This standard specifies the method for determining the moisture content of crop seeds. This standard is applicable to the quality testing of crop seeds. GB/T 3543.6-1995 Inspection procedures for crop seeds Determination of moisture content GB/T3543.6-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Rules for agricultural seed testing--- Determination of moisture content
Rules for agricultural seed testing--- Determination of moisture content1 Subject content and scope of application
This standard specifies the method for determining the moisture content of crop seeds. This standard is applicable to the detection of the quality of crop seeds. 2 Reference standards
GB/T3543.2 Rules for the inspection of crop seeds-Sampling 3 Terminology
Moisture content
GB/T 3543.6-1995
Replaces GB3543-83
The weight lost by drying the seed sample according to the prescribed procedure is expressed as the percentage of the weight loss to the original weight of the sample for inspection. 4 Instruments and equipment
Constant temperature oven: equipped with a movable porous wire mesh rack and a thermometer that can measure 0.5℃. a.
Crushing (grinding) machine: equipped with 0.5, 1.0 and 4.0 mm wire sieves. h.
Sample box, dryer, desiccant, etc.
d. Balance: sensitivity reaches 0.001g.
5 Determination procedure
Since free water is easily affected by external environmental conditions, some measures should be taken to prevent water loss as much as possible. For example, the samples to be tested must be placed in a moisture-proof container and the air in it must be removed as much as possible; the samples must be tested immediately after receipt; sampling, grinding and weighing during the determination process must be done quickly; avoid grinding evaporation, etc. The time required for this process of not grinding seeds shall not exceed 2 minutes. 5.1 Low constant temperature drying method
5.1.1 Applicable species
Allium spp., peanuts (Arachis hypogaea), Brassica spp., peppers (Capsicum spp.), soybeans (Glycine mar), cotton (Gossypium spp., sunflowers (Helianthus annuus), flax (linum usitatissimum), scissors (Raphanus sativus), hemp (Ricinus communis), sesame (Sesamum indicum), eggplant (Solanum melongena). This method must be carried out indoors with a relative humidity below 70%. 5.1.2 Sampling and grinding
The samples submitted for moisture determination must meet the requirements of GB/T3543.2. Use one of the following methods to mix thoroughly and take 15~25g of the sample submitted for testing.
Stir in the sample jar with a spoon.
GB/T3543.6--1995
b. Align the mouth of the original sample jar to the mouth of another empty jar of the same size, and pour the seeds back and forth between the two containers. See Table 1 for the types of seeds that must be ground before drying and the grinding fineness. Table 1 Types of seeds that must be ground and the grinding fineness Crop types
Avena spp.
Rice (Oryza sativa L.)
Fagopyrum esculentum,Fagopyrum tataricum
Rye (Secale cereale)
Sorghum spp.
Triticum spp.
Rice (Zea mays)
Soybean (Glycine mar)
Phaseotus spp.
Pea (Pisum sativum)
Citrullus lanatus
Vicia spp.
Gossypium spp.
Peanut (Arachis hypogaea)
Hemp (Ricinus communis)
Grinding fineness
At least 50% of the ground components pass through a wire sieve with a mesh size of 0.5 mm, and no more than 10% remain on a wire sieve with a mesh size of 1.0 mm. Coarse grinding is required, and at least 50% of the ground components pass through a 4.0 mm mesh. Grind or slice.
Two repeated independent test samples are required for determination. The distribution of the test sample in the sample box must not exceed 0.3 g per square centimeter.
