SU116573A1 - Method for colorimetric determination of nitrogen, phosphorus and potassium in plants - Google Patents

Description

Methods are known for determining the content of nitrogen, phosphorus and potassium in plants by comparing the intensity of staining of chemically treated samples with the previously prepared empirical scale of solution colors, corresponding to their true value of the content of the substance to be determined (the so-called colorimetric methods of analysis).

The proposed method favorably differs from those known for their simplicity and versatility.

Instead of preliminary preparation of the sample for analysis by grinding or squeezing the juice, or wet burning it, practiced in the known methods, the proposed method produces a thin cross section from a plant organ that is treated with appropriate chemical ingredients. In this case, an insignificant amount of the sample is required; any parts of a living plant can be analyzed without any appreciable damage to the plant as a whole (for example, part of a branch, leaf, flower, etc.), while other known methods of analysis require significant (by weight) of the sample quantity and even quite often whole plants, which is associated with the destruction of the latter.

For the purpose of rapid and mass determination of plant enrichment by the main nutrient pathways: nitrogen, phosphorus and potassium and a solution of the need and extent of fertilizer application, a method for analyzing plants available to any laboratory and agronome is proposed.

A cross section (piece) of a stem, leaf cutting, or other part of a plant, made with a razor or sharp knife, is used to determine nitrates on glass, and to determine phosphorus and potassium filter paper (in the case of phosphorus, the paper is pre-saturated with ammonium tibdate) then the slice is applied to cap. No. 116573-2 -

Relevant reagents: for the determination of nitrates - diphenylamine, phosphorus - benzidine and sodium acetate, potassium - dipicrylamine and hydrochloric acid. After treatment with these reagents, the sections are stained. The intensity of the color, which indicates the amount of the analyte, is compared with the color chart, which gives an indication of the degree of plant endowment with a particular nutrient element and the need for fertilizer.

The performance of the proposed method is not less than one hundred definitions per day per person. The method can be used to analyze any plants and any parts of them.

All necessary reagents, utensils and materials are mounted in one box, convenient not only for laboratory but also for field conditions.

The photo shows a general view of the field laboratory for the analysis of plants, in which six droppers / with reagents are placed, bottle 2 with water, scale 3 standards. In the bottom case 4 there are: a glass compartment 5 and phosphorus filter paper (pre-saturated with ammonium molybdate); in compartment 6, filter paper for analysis of potassium; in compartment 7, glasses for analyzing nitrates; in the front long compartment 8 - razor, lancet, tweezers and glass sticks-pestles

The proposed method is suitable both for practical agronomists and agrochemists of MTS, as well as for research work, especially in field expeditionary conditions.

Subject invention

Claims (2)

1. A method for colorimetric determination of nitrogen, phosphorus and potassium in a plant, characterized in that, in order to diagnose the nutritional regime of plants based on the rapid determination of reserve quantities of nitrogen, phosphorus and potassium in a living plant, from a stem, stem, leaf or other part of a plant make a cross-section, put it on glass or filter paper and treat with one drop of a chemical reagent, after which according to the intensity of the color of the slice, compared with a standard scale of colors characterizing the formation of reserve forms of nutrients, judging plant needs for nutrients. 2. A method according to claim 1, characterized in that for determining the nitrogen content, the slice placed on the glass is treated with diphenylamine, to determine the phosphorus content, the slice placed on the filter paper pre-soaked with ammonium molybdate is treated with benzidine and sodium acetate, To determine the potassium content, the slice placed on clean filter paper is treated with dipicrylamine and hydrochloric acid.