Better Together: The Synergies of Applying Sulfur and Phosphate

There are significant gains to be had when growers can apply both sulfur and phosphate in one pass – especially when those two critical nutrients come in one homogeneous granule. The advanced technology of Smart Nutrition™ MAP+MST® (9-43-0-16S) provides this option for growers in a convenient dry granule formulation.

Smart Nutrition MAP+MST is a unique way for growers to apply precise amounts of nutrients where and when the crop needs them. The Micronized Sulfur Technology (MST) delivers sulfur in a small particle size, which allows for quicker elemental sulfur oxidization and provides sulfur throughout the growing season. Sulfur plays a vital role in plant development. Plants require sulfur to produce chlorophyll, which is needed for photosynthesis.

Phosphate also plays a critical role in photosynthesis, as well as plant development and energy transfer, but it does not move through the soil easily. Smart Nutrition MAP+MST integrates the micronized sulfur particles directly in the manufacturing process of mono-ammonium phosphate granules. This creates a uniform distribution of MST in each granule, providing maximum soil-to-fertilizer contact and an increased oxidation rate for quick crop use.

The Smart Nutrition MAP+MST technology works for all crops and can provide significant savings in time and application costs, and a significant ROI when applied using the 4Rs – right time, right rate, right place and right product.

The proof is in the yield

Sulfur and phosphate provide a marked yield improvement when applied together at optimum rates. For example, in an Ethiopian wheat trial, the addition of 22 kg ha–1 (19.6 lb/ac.) phosphate with 15 kg ha–1 (13.4 lb/ac.) sulfur produced maximum grain yield (3526.8 kg ha−1) (3146.5 lb/ac. or 52.4 bu/ac.), which was significantly different from most other treatment combinations. This treatment has a yield advantage of 40 percent over control treatment, where neither sulfur nor phosphate were applied.

In a corn trial (Ali 2015), maximum biomass (both fresh and dry matter yield) was reportedly achieved when phosphate and sulfur were applied at the rate of 90 and 60 kg ha–1 (80.3 and 53.5 lb/ac.) respectively. Higher values of 1000 grain weight (248 g) (0.55 lb) and grain yield (2414 kg ha–1) (2153.5 lb/ac. or 38.5 bu/ac.) were obtained in plots treated with 120 kg + 45 kg ha–1 (264.4lbs + 40.1 lb/ac.) phosphate and sulfur respectively.

Finally, another trial (Uddin et al. 2014) reported that there was a synergistic interaction between sulfur and phosphate when combined and applied at 20 and 40 kg ha−1 (17.8 and 35.6 lb/ac.) respectively, on the yield of rice grown in Jodhpur and Bangladesh. According to these authors, the above treatment increased grain yield (61 percent) and straw yield (33 percent) of rice over the control where neither was applied.

The best time to apply

As with every nutrient applied to a growing crop, it is critical to understand the nutrients already present in the soil, the nutrient requirements of the crop to be planted and the conditions that might affect availability. The soil conditions that can limit availability of sulfur and phosphate by the plant are:

  • Low soil supply
  • Low organic matter levels
  • Acidic soil pH
  • Wet soils
  • Poor aeration (low oxygen)

If any of these conditions are present, applying both phosphate and sulfur in one pass makes a lot of sense. The maximum benefit will result when both phosphate and sulfur are low and are limiting crop growth. However, if there are high levels of one of the two nutrients, no yield increase is likely. It is important to also note that applying high levels of both phosphate and sulfur can cause their interactions to become antagonistic, and the result is reduced yield. Reasonable fertilizer application rates of both nutrients can provide remarkable benefits, but soil testing is the best tool for making those decisions.

Smart Nutrition MAP+MST provides easier flowability, consistent coverage across the field, and reduced waste of nutrients, money and time. The formulation technology ensures that nutrients are released when the plant needs them the most and provides consistent delivery throughout the season.

For more information go to: Smart Nutrition MAP+MST

For information on soil pH: Four Facts You Should Know

For information on soil testing: What Does Your Basic Soil Test Mean?