Halvorson, M.
Presented at the All Scientist Meeting (1999-07-20 to 1999-07-21 )
Agronomic yield is evaluated for each of the annually tilled cropping systems each year. The annual cropped systems are in a corn-soybean-wheat rotation. In 1998, the annual cropping systems treatment rotated into wheat. The annual cropped treatments are replicated six times and include Treatment 1, CT-Conventional Chemical Input/Conventional Tilled, Treatment 2, NT-Conventional Chemical Input/No Tillage, Treatment 3, LI-Low Chemical Input/Conventional Tillage, and Treatment 4, ZI-Zero Chemical Input/Conventional Tillage. Treatment 5 (Poplars) were harvested in the early spring of 1999. The trees were chipped and weighed at the KBS Dairy. Treatment 6 (alfalfa) was replanted to a Leaf Hopper Resistant variety this spring.Differences in annual cropping systems and how each is managed influence final grain yield (Fig. 1). Since 1996 grain yields on the LTER Main site have been estimated using a Global Positioning System (GPS). The GPS system uses 24 earth orbiting satellites to determine the JD 4425 Combines location during the harvesting operation with sub-meter accuracy. The coordinates are added to yield information in 1 second intervals and this data is used to generate yield maps following the harvesting operation. The yield monitor within the combine is connected to various electronic sensors within the combine and is calibrated prior to harvest for each crop. The yield monitor gives accurate on the go information to the combine operator during the harvest operation and this data is recorded and downloaded to a computer at the end of each harvest day. In 1998, all four treatments were evaluated for wheat yield across all six replicates; grain weights compared to actual grain weight by plot had generally less than 2% error. In 1996-corn , 1997-soybean and 1998 wheat harvests, the first four replicates of all four treatments were recorded (some of reps 5 and 6) using the yield monitor. The 1996 yield monitor data has been corrected for moisture and grain yield by plot and re-mapped. The 1996 – 1998 GIS yield monitoring data is available on the LTER web page and include geo-statistical analysis of this spatial data and are available at: http://lter.kbs.msu.edu/Yield_Data/index.html. Yield monitoring base data, frequency distributions, variograms, kriged data, cross validation of kriged data, isopleth map, and the GS+ file are available for each LTER plot where real-time corrected GIS data was collected and can be viewed at this site.The JD 4425 combine will be available for demonstration and yield maps for Treatment 3, Replicate 3 for 1996-corn, 1997-soybean, and 1998-wheat appear in Fig. 2 and in Fig. 3. These maps demonstrate similar yield trends for yields at a location and across years for different crops. These spatial similarities for yield show how changes in soil type influences final grain yields and these differences can also be picked up by looking at the low level infrared fly-over photographs taken each year prior to harvest.
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