Responses of Greenhouse‐grown Cannabis sativa L. to Nitrogen, Phosphorus, and Potassium¹

Abstract

Growers of illegal Cannabis sativa L. use various cultural practices to maximize crop production. The objective of this study was to evaluate the morphological and biochemical responses of greenhouse grown C. sativa to soil incorporated N, P, and K as they reflect the geographical origin of Cannabis derivatives. Fertilizers were blended with Ap horizon soil from a Gilpin silt loam before placement in 12‐cm pots. NH4NO3‐N was applied at 0, 25, and 125 ppm. Phosphorus and K from super‐phosphate and KCI, respectively, were applied at 0, 50, and 150 ppm. Forty‐five‐day‐old anthesic Cannabis plants were harvested and combined leaf and flower tissues were analyzed for cannabidiol (CBD) and Δ9‐tetrahydrocanna‐binol (Δ9THC). Nine essential elements were also measured in plant tissue. Plant growth, tissue yield, and concentration of CBD and Δ9THC were positively correlated with extractable P2O5 (p < 0.01). Phosphorus concentrations in tissue were similarly related to yield of dry matter and cannabinoid concentrations. Uptake of K was positively correlated with extractable K2O across all treatment levels (r=0.40**), but was negatively correlated with tissue yield (r=‐‐0.36**). Growth and tissue yields were negatively related to total plant N (p< 0.01). Levels of extractable P2O5, Mn, B, and Mg were associated with specific concentration ranges for several plant elements plus Δ9THC. Thus, it was possible to partially characterize a soil by tissue analysis. For example, all of the plants grown on soil with less than 100 ppm of extractable P2O5 contained less than 8,000 ppm Δ9THC. Usefulness of such relationships will be dependent upon extensive evaluation of Cannabis on different soils under various cultural conditions. At this time, the reliability required for determination of origin of Canabis derivatives via chemical analysis does not exist when only essential elements and cannabinoids are considered.

Multivariate classification based on chemical and stable isotopic profiles in sourcing the origin of marijuana samples seized in Brazil

“…The results of all set of elements are listed in Table 3 together with the data obtained from literature where by comparison the Brazilian samples presented high Fe, Sr and Ba levels and low concentrations of Mo and Cu. 8,9 It can be observed that nutrient contents in samples from Region 1 (Mato Grosso do Sul) were high, mainly for Cu and Fe. Aluminium, Ga and Ba levels were also higher than those for the other groups (Table 3).…”

“…38 In comparison to the literature data, Cu and Zn concentrations for these samples were similar to those obtained by Landi,14 although lower than those presented by Coffman and Gentner. 9 It is well known that Zn deficiency is the most generalized and critical in those regions and is probably related to the composition of the parent material. 38 The Mo value in Cannabis samples was also lower than those available in the literature, which may point out to a deficiency of this element in the soil.…”

“…8 Lately, the same authors evaluated the chemical composition (nutrients and cannabinoids levels) of plants cultivated using mineral fertilizers. 9 Although some correlations were noted, the data gathered did not prove conclusive to track the geographical origin of these samples due to the large quantity of related parameters. 9 The nutrient profile determined by atomic absorption spectrometry technique associated to linear discriminant analysis were used by Landi 14 in classifying samples from different regions of Italy, previously separated in inflorescences and leaves.…”

“…9 Although some correlations were noted, the data gathered did not prove conclusive to track the geographical origin of these samples due to the large quantity of related parameters. 9 The nutrient profile determined by atomic absorption spectrometry technique associated to linear discriminant analysis were used by Landi 14 in classifying samples from different regions of Italy, previously separated in inflorescences and leaves. Although 100% of inflorescences samples were successfully classified, according to the author the methodology did not prove itself potentially viable in the analysis of real samples due to the complexity of the problem.…”

“…This fingerprint can be established using samples organic, [8][9][10][11] inorganic 6,[12][13][14][15][16][17][18][19] or isotopic [20][21][22][23][24] profiles which are related to the plant growth conditions such as climatic conditions and elements availability in the soil. Although each one of these strategies provide very interesting and powerful results, the use of a set of variables independents from each other would be able to provides complementary information which could make it a distinct feature in the sourcing their origins.…”