By Andi Anderson
Sulfur, a crucial element for plant protein synthesis and chlorophyll production, plays a vital role in sustaining the health of pastures and supporting livestock nutrition. As an essential secondary macro-nutrient, sulfur's significance lies in its requirement at lower levels compared to other macro-nutrients like nitrogen, phosphorus, and potassium.
Plants, including those in pastures, require sulfur for various physiological functions, with legumes being particularly sensitive due to their need for higher sulfur levels in nitrogen fixation. Recognizing sulfur deficiency is vital, as it manifests in young leaves exhibiting light green veins and interveinal areas. This discoloration results from decreased chlorophyll content and hindered protein synthesis.
Goals:
When amending soil for sulfur, it's crucial to distinguish whether the goal is to adjust pH or add sulfur as a nutrient. Elemental sulfur (H₂SO₃) is an option for pH adjustment, causing acidification, which is beneficial in alkaline soils found in Western Ohio. However, this process takes several months to react. The alternative is sulfate, readily available in fertilizers like ammonium sulfate (NH₄)₂SO₄ and gypsum (Calcium Sulfate), which is quickly taken up by plants.
Historically, Eastern Ohio had high sulfur content in its soil due to the impact of coal energy production. However, after mitigating the effects of acid rain, sulfur levels decreased. Soil testing labs often establish a threshold of 15 ppm as the critical level for sulfur in the soil. Eastern Ohio has witnessed a shift, with soil tests showing deficiencies, emphasizing the need for amendments.
Testing:
Soil testing labs and forage analysis laboratories are valuable tools for assessing sulfur levels. A threshold of 15 ppm (Mehlich 3) is considered critical in soil tests. However, for a more accurate evaluation of sulfur deficiency, a forage analysis, which measures sulfur concentrations in tissue samples, is recommended. Adequate leaf concentrations range from 0.2% to 0.5%.
Amendments:
Adding sulfur to the soil can be done through elemental sulfur or sulfate-containing fertilizers. Elemental sulfur is suitable for pH adjustment but takes time to convert to a plant-usable form. Sulfate, found in fertilizers like ammonium sulfate, is a more immediate nutrient source for plants. Manure is also a rich source of organic sulfur and provides a balanced approach to nutrient addition.
Considering the cost difference between urea and granular ammonium sulfate, a forage analysis becomes a practical investment before a significant sulfur amendment. This analysis can help identify sulfur-deficient fields, allowing targeted and cost-effective amendments.
Addressing pH needs, followed by macro-nutrient requirements, and evaluating sulfur levels through soil and forage analysis is a comprehensive approach. Manure, if available, offers a well-balanced and cost-effective solution for sulfur addition. Ensuring optimal sulfur levels is not only essential for plant health but also contributes to the overall well-being of livestock in Eastern Ohio pastures.
Photo Credit:gettyimages-jacqueline-nix
Categories: Ohio, Harvesting