Foliar Blend by Agri-Gro

Roundup (glyphosate) and Roundup Ready(RR) technology has become a mainstay in American soybean production. However, hundreds of university and independent studies have shown there is a yield drag of 5–10% with RR varieties compared to comparable conventional varieties grown under similar and favorable conditions. In some trials, RR soybeans produced higher yields which were attributed to improved weed control. In other trials, RR soybeans performed poorly with the yield drag having severe economic consequences.

Continued research is being done to understand the yield drag in RR soybeans however recent evidence points to two possible explanations for this response. First, glyphosate, the active ingredient in Roundup, can suppress the formation of nitrogen nodules on soybean roots. This reduction in the development of nodules decreases the amount of nitrogen available to the soybean plant and can reduce yields. This effect from applied glyphosate is greater when the crop is under stress from conditions such as drought. The effect of

glyphosate is likely on the suppression of rhizobium, the symbiotic bacteria required for nodulation, but it may also be from a broader effect on the normal hysiology of the soybean plant. Second, glyphosate application may temporarily weaken the RR soybean plant immune response and defense mechanisms, especially when conditions place the plant under stress from environmental conditions or attack from pests or disease. With the plant’s ability to defend itself at a weakened level, the plant is more susceptible to yield loss.

Glyphosate, the active ingredient in Roundup, is a strong chelating agent which binds divalent micronutrients in the plant, especially manganese and iron. Flashing or yellowing of young leaves of RR crops is often the result of glyphosate binding these divalent micronutrients. FoliarBlend by Agri-Gro contains numerous plant growth stimulants plus chelated micro-nutrients including manganese and iron which may help reduce the negative effects of glyphosate on RR crops.

Since the micro-nutrients are chelated in FoliarBlend, it can be tank mixed with glyphosate without reducing the efficacy of the herbicide while enhancing plant growth and yield potential.

Glyphosate kills by shutting down the natural defense system within targeted weed species. This is done by chelating — and making unusable — key micronutrients required by certain biochemical pathways within the plant. The primary target of glyphosate is to shut down the shikimate pathway within the plant. This pathway produces Salicylic Acid, the signaling compound known to activate SAR (Systemic Acquired Resistance) within plants. SAR in turn activates the natural defense system within plants which can provide long lasting, broad based resistance to environmental stress and various pests and disease causing pathogens.

While RR crops can tolerate glyphosate without being killed, they still have a temporary reduction in the shikimate pathway which restricts the plants ability to produce Salicylic Acid. Without Salicylic Acid, the RR plant’s natural defense system cannot be activated, leaving the plant more susceptible to environmental stress and attack from various pests and disease causing pathogens. FoliarBlend by Agri-Gro contains Salicylic Acid, the signaling compound that glyphosate suppresses in order to kill plants. While the level of Salicylic Acid in FoliarBlend is sufficient to sustain plant vigor and elevation of the RR plants natural defense system, it does not limit nor prevent the herbicidal action on the targeted weeds. In fact, most growers report improved herbicide performance and weed control when glyphosate is applied in conjunction with FoliarBlend.

In addition to suppressing the plants' natural defense system, research indicates that glyphosate also promotes the proliferation of opportunistic disease causing pathogens in the soil, most notably the Fusarium and Pythium spp. Studies reveal that RR soybean plants have much higher levels of these pathogens on the roots when treated with glyphosate compared to RR soybean plants not sprayed with glyphosate. While RR soybean plants are not normally killed by these diseases, the plants use valuable energy to protect themselves from attack by these pathogens, likely contributing to yield reductions.

In 2006 and 2007, research was conducted between the University of Missouri and the USDA-ARS in Columbia, Missouri. The purpose of this research was to track FoliarBlend’s impact on crop yield along with measuring its ability to reduce pathogenic Fusarium colonies around the roots of RR soybean plants. As evidenced by the photographs below, fungal populations around the roots of RR soybeans treated with glyphosate were significantly higher compared to the check RR soybeans not treated with glyphosate. However, on RR soybeans treated with both glyphosate and FoliarBlend, the fungal populations were comparable to the

non-treated roots demonstrating FoliarBlend's ability to reduce the pathogenic stress on RR soybean plants caused by glyphosate. In fact, this trend held consistent throughout the entire course of the study with FoliarBlend reducing fusarium colonies in 100% of the test strips in 2006 and 2007. The average count of Fusarium colonies on the soybean roots over the entire 2 year study was 103.1 CFU/100 cm of roots for the glyphosate control plot and 48.6 CFUs for the treated plot which received both glyphosate and FoliarBlend. The effect on yield was significantly effected by FoliarBlend with average increases of 14 bushels per acre observed in the 2006 study.

The chart above demonstrates Agri-Gro's ability to suppress soil borne pathogenic microbes in both low yielding and high yielding soils.

This represents a 63% reduction in the low yielding soils and 92% reduction in high yielding soils. Study performed in Florida.

View Additional Soybean Studies [2006]...

Soybean growers depend on the nitrogen fixation process to supply the nitrogen required by soybean crops in addition to producing excess available nitrogen for the following crop. This free nitrogen is produced by a symbiotic relationship between the soybean plant and specific strains of rhizobium bacteria. The continued use of glyphosate, however, appears to reduce the rhizobium population in the soil resulting in fewer nitrogen nodules on soybean roots. In some cases, rhizobium levels and thus nodulation by soybeans are so low that it may be necessary to inoculate the soybean seed with rhizobium to get rhizobium levels high enough to sustain good nodulation by soybeans. The combination of Agri-Gro and FoliarBlend have demonstrated improved plant health and higher yields while keeping microbial populations in the soil more in balance and helping to stabilize rhizobium populations.