Soil Inorganic Nitrogen by Depth - Deep Cores
Soil nitrate and ammonium concentrations with depth in soils of the Living Field Lab Experiment.
This datatable is part of the Living Field Laboratory dataset.
The Living Field Laboratory is a long-term rotation study established in 1993 under the direction of Emeritus Professor Dr. Richard Harwood to evaluate the benefits of cover crops (as green manure) and/or the addition of composted dairy manure in two integrated systems compared to a conventional and an organic system. The LFL accommodates every entry point of the crop rotation each year and has a factorial design that allows for the comparison of a number of interactions. These interactions include: differences in N management, rotation effects, and cover crops. From 1993 through 2005, the rotation consisted of corn (Zea mays L.)/corn/soybean (Glycine max)/wheat (Triticum aestivum) vs. continuous corn. During this period, crimson clover (Trifolium incarnatum L.) was seeded to 1st yr. corn, 2nd yr corn was in rye grass (Lolium multiflorum), soybean had no cover, and red clover (Trifolium pretense L.) was frost-seeded into wheat.
In 2006, under the direction of Dr. Sieglinde Snapp and through consultation with a farmer advisory group, the rotation was shortened to a 3 yr rotation of corn/soybean/wheat vs. continuous corn. The remaining plot in each management system was converted to a 2 yr rotation of corn/soybean. Cereal rye (Secale cereale) is now planted after corn regardless of crop rotation. Cereal rye follows soybean in the 2-yr rotation. Red clover is frost-seeded into wheat.
The management systems are: Conventional, Integrated Fertilizer and Integrated Compost. Weed management is identical across systems, and nitrogen fertilizer management adjusted to take into account soil N availability and balance nitrogen inputs across treatments. The cover crop is present as a split plot (plus minus) within each system. The split-plot cover crop treatment was established in 1993 in Integrated Fertilizer and in Integrated Compost, while the split-plot cover crop treatment was established 14 years later in 2007 in the Conventional treatment, to allow a comparison of short and long-term cover crop presence.
In 2007, the organic management system was changed to a comparison of a perennial grain systems (perennial wheat-alfalfa intercrop) and a 4-yr rotation of corn/soybean/wheat/ alfalfa (Medicago sativa). This allows the comparison of a typical Michigan field crop organic system to a novel system that involves a new, perennial system.
|Experiment:||Living Field Lab (LFL) Study|
|Data available from:||January 1993 to January 2001|
|Core Areas||Inorganic Nutrients,Disturbance|
|Year||year in which the date occurs|
|Cover||cover crop present or not|
|Spring Crop||crop planted in the spring|
|Fall Crop||crop planted in the fall|
|Depth||depth of soil sample||centimeter|
|Sample Date||date soil was sampled|
|LFL: Deep core protocol|
|1993||101||1||no cover||conventional||1st yr corn||0-30||1993-04-14 00:00:00 UTC||2.46||0.99|
|1993||102||1||no cover||conventional||cont corn||0-30||1993-04-14 00:00:00 UTC||1.82||0.94|
|1993||103||1||no cover||conventional||2nd yr corn||0-30||1993-04-14 00:00:00 UTC||1.12||1.00|
|1993||104||1||no cover||conventional||soybean||0-30||1993-04-14 00:00:00 UTC||2.35||1.55|
|1993||105||1||no cover||conventional||wheat||0-30||1993-04-14 00:00:00 UTC||2.87||2.29|