Soil is one of the most important and common factors in agriculture. Soil health, sometimes referred to as soil quality, is defined as the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans. This definition speaks to the importance of managing soils so they are sustainable for future generations.
To do this, we need to remember that the SOIL IS ALIVE and contains living organisms (or, soil biota) that when provided the basic necessities of life – food, shelter, and water – perform functions required to produce food and fiber.
Regardless of your definition of soil health, USDA-NRCS recommends the following to protect soil and all that it provides:
1. Keep the soil covered as much as possible;
2. Disturb the soil as little as possible;
3. Keep plants growing throughout the year to feed the soil;
4. Diversify as much as possible using crop rotation and cover crops.
Healthy soil gives us...
Healthy soil gives us clean air and water, bountiful crops and forests, productive grazing lands, diverse wildlife, and beautiful landscapes. Soil does all this by performing five essential functions:
- Regulating water – Soil helps control where rain, snow melt, and irrigation water goes. Water and dissolved solutes flow over the land or into and through the soil.
- Sustaining plant and animal life – The diversity and productivity of living things depends on soil.
- Filtering and buffering potential pollutants – The minerals and microbes in soil are responsible for filtering, buffering, degrading, immobilizing, and detoxifying organic and inorganic materials, including industrial and municipal by-products and atmospheric deposits.
- Cycling nutrients – Carbon, nitrogen, phosphorus, and many other nutrients are stored, transformed, and cycled in the soil.
- Physical stability and support – Soil structure provides a medium for plant roots. Soils also provide support for human structures and protection for archaeological treasures.
Inherent Soil Properties
The inherent properties of soil are things that we cannot change; for example soil texture, type of clay and depth to bedrock. Dynamic properties of soil are the things that we can change, including: organic matter, infiltration rate, soil structure, bulk density and water & nutrient holding capacity. Conservation practices, such as cover crops and no-till, can improve soil quality by increasing organic matter, improving soil structure and water & nutrient holding capacity.
The creatures living in the soil are critical to soil health. They affect soil structure and therefore soil erosion and water availability. They can protect crops from pests and diseases. They are central to decomposition and nutrient cycling and therefore affect plant growth and amounts of pollutants in the environment. Finally, the soil is home to a large proportion of the world’s genetic diversity.
Learn more about soil biology by reviewing the NRCS Soil Biology Primer.
Unlock the Secrets in the Soil
We all want healthy soil! Today, more farmers are managing for soil health by disturbing their soil as little as possible, growing as many different species of plants as practical, keeping living plants in the soil as often as possible, and keeping the soil covered constantly. More information on soil health can be found on USDA’s website, Unlock the Secrets in the Soil.
Case Studies: Economic Benefits of Applying Soil Health Practices: Funded by an NRCS Conservation Innovation Grant (CIG) awarded in 2018, American Farmland Trust (AFT) and NRCS have started to release a series of Soil Health Economics case studies. USDA and NRCS have invested in the people and tools that provide these quantitative assessments. AFT utilized this infrastructure to show the economic benefits across a broad sampling of farming operations and worked closely with NRCS Economists & Soil Health Specialists to review these case studies.
The 4R Nutrient Philosophy
In addition to cover crops and no-till, proper fertilizer management is another tool to help producers manage and improve soil health. The 4 R Nutrient Philosophy is an innovative, science-based approach that offers increased production, increased farmer profitability, improved sustainability and enhanced environmental protection. The concept is to use the right fertilizer source, with the right placement, at the right rate and the right time.
The 4R Tomorrow program is an outreach program designed to help communities find ways to improve soil health and water quality – working together we can face the challenge’s Ohio faces with natural resource protection. We are ALL a cause of the issues at hand and we are ALL a part of the solution!
Right Source: Make sure that the soil is receiving the proper nutrients, whether that be through natual planing practices or by supplementing with commercial products.
Right Rate: Use the principles of supply and demand to appropriately make financial decisions for your soil health.
Right Time: Make timely decsions regardig the scheduling of uptake of nutrients, nutrient loss, and field operations.
