A method for sampling and detecting soil in agricultural land

Abstract

A method for sampling and detecting soil for agricultural land, belonging to the field of detection technology, the method includes sampling, sampling, pretreatment, digestion, sample preparation, detection, comparison and judgment of accuracy, comparison and judgment of soil component changes, etc. The sampling and detection method of the present invention is aimed at agricultural soil, changes the traditional simple soil sampling method, and improves the accuracy of soil detection through multi-point depth sampling, single-point sample and combined sample comparison detection, and adopts a rapid digestion method, that is, two vacuum immersions, microwave digestion and then evaporation to block, evaporation to block in order to reorganize the binding of soil particles, the purpose of crushing is to re-cut the soil particle size and form a new surface; after the microwave digestion of the first crushed particle surface, the second new crushed particle surface digestion is carried out to achieve more complete digestion, improve the digestion degree and detection accuracy, achieve the effect of rapid and accurate testing, and provide effective judgment value.

Description

Technical Field

[0001] The invention belongs to the field of detection technology, and in particular relates to a method for sampling and detecting agricultural land soil. Background Art

[0002] Agricultural land refers to land used directly or indirectly for agricultural production. Among them, cultivated land is the main agricultural land. The cultivated land standards require the unity of environmental, social, economic, ecological and other benefits in order to maintain a virtuous cycle and sustainable use.

[0003] Soil nutrients determine the sustainable utilization efficiency of arable land, as well as the types of crops that can be planted on the arable land and the growth conditions of the crops.

[0004] Soil element detection is an important part of soil nutrient evaluation. The accuracy of soil sampling and detection directly affects soil evaluation, which is related to the amount of fertilizer applied to crops and the selection of crop varieties.

[0005] Traditional soil sampling methods are simple and single, which affects the accuracy of test results and affects the overall judgment to a certain extent.

[0006] In addition, the degree of soil digestion treatment also determines the accuracy of element detection results. Currently, the main methods of soil digestion include wet digestion, microwave digestion, high-pressure digestion and alkaline digestion.

[0007] In this regard, CN107462690A discloses a soil detection method and its application, wherein soil samples are weighed and placed in a digestion device, nitric acid and hydrofluoric acid are added, and then microwave digestion is performed, and an acid solution is added, heated to dissolve, constant volume is added, and detection is performed. The measurement results of this digestion method are closer to the true value, and the standard deviation is about 5-15%.

[0008] CN109975101A discloses a soil detection method, which comprises adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 to the soil, stirring for 10 to 20 minutes to mix evenly, and then performing microwave digestion. After that, the digested sample is cooled to room temperature, and then evaporated to dryness at 150°C. Finally, a hydrochloric acid solution is added, heated to dissolve, fixed to volume, and detected. The standard deviation value of the test result is reduced to within 5%.

[0009] Although the above two digestion methods combine acid and microwave thermal dissolution, they cannot determine the sampling reliability of soil samples, and therefore cannot guarantee the accuracy of the test results and provide a reference value for judgment; and the digestion process takes a long time and is not suitable for rapid detection and comparison, which affects the detection efficiency. Summary of the invention

[0010] In view of the defects of the existing soil sampling and detection technology, such as the inability to judge the sampling reliability of soil samples, the inability of test results to give accurate reference values, the long digestion process time, the unsuitability for rapid detection and comparison, and the low efficiency, the present invention provides a method for sampling and detecting agricultural land soil. For agricultural soil, the traditional simple soil sampling method is changed, and the accuracy of soil detection is improved by multi-point depth sampling, single-point sample and combined sample comparison detection, and the rapid digestion method is adopted to improve the detection efficiency, so as to achieve the effect of rapid and accurate testing and provide effective judgment value. The specific technical scheme is as follows:

[0011] A method for sampling and detecting agricultural land soil comprises the following steps:

[0012] Step 1, sampling:

[0013] (1) Sampling before crop planting:

[0014] For three-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 1 was 1 / 2 times the ridge height, sampling point 2 was 1 times the ridge height, and sampling point 3 was 1.5 times the ridge height;

[0015] For two-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 4 was the ridge surface, and sampling point 5 was 1 times the ridge depth;

[0016] (2) Sampling during the growth period after crop planting:

[0017] Two-point slope sampling, the sampler is inserted obliquely into the slope between the ridge platform and the furrow, and the sampling depths are: sampling point 6 is 1 times the height of the ridge platform, and sampling point 7 is 1.5 times the height of the ridge platform;

[0018] Step 2, sample division:

[0019] The soil at sampling point 1 is sample 1, the soil at sampling point 2 is sample 2, the soil at sampling point 3 is sample 3, the soil at sampling point 4 is sample 4, the soil at sampling point 5 is sample 5, the soil at sampling point 6 is sample 6, the soil at sampling point 7 is sample 7, the soils at sampling point 1, sampling point 2 and sampling point 3 are mixed into sample 8, the soils at sampling point 4 and sampling point 5 are mixed into sample 9, and the soils at sampling point 6 and sampling point 7 are mixed into sample 10;

[0020] Step 3, preprocessing:

[0021] Samples 1 to 10 were dried to remove moisture, and then agglomerated and crushed;

[0022] Step 4, digestion:

[0023] (1) Weighing powders of samples 1 to 10 respectively, adding a mixed acid solution of nitric acid and hydrochloric acid, soaking for 5 to 10 minutes under vacuum conditions, then performing microwave digestion for 5 to 10 minutes, and finally evaporating to a block to obtain a block A;

[0024] (2) then crushing the block A, adding a mixed acid solution of nitric acid and hydrochloric acid for the second time, soaking for 5 to 10 minutes under vacuum conditions, then performing microwave digestion for 5 to 10 minutes, and finally evaporating to a block to obtain a block B;

[0025] Step 5, sample preparation:

[0026] The block B is crushed, the crushed powder is accurately weighed, and a hydrochloric acid solution is added, and the mixture is heated and dissolved at 130 to 150° C. for 10 to 15 minutes, and finally diluted and fixed to volume to obtain fixed-volume samples 1 to 10;

[0027] Step 6, detection:

[0028] Using inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry or flame atomic absorption spectrophotometry to perform qualitative or quantitative detection of elements, and obtain the detection results of samples 1 to 10;

[0029] Step 7: Compare and judge the accuracy:

[0030] Compare the test results of samples 1 to 10, wherein the test results of samples 1, 2, 3 and 8 are compared to determine the test accuracy; the test results of samples 4, 5 and 9 are compared to determine the test accuracy; the test results of samples 6, 7 and 10 are compared to determine the test accuracy;

[0031] Step 8: Compare and judge the changes in soil composition:

[0032] Calculate the average m of the results of samples 1, 2, 3 and 8, calculate the average n of the results of samples 6, 7 and 10, and calculate the average w of the results of samples 4, 5 and 9; compare m with n to determine the changes in soil composition during crop growth; compare m with w to determine the extent of the impact of water loss on soil composition.

[0033] In step 1 of the above technical solution, the sampling is performed using a sampler. Before the sampler is inserted into the sampling point, the sampling port is closed. When the depth of the sampling point is reached, the sampling port is controlled to be opened for sampling, and then the sampling port is controlled to be closed and the sampler is pulled out. The sampler is provided with a depth scale.

[0034] In the above technical solution, the pulverization is performed using a small-sized Chinese medicine pulverizer.

[0035] In step 2 of the above technical solution, the soils from sampling points 1, 2 and 3 are mixed in a mass ratio of 1:1:1 to form sample 8, the soils from sampling points 4 and 5 are mixed in a mass ratio of 1:1 to form sample 9, and the soils from sampling points 6 and 7 are mixed in a mass ratio of 1:1 to form sample 10.

[0036] In step 3 of the above technical solution, the particle size of the crushed particles is below 800 nm.

