Improved simple on-site soil quality testing for soils in the Intermountain West

View the project final report

Commodities

• Fruits: apples, apricots, cherries, peaches, pears, plums, general tree fruits

Practices

• Education and Training: demonstration, mentoring
• Soil Management: earthworms, soil analysis, soil quality/health

Farmers would benefit from knowing whether their management practices are aggrading or degrading their soils. Soil quality problems such as soil loss, depleted soil organic matter, nutrient reserves, and reduced water holding capacity are of increasing concern to farmers in the Intermountain West. Marginal soils require more amendments and fertilizers to meet crop needs. As input costs rise and water resources become increasingly limited, effective methods of evaluating soil quality and fertility is of growing importance. Attempts in making soil quality assessments more available to farmers have had limited success. Standard commercial tests typically quantify soil nitrogen (N), phosphorus (P), potassium (K), pH, and salinity. While these tests are important, they do not address physical or biological aspects of soil fertility. As comprehensive soil quality testing is not routine, tests are not always available and, when they are, prices are often prohibitive. Even if a grower does obtain results on soil quality, results can be time consuming and confusing to interpret. Other attempts in improving farmer access to soil quality assessment include soil health cards and soil test kits. Neither of these have been widely adopted by farmers, likely due to the farmer’s conception of them being too subjective, time-consuming, or technical. The objective of this research is to identify a subset of user-friendly tests that are most indicative of soil quality on farms in the Intermountain West. Indicative on-site soil tests will be used to measure aggregate stability, water infiltration, decomposition rates, macroflora, macronutrients, and pH, then compared to comparable lab analyses. Soil samples will be collected from two experimental peach orchards located on the Utah State University Research farm in Kaysville, Utah. The orchards consist of 12 replicated orchard floor treatments with documented differences in soil quality. The goal of this study is to increase the participatory role of farmers in the maintenance and health of their soils, which could potentially reduce nutrient overload, soil erosion, and degradation of ecosystem services on and off-site

The overall goal of this research is to find or create reliable soil tests that farmers can easily do themselves. A shortlist of the most indicative in-field soil tests will be compiled and tested by growers for ease of use.

1.  Compare results of simple soil testing strategies to comparable standard lab tests

There are limited studies that have compared the effectiveness of on-site soil quality tests, and no studies specifically done in Utah. Chemical fertility tests will be compared among different brands and price ranges. Physical soil quality tests will also be compared to comparable lab tests. On-site soil tests have largely neglected the biological component of soil. The two most common tests are soil respiration and earthworm counts. Other biological on-site tests will be measured and compared to these tests. Currently most field tests tend to be most helpful for extension personnel; less so for the general public. In order for the tests to gain trust from farmers and others, these tests need to compare favorably to their lab counterparts.

2.  Determine the most predictive soil quality tests by comparing results to an existing database collected from the Kaysville systems orchards.

It is not only important for the tests to compare well to lab measures, but they must also be predictive of overall soil quality. We will use an existing orchard with twelve different orchard floor management treatments and existing documented differences in soil quality.

The tests most predictive of overall soil quality and tree growth will be presented and demonstrated to farmers. On-site soil testing information is generally extensive and confusing to sift through. Therefore, a very useful compilation would be a short list of easy tests

3.  Conduct onsite training sessions with growers to determine usefulness of the tests in a range of field settings.

This objective will ensure that the tests are easy to use and are applicable across a range of farms. The more farmers able to test them and the more sites that the tests are tested on, the greater the applicability and likelihood they will be adopted.

4.  Collect feedback from growers on ease of use and applicability.

In order for this study to be best suited to growers and their needs, the study needs to involve the growers every step of the way. Tests will be modified or others selected based on this feedback. It is important that these tests are adapted to those who will benefit most by their application.