done. After all the field data and yield data have been gathered,
reports are sent to growers for review and to help them adjust their fertilizer
programs for the next year.