[0037] In step 4 (1) of the above technical solution, the mixed acid solution is nitric acid and hydrochloric acid in a volume ratio of 5:1, and the mixed acid solution is added in a ratio of 5 to 15 ml / g.

[0038] In step 4 (2) of the above technical solution, the particle size of the crushed particles is below 800 nm.

[0039] In step 4 (2) of the above technical solution, the mixed acid solution is a mixture of nitric acid and hydrochloric acid in a volume ratio of 5:1, and the mixed acid solution is added in a ratio of 5 to 15 ml / g.

[0040] In step 5 of the above technical solution, the particle size of the crushed particles is below 800 nm.

[0041] In step 5 of the above technical solution, the hydrochloric acid solution is a 15% hydrochloric acid solution, and the addition ratio of the hydrochloric acid solution is 10 to 15 mL / g.

[0042] Compared with the prior art, the agricultural land soil sampling and detection method of the present invention has the following beneficial effects:

[0043] 1. The present invention uses a fixed-point sampler for sampling, which ensures accurate and pollution-free sampling, prevents poor contamination between sample points, and ensures more accurate test results.

[0044] Second, the sampling point depth selection of the present invention is around the crop root range, which can more accurately judge the change of soil composition during the crop growth cycle or after soil erosion.

[0045] 3. The sample separation method of the present invention compares each sampling point and performs mixed comparison, which can better determine whether the test result is accurate and effectively determine the relative deviation of the result.

[0046] Fourth, the present invention pre-treats the soil sample and grinds it to a particle size of less than 800 nm after drying, which can remove moisture and facilitate grinding to a required particle size. A particle size of less than 800 nm can facilitate subsequent complete digestion.

[0047] 5. The present invention adopts two vacuum immersions, microwave digestion and then evaporation to blocks. The purpose of evaporation to blocks is to reorganize the binding properties of soil particles. The purpose of crushing is to re-cut the soil particle size and form a new surface. After the microwave digestion of the first crushed particle surface, the second new crushed particle surface digestion is carried out to achieve more complete digestion and improve detection accuracy.

[0048] 6. The third crushing particle size is below 800nm. On the one hand, a new surface is formed by mechanical cutting to promote hydrochloric acid digestion. On the other hand, the small particle size promotes more complete constant volume dissolution and dispersion, thereby improving detection accuracy.

[0049] 7. The present invention adds less acid each time. For particles with a size below 800 nm, a small amount of acid is sufficient to dissolve the particle surface, thus saving acid usage. In addition, a small amount of acid can speed up the evaporation speed, quickly form agglomerates, and reduce pollution.

[0050] 8. The method of the present invention compares the test results of samples 1 to 10, wherein the test results of samples 1, 2, 3 and 8 are compared to determine the test accuracy; the test results of samples 4, 5 and 9 are compared to determine the test accuracy; the test results of samples 6, 7 and 10 are compared to determine the test accuracy; this sample comparison makes the data more reliable and can provide an effective basis for judging soil composition and predicting the amount of fertilizer to be applied.

[0051] 9. The method of the present invention calculates the average m of the results of samples 1, 2, 3 and 8, calculates the average n of the results of samples 6, 7 and 10, and calculates the average w of the results of samples 4, 5 and 9; compares m with n to determine the changes in soil composition during crop growth; compares m with w to determine the degree of influence of water loss on soil composition; provides an effective basis for the prognosis of crop extension growth, and is particularly suitable for experimental field research and development analysis.

[0052] 10. The present invention samples crops during the growth period after planting, and adopts inclined surface insertion sampling, which does not damage the roots and stems of crops and is safe and reliable.

[0053] In summary, the present invention changes the traditional simple soil sampling method for agricultural soil, improves the accuracy of soil detection through multi-point depth sampling, and comparative detection of single-point samples and combined samples. The detection method has an overall fast digestion speed, is convenient for rapid detection, improves detection efficiency, achieves fast and accurate testing results, and provides effective judgment value. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A schematic diagram of sampling points before crop planting in a method for sampling and detecting agricultural land soil of the present invention, wherein: 1-sampling point 1, 2-sampling point 2, 3-sampling point 3, 4-sampling point 4, 5-sampling point 5;

[0055] Figure 2 This is a schematic diagram of sampling points during the growth period after crop planting in a method for sampling and detecting agricultural land soil of the present invention, wherein: 6 refers to sampling point 6, and 7 refers to sampling point 7. DETAILED DESCRIPTION

[0056] The following is a combination of specific implementation cases and attached Figure 1-2 The present invention is further described below, but the present invention is not limited to these embodiments.

[0057] Example 1

[0058] A method for sampling and detecting agricultural land soil comprises the following steps:

[0059] Step 1, sampling:

[0060] (1) Sampling before crop planting:

[0061] For three-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 1 was 1 / 2 times the ridge height, sampling point 2 was 1 times the ridge height, and sampling point 3 was 1.5 times the ridge height. Figure 1 As shown;

[0062] For two-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 4 was the ridge surface, sampling point 5 was 1 times the ridge depth; Figure 1 As shown;

[0063] (2) Sampling during the growth period after crop planting:

[0064] Two-point slope sampling, the sampler is inserted obliquely into the slope between the ridge platform and the ridge ditch, and the sampling depths are: sampling point 6 is 1 times the height of the ridge platform, and sampling point 7 is 1.5 times the height of the ridge platform; Figure 2 As shown;

[0065] The sampling is performed using a sampler. Before the sampler is inserted into the sampling point, the sampling port is closed. When the sampling point depth is reached, the sampling port is controlled to be opened for sampling. Then, the sampling port is controlled to be closed and the sampler is withdrawn. The sampler is provided with a depth scale.

[0066] Step 2, sample division:

[0067] The soil at sampling point 1 is sample 1, the soil at sampling point 2 is sample 2, the soil at sampling point 3 is sample 3, the soil at sampling point 4 is sample 4, the soil at sampling point 5 is sample 5, the soil at sampling point 6 is sample 6, the soil at sampling point 7 is sample 7, the soils at sampling point 1, sampling point 2 and sampling point 3 are mixed in a mass ratio of 1:1:1 to form sample 8, the soils at sampling point 4 and sampling point 5 are mixed in a mass ratio of 1:1 to form sample 9, and the soils at sampling point 6 and sampling point 7 are mixed in a mass ratio of 1:1 to form sample 10;

[0068] Step 3, preprocessing:

[0069] Samples 1 to 10 were dried to remove moisture, and then agglomerated and crushed to a particle size of less than 700 nm;

[0070] Step 4, digestion:

[0071] (1) Weighing powders of samples 1 to 10 respectively, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 at a ratio of 15 ml / g, soaking for 10 min under vacuum conditions, then performing microwave digestion for 5 min, and finally evaporating to a block to obtain a block A;

[0072] (2) then crushing the block A to a particle size of less than 700 nm, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 for the second time at a ratio of 15 ml / g, soaking for 10 min under vacuum conditions, then performing microwave digestion for 5 min, and finally evaporating to a block to obtain a block B;

[0073] Step 5, sample preparation:

[0074] The block B was crushed to a particle size of less than 700 nm, the crushed powder was accurately weighed, 15% hydrochloric acid solution was added at a ratio of 15 mL / g, and heated to dissolve at 130° C. for 15 min, and finally diluted and fixed to volume to obtain fixed-volume samples 1 to 10;

[0075] Step 6, detection:

[0076] Using inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry or flame atomic absorption spectrophotometry to perform qualitative or quantitative detection of elements, and obtain the detection results of samples 1 to 10;

[0077] Step 7: Compare and judge the accuracy:

[0078] Compare the test results of samples 1 to 10, wherein the test results of samples 1, 2, 3 and 8 are compared to determine the test accuracy; the test results of samples 4, 5 and 9 are compared to determine the test accuracy; the test results of samples 6, 7 and 10 are compared to determine the test accuracy;

[0079] Step 8: Compare and judge the changes in soil composition:

[0080] Calculate the average m of the results of samples 1, 2, 3 and 8, calculate the average n of the results of samples 6, 7 and 10, and calculate the average w of the results of samples 4, 5 and 9; compare m with n to determine the changes in soil composition during crop growth; compare m with w to determine the degree of influence of water loss on soil composition;

[0081] In the method of this embodiment, a small-sized Chinese medicine grinder is used to grind the sample.

