Importance of Adequate & Timely Sidedress Applications in Cotton
The 2019 planting season has been one of the most challenging in recent memory across the cotton belt. Each region has faced challenges from flooding, drought, cool temperatures, or excessive early season heat. In years where yield potential has been knocked early on, or if you are in a late or re-plant situation, it’s tempting to shift into low management mode. However, with a shortened season, depriving your crop of key inputs will only exacerbate yield losses. It is even more important to feed your cotton the right balance of nutrition to achieve every bit of yield potential possible.
This is especially important for nitrogen. Nitrogen management in cotton production is critical for producing optimum yields. Too little nitrogen can cause a determinate bloom pattern in cotton, alter the rate of photosynthesis in the plant and decrease the plant's ability to transport water from the soil to the leaves (hydraulic conductivity). Nitrogen deficiency also increases fruit shed and suppresses fruiting branch development. The amount of nitrogen available to the plant impacts the top-to-root ratio. Limited nitrogen will result in photosynthate normally used for leaf expansion to become available for root growth. This explains the smaller leaves and overall less robust vegetative growth of a nitrogen deficient plant. If you are growing cotton in a region with saturated fields, most nitrogen has likely been lost through leaching or nitrification. Since planting in these areas happened rapidly when dry weather showed up, early nitrogen applications may not have been made. A robust rate of nitrogen at sidedress is all the more essential.
Timeliness of nitrogen sidedress application is also extremely critical in cotton production. Especially in a shortened or stressed year, monitoring plant growth to determine when to pull the trigger on sidedress is essential. Ensuring cotton has the required nutrients during peak demand is a must for optimum yields. Demand for nitrogen begins to increase at squaring and reach peak demand during bloom. Importantly, any increase in nitrogen demand also increases sulfur demand in lockstep. Since nitrogen and sulfur move primarily by mass flow into the plant, having these nutrients applied before demand hits is crucial. These nutrients are solubilized in soil solution and carried toward the root hairs by the flow of water. Applying sidedress nitrogen and sulfur during first square will ensure nutrients are available to the plant during peak demand in flowering.
YaraVera AMIDAS (40-0-0 +5.5) is a homogeneous fertilizer that provides available N and S at a ratio of 7:1 which is optimal for cotton growth.
The homogeneous nature of YaraVera Amidas allows uptake of N as ammonium and S as sulfate at the fertilizer microsite. Physical blends of urea and sulfate with high nitrogen content do not have this property. The cationic (+) nature of ammonium and the anionic (-) nature of sulfur attract and work together to move into the cotton plant. This maximizes N and S utilization. YaraVera Amidas has superior hardness compared to urea and ammonium sulfate, making it an ideal material for sidedress cotton applications.
Christy Hicks
Sales Agronomist, Southeast
christy.hicks@yara.com
