Seed clarity analysis

Seed clarity analysis concept: Seed clarity analysis refers to the determination of the percentage by weight of net seeds, other plant seeds and impurities in the test sample and the characteristics of the test sample mixture, and then the composition of this sample is obtained.

Seed clarity analysis Objective: Through the analysis of the three components of crop net seeds, other plant seeds and impurities, understand the true weight of clean use available in the seed lot and the types and contents of other plant seeds and inanimate impurities, in order to evaluate the seed quality. Provides the basis.

Seeds in the analysis of seed clarity generally refer to crop seeds such as cereals, fibers, oils, etc. The quality standards for these three seeds were raised once in 1996, but the standard requirements are not high, and the degree of clarity in actual work is not. The phenomenon of analysis often exists and it is difficult to integrate with international standards. Thus, in 2008, a series of amendments were made to the original seed quality standards, including individual terms, quality characteristic values, and inspection rules. So far, with regard to the issue of seed quality, there have been relatively strict domestic standards. Seed companies and inspection agencies have begun to pay attention to the issue of seed quality. Seed quality includes the following four parts: clarity, purity, germination rate, and moisture. The analysis of seed's clarity is relatively complex in both operation and calculation. In the following, we will specifically analyze the process and points of attention for the analysis of seed cleanliness.

1. Prepare to master the criteria for identifying net seeds, other plant seeds, and impurities - the key to the analysis of seed's clarity

The key to the analysis of seed clarity is to distinguish net seeds from other plant seeds and impurities. Although there are some rules that can be referenced, we still have to specifically consider the genus or species of seeds for the actual problems we encounter, and then target different species. For different analysis. The following six methods are simply to determine which type of seed is measured. (1) The damaged seed unit is larger than half of the original seed's own size. Although there is no embryo, it is still a net seed, and the other half is less than half of the original seed's own size. Although there are embryos, it should be classified as impurities; (2) Gramineae The net seed of the seed must have endosperm; (3) the structure not described in the net seed definition is classified as impurity, such as peanut husk is classified as impurity; (4) the separation is separated, for example, the length of rice or barley awn exceeds the length of floret, Should be removed as impurities; (5) Damaged seeds that have not apparently injured seed coat or pericarp, whether empty or full, are net seeds or other plant seeds; (6) must quickly determine if the remaining seed units exceed If half of the original size cannot be determined quickly, the seed unit is classified as a net seed or other plant seeds.

2, the correct choice balance

The selection of the balance is also important in the analysis of the seed's clarity, because the weight of each component of the test sample is weighed with a balance, and the precision of the balance must meet certain requirements.

3. Determine the weight of the sample (send sample and clarity sample)

The sent sample is the sample sent to the laboratory, and the clean sample is the sample used for the test item. The quality of these two kinds of samples has a standard requirement and must meet certain requirements. The amount marked in the standard here is the minimum amount, and the difference between them is more than one order of magnitude. The reasons are as follows: (1) The sample size is too small, the sample is inaccurate, and the representativeness is not strong; (2) There must be enough samples to meet the detection of other items, such as germination test; (3) sometimes need to do the second (4) The "Regulations" stipulates that the amount of samples required for the determination of the number of seeds of other plants is large; (5) The test samples need to be separated from a certain number of seeds to keep a growing season in preparation for Review.

4, correctly identify heavy-duty hybrids

Heavy-duty hybrids are those that are significantly different in quality or size from the tested seeds, such as clods, small stones, and the like. This can summarize the characteristics of heavy-duty hybrids: the volume or weight is significantly different from the tested seeds; the clarity analysis results have been seriously affected. Therefore, we must eliminate the heavy-duty mixture before the clarity analysis. On the one hand, it may block the sampler. On the other hand, the clarity analysis results have obvious deviations, affecting the reputation of the company or the interests of consumers.

5, independent sampling test sample

Seed clarity analysis can be performed with one sample (full sample) or two half samples (half sample weight) of the specified weight.

6, a reasonable selection of sieve

Seed clarity analysis of the separation of impurities and other plant seeds through a set of sieves, sets of sieves generally consists of upper and lower two layers, the upper layer is a large hole sieve, the lower layer is a small hole sieve. At the same time, the mesh can be divided into two kinds: round hole and long hole. For different seeds, different sets of sieves can be selected according to the shape and size of the seeds.

7, carefully separate, analyze, identify and calculate the results

After the previous steps of screening, we obtained net seeds, other plant seeds, and impurities. The three seeds were individually filled into containers and weighed using a balance. Then, according to the following steps, calculate the corresponding values: (1) Calculate the sum of the weights of the three components of the net seed, other plant seeds, and impurities after the analysis; (2) Compare the sum of the weights of the three components with the weight of the original sample and check it. During the analysis, whether the loss of material exceeds 5% of the weight of the original sample, which is more than redo; (3) Calculate the weight percentage of the three components. Calculate the sum of the weights of the three components as the denominator. Decimal, semi-sample calculation to two decimal places, the final result is one decimal place; (4) The final result of the 3 components retains a decimal, the sum is 100.0%, less than 0.05% is expressed in “micro”, in the calculation Removed, the result is zero with "-0.0-" said. If the sum of the three components is 99.9% or 100.1%, increase or decrease 0.1% from the maximum component of the net seed component. If the rounding value is greater than 0.1%, check for errors in the calculations; (5) The test results for the netity analysis include the weight percentages of the three components of net seeds, other plant seeds, and impurities. When determining the weight percentage of a certain kind of impurity or a certain other plant seed reaching or exceeding 1.0%, the type should be indicated in the result report.

Figure Seed Clarity Workbench