[0082] In this embodiment, FP640 flame photometer is used to detect samples from a test field, and the potassium content of sample 1 is 123.2 mg / kg, the potassium content of sample 2 is 123.9 mg / kg, the potassium content of sample 3 is 124.2 mg / kg, the potassium content of sample 4 is 122.8 mg / kg, the potassium content of sample 5 is 124.0 mg / kg, the potassium content of sample 6 is 80.4 mg / kg, the potassium content of sample 7 is 85.6 mg / kg, the potassium content of sample 8 is 123.8 mg / kg, the potassium content of sample 9 is 123.4 mg / kg, and the potassium content of sample 10 is 83.0 mg / kg; the average number m of the results of sample 1, sample 2, sample 3 and sample 8 is calculated to be 123.8 mg / kg; the average number n of the results of sample 6, sample 7 and sample 10 is calculated to be 83.0 mg / kg; the average number w of the results of sample 4, sample 5 and sample 9 is calculated to be 123.4 mg / kg.

[0083] By comparing the results, it can be seen that the detection accuracy is very high. The amount of potassium consumed during the crop growth stage and rainwater in the ridge ditch will cause a certain amount of potassium loss. According to the loss and growth consumption, a reference basis is provided for the planned amount of fertilizer.

[0084] Example 2

[0085] A method for sampling and detecting agricultural land soil comprises the following steps:

[0086] Step 1, sampling:

[0087] (1) Sampling before crop planting:

[0088] For three-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 1 was 1 / 2 times the ridge height, sampling point 2 was 1 times the ridge height, and sampling point 3 was 1.5 times the ridge height. Figure 1 As shown;

[0089] For two-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 4 was the ridge surface, sampling point 5 was 1 times the ridge depth; Figure 1 As shown;

[0090] (2) Sampling during the growth period after crop planting:

[0091] Two-point slope sampling, the sampler is inserted obliquely into the slope between the ridge platform and the ridge ditch, and the sampling depths are: sampling point 6 is 1 times the height of the ridge platform, and sampling point 7 is 1.5 times the height of the ridge platform; Figure 2 As shown;

[0092] The sampling is performed using a sampler. Before the sampler is inserted into the sampling point, the sampling port is closed. When the sampling point depth is reached, the sampling port is controlled to be opened for sampling. Then, the sampling port is controlled to be closed and the sampler is withdrawn. The sampler is provided with a depth scale.

[0093] Step 2, sample division:

[0094] The soil at sampling point 1 is sample 1, the soil at sampling point 2 is sample 2, the soil at sampling point 3 is sample 3, the soil at sampling point 4 is sample 4, the soil at sampling point 5 is sample 5, the soil at sampling point 6 is sample 6, the soil at sampling point 7 is sample 7, the soils at sampling point 1, sampling point 2 and sampling point 3 are mixed in a mass ratio of 1:1:1 to form sample 8, the soils at sampling point 4 and sampling point 5 are mixed in a mass ratio of 1:1 to form sample 9, and the soils at sampling point 6 and sampling point 7 are mixed in a mass ratio of 1:1 to form sample 10;

[0095] Step 3, preprocessing:

[0096] Samples 1 to 10 were dried to remove moisture, and then agglomerated and crushed to a particle size of less than 500 nm;

[0097] Step 4, digestion:

[0098] (1) Weighing powders of samples 1 to 10 respectively, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 at a ratio of 10 ml / g, soaking for 5 min under vacuum conditions, then performing microwave digestion for 10 min, and finally evaporating to a block to obtain a block A;

[0099] (2) then crushing the block A to a particle size of less than 500 nm, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 for the second time at a ratio of 10 ml / g, soaking for 5 min under vacuum conditions, then performing microwave digestion for 10 min, and finally evaporating to a block to obtain a block B;

[0100] Step 5, sample preparation:

[0101] The block B was crushed to a particle size of less than 500 nm, the crushed powder was accurately weighed, 15% hydrochloric acid solution was added at a ratio of 10 mL / g, and the mixture was heated and dissolved at 150° C. for 12 min, and finally diluted and fixed to volume to obtain fixed-volume samples 1 to 10;

[0102] Step 6, detection:

[0103] Using inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry or flame atomic absorption spectrophotometry to perform qualitative or quantitative detection of elements, and obtain the detection results of samples 1 to 10;

[0104] Step 7: Compare and judge the accuracy:

[0105] Compare the test results of samples 1 to 10, wherein the test results of samples 1, 2, 3 and 8 are compared to determine the test accuracy; the test results of samples 4, 5 and 9 are compared to determine the test accuracy; the test results of samples 6, 7 and 10 are compared to determine the test accuracy;

[0106] Step 8: Compare and judge the changes in soil composition:

[0107] Calculate the average m of the results of samples 1, 2, 3 and 8, calculate the average n of the results of samples 6, 7 and 10, and calculate the average w of the results of samples 4, 5 and 9; compare m with n to determine the changes in soil composition during crop growth; compare m with w to determine the degree of influence of water loss on soil composition;

[0108] In the method of this embodiment, a small-sized Chinese medicine grinder is used to grind the sample.

[0109] In this embodiment, the available phosphorus in the soil of a certain test field sample is detected by using an N2S visible spectrophotometer, and the phosphorus content of sample 1 is 50.6 mg / kg, the phosphorus content of sample 2 is 50.9 mg / kg, the phosphorus content of sample 3 is 49.2 mg / kg, the phosphorus content of sample 4 is 50.1 mg / kg, the phosphorus content of sample 5 is 49.6 mg / kg, the phosphorus content of sample 6 is 38.2 mg / kg, the phosphorus content of sample 7 is 37.5 mg / kg, the phosphorus content of sample 8 is 50.2 mg / kg, the phosphorus content of sample 9 is 49.7 mg / kg, and the phosphorus content of sample 10 is 37.9 mg / kg; the average number m of the results of sample 1, sample 2, sample 3 and sample 8 is calculated to be 50.2 mg / kg; the average number n of the results of sample 6, sample 7 and sample 10 is calculated to be 37.9 mg / kg; the average number w of the results of sample 4, sample 5 and sample 9 is calculated to be 49.7 mg / kg.

[0110] By comparing the results, it can be seen that the detection accuracy is very high. The amount of phosphorus consumed during the crop growth stage and rainwater in the ridge ditch will cause a certain loss of phosphorus. According to the loss and growth consumption, a reference basis is provided for the planned amount of fertilizer.

[0111] Example 3

[0112] A method for sampling and detecting agricultural land soil comprises the following steps:

[0113] Step 1, sampling:

[0114] (1) Sampling before crop planting:

[0115] For three-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 1 was 1 / 2 times the ridge height, sampling point 2 was 1 times the ridge height, and sampling point 3 was 1.5 times the ridge height. Figure 1 As shown;

[0116] For two-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 4 was the ridge surface, sampling point 5 was 1 times the ridge depth; Figure 1 As shown;

[0117] (2) Sampling during the growth period after crop planting:

[0118] Two-point slope sampling, the sampler is inserted obliquely into the slope between the ridge platform and the ridge ditch, and the sampling depths are: sampling point 6 is 1 times the height of the ridge platform, and sampling point 7 is 1.5 times the height of the ridge platform; Figure 2 As shown;

[0119] The sampling is performed using a sampler. Before the sampler is inserted into the sampling point, the sampling port is closed. When the sampling point depth is reached, the sampling port is controlled to be opened for sampling. Then, the sampling port is controlled to be closed and the sampler is withdrawn. The sampler is provided with a depth scale.

