Determination of the response of plants in soil improvers and culture substrates. Part 1: Chinese cabbage pot growth test (EN 16086-1: 2011 Standard).
The EN 16086-1 standard describes the procedure to determine the effect of soil improvers and crop substrates or their ingredients using Chinese cabbage (Brassica napa subsp. pekinensis) or with spring barley (Hordeum vulgare), determining the variation in the germination and/or growth of the plant when planted and cultivated in its presence.
The test is carried out in a pot in which the culture substrate under test is dispensed, for a period of time and evaluating the response of the plant through the degree of germination, fresh weight, abnormalities and general growth of the plant. When grass herbicides are suspected, spring barley should be used in addition to Chinese cabbage.
An extract of the original sample obtained with a nutrient solution along 4 hours at room temperature can be used, collecting the drained nutrient solution, in which case the pots are filled with perlite saturated with the extract, watering with the extract and later with water.
The sample under test must be passed through a sieve and any foreign materials (plastics, metals, glass,...) that they may contain must be removed. If there are materials such as coconut fiber or straw, they must be cut using scissors.
The material under test is mixed with sphaganum peat and adjusted to the appropriate pH, adding ground limestone with a minimum size and adjusting the humidity, if necessary. Additionally, a complete fertilizer with essential micronutrients is added.
Each pot is filled with the sample to the brim, compacted and moistened or dried as required after carrying out the corresponding tests. On the sample, in three pots, Chinese cabbage seeds are spread and covered with a thin layer of tiny sample, keeping it between 18ºC and 30ºC, until 50% of the seeds have germinated, with adequate light per day, and humidity. Fertilized sphaganum peat should be used as a control. A germination of 85% should be obtained after 5 days.
At the end of the test, the degree of germination per pot, the average degree of germination and the coefficient of variation, the inhibition of germination, the fresh weight, the average weight in grams of the plants per pot, the average weight of the plants and the coefficient of variation, as well as that of the control sample, and the differences between the control sample and the samples tested. Likewise, the degree of inhibition is calculated by means of the difference in weight of the plants of the control sample and those of the test.
Differences from the control should be described in terms of leaf color and morphology, shoot morphology, root color and morphology, and root mortality.