This article was prepared on behalf of Aquatrols
Nitrogen is a critical component for a healthy plant. While nitrogen exists in several forms, nitrate (NO3) is the most available to plants.
Nitrate is very soluble in water and is easily carried to plant roots as the crop uses water.
However, nitrate that is not used by the plant can move with water as it percolates through the soil. This nitrate has potential to contaminate groundwater.
As input costs continue to rise, finding ways to influence the efficient use of soil-applied chemicals and minimize water use becomes more critical to identify.
Over the years, research has been conducted to validate the claim that soil surfactants can help move water off the surface into the soil.
While most surfactants can make this claim, not all surfactants can provide other important benefits.
Finding a soil surfactant that can move water off the soil surface and laterally and downward to the rootzone–while improving moisture levels in the soil, is not as easy.
University and field research have shown that optimum moisture levels can be achieved with the use of Surfactants Powered by Aquatrols Surfactant Technologies, such as IrrigAidGold (available as WaterMaxx2 from Crop Production Services).
Moreover, if moisture levels are uniform in the soil, the chemicals, such as fertilizers, applied with the water will also be distributed uniformly providing improved fertilizer efficiency.
Beginning in 2003, research to validate the claim of improved nitrogen efficiency was conducted by Birl Lowery, a soil scientist with the University of Wisconsin, Madison.
IrrigAid Gold was applied to the center of a potato row at emergence.
A one-time gallon-per-acre application resulted in an increase in soil moisture content in the center of the row by as much as 50 percent following subsequent irrigation or rainfall.
Moisture content in the center of the hill was consistently higher in the IrrigAid Gold treated area than in the untreated. In addition, surfactant-treated soils were able to store more water and did not dry down as the untreated soils did, thus improving the available water to the plants.
As stated above, if moisture levels are uniform in the soil, the chemicals applied with the water will also be distributed uniformly. The uniform distribution of chemicals with the use of IrrigAid Gold was also proven in Lowery’s research in 2003.
In the study cited above, analysis of water collected in suction cups buried at a 1 meter depth indicated that nitrate leaching was lower in the IrrigAid Gold treated soils. (see figure 1)
Samples were taken over a 65 day period which began on day 160 (in the calendar year) when urea (46-0-0) was applied at 120 pounds/acre. (60 pounds/acre of the urea was also applied at tuberization).
When evaluating total nitrate leaching over the 65 day period, the cumulative nitrate–nitrogen leaching in the IrrigAid Gold treated area was 35percent lower at the 1 meter depth than in the untreated area. (Figure 2)
This means the untreated soil lost nitrate-nitrogen faster than the areas treated with IrrigAid Gold.
If nitrate leaching is slowed down with the application of IrrigAid Gold, one can determine that more nitrogen is retained in the rootzone and is available to the crop. Evaluation of the crop nitrogen use revealed that the IrrigAid Gold treated consumed 156 pounds of the total applied 180 pounds of nitrogen while the untreated side utilized only 135 pounds of the total 180 pounds applied.
That is a 15.5 percent increase in nitrogen uptake with the use of IrrigAid Gold.
In 2008, in a study on Tygress tomato plants conducted by Bielinski Santos at the University of Florida, Gulf Coast Research and Education Center in Balm, IrrigAid Gold treated plants showed a 13 percent increase in nitrate-nitrogen concentration in leaf petioles over untreated plants even under 80 percent of standard irrigation regime. (see chart)
In 2009, Santos continued analysis of the nitrate-nitrogen retention benefits with applications of IrrigAid Gold.
In a block design replicated greenhouse study, he evaluated the impact IrrigAid Gold had on NO3-N petiole concentrations and the plant root biomass as a result of the increased nitrogen efficiency.
The study was set up with Tygress tomato plants in one gallon pots filled with a sand based nursery mix. IrrigAid Gold treatments were applied at a one gallon per acre rate starting two weeks after transplanting.
One set of plants were treated every other week for a three time application and another was treated every other week for a five-time application. Results showed plants treated three times had a 37 percent increase in NO3-N petiole concentration over the untreated control.
Those treated five times had a 58 percent increase in NO3-N over the untreated. The root biomass data (a 66 percent increase in grams/plant over the control) and this photo (Figure 4) supports the theory that increased levels of NO3-N will produce better plants.