Right Place: Be aware of the space you have when managing nutrients, and plan out the specific site-crop locations to limit losses from the field.
Nutrient Management is the matching of site specific soil, production history and crop management to the “Right Rate”, “Right Source”, “Right Time” and “Right Place,” commonly known as the 4Rs of nutrient stewardship.
- Nutrient Management – The Natural Resources Conservation Service can help producers develop nutrient management plans that are designed to address natural resource concerns related to soil erosion, water quality and nutrient applications.
- Water Quality & Nutrient Management – Water quality and nutrient stewardship go hand-in-hand. Nutrient pollution, which is caused by too much nitrogen and phosphorus in the water (from fertilizer runoff and other sources), is the most widespread, costly and challenging environmental problems our nation faces.
- Ohio’s Nutrient Reduction Strategy: the Ohio Department of Agriculture, Ohio Department of Natural Resources and Ohio EPA have developed a statewide plan to reduce nutrient pollution.
Web Soil Survey
Web Soil Survey (WSS) provides basic soils data and information produced by the National Cooperative Soil Survey. It is operated by the USDA Natural Resources Conservation Service (NRCS) and provides access to the largest natural resource information system in the world. NRCS has soil maps and data available online for more than 95 percent of the nation’s counties and anticipates having 100 percent in the near future. The site is updated and maintained online as the single authoritative source of soil survey information.
Soil surveys can be used for general farm, local, and wider area planning. Onsite investigation is needed in some cases, such as soil quality assessments and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center.
Check out the WSS Interactive Map to check the soils in your area.
- Why Is Soil Testing Important?
- Taking Soil Samples
- Local Soil Testing Labs
- Interpreting Soil Test Results
- 4R Soils & Nutrients Fact Sheets
WHY IS SOIL TESTING IMPORTANT? Soil testing allows producers to evaluate the current condition of soil (including imbalances, deficiencies and excesses) and to better understand plant growth. Having this information allows producers to make informed decisions about fertilizer and lime applications.
WHAT ARE THE BENEFITS: Making informed decisions prevents the over application of fertilizers and reduces costs. Continued soil sampling over a number of years allows producers to adjust management decisions, optimize soil conditions and improve yields.
WHAT IS BEING TESTED IN A SOIL SAMPLE? The standard soil test includes determination of soil pH, available phosphorus, potassium, calcium, and magnesium levels as well as recommendations for lime and fertilizer. Other soil tests, such as ones for organic matter and zinc-manganese, are available for additional fees.
HOW CAN I GET STARTED?: Local OSU Extension and SWCD offices can help you get started with soil sampling.
Information provided by SARE:
The usual time to take soil samples for general fertility evaluation is in the fall or the spring, before the growing season has begun.
GUIDELINES FOR TAKING SOIL SAMPLES
- The best time to sample for a general soil test is usually in the fall. Spring samples should be taken early enough to have the results in time to properly plan nutrient management for the crop season.
- Take cores from at least fifteen to twenty spots randomly over the field to obtain a representative sample. One sample should not represent more than 10 to 20 acres.
- Sample between rows. Avoid old fence rows, dead furrows, and other spots that are not representative of the whole field.
- 4. Take separate samples from problem areas if they can be treated separately.
- Soils are not homogeneous—nutrient levels can vary widely with different crop histories or topographic settings. Sometimes different colors are a clue to different nutrient contents. Consider sampling some areas separately, even if yields are not noticeably different from the rest of the field.
- In cultivated fields, sample to plow depth.
- Take two samples from no-till fields: one to a 6-inch depth for lime and fertilizer recommendations, and one to a 2-inch depth to monitor surface acidity.
- Sample permanent pastures to a 3 or 4-inch depth.
- Collect the samples in a clean container. A clean spade or shovel can be used. Use clean, plastic buckets
- Mix the core samplings, remove roots and stones, and allow mixed sample to air dry.
- Fill the soil-test mailing container.
- Complete the information sheet, giving all of the information requested. Remember, the recommendations are only as good as the information supplied.
- Sample fields at least every three years and at the same season of the year each time. On higher-value crops annual soil tests will allow you to fine-tune nutrient management and may allow you to cut down on fertilizer use.
