Sanborn Field -- The Second Century Plan Summary (Initiated
1990-91)
There are 38 plots of the original field remaining. In addition, six
other plots are used for special studies.
Continuous Wheat
A set of plots which have been in wheat annually since 1888 except for
two years when the seeeding failed and spring oats were used.
Plot 2 - Nutrients added based upon soil tests and applicable
recommendations for 70 bushels per acre.
Plot 9 - Untreated since 1888.
Plot 10 - Six tons of manure annually since 1888.
Plot 5 - Six tons of manure annually plus fertilizer N to equal N
applied to Plot 2.
Continuous Corn
Two plots (17 and 18) have been in corn since 1888. Two other plots (6
and 7) have been in corn since 1950.
Plot 6 - Fertilizer recommendations based on soil tests for 130 bushels
of corn; moldboard plowed.
Plot 7 - Like Plot 6 except planted no-till.
Plot 17 - No treatment; moldboard plow.
Plot 18 - Six tons of manure per acre; moldboard plow.
Continuous Timothy
Two plots which have been continually cropped to timothy since 1888.
These were reseeded in 1989. The shifting population of species will be
documented in the future.
Plot 23 - No treatment.
Plot 22 - Six tons of manure per acre annually.
Corn-Wheat-Clover Rotation
The rotation was initiated on Plots 25 through 28 in 1888. In addition,
1, 3, and 4 were switched to this rotation in 1950 under "full
treatment." A given crop in the rotation in on all plots in 25 through
28 in a given year while each of the three crops is on one of Plots 1, 3,
or 4 each year.
Plot 25 - Six tons manure annually.
Plot 26 - Nutrients added based on soil tests for per acre yields of 130
bushels corn, 70 bushels wheat, and 4.2 tons clover hay.
Plot 27 - No treatment.
Plot 28 - Like Plot 26 except no nitrogen will be used on any crop.
Plots 1, 3, 4 - Same as Plot 26.
Corn-Soybeans-Wheat(Clover) Rotation
This intensive rotation, which includes a green manure clover crop, has
been in use in the field since 1928 (Plots 31, 32, and 33). It is being
expanded to other plots primarily to study the effects of the legumes on
the soil and N balance. Plots 37 and 38 will be sequenced so that with
Plot 31 each crop will appear each year for comparison with Plots 1, 3,
and 4.
Plot 31 - Nutrients added for per acre yield goals of 130 bushels of corn,
60 bushels of soybeans, and 70 bushels of wheat.
Plot 32 - Same as Plot 31 except no fertilizer potassium (K)is used.
Plot 33 - Same as Plot 31 except no fertilizer phosphorus (P) is used.
Plot 34 - Six tons manure per acre annually.
Plot 35 - No treatment.
Plot 36 - Same ad Plot 31; delete the clover green manure crop.
Plot 37 - Same as Plot 31.
Plot 38 - Same as Plot 31.
Corn-Soybean-Wheat-Clover Rotation
This is a new rotation to Sanborn Field. Each crop will be grown each
year on two plots, one of which will receive N for corn and wheat and one
no N when these crops are grown on those plots.
Plots 11, 13, 16, 29 - Nutrients added based upon soil tests for per acre
yields of 130 bushels of corn, 60 bushels of soybeans, 70
bushels of wheat, and 4.2 tons per acre clover hay.
Plots 12, 14, 15, 30 - As above except no fertilizer nitrogen will be
applied for any crop.
Grain Sorghum-Soybean-Wheat(Clover) Rotation
This rotation is also new to the field and was initiated to compare with
the rotation on Plots 31-38 except grain sorghum is substituted for
corn. Each crop will be grown each year to compare most directly with
Plots 31, 37, and 38. Nutrients will be added based upon soil tests for
per acre target yields of 110 bushels of grain sorghum, 60 bushels of
soybeans, and 70 bushels of wheat.
Plots 19, 20, 21 - Full nutrient treatment to meet yield goals.
Continuous Soybeans
Plot 39 will be used to document the effects of continuous soybeans using
treatments for a yield goal of 60 bushels per acre.
Forage Plots
Several plots were placed in continuous forages with fertility to be
added based on soil tests to achieve hay yields of 4 tons per acre for
cool season grasses, 3 tons per acre for warm season grasses, and 5 tons
per acre for alfalfa.
Plot 24 - Tall fescue (south half, weather station occupies north
half).
Plot 40 - Alternate crops demonstration.
Plot 41 - Orchardgrass
Plot 42 - Alfalfa
Plot 43 - Orchardgrass/alfalfa
Plot 44 - Orchardgrass/red clover
Plot 45 - Warm season grass mix
Keep in mind as you view the plots on Sanborn Field that changes in soil
systems are slow to occur under cropping. What you see in the
historical plots are the result of over a century of activity. On the
other plots, remember that crop year 1991 was actually the start.
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