The Main Cropping System Experiment (MCSE) is the signature KBS LTER long-term experiment to address the impact of cropping system management on the delivery of ecosystem services. It consists of 4 annual and 3 perennial crop treatments and 4 successional communities; these 11 systems represent a gradient of decreasing chemical and management inputs. Seven systems (T1-T7) were established at the LTER Main Site in 1989 and assigned to 1 ha plots (87 x 105 m) in each of 6 replicate blocks. The remaining systems were added in 1993 and are replicated in the KBS landscape. All systems are on the same soil series.
The four annual crop treatments are a corn – soybean – winter wheat rotation that is managed differently. The Conventional (T1) and No-till (T2) treatments receive conventional levels of chemical inputs, but with chisel plow and no-till management, respectively. The Reduced Input (T3) and Biologically Based (T4) treatments are low-chemical/biologically-based input systems with a winter leguminous cover crop; T3 receives banded herbicide and starter N at planting and T4 (certified organic) receives no chemical inputs nor compost or manure. Both T3 and T4 receive additional post-planting cultivation and T4 is rotary-hoed to control weeds.
The three perennial crop treatments include continuous alfalfa (T6) and short (~10 years) rotation poplars (T5), both at the LTER Main Site, and long-rotation Coniferous Forest (CF) established on KBS property in 1965. Continuous alfalfa was replaced by switchgrass in 2018.
Two of the four successional communities are at the LTER Main Site. A native Early Successional (T7) community was established by abandonment after a 1989 spring plowing and has been maintained since 1997 by an annual spring burn. A Mown Grassland (never-tilled) community (T8), located 200 meters south of the main plot, has never been tilled or in agriculture and thus provides a historical reference for soil organic matter studies. This system is mown annually in the fall to control woody growth and is replicated in four 15 x 30 m plots randomly distributed within a 10-ha former woodlot that was cleared in ~1959. Mid-successional (SF) and Deciduous Forest (DF) communities comprise the remaining two successional communities and are replicated in the KBS landscape.
Subplots established within MCSE treatment plots address specific process level hypotheses:
- T1 and T2 subplots examine long-term effects of weed populations without herbicide applications (since 1989)
- T3 and T4 subplots examine the influence of weed populations and nitrogen availability on crop yield (since 2006)
- T5 subplots examine the effect of nitrogen fertilizer rates and timing on tree biomass (since 2011)
- T7 subplots determine how succession is influenced by chisel plowing and nitrogen fertilization (since 1989)
- T8 has been shared with the Interactions Experiment (since 1985)
Each MCSE plot also contains a permanent set of 5 sampling stations at which most within-plot sampling is performed. See sampling station location maps below.
Summary and Additional Information
Plot size and replication
- Treatments 1-7: 105 x 87 meters (~1 hectare), 6 replicate blocks
- Treatment 8: 15 x 40 meters, 4 replicates
- Current Plot
- Past Plots (1989 onwards)
- Sampling Stations (T1, T2, T3, T4, T6, T7)
- Sampling Stations (T5)
- Sampling Stations (T8)
- MCSE Successional and Forest sites (SF, CF, and DF)
Major Management Changes
- 1989: T5 Poplars planted as stem cuttings (Populus × canadensis Moench ‘Eugenei’ ([Populus deltoides × P. nigra], also known as Populus × euramericana ‘Eugenei’).
- 1993: T1-T2 rotation changed from corn-soybean to corn-soybean-wheat to match T3 and T4 rotations.
- 1994: T1 cultivation changed from moldboard plow to chisel plow.
- 1994: T2 (Replicate 5) accidentally plowed. Renamed T21.
- 1997: T7 Biannual spring burning implemented to prevent tree colonization.
- 1999: T5 Poplars harvested in February and allowed to coppice (stem sprout).
- 2002: T7 Annual spring burning implemented.
- 2008: T5 Poplars harvested in January and allowed to go fallow for field season in order to suppress weeds.
- 2009: T5 Poplars replanted as stem cuttings of Populus nigra x P. maximowiczii (‘NM6’).
- 2009: T1-T3 Soybean varieties changed from conventional to transgenic (glyphosate resistant); T4 variety remains conventional.
- 2009: T3 Soybean weed control changed from mechanical + banded herbicides to broadcast application of glyphosate (same as T1).
- 2011: T1-T3 Corn varieties changed from conventional to transgenic (glyphosate, European corn borer, and root worm resistant); T4 variety remains conventional.
- 2014: T1-T3 Switched to low pressure injection system for N application.
- 2016: T1-T3 Switched to stream bar nozzle application system for N application in wheat.
- 2018: T5 Alfalfa replaced by switchgrass.