[0120] Step 2, sample division:

[0121] The soil at sampling point 1 is sample 1, the soil at sampling point 2 is sample 2, the soil at sampling point 3 is sample 3, the soil at sampling point 4 is sample 4, the soil at sampling point 5 is sample 5, the soil at sampling point 6 is sample 6, the soil at sampling point 7 is sample 7, the soils at sampling point 1, sampling point 2 and sampling point 3 are mixed in a mass ratio of 1:1:1 to form sample 8, the soils at sampling point 4 and sampling point 5 are mixed in a mass ratio of 1:1 to form sample 9, and the soils at sampling point 6 and sampling point 7 are mixed in a mass ratio of 1:1 to form sample 10;

[0122] Step 3, preprocessing:

[0123] Samples 1 to 10 were dried to remove moisture, and then agglomerated and crushed to a particle size of less than 600 nm;

[0124] Step 4, digestion:

[0125] (1) Weighing powders of samples 1 to 10 respectively, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 at a ratio of 8 ml / g, soaking for 6 min under vacuum conditions, then performing microwave digestion for 8 min, and finally evaporating to a block to obtain a block A;

[0126] (2) then crushing the block A to a particle size of less than 800 nm, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 for the second time at a ratio of 8 ml / g, soaking for 6 min under vacuum conditions, then performing microwave digestion for 8 min, and finally evaporating to a block to obtain a block B;

[0127] Step 5, sample preparation:

[0128] The block B was crushed to a particle size of less than 600 nm, the crushed powder was accurately weighed, 15% hydrochloric acid solution was added at a ratio of 12 mL / g, and heated to dissolve at 140°C for 12 min, and finally diluted and fixed to volume to obtain fixed-volume samples 1 to 10;

[0129] Step 6, detection:

[0130] Using inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry or flame atomic absorption spectrophotometry to perform qualitative or quantitative detection of elements, and obtain the detection results of samples 1 to 10;

[0131] Step 7: Compare and judge the accuracy:

[0132] Compare the test results of samples 1 to 10, wherein the test results of samples 1, 2, 3 and 8 are compared to determine the test accuracy; the test results of samples 4, 5 and 9 are compared to determine the test accuracy; the test results of samples 6, 7 and 10 are compared to determine the test accuracy;

[0133] Step 8: Compare and judge the changes in soil composition:

[0134] Calculate the average m of the results of samples 1, 2, 3 and 8, calculate the average n of the results of samples 6, 7 and 10, and calculate the average w of the results of samples 4, 5 and 9; compare m with n to determine the changes in soil composition during crop growth; compare m with w to determine the degree of influence of water loss on soil composition;

[0135] In the method of this embodiment, a small-sized Chinese medicine grinder is used to grind the sample.

[0136] In this embodiment, FP640 flame photometer is used to detect soil samples from cultivated land in a certain village, and the potassium content of sample 1 is 98.2 mg / kg, the potassium content of sample 2 is 98.6 mg / kg, the potassium content of sample 3 is 98.1 mg / kg, the potassium content of sample 4 is 97.5 mg / kg, the potassium content of sample 5 is 98.1 mg / kg, the potassium content of sample 6 is 71.8 mg / kg, the potassium content of sample 7 is 72.1 mg / kg, the potassium content of sample 8 is 98.3 mg / kg, the potassium content of sample 9 is 97.8 mg / kg, and the potassium content of sample 10 is 72.0 mg / kg; the average number m of the results of sample 1, sample 2, sample 3 and sample 8 is calculated to be 98.3 mg / kg; the average number n of the results of sample 6, sample 7 and sample 10 is calculated to be 72.0 mg / kg; the average number w of the results of sample 4, sample 5 and sample 9 is calculated to be 97.8 mg / kg.

[0137] By comparing the results, it can be seen that the detection accuracy is very high. The amount of potassium consumed during the crop growth stage and rainwater in the ridge ditch will cause a certain amount of potassium loss. According to the loss and growth consumption, a reference basis is provided for the planned amount of fertilizer.

[0138] Example 4

[0139] A method for sampling and detecting agricultural land soil comprises the following steps:

[0140] Step 1, sampling:

[0141] (1) Sampling before crop planting:

[0142] For three-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 1 was 1 / 2 times the ridge height, sampling point 2 was 1 times the ridge height, and sampling point 3 was 1.5 times the ridge height. Figure 1 As shown;

[0143] For two-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 4 was the ridge surface, sampling point 5 was 1 times the ridge depth; Figure 1 As shown;

[0144] (2) Sampling during the growth period after crop planting:

[0145] Two-point slope sampling, the sampler is inserted obliquely into the slope between the ridge platform and the ridge ditch, and the sampling depths are: sampling point 6 is 1 times the height of the ridge platform, and sampling point 7 is 1.5 times the height of the ridge platform; Figure 2 As shown;

[0146] The sampling is performed using a sampler. Before the sampler is inserted into the sampling point, the sampling port is closed. When the sampling point depth is reached, the sampling port is controlled to be opened for sampling. Then, the sampling port is controlled to be closed and the sampler is withdrawn. The sampler is provided with a depth scale.

[0147] Step 2, sample division:

[0148] The soil at sampling point 1 is sample 1, the soil at sampling point 2 is sample 2, the soil at sampling point 3 is sample 3, the soil at sampling point 4 is sample 4, the soil at sampling point 5 is sample 5, the soil at sampling point 6 is sample 6, the soil at sampling point 7 is sample 7, the soils at sampling point 1, sampling point 2 and sampling point 3 are mixed in a mass ratio of 1:1:1 to form sample 8, the soils at sampling point 4 and sampling point 5 are mixed in a mass ratio of 1:1 to form sample 9, and the soils at sampling point 6 and sampling point 7 are mixed in a mass ratio of 1:1 to form sample 10;

[0149] Step 3, preprocessing:

[0150] Samples 1 to 10 were dried to remove moisture, and then agglomerated and crushed to a particle size of less than 500 nm;

[0151] Step 4, digestion:

[0152] (1) Weighing powders of samples 1 to 10 respectively, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 at a ratio of 5 ml / g, soaking for 5 min under vacuum conditions, then performing microwave digestion for 8 min, and finally evaporating to a block to obtain a block A;

[0153] (2) then crushing the block A to a particle size of less than 500 nm, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 for the second time at a ratio of 5 ml / g, soaking for 5 min under vacuum conditions, then performing microwave digestion for 8 min, and finally evaporating to a block to obtain a block B;

[0154] Step 5, sample preparation:

[0155] The block B was crushed to a particle size of less than 500 nm, the crushed powder was accurately weighed, 15% hydrochloric acid solution was added at a ratio of 10 mL / g, and heated to dissolve at 135°C for 10 min, and finally diluted and fixed to volume to obtain fixed-volume samples 1 to 10;

[0156] Step 6, detection:

[0157] Using inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry or flame atomic absorption spectrophotometry to perform qualitative or quantitative detection of elements, and obtain the detection results of samples 1 to 10;

[0158] Step 7: Compare and judge the accuracy:

[0159] Compare the test results of samples 1 to 10, wherein the test results of samples 1, 2, 3 and 8 are compared to determine the test accuracy; the test results of samples 4, 5 and 9 are compared to determine the test accuracy; the test results of samples 6, 7 and 10 are compared to determine the test accuracy;

[0160] Step 8: Compare and judge the changes in soil composition:

[0161] Calculate the average m of the results of samples 1, 2, 3 and 8, calculate the average n of the results of samples 6, 7 and 10, and calculate the average w of the results of samples 4, 5 and 9; compare m with n to determine the changes in soil composition during crop growth; compare m with w to determine the degree of influence of water loss on soil composition;

[0162] In the method of this embodiment, a small-sized Chinese medicine grinder is used to grind the sample.

