Increasing cotton yields with Smart Nutrition™ MAP+MSTĀ®

When it comes to cotton production, soil fertility inputs are the biggest investment for maximizing yields. Farmers mostly focus on nitrogen fertility due to the delicate balance between too little and too much. However, sulfur deficiency is appearing more often and reducing cotton lint yield.

A summary of 13 cotton trials conducted in Georgia, Mississippi, Alabama, and Virginia from 2018 to 2020 shows a 9 percent (roughly 110 pounds per acre) increase in cotton lint yield with the application of sulfur, either as Smart Nutrition MAP+MST, MAP and ammonium sulfate (AMS) blend or MAP and sulfur competitor blend. This is a significant increase in yield with sulfur rates around 15 to 20 pounds per acre. Similar yields of MAP+MST and AMS suggest sulfur oxidation rates were sufficient to match sulfur availability from AMS and ensure maximum yields. Keep in mind crop rotation can impact response to sulfur application.

Cotton grown following peanut production may not respond to supplemental sulfur applications due to high rates of sulfur applied as gypsum to peanuts. A soil test may give some indication on potential yield response.

Cotton grown on coarse textured soil carries a higher potential for sulfate leaching losses, especially from a source like AMS where all the sulfur present is in the sulfate form. Split applications of AMS are recommended due to the increased risk of leaching. Smart Nutrition MAP+MST offers season long sulfur availability as a slow release fertilizer while giving the farmer added protection from sulfate leaching.

Summary of third-party trials from 2018-2020. Treatments with different letters are significantly different.

Smart Nutrition MAP+MST has the added benefit of containing both nitrogen and phosphorus. Applied as a starter fertilizer, Smart Nutrition MAP+MST can aid in faster initial growth and potentially decrease time to maturity and weed interference. Generally, farmers could see the greatest benefit of starter application in medium to heavy textured soils and soils low in soil test phosphorus.