Expanded Agronomic Log

This datatable is part of the Main Cropping System Experiment dataset. 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:

• T1. Conventional: standard chemical input corn/soybean/wheat rotation conventionally tilled (corn/soybean prior to 1992)
• T2. No-till: standard chemical input corn/soybean/wheat rotation no-tilled (corn/soybean prior to 1992)
• T3. Reduced input: low chemical input corn/soybean/wheat rotation conventionally tilled (ridge till prior to 1994)
• T4. Biologically based: zero chemical input corn/soybean wheat rotation conventionally tilled (ridge till prior to 1994)
• T5. Poplar: Populus clones on short-rotation (6-7 year) harvest cycle
• T6. Alfalfa: continuous alfalfa, replanted every 6-7 years (converted to switchgrass in 2018)
• T7. Early successional community: historically tilled soil
• T8. Mown grassland community: 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:

• TCF. Coniferous forest: three conifer plantations, 40-60 years old
• TDF. Decidious forest: three deciduous forest stands, two old-growth and one 40-60 years post-cutting
• TSF. Mid-successional forest: 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.