[0163] In this embodiment, FP640 flame photometer is used to detect soil samples from cultivated land in a certain village, and the potassium content of sample 1, sample 2, sample 3, sample 3, sample 4, sample 4, sample 5, sample 5, sample 6, sample 6, sample 7, sample 7, sample 7, sample 8, sample 9, sample 9, sample 10, sample 10, sample 10, potassium content 79.0 mg / kg; the average m of the results of sample 1, sample 2, sample 3 and sample 8 is calculated to be 103.9 mg / kg; the average n of the results of sample 6, sample 7 and sample 10 is calculated to be 79.0 mg / kg; the average w of the results of sample 4, sample 5 and sample 9 is calculated to be 103.4 mg / kg.

[0164] By comparing the results, it can be seen that the detection accuracy is very high. The amount of potassium consumed during the crop growth stage and rainwater in the ridge ditch will cause a certain amount of potassium loss. According to the loss and growth consumption, a reference basis is provided for the planned amount of fertilizer.

[0165] Example 5

[0166] A method for sampling and detecting agricultural land soil comprises the following steps:

[0167] Step 1, sampling:

[0168] (1) Sampling before crop planting:

[0169] For three-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 1 was 1 / 2 times the ridge height, sampling point 2 was 1 times the ridge height, and sampling point 3 was 1.5 times the ridge height. Figure 1 As shown;

[0170] For two-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 4 was the ridge surface, sampling point 5 was 1 times the ridge depth; Figure 1 As shown;

[0171] (2) Sampling during the growth period after crop planting:

[0172] Two-point slope sampling, the sampler is inserted obliquely into the slope between the ridge platform and the ridge ditch, and the sampling depths are: sampling point 6 is 1 times the height of the ridge platform, and sampling point 7 is 1.5 times the height of the ridge platform; Figure 2 As shown;

[0173] The sampling is performed using a sampler. Before the sampler is inserted into the sampling point, the sampling port is closed. When the sampling point depth is reached, the sampling port is controlled to be opened for sampling. Then, the sampling port is controlled to be closed and the sampler is withdrawn. The sampler is provided with a depth scale.

[0174] Step 2, sample division:

[0175] The soil at sampling point 1 is sample 1, the soil at sampling point 2 is sample 2, the soil at sampling point 3 is sample 3, the soil at sampling point 4 is sample 4, the soil at sampling point 5 is sample 5, the soil at sampling point 6 is sample 6, the soil at sampling point 7 is sample 7, the soils at sampling point 1, sampling point 2 and sampling point 3 are mixed in a mass ratio of 1:1:1 to form sample 8, the soils at sampling point 4 and sampling point 5 are mixed in a mass ratio of 1:1 to form sample 9, and the soils at sampling point 6 and sampling point 7 are mixed in a mass ratio of 1:1 to form sample 10;

[0176] Step 3, preprocessing:

[0177] Samples 1 to 10 were dried to remove moisture, and then agglomerated and crushed to a particle size of less than 800 nm;

[0178] Step 4, digestion:

[0179] (1) Weighing powders of samples 1 to 10 respectively, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 at a ratio of 12 ml / g, soaking for 6 min under vacuum conditions, then performing microwave digestion for 8 min, and finally evaporating to a block to obtain a block A;

[0180] (2) then crushing the block A to a particle size of less than 800 nm, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 for the second time at a ratio of 12 ml / g, soaking for 6 min under vacuum conditions, then performing microwave digestion for 8 min, and finally evaporating to a block to obtain a block B;

[0181] Step 5, sample preparation:

[0182] The block B was crushed to a particle size of less than 800 nm, the crushed powder was accurately weighed, 15% hydrochloric acid solution was added at a ratio of 10 mL / g, and heated to dissolve at 145°C for 10 min, and finally diluted and fixed to volume to obtain fixed-volume samples 1 to 10;

[0183] Step 6, detection:

[0184] Using inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry or flame atomic absorption spectrophotometry to perform qualitative or quantitative detection of elements, and obtain the detection results of samples 1 to 10;

[0185] Step 7: Compare and judge the accuracy:

[0186] Compare the test results of samples 1 to 10, wherein the test results of samples 1, 2, 3 and 8 are compared to determine the test accuracy; the test results of samples 4, 5 and 9 are compared to determine the test accuracy; the test results of samples 6, 7 and 10 are compared to determine the test accuracy;

[0187] Step 8: Compare and judge the changes in soil composition:

[0188] Calculate the average m of the results of samples 1, 2, 3 and 8, calculate the average n of the results of samples 6, 7 and 10, and calculate the average w of the results of samples 4, 5 and 9; compare m with n to determine the changes in soil composition during crop growth; compare m with w to determine the degree of influence of water loss on soil composition;

[0189] In the method of this embodiment, a small-sized Chinese medicine grinder is used to grind the sample.

[0190] In this embodiment, the available phosphorus in the cultivated soil of a certain village is detected by using N2S visible spectrophotometer, and the phosphorus content of sample 1 is 45.3 mg / kg, the phosphorus content of sample 2 is 46.2 mg / kg, the phosphorus content of sample 3 is 45.8 mg / kg, the phosphorus content of sample 4 is 45.5 mg / kg, the phosphorus content of sample 5 is 45.7 mg / kg, the phosphorus content of sample 6 is 30.2 mg / kg, the phosphorus content of sample 7 is 31.2 mg / kg, the phosphorus content of sample 8 is 45.8 mg / kg, the phosphorus content of sample 9 is 45.6 mg / kg, and the phosphorus content of sample 10 is 30.7 mg / kg; the average number m of the results of sample 1, sample 2, sample 3 and sample 8 is calculated to be 45.8 mg / kg; the average number n of the results of sample 6, sample 7 and sample 10 is calculated to be 30.7 mg / kg; the average number w of the results of sample 4, sample 5 and sample 9 is calculated to be 45.6 mg / kg.

[0191] By comparing the results, it can be seen that the detection accuracy is very high. The amount of phosphorus consumed during the crop growth stage and rainwater in the ridge ditch will cause a certain loss of phosphorus. According to the loss and growth consumption, a reference basis is provided for the planned amount of fertilizer.

[0192] Example 6

[0193] A method for sampling and detecting agricultural land soil comprises the following steps:

[0194] Step 1, sampling:

[0195] (1) Sampling before crop planting:

[0196] For three-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 1 was 1 / 2 times the ridge height, sampling point 2 was 1 times the ridge height, and sampling point 3 was 1.5 times the ridge height. Figure 1 As shown;

[0197] For two-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 4 was the ridge surface, sampling point 5 was 1 times the ridge depth; Figure 1 As shown;

[0198] (2) Sampling during the growth period after crop planting:

[0199] Two-point slope sampling, the sampler is inserted obliquely into the slope between the ridge platform and the ridge ditch, and the sampling depths are: sampling point 6 is 1 times the height of the ridge platform, and sampling point 7 is 1.5 times the height of the ridge platform; Figure 2 As shown;

[0200] The sampling is performed using a sampler. Before the sampler is inserted into the sampling point, the sampling port is closed. When the sampling point depth is reached, the sampling port is controlled to be opened for sampling. Then, the sampling port is controlled to be closed and the sampler is withdrawn. The sampler is provided with a depth scale.

[0201] Step 2, sample division:

[0202] The soil at sampling point 1 is sample 1, the soil at sampling point 2 is sample 2, the soil at sampling point 3 is sample 3, the soil at sampling point 4 is sample 4, the soil at sampling point 5 is sample 5, the soil at sampling point 6 is sample 6, the soil at sampling point 7 is sample 7, the soils at sampling point 1, sampling point 2 and sampling point 3 are mixed in a mass ratio of 1:1:1 to form sample 8, the soils at sampling point 4 and sampling point 5 are mixed in a mass ratio of 1:1 to form sample 9, and the soils at sampling point 6 and sampling point 7 are mixed in a mass ratio of 1:1 to form sample 10;

[0203] Step 3, preprocessing:

[0204] Samples 1 to 10 were dried to remove moisture, and then agglomerated and crushed to a particle size of less than 600 nm;

[0205] Step 4, digestion:

[0206] (1) Weighing powders of samples 1 to 10 respectively, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 at a ratio of 15 ml / g, soaking for 10 min under vacuum conditions, then performing microwave digestion for 10 min, and finally evaporating to a block to obtain a block A;

[0207] (2) then crushing the block A to a particle size of less than 600 nm, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 for the second time at a ratio of 15 ml / g, soaking for 10 min under vacuum conditions, then performing microwave digestion for 10 min, and finally evaporating to a block to obtain a block B;

[0208] Step 5, sample preparation:

[0209] The block B was crushed to a particle size of less than 800 nm, the crushed powder was accurately weighed, 15% hydrochloric acid solution was added at a ratio of 15 mL / g, and heated to dissolve at 130° C. for 15 min, and finally diluted and fixed to volume to obtain fixed-volume samples 1 to 10;

[0210] Step 6, detection:

[0211] Using inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry or flame atomic absorption spectrophotometry to perform qualitative or quantitative detection of elements, and obtain the detection results of samples 1 to 10;

[0212] Step 7: Compare and judge the accuracy:

[0213] Compare the test results of samples 1 to 10, wherein the test results of samples 1, 2, 3 and 8 are compared to determine the test accuracy; the test results of samples 4, 5 and 9 are compared to determine the test accuracy; the test results of samples 6, 7 and 10 are compared to determine the test accuracy;

[0214] Step 8: Compare and judge the changes in soil composition:

[0215] Calculate the average m of the results of samples 1, 2, 3 and 8, calculate the average n of the results of samples 6, 7 and 10, and calculate the average w of the results of samples 4, 5 and 9; compare m with n to determine the changes in soil composition during crop growth; compare m with w to determine the degree of influence of water loss on soil composition;

[0216] In the method of this embodiment, a small-sized Chinese medicine grinder is used to grind the sample.

[0217] In this embodiment, FP640 flame photometer is used to detect soil samples from cultivated land in a certain village, and the potassium content of sample 1 is 84.6 mg / kg, the potassium content of sample 2 is 85.1 mg / kg, the potassium content of sample 3 is 84.9 mg / kg, the potassium content of sample 4 is 82.6 mg / kg, the potassium content of sample 5 is 83.4 mg / kg, the potassium content of sample 6 is 61.2 mg / kg, the potassium content of sample 7 is 60.6 mg / kg, the potassium content of sample 8 is 84.9 mg / kg, the potassium content of sample 9 is 83.0 mg / kg, and the potassium content of sample 10 is 60.9 mg / kg; the average number m of the results of sample 1, sample 2, sample 3 and sample 8 is calculated to be 84.9 mg / kg; the average number n of the results of sample 6, sample 7 and sample 10 is calculated to be 60.9 mg / kg; the average number w of the results of sample 4, sample 5 and sample 9 is calculated to be 83.0 mg / kg.

[0218] By comparing the results, it can be seen that the detection accuracy is very high. The amount of potassium consumed during the crop growth stage and rainwater in the ridge ditch will cause a certain amount of potassium loss. According to the loss and growth consumption, a reference basis is provided for the planned amount of fertilizer.

[0219] Example 7

[0220] A method for sampling and detecting agricultural land soil comprises the following steps:

[0221] Step 1, sampling:

[0222] (1) Sampling before crop planting:

[0223] For three-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 1 was 1 / 2 times the ridge height, sampling point 2 was 1 times the ridge height, and sampling point 3 was 1.5 times the ridge height. Figure 1 As shown;

[0224] For two-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 4 was the ridge surface, sampling point 5 was 1 times the ridge depth; Figure 1 As shown;

[0225] (2) Sampling during the growth period after crop planting:

[0226] Two-point slope sampling, the sampler is inserted obliquely into the slope between the ridge platform and the ridge ditch, and the sampling depths are: sampling point 6 is 1 times the height of the ridge platform, and sampling point 7 is 1.5 times the height of the ridge platform; Figure 2 As shown;

[0227] The sampling is performed using a sampler. Before the sampler is inserted into the sampling point, the sampling port is closed. When the sampling point depth is reached, the sampling port is controlled to be opened for sampling. Then, the sampling port is controlled to be closed and the sampler is withdrawn. The sampler is provided with a depth scale.

[0228] Step 2, sample division:

[0229] The soil at sampling point 1 is sample 1, the soil at sampling point 2 is sample 2, the soil at sampling point 3 is sample 3, the soil at sampling point 4 is sample 4, the soil at sampling point 5 is sample 5, the soil at sampling point 6 is sample 6, the soil at sampling point 7 is sample 7, the soils at sampling point 1, sampling point 2 and sampling point 3 are mixed in a mass ratio of 1:1:1 to form sample 8, the soils at sampling point 4 and sampling point 5 are mixed in a mass ratio of 1:1 to form sample 9, and the soils at sampling point 6 and sampling point 7 are mixed in a mass ratio of 1:1 to form sample 10;

[0230] Step 3, preprocessing:

[0231] Samples 1 to 10 were dried to remove moisture, and then agglomerated and crushed to a particle size of less than 800 nm;

[0232] Step 4, digestion:

[0233] (1) Weighing powders of samples 1 to 10 respectively, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 at a ratio of 5 ml / g, soaking for 5 min under vacuum conditions, then performing microwave digestion for 5 min, and finally evaporating to a block to obtain a block A;

[0234] (2) then crushing the block A to a particle size of less than 800 nm, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 for the second time at a ratio of 5 ml / g, soaking for 5 min under vacuum conditions, then performing microwave digestion for 5 min, and finally evaporating to a block to obtain a block B;

[0235] Step 5, sample preparation:

[0236] The block B was crushed to a particle size of less than 800 nm, the crushed powder was accurately weighed, 15% hydrochloric acid solution was added at a ratio of 10 mL / g, and heated to dissolve at 140° C. for 15 min, and finally diluted and fixed to volume to obtain fixed-volume samples 1 to 10;

[0237] Step 6, detection:

[0238] Using inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry or flame atomic absorption spectrophotometry to perform qualitative or quantitative detection of elements, and obtain the detection results of samples 1 to 10;

[0239] Step 7: Compare and judge the accuracy:

[0240] Compare the test results of samples 1 to 10, wherein the test results of samples 1, 2, 3 and 8 are compared to determine the test accuracy; the test results of samples 4, 5 and 9 are compared to determine the test accuracy; the test results of samples 6, 7 and 10 are compared to determine the test accuracy;

[0241] Step 8: Compare and judge the changes in soil composition:

[0242] Calculate the average m of the results of samples 1, 2, 3 and 8, calculate the average n of the results of samples 6, 7 and 10, and calculate the average w of the results of samples 4, 5 and 9; compare m with n to determine the changes in soil composition during crop growth; compare m with w to determine the degree of influence of water loss on soil composition;

[0243] In the method of this embodiment, a small-sized Chinese medicine grinder is used to grind the sample.

[0244] In this embodiment, FP640 flame photometer is used to detect soil samples from cultivated land in a certain village, and the potassium content of sample 1 is 94.3 mg / kg, the potassium content of sample 2 is 94.6 mg / kg, the potassium content of sample 3 is 93.5 mg / kg, the potassium content of sample 4 is 92.8 mg / kg, the potassium content of sample 5 is 93.1 mg / kg, the potassium content of sample 6 is 68.2 mg / kg, the potassium content of sample 7 is 69.5 mg / kg, the potassium content of sample 8 is 94.1 mg / kg, the potassium content of sample 9 is 92.9 mg / kg, and the potassium content of sample 10 is 68.8 mg / kg; the average number m of the results of sample 1, sample 2, sample 3 and sample 8 is calculated to be 94.1 mg / kg; the average number n of the results of sample 6, sample 7 and sample 10 is calculated to be 68.8 mg / kg; the average number w of the results of sample 4, sample 5 and sample 9 is calculated to be 92.9 mg / kg.

