Texas A&M Leachate Study

Texas A&M Leachate Study Purpose: 60-day study was conducted to evaluate the release patterns of SUL4R-PLUS® fertilizer as compared to two commonly available and widely applied Sulfur fertilizer sources. Study included a control with no application of Sulfur fertilizer. Study evaluated three different soil types. Leachate was collected to measure plant available-Sulfur as Sulfate.

Study analyzed sustained release of Sulfur from three products: Texas A&M Leachate Study Study analyzed sustained release of Sulfur from three products: SUL4R-PLUS® fertilizer --- 00-00-00-21Ca-17S Ammonium Sulfate (AMS) --- 21-00-00-24S Elemental Sulfur --- 00-00-00-90S No Sulfur applied --- Control

Method: Three soils received 7 fertilizer treatments. Texas A&M Leachate Study Method: Three soils received 7 fertilizer treatments. Low rate of S—equivalent to 16 lbs./acre. High rate of S—equivalent to 32 lbs./acre. Replicated four times. Soils were leached at pre-determined intervals and the leachate collected to measure plant available-Sulfur as Sulfate over a 60 day period. Leachate collected at following intervals: Initial (0); Day 5; Day10; Day 15; Day 20; Day 30; Day 40; Day 50; Day 60.

Study analyzed three different soil series: Texas A&M Leachate Study Study analyzed three different soil series: Clay - 31% clay, consisting of very deep clayey alluvium, moderately well drained, nearly level to gently sloping, 0 to 5 % slope. (Texas series name is Burleson.) Silt-Loam - 15% clay, consisting of very deep moderately permeable soil that formed in calcerous loamy alluvium, well drained, nearly level to moderately sloping flood plain. (Texas series name is Weswood.) Fine Sandy-Loam - 5% clay, consisting of very deep moderately well drained, very slowly permeable soils that formed in slightly acid to alkaline clayey and loamy alluvium derived from sandstone and shale. Slope 0 to 3% - nearly level to gently sloping. (Texas series name is Rader.) Each soil collected used in agricultural production. Clay (Burleson) — under a corn/cotton/sorghum rotation. Silt-Loam (Weswood) — under a corn/sorghum rotation. Sandy-Loam (Rader) — under perennial hybrid Bermuda pasture.

Key Points - SUL4R-PLUS® fertilizer: Texas A&M Leachate Study Key Points - SUL4R-PLUS® fertilizer: Provide sustained release of Sulfate-Sulfur throughout the growth cycle of a crop plant. Protected applied nutrient Sulfate-Sulfur from losses due to early uncontrolled release and leaching below the root zone. Released a moderate amount of Sulfate-Sulfur over the initial 10 days of study. Continued to release between 2 to 5 lbs./acre of plant available Sulfate Sulfur, depending on rate applied every 10 days throughout the 60 day study. Moderately water-soluble compared to other Sulfate-Sulfur fertilizer sources. Protects Sulfate-Sulfur from rapid early losses while continuing to supply more than adequate amounts of sulfur nutrition in plant available form for the duration of the growing cycle of most major crops. Does not contribute to the acidification of soils.

Key Points - AMS (Ammonium Sulfate): Texas A&M Leachate Study Key Points - AMS (Ammonium Sulfate): Released all applied Sulfate-Sulfur as plant available and all potential leachable Sulfate within the first 5 days of study; regardless of rate. Contributes to the acidification of soils.

Key Points - Elemental Sulfur: Texas A&M Leachate Study Key Points - Elemental Sulfur: Applied to the soils released no appreciable amounts of plant-available Sulfur over the length of the study. Not suitable Sulfate-Sulfur fertilizer source to deliver Sulfur nutrition for a crop during growing season. Poorly water-soluble. Incapable of providing significantly more Sulfate-Sulfur to growing crop than controls receiving no Sulfur fertilizer. Contributes to the acidification of soils.

Summary of Study Results: Texas A&M Leachate Study Summary of Study Results: Ammonium Sulfate released all applied fertilizer Sulfate-Sulfur as plant-available, but also potentially leachable, Sulfate-Sulfur within the first 5 days. Elemental Sulfur applied to the soils released no appreciable amounts of plant-available sulfur over the entire duration of the study. SUL4R-PLUS® fertilizer, however, released a moderate amount of Sulfate-Sulfur over the initial 10 days of the study, and continued to release between 2 to 5 lbs./acre, depending on the rate applied, of plant available sulfur every 10 days thereafter. SUL4R-PLUS® fertilizer best mimicked the sustained need of crop plants for Sulfur nutrition over the course of a growing season. SUL4R-PLUS® fertilizer is also a superior source of Sulfate-Sulfur where fall application of dry fertilizers is common practice to feed crops during spring emergence when compared to other commonly used sulfur sources.