Include contact info for local labs
Below is an example provided by SARE. Refer to their website for more info or contact your local SWCD.
From time to time we’ve come across unusual soil test results. A few examples and their typical causes are given below:
- Very high phosphorus levels—High poultry or other manure application over many years.
- Very high salt concentration in humid region— Recent application of large amounts of poultry manure, or location immediately adjacent to road where de-icing salt was used.
- Very high pH and high calcium levels relative to potassium and magnesium—Large amounts of limestabilized sewage sludge used.
- Very high calcium levels given the soil’s texture and organic matter content—Use of an acid solution, such as the Morgan, Mehlich 1, or Mehlich 3, to extract soils containing free limestone, causing some of the lime to dissolve.
- Soil pH >7 and very low P—Use of an acid such as Mehlich I or Mehlich 3 on an alkaline, calcareous soil; the soil neutralizes much of the acid, and so little P is extracted.
Soil Test #3 Report Summary*
Field name: #12
Sample date: December (no sample for PSNT will be taken)
Soil type: clay (somewhat poorly drained)
Manure added: none
Cropping history: continuous corn
Crop to be grown: corn
|MEASUREMENT||LBS/ACRE||PPM||Soil Test CATEGORY||Recommendation SUMMARY|
|P||20||10||very low||30 lbs P2O5/acre|
|K||58||29||very low||200 lbs K2O/acre|
|pH||6.8||no lime needed|
|OM||4.3%||rotate to forage legume crop|
|N||no N soil test||100–130 lbs N/acre|
*All nutrient needs were determined using the Mehlich 3 solution (see table 21.3C).
Note: ppm = parts per million; P = phosphorus; K = potassium; Mg = magnesium; Ca = calcium; OM = organic matter; me = milliequivalent; PSNT = pre-sidedress nitrate test; N = nitrogen.
What can we tell about soil #3 based on the soil test?
- The high pH indicates that this soil does not need any lime.
- Phosphorus and potassium are low. [Note: 20 pounds of P per acre is low, according to the soil test used (Mehlich 3). If another test, such as Morgan’s solution, was used, a result of 20 pounds of P per acre would be considered a high result.]
- The organic matter is relatively high. However, considering that this is a somewhat poorly drained clay, it probably should be even higher.
- About half of the CEC is probably due to the organic matter and the rest probably due to the clay.
- Low potassium indicates that this soil has probably not received high levels of manures recently.
- There was no test done for nitrogen, but given the field’s history of continuous corn and little manure, there is probably a need for nitrogen. A low amount of active organic matter that could have supplied nitrogen for crops is indicated by the history (the lack of rotation to perennial legume forages and lack of manure use) and the moderate percent of organic matter (considering that it is a clay soil).
- This field should probably be rotated to a perennial forage crop.
- Phosphorus and potassium are needed—probably around 30 pounds of phosphate and 200 or more pounds of potash applied broadcast, preplant, if a forage crop is to be grown. If corn will be grown again, all of the phosphate and 30 to 40 pounds of the potash can be applied as starter fertilizer at planting. Although magnesium, at about 3% of the effective CEC, would be considered low by relying exclusively on a basic cation saturation ratio system recommendation, there is little likelihood of an increase in crop yield or quality by adding magnesium.
- Nitrogen fertilizer is probably needed in large amounts (100 to 130 pounds/acre) for high N-demanding crops, such as corn. If no in-season soil test (like the PSNT) is done, some preplant N should be applied (around 50 pounds/acre), some in the starter band at planting (about 15 pounds/acre) and some side-dressed (about 50 pounds).
- One way to meet the needs of the crop is as follows:
- broadcast 500 pounds per acre of an 11-0-44 bulk blended fertilizer;
- use 300 pounds per acre of a 5-10-10 starter; and
side-dress with 150 pounds per acre of ammonium nitrate.
This will supply approximately 120 pounds of N, 30 pounds of phosphate, and 210 pounds of potash.
Below are helpful fact sheets provided by the 4R Tomorrow Program.