This dataset includes information about the LTER main site treatments, agronomic practices carried out on the treatments and approved site use requests.

Most long-term hypotheses associated with the KBS LTER site are being tested within the context of the main cropping systems study. This study was established on a 48 ha area on which a series of 7 different cropping systems were established in spring 1988, each replicated in one of 6 ha blocks. An eighth never-tilled successional treatment, is located 200 m off-site, replicated as four 0.06 ha plots.

Cropping systems include the following treatments:

1. standard chemical input corn/soybean/wheat rotation conventionally tilled (corn/soybean prior to 1992)
2. standard chemical input corn/soybean/wheat rotation no-tilled (corn/soybean prior to 1992)
3. low chemical input corn/soybean/wheat rotation conventionally tilled (ridge till prior to 1994)
4. zero chemical input corn/soybean wheat rotation conventionally tilled (ridge till prior to 1994)
5. Populus clones on short-rotation (6-7 year) harvest cycle
6. continuous alfalfa, replanted every 6-7 years
7. early successional community on historically tilled soil
8. successional community on never-tilled soil.

For specific crops in a given year see the Annual Crops Summary Table.

In 1993 a series of forest sites were added to the main cropping system study to provide long-term reference points and to allow hypotheses related to substrate diversity to be tested. These include:

• DF – three deciduous forest stands, two old-growth and one 40-60 years post-cutting
• CF – three conifer plantations, 40-60 years old
• SF – three old-field (mid-successional) sites 40+ years post-abandonment.

All share a soil series with the main cropping system treatments, and are within 5 km of all other sites.

For each system (and for a number of microplot treatments nested within the main treatment plots) the following baseline variates are being measured (described in greater detail in other data set descriptors):

• plant characteristics, including species distributions and abundances, net aboveground productivity by functional group (crop vs. non dominant biomass, selected non dominant biomass), economic yields, tissue C and N contents, seed bank composition;
• soil chemical and physical characteristics, including soil moisture, pH, inorganic N and P pools, total C, N, and P pools, bulk density;
• soil biological characteristics, including microbial biomass C and N, N mineralization rates (buried bags), microbial populations, invertebrate populations; and
• insect and pathogen dynamics, including distributions and abundances of major insect pests and predators and of Fusarium pathogens.