Do not touch the seeds directly with your hands when sampling, but use a spoon or shovel. 5.1.3 Drying and weighing
Pre-dry, cool, and weigh the sample box, and record the box number. Take two samples (the ground seeds should be taken from different parts), each 4.5~~5.0 g, put the sample into the pre-dried and weighed sample box, and then weigh it (accurate to 0.001g). Preheat the oven to 110~115℃, spread the sample flat and put it in the upper layer of the oven, with the sample box about 2.5cm away from the mercury ball of the thermometer, and quickly close the oven door. When the oven temperature rises to 103±2℃ within 5~10min, start counting the time, and bake for 8h. Cover the box with tongs or gloves (cover the box), take it out and put it in a desiccator to cool to room temperature, and weigh it after about 30~45min. 5.2 High temperature baking method
Applicable to the following seed types: celery (Apium graveolens), asparagus (Asparagus officinalis), oats (Avenas spp.), beets (Beta ulgaris), watermelons (Citrullus lanatus), melons (Cucumis spp.), pumpkins (Cucurbita spp.), carrots (Daucus carota), sweet buckwheat (Fagopyrum esculentum), bitter buckwheat (Fagopyrum tataricum), barley (Hordeum vulgare), lettuce (Lactuca sativa), tomatoes (Lycopersicon lycopersicum), mosses (Medicago spp.), coconut palms (Melilotus spp.), tobacco (Nicotiana tabacum), rice (Oryza sativa), millet (Panicum spp.), beans (Phase-olus spp.), peas (Pisum sativum), onion (Scorzonera hispanica), rye (Secale cereale), Setaria spp., sorghum spp., spinach (Spinacia oleracea), wheat (Triticum spp.), vetch (Vicia spp.), corn (Zea mays).
The procedure is the same as the low constant temperature drying method. The types of seeds that must be ground and the grinding fineness are shown in Table 1. First, preheat the oven to 140~145℃. After opening the oven door for 5~10min, the oven temperature must be maintained at 130~133℃. The sample drying time is 1h.
5.3 High-moisture pre-drying method
GB/T 3543.6—1995
For seeds that need to be ground, if the moisture content of cereal seeds exceeds 18%, and the moisture content of beans and oil crops exceeds 16%, the pre-drying method must be used.
Weigh two samples of 25.00±0.02g each, place them in a sample box with a diameter greater than 8cm, and pre-dry them in an oven at 103±2C for 30min (oil seeds are pre-dried at 70℃ for 1h). After taking them out, cool them at room temperature and weigh them. Immediately thereafter, grind the two semi-dried samples separately, and take a sample of each of the grinded materials for determination according to the method specified in Article 5.1 or 5.2. 6 Calculation of results
6.1 Calculation of results
Calculate the percentage of seed moisture according to the weight lost after drying, and calculate to one decimal place according to formula (1): M. -M×100
Seed moisture (%) III
Where: M-
weight of sample box and cover, g;
weight of sample box, cover and sample before drying, g; M
weight of sample box, cover and sample after drying, g. Mwww.bzxz.net
M2 Mi
If the pre-drying method is used, the original moisture of the sample can be converted from the moisture results calculated by the above formula for the first (pre-drying) and the second time, and calculated according to formula (2).
S,X S2
Seed moisture (%)=S,+S2
Where: S1—moisture loss of whole seeds after the first drying, %; S——moisture loss of ground seeds after the second drying, %. 6.2 Tolerance
· (2)
If the difference between two measurements of a sample does not exceed 0.2%, the result can be expressed as the arithmetic mean of the two measurement values. If not, repeat the two measurements.
7 Result Report
The result shall be reported in the specified space on the test result report with an accuracy of 0.1%. Additional Notes:
This standard was proposed by the Ministry of Agriculture of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Standardization of Crop Seeds. This standard was drafted by the National Seed Station, Zhejiang Agricultural University, Sichuan Province, Heilongjiang Province, Tianjin Seed Company (Station), Nanjing Agricultural University, Beijing, Hunan Seed Company. The main drafters of this standard are Zhi Juzhen, Bi Xinhua, Du Kemin, Chang Xiulan, Yang Shuhui, Ren Shuping, Wu Zhixing, Li Renfeng, Zhao Juying. This standard was first issued in March 1983.
This standard refers to the International Seed Inspection Procedure (ISTA, 1993 edition) Part 9 Moisture Determination.
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