Solvita® simply explained.

Solvita® is a diagnostic test requiring no prior experience or chemistry skills in order to obtain an accurate and useful result. The kit measures both carbon-dioxide (CO2) and ammonia (NH3) which are the two most common gaseous emissions of composting materials. High rates of emission of either or both gases are indicative an actively degrading compost.

The test results together can be used to obtain a Maturity Index.The concept of a maturity index arose over time based on the widespread experience that using a test for CO2 alone to infer maturity is not as reliable as using a double test.

Solvita is a volumetric procedure. This means, it is measuring respiration per unit volume of compost, and not per unit weight. The advantage of measuring respiration per volume is that the results are immediately relevant for horticultural media and constructed soils  that are interested in optimizing high rates of compost.

Solvita may be used to provide  useful information about the entire composting process. The test is applicable on-site to monitor the process, and for gauging the end  of composting  where CO2 rate and ammonia are expected to have attained low levels.  The test is helpful to infer aeration requirements based on the indicated depletion of oxygen during the test (Version 5 and later).

Solvita Chemistry

Solvita® measures the two chemicals – CO2 and NH3 - which are frequently cited factors of volatile compost emissions. While CO2 is itself odorless and non toxic per se, high CO2-respiration composts are associated with many undesired traits: high-heating potential, odor and oxygen depletion in growing media. Elevated ammonia  may indicate workplace hazard (while turning composts or storing compost indoors), and potential plant damage. High ammonia may also indicate a temporary imbalance in compost C:N (such as when manure or sludge is added to woodchips or sawdust, and the nitrogen component breaks down far faster than the woody part can absorb it). The Solvita® ammonia test may be useful all by itself just to estimate volatile ammonia in manures, sludges and composts.

Woods End’s field research shows that compost that is not fully matured is also unstable, possibly very odorous and is capable of causing depression of plant growth, the latter caused by depletion of soil-pore space oxygen. The Solvita® test used in the proper manner offers a very reliable and important yard stick for factors that may have significant impact on soils and plants.

Solvita® detection is based on a novel, patented gel-colorimetry technique, analogous to Beer-Lambert’s law governing optical-chemical reactions to changing concentrations of dissolved molecules,  carbonic acid and ammonium hydroxide. With the new DCR (digital color reader), the optical properties are measured with more precisions and accuracy (± 0.05 unit).

Each Solvita® Classic kit is furnished with 6 CO2 + 6 NH3 test strips, incubation jars and an instruction manual that provides insight into the compost process and gives guidelines for proper use of compost products at each level of maturity and activity. An upgrade to digital is readily available.

Validation test results for Solvita® have been done by many Universities worldwide over many years, so that currently Solvita is undoubtedly the most widely tested compost and soil-respiration system. Solvita® has been compared favorably to virtually all other compost ”stability” tests. Yet, Solvita differs from a strict lab procedure and can be implemented in the field with similar results. While providing lab quantitation capability, it is therefore broadly meaningful.

For DCR Information:

DCR Information

For Toll-Free
Phone Orders: 1-800-451-0337 or 207 293 2457

fax orders 207 293 2488

ABOUT THE SOLVITA® DIGITAL COLOR READER (DCR) AVAILABLE NOW

Woods End recently announced an innovation making possible more precise color readings of Solvita® kits. A Digital Color Reader (DCR) eliminates the subjectivity of color discrimination and notably improves the scale of readability. With more precise
color readings, a tool approaching quantitative is realized.

The DCR invention is based on modern LED technology, where color wavelengths bounced off the Solvita® gels are measured
by 16-bit micro-arrays and converted into RGB dynamic frequencies, translated directly into color units – equivalent to a handheld spectrophotometer. The DCR increases resolution of perhaps 50-fold to visual estimation of color.

For composters using the DCR, Woods End has added some useful applications. For example, the molar-CO2% can be determined (in the head space), serving to directly indicate oxygen consumption under the conditions of the test (at standard bulk-density). Lab procedures claiming to be “stability” tests are often only reporting laboratory artifacts- by removing the context of volume density and converting results to a gravimetric (weight basis), an interesting a possibly meaningless value is obtained that does not relate to the actual composting practice.

For persons requiring lab certifiable of analyses, it is a good idea to also use a Solvita volume-density test, to see if results are comparable.

In a soon to come update, Solvita-compost will be able to mimic the costly and time consuming lab test for CO2 respiration: if the weight of the compost is taken before the Solvita® test, then the DCR output may be used to obtain respiration in units such as mg CO2-C g TS.

Validation of Solvita® Protocol

Solvita® or compost is the most widely recognized and most validated test for compost respiration.  Independent published reports are listed in this section.

Published Solvita® Comparison
Studies: