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 May 3 – 9 from K-State’s Precision Agriculture Laboratory continues to show widespread low NDVI values. This is due largely to the rainy pattern of the previous week that delayed vegetative activity. Moderate photosynthetic activity is visible in the South Central and Southeastern Divisions, where rainfall was less extreme. The Flint Hills continue to show relatively low photosynthetic activity where cool temperatures and cloudy conditions have limited green up.
Figure 2. Compared to the previous year at this time for Kansas, the current Vegetation Condition Report for May 3 – 9 from K-State’s Precision Agriculture Laboratory shows vegetative production much lower across the northeast and east central areas of the state. Much of this is due to excessive rainfall this year, as compared to last. In extreme northwest Kansas, cool temperatures and a late-season snow have delayed vegetative activity this year.
Figure 3. Compared to the 27-year average at this time for Kansas, this year’s Vegetation Condition Report for May 3 – 9 from K-State’s Precision Agriculture Laboratory shows below-average vegetative activity continues in the extreme northeastern areas of the state, where rain lingered. Increased photosynthetic activity is most visible in the Southwest and Central Divisions. Warmer temperatures in these regions have allowed vegetation to capitalize on the wetter-than-average April.
Figure 4. The Vegetation Condition Report for the U.S for May 2 - 9 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 photosynthetic activity in these areas. A pocket of lower photosynthetic activity continues to be visible along the lower Mississippi River, where flooding is an issue. Low photosynthetic activity from the Central Plains through the Ohio River Valley is due to heavy rainfall and lingering cloud cover.
Figure 5. The U.S. comparison to last year at this time for the period May 3 – 9 from K-State’s Precision Agriculture Laboratory shows that lower NDVI values are most evident in the eastern U.S. Drier-than-average conditions have delayed vegetation compared to last year. In contrast, the lower NDVI values in northern California are due to a much larger snow pack in the region this year. South Dakota stands out in the Plains with much higher photosynthetic activity, as the vegetation broke dormancy early and is taking advantage of favorable soil moisture.
Figure 6. The U.S. comparison to the 27-year average for the period May 3 - 9 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. The heavy rains from last week moved east, and the resulting cloud cover has reduced NDVI readings in those areas. Vegetative activity has rebounded in east Texas as the floods of April recede.

Mary Knapp, Weather Data Library

Ray Asebedo, Precision Agriculture

Nan An, Imaging Scientist