[0245] By comparing the results, it can be seen that the detection accuracy is very high. The amount of potassium consumed during the crop growth stage and rainwater in the ridge ditch will cause a certain amount of potassium loss. According to the loss and growth consumption, a reference basis is provided for the planned amount of fertilizer.

[0246] Example 8

[0247] A method for sampling and detecting agricultural land soil comprises the following steps:

[0248] Step 1, sampling:

[0249] (1) Sampling before crop planting:

[0250] For three-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 1 was 1 / 2 times the ridge height, sampling point 2 was 1 times the ridge height, and sampling point 3 was 1.5 times the ridge height. Figure 1 As shown;

[0251] For two-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 4 was the ridge surface, sampling point 5 was 1 times the ridge depth; Figure 1 As shown;

[0252] (2) Sampling during the growth period after crop planting:

[0253] Two-point slope sampling, the sampler is inserted obliquely into the slope between the ridge platform and the ridge ditch, and the sampling depths are: sampling point 6 is 1 times the height of the ridge platform, and sampling point 7 is 1.5 times the height of the ridge platform; Figure 2 As shown;

[0254] The sampling is performed using a sampler. Before the sampler is inserted into the sampling point, the sampling port is closed. When the sampling point depth is reached, the sampling port is controlled to be opened for sampling. Then, the sampling port is controlled to be closed and the sampler is withdrawn. The sampler is provided with a depth scale.

[0255] Step 2, sample division:

[0256] The soil at sampling point 1 is sample 1, the soil at sampling point 2 is sample 2, the soil at sampling point 3 is sample 3, the soil at sampling point 4 is sample 4, the soil at sampling point 5 is sample 5, the soil at sampling point 6 is sample 6, the soil at sampling point 7 is sample 7, the soils at sampling point 1, sampling point 2 and sampling point 3 are mixed in a mass ratio of 1:1:1 to form sample 8, the soils at sampling point 4 and sampling point 5 are mixed in a mass ratio of 1:1 to form sample 9, and the soils at sampling point 6 and sampling point 7 are mixed in a mass ratio of 1:1 to form sample 10;

[0257] Step 3, preprocessing:

[0258] Samples 1 to 10 were dried to remove moisture, and then agglomerated and crushed to a particle size of less than 600 nm;

[0259] Step 4, digestion:

[0260] (1) Weighing powders of samples 1 to 10 respectively, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 at a ratio of 12 ml / g, soaking for 9 minutes under vacuum conditions, then performing microwave digestion for 9 minutes, and finally evaporating to a block to obtain a block A;

[0261] (2) Then the block A was crushed to a particle size of less than 600 nm, and a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 was added for the second time at a ratio of 12 ml / g, and the mixture was soaked under vacuum conditions for 9 minutes, and then microwave digested for 9 minutes, and finally evaporated to a block to obtain a block B;

[0262] Step 5, sample preparation:

[0263] The block B was crushed to a particle size of less than 600 nm, the crushed powder was accurately weighed, 15% hydrochloric acid solution was added at a ratio of 12 mL / g, and heated to dissolve at 130° C. for 13 min, and finally diluted and fixed to volume to obtain fixed-volume samples 1 to 10;

[0264] Step 6, detection:

[0265] Using inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry or flame atomic absorption spectrophotometry to perform qualitative or quantitative detection of elements, and obtain the detection results of samples 1 to 10;

[0266] Step 7: Compare and judge the accuracy:

[0267] Compare the test results of samples 1 to 10, wherein the test results of samples 1, 2, 3 and 8 are compared to determine the test accuracy; the test results of samples 4, 5 and 9 are compared to determine the test accuracy; the test results of samples 6, 7 and 10 are compared to determine the test accuracy;

[0268] Step 8: Compare and judge the changes in soil composition:

[0269] Calculate the average m of the results of samples 1, 2, 3 and 8, calculate the average n of the results of samples 6, 7 and 10, and calculate the average w of the results of samples 4, 5 and 9; compare m with n to determine the changes in soil composition during crop growth; compare m with w to determine the degree of influence of water loss on soil composition;

[0270] In the method of this embodiment, a small-sized Chinese medicine grinder is used to grind the sample.

[0271] In this embodiment, the available phosphorus in the agricultural soil of a certain village is detected by using N2S visible spectrophotometer, and the phosphorus content of sample 1 is 35.2 mg / kg, the phosphorus content of sample 2 is 35.8 mg / kg, the phosphorus content of sample 3 is 34.6 mg / kg, the phosphorus content of sample 4 is 34.8 mg / kg, the phosphorus content of sample 5 is 35.1 mg / kg, the phosphorus content of sample 6 is 18.6 mg / kg, the phosphorus content of sample 7 is 19.2 mg / kg, the phosphorus content of sample 8 is 35.2 mg / kg, the phosphorus content of sample 9 is 35.0 mg / kg, and the phosphorus content of sample 10 is 18.9 mg / kg; the average number m of the results of sample 1, sample 2, sample 3 and sample 8 is calculated to be 35.2 mg / kg; the average number n of the results of sample 6, sample 7 and sample 10 is calculated to be 18.9 mg / kg; the average number w of the results of sample 4, sample 5 and sample 9 is calculated to be 35.0 mg / kg.

[0272] By comparing the results, it can be seen that the detection accuracy is very high. The amount of phosphorus consumed during the crop growth stage and rainwater in the ridge ditch will cause a certain loss of phosphorus. According to the loss and growth consumption, a reference basis is provided for the planned amount of fertilizer.

[0273] Example 9

[0274] A method for sampling and detecting agricultural land soil comprises the following steps:

[0275] Step 1, sampling:

[0276] (1) Sampling before crop planting:

[0277] For three-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 1 was 1 / 2 times the ridge height, sampling point 2 was 1 times the ridge height, and sampling point 3 was 1.5 times the ridge height. Figure 1 As shown;

[0278] For two-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 4 was the ridge surface, sampling point 5 was 1 times the ridge depth; Figure 1 As shown;

[0279] (2) Sampling during the growth period after crop planting:

[0280] Two-point slope sampling, the sampler is inserted obliquely into the slope between the ridge platform and the ridge ditch, and the sampling depths are: sampling point 6 is 1 times the height of the ridge platform, and sampling point 7 is 1.5 times the height of the ridge platform; Figure 2 As shown;

[0281] The sampling is performed using a sampler. Before the sampler is inserted into the sampling point, the sampling port is closed. When the sampling point depth is reached, the sampling port is controlled to be opened for sampling. Then, the sampling port is controlled to be closed and the sampler is withdrawn. The sampler is provided with a depth scale.

