Education
Unlocking Alfalfa’s Potential: The Impact of 98G and SO4 on Production

The importance of soil pH to your alfalfa crop
There are several factors that go into producing a high quality and yielding alfalfa crop. The first criteria that growers striving for high yielding alfalfa need to focus on is that their soil pH is at a level that the alfalfa plant can thrive in. For alfalfa, most researchers have targeted a soil pH between 6.5 and 7.0 which is higher than other row crops like corn and soybeans where a pH of 6.0 to 6.5 is the target. Proper soil pH can improve the availability of nutrients that are critical to the alfalfa crop’s yield and quality attributes, like phosphorus (P) and potassium (K). Soil pH below 6.0 can negatively affect the alfalfa plant’s root development and nodulation potential which can lead to nitrogen deficiency and up to a 30% decrease in yield.
How can 98G Pelletized Limestone help with soil pH issues?
98G Pelletized Limestone can be a quick and effective method to correct or maintain the soil pH in your existing alfalfa stands or new seedings. 98G is manufactured from a 98% purity limestone source, one of the highest quality deposits in the world. Due to the high quality of the raw material and the fineness of grind the pellets are made from, 98G offers a quicker breakdown and correction of your soil pH issues than that of typical aglime sources. 98G can be blended with other dry fertilizer products and applied prior to, or at seeding to quickly adjust low pH issues prior to new seeding germination and emergence.
Learn more about our lime source comparison study here.
The importance of sulfur and calcium for alfalfa
Once soil pH has been corrected to a favorable level, attention can then be turned towards the macro and micronutrients important for alfalfa production. According to University of Wisconsin research, calcium is third on the list of nutrient removal at 30 units per ton of dry matter. Further down the list is sulfur at 6 units per ton of dry matter, similar to the removal of phosphorus. Sulfur and calcium are both important to an alfalfa crop for multiple reasons. Calcium is a key component in the strengthening of cell walls and as a signaling mechanism within the plant. Stands with adequate calcium levels will have reduced susceptibility to plant diseases and improved stand longevity. Sulfur is involved in the synthesis of protein within the alfalfa plant. The alfalfa plant uses sulfur to produce two key amino acids, cysteine and methionine, which contribute to overall protein content of the forage.
Why use SO4 Pelletized Gypsum vs other fertilizer sources?
SO4 Pelletized Gypsum is the one product solution to supply your alfalfa stand with a soluble source of both sulfate sulfur and plant available calcium. Due to the gradual breakdown and release of nutrients from SO4, your alfalfa will have access to a consistent and stable nutrient source throughout the growing season.
Other benefits to utilizing SO4 pelletized gypsum:
- SO4 is a pH neutral nutrient source unlike other sulfur fertilizers like Elemental Sulfur or Ammonium Sulfate (AMS) that will acidify the soil.
- SO4 has shown to increase Relative Feed Value in alfalfa vs. AMS. See the link to our research brief.
- SO4 can be blended and applied accurately with other dry fertilizer sources saving an additional trip across the field.
- Over time, gypsum will enhance the physical properties of your soil by improving aggregation leading to increased pore space. Increased pore space will allow the movement of water and nutrients deeper into the soil profile for alfalfa’s deep taproot system.
Contact your local retail sales agronomist or Calcium Products Territory Sales Manager to learn more about how you can increase your alfalfa yield and quality in 2025 with 98G and SO4.
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