Can you believe there is only one month left of the International Year of Soil? 2015 has flown by, but we would be remiss if we didn’t dedicate a blog to this crucial element of life. Soil plays an integral role in human, animal and plant life; we wouldn’t be here without it!
Soil, as defined by the Soil Science Society of America, is “the unconsolidated mineral or organic material on the immediate surface of the Earth that serves as a natural medium for the growth of land plants.” Pretty important, right? But more important than just having soil is having healthy soil, or soil that can continue to provide a living ecosystem to sustain plants, animals, and humans. With proper soil management by farmers and other Earth caretakers, the soil we have now can continue to serve its important functions:
- Provide nutrients for plant growth, such as nitrogen, potassium and phosphorus
- Absorb and hold rainwater, which improves food security and resilience to droughts and floods
- Filter and buffer potential pollutants to help keep water sources clean
- Provide habitat for soil microbes and half of the world’s biodiversity
- Play a key role in the carbon cycle and mitigating climate change through carbon sequestration
- Be a foundation for agriculture and the production of food, feed, fiber and fuel
The task of keeping soil healthy is not one that is taken lightly. There are many ways that farmers can work to build and maintain soil health, most of which relate preventing erosion and degradation and improving soil nutrients and structure. Most Iowa farmers work with soils that are very nutrient-rich, have good water holding capacity and a very deep topsoil layer – that’s what makes Iowa such a great place for agriculture! Because the soil is so valuable, farmers choose to use the following practices:
- Cover crops reduce soil compaction, improve water filtration, and prevent erosion. The plants’ roots break up compaction all while holding soils in place during times the soil would otherwise be fallow, such as late fall, winter, and early spring. Cover crops can also add nutrients like nitrogen to the soil and reduce weed pressure.
- Crop rotation is a well-known tool that farmers use to increase yields, but also has strong soil health benefits. Transitioning fields from one crop to another each year can improve soil organic matter, reduce soil erosion, and improve soil structure over time.
- Proper soil nutrient management is a key part of managing soils. Farmers can take soil samples from fields to determine the levels of nutrients, such as nitrogen, potassium and phosphorus, which are needed for optimum plant growth. Using the resulting data, farmers can apply precise amounts of fertilizer to their soils to replenish lost nutrients. Some farmers use liquid manure, which should be applied at soil temperatures of 55 degrees or less, while others apply fertilizers such as anhydrous ammonia, to accomplish this goal. Proper nutrient management is important for supplying nutrients for plant needs without over applying.
- Minimal or no-tillage practices work for farmers who can plant a new crop directly into the leftover organic matter from the previous year with little to no working, or tillage, of the soil. This works by keeping the soil covered and protected from wind, snow and rain by organic matter residue leftover from the previous crop. Some farmers at this time of year may choose to till only the headlands, or end rows where the farm machinery turns around, to break up soils that may have become compacted from tractors, trucks and combines.
The soil is a very valuable resource, and farmers know it is also a key resource for ensuring future generations will have land to farm and the capability to feed a growing population. Even though the International Year of Soil is almost over, the need for healthy soils is not. Farmers are working every day to maintain and improve the health of the soil we depend on for a healthy planet and a healthy life. What can you do to help?