[0282] Step 2, sample division:

[0283] The soil at sampling point 1 is sample 1, the soil at sampling point 2 is sample 2, the soil at sampling point 3 is sample 3, the soil at sampling point 4 is sample 4, the soil at sampling point 5 is sample 5, the soil at sampling point 6 is sample 6, the soil at sampling point 7 is sample 7, the soils at sampling point 1, sampling point 2 and sampling point 3 are mixed in a mass ratio of 1:1:1 to form sample 8, the soils at sampling point 4 and sampling point 5 are mixed in a mass ratio of 1:1 to form sample 9, and the soils at sampling point 6 and sampling point 7 are mixed in a mass ratio of 1:1 to form sample 10;

[0284] Step 3, preprocessing:

[0285] Samples 1 to 10 were dried to remove moisture, and then agglomerated and crushed to a particle size of less than 700 nm;

[0286] Step 4, digestion:

[0287] (1) Weighing powders of samples 1 to 10 respectively, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 at a ratio of 10 ml / g, soaking for 10 min under vacuum conditions, then performing microwave digestion for 10 min, and finally evaporating to a block to obtain a block A;

[0288] (2) then crushing the block A to a particle size of less than 700 nm, adding a mixed acid solution of nitric acid and hydrochloric acid in a volume ratio of 5:1 for the second time at a ratio of 10 ml / g, soaking for 10 min under vacuum conditions, then performing microwave digestion for 10 min, and finally evaporating to a block to obtain a block B;

[0289] Step 5, sample preparation:

[0290] The block B was crushed to a particle size of less than 700 nm, the crushed powder was accurately weighed, 15% hydrochloric acid solution was added at a ratio of 10 mL / g, and heated to dissolve at 130° C. for 10 min, and finally diluted and fixed to volume to obtain fixed-volume samples 1 to 10;

[0291] Step 6, detection:

[0292] Using inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry or flame atomic absorption spectrophotometry to perform qualitative or quantitative detection of elements, and obtain the detection results of samples 1 to 10;

[0293] Step 7: Compare and judge the accuracy:

[0294] Compare the test results of samples 1 to 10, wherein the test results of samples 1, 2, 3 and 8 are compared to determine the test accuracy; the test results of samples 4, 5 and 9 are compared to determine the test accuracy; the test results of samples 6, 7 and 10 are compared to determine the test accuracy;

[0295] Step 8: Compare and judge the changes in soil composition:

[0296] Calculate the average m of the results of samples 1, 2, 3 and 8, calculate the average n of the results of samples 6, 7 and 10, and calculate the average w of the results of samples 4, 5 and 9; compare m with n to determine the changes in soil composition during crop growth; compare m with w to determine the degree of influence of water loss on soil composition;

[0297] In the method of this embodiment, a small-sized Chinese medicine grinder is used to grind the sample.

[0298] In this embodiment, FP640 flame photometer is used to detect soil samples from cultivated land in a certain village, and the potassium content of sample 1, sample 2, sample 3, sample 3, sample 4, sample 4, sample 5, sample 5, sample 6, sample 6, sample 7, sample 7, sample 8, sample 9, sample 9, sample 10, sample 10, potassium content, 96.1 mg / kg; the average m of the results of sample 1, sample 2, sample 3 and sample 8 is calculated to be 133.6 mg / kg; the average n of the results of sample 6, sample 7 and sample 10 is calculated to be 96.1 mg / kg; the average w of the results of sample 4, sample 5 and sample 9 is calculated to be 126.8 mg / kg.

[0299] By comparing the results, it can be seen that the detection accuracy is very high. The amount of potassium consumed during the crop growth stage and rainwater in the ridge ditch will cause a certain amount of potassium loss. According to the loss and growth consumption, a reference basis is provided for the planned amount of fertilizer.

Claims

1. A method for sampling and detecting agricultural land soil, characterized in that: The steps include: Step 1, sampling: (1) Sampling before crop planting: For three-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 1 was 1 / 2 times the ridge height, sampling point 2 was 1 times the ridge height, and sampling point 3 was 1.5 times the ridge height; For two-point ridge sampling, the sampler was inserted vertically into the center of the ridge, and the sampling depths were: sampling point 4 was the ridge surface, and sampling point 5 was 1 times the ridge depth; (2) Sampling during the growth period after crop planting: Two-point slope sampling, the sampler is inserted obliquely into the slope between the ridge platform and the furrow, and the sampling depths are: sampling point 6 is 1 times the height of the ridge platform, and sampling point 7 is 1.5 times the height of the ridge platform; Step 2, sample division: The soil at sampling point 1 is sample 1, the soil at sampling point 2 is sample 2, the soil at sampling point 3 is sample 3, the soil at sampling point 4 is sample 4, the soil at sampling point 5 is sample 5, the soil at sampling point 6 is sample 6, the soil at sampling point 7 is sample 7, the soils at sampling point 1, sampling point 2 and sampling point 3 are mixed in a mass ratio of 1:1:1 to form sample 8, the soils at sampling point 4 and sampling point 5 are mixed in a mass ratio of 1:1 to form sample 9, and the soils at sampling point 6 and sampling point 7 are mixed in a mass ratio of 1:1 to form sample 10; Step 3, preprocessing: Samples 1 to 10 were dried to remove moisture, and then agglomerated and crushed; Step 4, digestion: (1) Weighing powders of samples 1 to 10 respectively, adding a mixed acid solution of nitric acid and hydrochloric acid, soaking for 5 to 10 minutes under vacuum conditions, then performing microwave digestion for 5 to 10 minutes, and finally evaporating to a block to obtain a block A; (2) then crushing the block A, adding a mixed acid solution of nitric acid and hydrochloric acid for the second time, soaking for 5 to 10 minutes under vacuum conditions, then performing microwave digestion for 5 to 10 minutes, and finally evaporating to a block to obtain a block B; Step 5, sample preparation: The block B is crushed, the crushed powder is accurately weighed, and a hydrochloric acid solution is added, and the mixture is heated and dissolved at 130 to 150° C. for 10 to 15 minutes, and finally diluted and fixed to volume to obtain fixed-volume samples 1 to 10; Step 6, detection: Using inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry or flame atomic absorption spectrophotometry to perform qualitative or quantitative detection of elements, and obtain the detection results of samples 1 to 10; Step 7: Compare and judge the accuracy: Compare the test results of samples 1 to 10, wherein the test results of samples 1, 2, 3 and 8 are compared to determine the test accuracy; the test results of samples 4, 5 and 9 are compared to determine the test accuracy; the test results of samples 6, 7 and 10 are compared to determine the test accuracy; Step 8: Compare and judge the changes in soil composition: Calculate the average m of the results of samples 1, 2, 3 and 8, calculate the average n of the results of samples 6, 7 and 10, and calculate the average w of the results of samples 4, 5 and 9; compare m with n to determine the changes in soil composition during crop growth; compare m with w to determine the extent of the impact of water loss on soil composition.

2. The method for sampling and detecting agricultural land soil according to claim 1, characterized in that: In step 1, the sampling is performed using a sampler, and the sampling port of the sampler is closed before it is inserted into the sampling point. When the depth of the sampling point is reached, the sampling port is controlled to be opened for sampling, and then the sampling port is controlled to be closed and the sampler is pulled out; the sampler is provided with a depth scale.

3. The method for sampling and detecting agricultural land soil according to claim 1, characterized in that: The pulverizing is carried out using a small-sized Chinese medicine pulverizer.

4. The method for sampling and detecting agricultural land soil according to claim 1, characterized in that: In step 3, the particle size of the crushed material is below 800 nm.

5. The method for sampling and detecting agricultural land soil according to claim 1, characterized in that: In step 4 (1), the mixed acid solution is a mixture of nitric acid and hydrochloric acid in a volume ratio of 5:1, and the mixed acid solution is added in a ratio of 5 to 15 ml / g.

6. The method for sampling and detecting agricultural land soil according to claim 1, characterized in that: In step 4 (2), the particle size of the crushed product is less than 800 nm.

7. The method for sampling and detecting agricultural land soil according to claim 1, characterized in that: In step 4 (2), the mixed acid solution is a mixture of nitric acid and hydrochloric acid in a volume ratio of 5:1, and the mixed acid solution is added in a ratio of 5 to 15 ml / g.

8. The method for sampling and detecting agricultural land soil according to claim 1, characterized in that: In step 5, the particle size of the crushed material is below 800 nm.

9. The method for sampling and detecting agricultural land soil according to claim 1, characterized in that: In step 5, the hydrochloric acid solution is a 15% hydrochloric acid solution, and the addition ratio of the hydrochloric acid solution is 10-15 mL / g.

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