Volatile prices, changing foreign markets and weather events represent some of the uncontrollable factors facing farmers every year. As you look to limit that risk by eliminating yield-inhibiting factors, you may want to start with the soil beneath their feet. Making sure your soil is up to the challenge of the upcoming season is the first step toward minimizing risk.
Executive Summary
- Soil acidification is a natural process in high rainfall environments where leaching slowly acidifies soil over time.
- Intensive agriculture can speed up soil acidification through many processes – increasing leaching, addition of fertilizers, removal of produce and build-up of soil organic matter.
- Of all the major fertilizer nutrients, nitrogen is the main nutrient affecting soil pH, and soils can become more acidic or more alkaline depending on the type of nitrogen fertilizer used.
- Nitrate-based products are the least acidifying of the nitrogen fertilizers, while ammonium-based products have the greatest potential to acidify soil.
- Soil acidification due to use of phosphorus fertilizers is small compared to that attributed to nitrogen, due to the lower amounts of this nutrient used and the lower acidification per kg phosphorus. Phosphoric acid is the most acidifying phosphorus fertilizer.
- Potassium fertilizers have little or no effect on soil pH.
Gypsum is a common mineral obtained from surface and underground deposits. It can be a valuable source of both calcium (Ca) and sulfur (S) for plants and can benefit certain soil properties under specific conditions.
Managing nitrogen nutrition makes a big contribution to the yield and quality of winter wheat. Choosing the right source, rate, time and place of nitrogen application improves not only your own profit, but also, food and nutrition security for people around the world.
- Sulfate-Sulfur is the only form of S the plant can utilize.
- Elemental S is dependent upon time, temperature and moisture to be available to the plant.
- Sulfate-Sulfur will not acidify the soil.
For various reasons, sulfur (S) deficiencies are increasing in many areas of the country. Consequently, fertility programs use this nutrient more routinely. The most common chemical forms of S used in fertilizers are sulfate S (SO₄²⁻) and elemental S (S⁰). But these two forms of S react quite differently in soils. It’s very important to understand the differences between SO₄²⁻ and S⁰ in order to use these two forms in the most effective manner possible.
Every January, millions of resolutions are made to eat healthier, get organized, or stop bad habits. But New Year’s resolutions can be made on the farm, too – especially when it comes to improving your soil fertility.
The status of soil fertility levels is an indicator of the sustainability of farming. Every five years, the staff of IPNI and cooperating private and public laboratories across the United States and Canada summarize soil test levels for phosphorus (P) and potassium (K) as well as pH to get an inventory of soil fertility levels across North America.
Worldwide, most soils and crops require phosphorus (P) additions to improve fertility and production. Directly applying unprocessed phosphate rock to soil may provide a valuable source of plant nutrients in specific conditions, but growers must consider several complicating factors and limitations.