Thursday, July 30, 2009

SoyMVP Article on College of Agriculture Website

Soybean Canopy Development

These pictures have been taken throughout the season in the location in our SoyMVP field in Hickman County.

June 30, 2009 - V4

July 8, 2009 - V5

July 14, 2009 - V8

July 21, 2009 - R1 (V11)

July 30, 2009 - R2 (V15) (same field, different location)

In order to ensure maximum yield potential, the crop must be able to intercept its maximum level of solar radiation. You can think of it as the crop ability to "harvest light" and convert it to seed.

Everything leading up to reproductive growth, such as plant population and weed control timing, effect the ability of the crop to reach full canopy by this point.

Tuesday, July 28, 2009

Herbicide Injury in Soybean - UPDATE

Last week I described a condition I was seeing in soybean sprayed with Pursuit (imazethapyr) plus glyphosate in which leaves were yellowing in a mosaic fashion.

In those same fields this week, leaves are back to good coloration and are showing no signs of the yellowing I was seeing last week.

Wednesday, July 22, 2009

Effects of Standing Water on Soybean

Over the last couple of weeks I have come across several fields with standing water in low-lying areas.

Standing water can be detrimental to crop stands and in turn yields, but the severity of the effect is dependent upon several factors. The growth stage of the crop during flooding, duration of the flood, temperature while the water is standing, and rate of drying after the flood.

If fields are under standing water for 48 hours or less, yields losses are generally minimal or non-existent. Flooding for 4-6 days can delay plant growth, cause the plants to be shorter with fewer nodes and can depress yields significantly. If fields are flooded for a week or more, entire losses of stand can occur.

Low oxygen levels in are detrimental to respiration, a vital function for plant growth. Considering the low levels of oxygen contained in water when compared to air, plants in a flooded field get far less oxygen for needed processes. Depending on water movement, oxygen levels in flooded soils can reach zero within 24 hours. One advantage that we have had during this growing season as it relates to water in the field is the cool temperatures that we have been experiencing in Kentucky. Warm air temperatures increase the speed of respiration and depletes the oxygen from the soil even quicker, leading to rotting and death of the plants. This increased respiration by plants and soil microbes also leads to exponential increases in CO2 levels, which has as great or greater effect than lack of oxygen.

Other effects of waterlogged soils include root diseases, and nutrient deficiencies, including nitrogen, potassium, and manganese.

Image: Potassium deficiency in soybean

References: University of Minnesota Extension, Iowa State University Extension

K deficiency image courtesy of Chad Lee, University of Kentucky

Monday, July 20, 2009

Herbicide Injury in Soybean

Below are some pictures from the field, taken July 20, 2009.

These plants were sprayed with Pursuit (imazethapyr) and glyphosate on July 14 (photos 1 and 2) or July 11 (photos 3 and 4).


The chlorosis of the leaves and purpling of veins is characteristic of ALS inhibitor injury in soybean. Severity of injury is determined by environmental characteristics at the time of application and thereafter. Recovery is often slower with low soil moisture and high air temperatures. Injury symptoms are generally gone 21 days after application.


The Univeristy of Illinois found that in over 95% of fields with ALS injury, no yield loss was observed. The fields where yield loss occured were late planted and/or the herbicide application was late in the season. These are times when the crop is more likely to be in conditions of low soil moisture and warmer air temperatures. The risk of yield loss due to labeled applications of these herbicides is far less than allowing for crop competition with weeds or failing to adequately control weeds.

References: University of Illinois Extension Purdue University Extension Weed Science

Friday, July 17, 2009

Updated USDA Oil Crops Outlook

U.S. acreage planted to soybeans reaches an all-time high in 2009

U.S. farmers reported planting a record 77.5 million acres of soybeans in 2009, raising this month’s projection of 2009 production by 65 million bushels to 3.26 billion. The larger soybean supply is expected to boost 2009/10 ending stocks to 250 million bushels, compared to the previous forecast of 210 million. Soybean farm prices for 2009/10 could drop to $8.30-$10.30 per bushel, compared to last month’s forecast of $9.00-$11.00.

Led by better prospects for U.S. production, world soybean output in 2009/10 is expected to expand to a record 243.7 million metric tons from 210.6 million this year. For 2008/09, global ending stocks for soybeans are estimated at a 5-year low of 41 million tons. Production increases for the United States, Argentina, and Brazil in 2009/10 are expected to restore global soybean stocks to 51.8 million tons.

Source: USDA

Some recent shots from the field

Thursday, July 16, 2009

Crop Update

Two fields in the program have reached reproductive growth, with canopy at 90-95 percent in both. This is, of course, what we like to see.

It's amazing how quickly the crop is progressing. With the rain events we have had combined with the warm daytime and nighttime temperatures, you can nearly see the plants grow right before your eyes.

Wednesday, July 1, 2009

Japanese Beetles in Kentucky Soybean

Japanese beetles appear to be coming out in full force again this year. From what I have observed thus far, they are staying mainly in the corn crop as opposed to soybean.

According to UK entomologists, the economic threshold for Japanese Beetle defoliation is 35% in the vegetative stages.

Click here to learn about Japanese Beetles in Kentucky soybean.

Much more information can be found about insect damage in the Kentucky Integrated Pest Management Manual for Soybean.