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 April 19 – 25 from K-State’s Precision Agriculture Laboratory continues to show further expansion of the area of highest plant production into north central Kansas. The highest NDVI values are still in Sumner and Harper counties. The Flint Hills continue to show relatively low photosynthetic activity. Recent rainfall is likely to accelerate the greenup in this region, but cooler temperatures and cloudy conditions will limit that progress.
Figure 2. Compared to the previous year at this time for Kansas, the current Vegetation Condition Report for April 19 - 25 from K-State’s Precision Agriculture Laboratory shows a small portion of the state has lower photosynthetic activity. Part of that is due to dry conditions in March and early April, while some is due to excessive rain.
Figure 3. Compared to the 27-year average at this time for Kansas, this year’s Vegetation Condition Report for April 19 – 25 from K-State’s Precision Agriculture Laboratory shows that the area of above-average photosynthetic activity has begun to expand again. The areas of lower productivity in east central and southeast Kansas are due to recent cloud cover.
Figure 4. The Vegetation Condition Report for the U.S for April 19 – 25 from K-State’s Precision Agriculture Laboratory shows high NDVI values along much of the West Coast, and in northern Idaho. Favorable moisture continues to drive active photosynthesis in these areas. A pocket of lower photosynthetic activity continues to be visible along the lower Mississippi River, where flooding is an issue.
Figure 5. The U.S. comparison to last year at this time for the period April 19 – 25 from K-State’s Precision Agriculture Laboratory shows that lower NDVI values are most evident in Minnesota and Wisconsin, thanks to a late-season snow event. This is also true in Colorado and Wyoming, although to a lesser degree. In contrast, much higher NDVI values are visible in New England. Despite the recent snows in this area, the overall snow depth is less than last year, and more vegetation is active. In the Southern Plains, lower NDVI values are the result of heavier rains this season.
Figure 6. The U.S. comparison to the 27-year average for the period April 19 – 25 from K-State’s Precision Agriculture Laboratory shows above-average photosynthetic across the Pacific Northwest, where winter moisture has reduced drought impacts. Snow pack from the late-season storms in the central Rockies has reduced photosynthetic activity in these areas. Persistent clouds in southeastern Oklahoma, east Texas, Louisiana, and eastward have masked NDVI readings in those regions.

Mary Knapp, Weather Data Library

Ray Asebedo, Precision Agriculture

Nan An, Imaging Scientist