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 August 23– August 29, 2016 from K-State’s Precision Agriculture Laboratory shows fewer areas of high NDVI values. Such areas are mainly across the eastern third of the state. Low NDVI values are most visible in parts of central Kansas. While moderate drought continues in northwest Kansas, heavy rains and saturated soils have dominated the central parts of the state.
Figure 2. Compared to the previous year at this time for Kansas, the current Vegetation Condition Report for August 23 – August 29, 2016 from K-State’s Precision Agriculture Laboratory shows lower NDVI values across the southeastern section of the state. This is due to persistent rain and cloud cover compared to last year at this time. Many locations reported rainfall in excess of 4 inches for the period. One station near Overland Park recorded 8.54 inches for the period compared to 1.45 inches in 2015.
Figure 3. Compared to the 27-year average at this time for Kansas, this year’s Vegetation Condition Report for August 23 – August 29, 2016 from K-State’s Precision Agriculture Laboratory shows below-average vegetative activity in a band from southwest to northeast Kansas. That parallels the line of heavy rain and cloud cover that dominated the period. In contrast, the area of below-average vegetative activity in the Northwestern Division has been reduced, thanks to timely rains and favorable temperatures.
Figure 4. The Vegetation Condition Report for the U.S for August 23 – August 29, 2016 from K-State’s Precision Agriculture Laboratory shows high NDVI values continue in the western Corn Belt, particularly Iowa and eastern Nebraska. Favorable rainfall and more seasonal temperatures continue to favor photosynthetic activity across this region. Low NDVI values due to excessive rains have developed in the southeast, particularly in the Carolinas and southern Florida. The low NDVI values continue in southern Louisiana and eastern Texas, as the region is still experiencing high waters/flooding from the recent rains.
Figure 5. The U.S. comparison to last year at this time for August 23 – August 29, 2016 from K-State’s Precision Agriculture Laboratory shows that lower NDVI values continue across much of the eastern U.S. west of the Rockies. Persistent rain continues to mask vegetative activity in the region. There are lower NDVI values in parts of the east due to persistent cloud cover. However, western New York and southern New England didn't have that masking effect from the clouds, and missed the beneficial rainfall. This area shows higher NDVI values even with worse drought conditions. In contrast the low NDVI values in eastern Wyoming, western Nebraska, and much of South Dakota are due entirely to the increasing drought in these areas. There is a small pocket of much higher vegetative activity in northern California, where favorable rains have reduced some of the long-term drought impacts.
Figure 6. The U.S. comparison to the 27-year average for the period August 23 – August 29, 2016 from K-State’s Precision Agriculture Laboratory shows areas of below-average photosynthetic activity in the Desert Southwest. Onset of the monsoon season has resulted in heavy rains and persistent clouds in the area. Similar patterns can be seen along the Gulf Coast and the mid-Atlantic. Flooding continues to be an issue in Louisiana. Below-average vegetative activity in New England and northern Georgia is due to moderate to severe drought in the region.

Mary Knapp, Weather Data Library

Ray Asebedo, Precision Agriculture

Nan An, Imaging Scientist