Authors: Mary Knapp, Ray Asebedo, Nan An

The weekly Vegetation Condition Report maps below can be a valuable tool for making crop selection and marketing decisions.

The objective of these reports is to provide users with a means of assessing the relative condition of crops and grassland. The maps can be used to assess current plant growth rates, as well as comparisons to the previous year and relative to the 27-year average. The report is used by individual farmers and ranchers, the commodities market, and political leaders for assessing factors such as production potential and drought impact across their state.

The Vegetation Condition Report (VCR) maps were originally developed by Dr. Kevin Price, K-State professor emeritus of agronomy and geography. His pioneering work in this area is gratefully acknowledged.

The maps have recently been revised, using newer technology and enhanced sources of data. Dr. Nan An, Imaging Scientist, collaborated with Dr. Antonio Ray Asebedo, assistant professor and lab director of the Precision Agriculture Lab in the Department of Agronomy at Kansas State University, on the new VCR development. Multiple improvements have been made, such as new image processing algorithms with new remotely sensed data from EROS Data Center.

These improvements increase sensitivity for capturing more variability in plant biomass and photosynthetic capacity. However, the same format as the previous versions of the VCR maps was retained, thus allowing the transition to be as seamless as possible for the end user. For this spring, it was decided not to incorporate the snow cover data, which had been used in past years. However, this feature will be added back at a later date. In addition, production of the Corn Belt maps has been stopped, as the continental U.S. maps will provide the same data for these areas. Dr. Asebedo and Dr. An will continue development and improvement of the VCRs and other advanced maps.

The maps in this issue of the newsletter show the current state of photosynthetic activity in Kansas, and the continental U.S., with comments from Mary Knapp, assistant state climatologist:

Figure 1. The Vegetation Condition Report for Kansas for July 12 – July 18, 2016 from K-State’s Precision Agriculture Laboratory continues to show high NDVI values across most of the eastern third of the state, as well as pockets in central and southwest Kansas. There are higher NDVI values now along the Republican River Basin in north central Kansas. Lower NDVI values are visible in parts of eastern Kansas, south of the Kansas River, where excessive rainfall stunted plant development.
Figure 2. Compared to the previous year at this time for Kansas, the current Vegetation Condition Report for July 12 – July 18, 2016 from K-State’s Precision Agriculture Laboratory shows much higher photosynthetic activity across most of the state. The greatest increase in photosynthetic activity is in western Kansas. Rainfall has continued to be well distributed in the region and crop progress continues ahead of last year at this time. In eastern Kansas, the rapid switch from wetter conditions to hot, dry conditions has had a negative impact on vegetative activity this year compared to last year.
Figure 3. Compared to the 27-year average at this time for Kansas, this year’s Vegetation Condition Report for July 12 – July 18, 2016 from K-State’s Precision Agriculture Laboratory shows below-average vegetative activity in the northeastern portion of the state. Wet conditions slowed root development, and the rapid switch to hot weather has stressed vegetation.
Figure 4. The Vegetation Condition Report for the U.S for July 12 – July 18, 2016 from K-State’s Precision Agriculture Laboratory shows high NDVI values in the western Corn Belt. Favorable rainfall and more seasonal temperatures favored photosynthetic activity across the region. In contrast, the western High Plains of South Dakota, eastern Montana and eastern Wyoming have reduced vegetative activity as drought intensifies in these areas. The patch of reduced vegetative activity in western Kentucky marks an area of excessive rainfall. Some locations had more than 8 inches in a 24-hour period.
Figure 5. The U.S. comparison to last year at this time for July 12-July 18, 2016 from K-State’s Precision Agriculture Laboratory shows that lower NDVI values are most evident in the western High Plains where continued drier-than-average conditions, coupled with extremely hot weather, have stressed vegetation compared to last year. In the East, heavy rains have limited NDVI values.
Figure 6. The U.S. comparison to the 27-year average for the period July 12 – July 18, 2016 from K-State’s Precision Agriculture Laboratory shows areas of below-average photosynthetic activity across most of the northern continental U.S. Rapidly drying conditions in the Pacific Northwest are the major cause of the lower than NDVI values in that area. Heavy rains reduced NDVI values in western Kentucky, while flash drought conditions are developing in New England.

Mary Knapp, Weather Data Library

Ray Asebedo, Precision Agriculture

Nan An, Imaging Scientist