NY/T 1121.4-2006 Soil testing Part 4: Determination of soil bulk density NY/T1121.4-2006 standard download decompression password: www.bzxz.net

ICS13.080.05
Agricultural Industry Standard of the People's Republic of China
NY/T1121.4—2006
Soil Testing
Part 4: Method for determination of soil bulk density
Soil Testing
Part 4: Method for determination of soil bulk density density2006-07-10 Issued
2006-10-01 Implementation
The Ministry of Agriculture of the People's Republic of China issued
NY/T1121 "Soil Testing" is a series of standards, including the following parts: Part 1: Collection, processing and storage of soil samples Part 2: Determination of soil pH
Part 3: Determination of physical and mechanical composition
Part 4: Determination of soil bulk density
Part 5: Determination of cation exchange capacity of calcareous soils Part 6: Determination of soil organic matter
Part 7: Determination of available phosphorus in acidic soils-Part 8 Part 1: Determination of available molybdenum in soil Part 10: Determination of total mercury in soil Part 11: Determination of total molybdenum in soil Part 12: Determination of total chromium in soil Part 13: Determination of exchangeable calcium and magnesium in soil Part 14: Determination of available sulfur in soil Part 15: Determination of available silicon in soil Part 16: Determination of total water-soluble salt content in soil Part 17: Determination of chloride ion content in soil Part 18: Determination of sulfate ion content in soil This part is Part 4 of NY/T 1121. This part is proposed and managed by the Ministry of Agriculture of the People's Republic of China. NY/T1121.4—2006
The drafting units of this part are: National Agricultural Technology Extension Service Center, Institute of Agricultural Resources and Agricultural Zoning of Chinese Academy of Agricultural Sciences, Hunan Soil and Fertilizer Workstation, Liaoning Soil and Fertilizer General Station. The main drafters of this part are: Tian Youguo, Xin Jingshu, Ren Yi, Huang Tieping, Long Huaiyu, Lu Yu, Zheng Lei. 1 Application diagramwwW.bzxz.Net
Soil testing
Part 4: Determination of soil bulk density
This part is applicable to the determination of bulk density of all kinds of soils except hard and brittle soils. 2 Determination principle
NY/T1121.4—2006
Use a ring knife of a certain volume to cut the soil sample in its natural state so that the soil sample fills it. After weighing, calculate the mass of the dried soil sample per unit volume, which is the bulk density.
3 Main instruments and equipment
3.1 Ring knife (volume 100cm)
3.2 Steel ring knife holder
There are two small exhaust holes.
3.3 Soil cutting knife
The blade should be straight
3.4 ​​Small iron shovel
3.5 Wooden hammer
3.6 Balance (sensitivity 0.1g)
3.7 Electric constant temperature drying oven
3.8 Dryer
4 Analysis steps
Before sampling, apply a thin layer of vaseline evenly on the inner wall of each ring knife, and weigh the mass of each ring knife (m1) one by one, accurate to 0.1g. After selecting the soil surface, use the ring knife to sample the middle of each layer from top to bottom according to the soil surface layer. First, use a shovel to flatten the soil surface of the sampling layer, put the ring knife holder on the bladeless end of the ring knife, with the blade of the ring knife facing down, and press the ring knife holder handle evenly to press the ring knife vertically into the soil. If the soil is hard and the ring knife is not easy to insert into the soil, you can use a soil hammer to gently hit the ring knife holder handle. When the entire ring knife is pressed into the soil and the soil surface is about to touch the top of the ring knife holder (which can be seen from the small hole on the ring knife holder cover), stop pressing down. Use a shovel to dig out the soil around the ring knife, cut it off below the ring knife, and leave some excess soil below. Take out the ring knife, turn it over, with the blade facing up, and use a soil cutter to quickly scrape off the soil adhering to the outer wall of the ring knife, and then use the soil cutter to flatten the soil surface from the edge to the middle so that it is flush with the blade. Cover the top cover of the ring knife, turn the ring knife over again, so that the blade end covered with the top cover faces down, and remove the ring knife holder. Similarly, flatten the soil surface at the bladeless end and cover the bottom cover. Take another 20g soil sample at a position close to the bottom of the ring knife sampling, put it into a covered aluminum box, and determine the water content (W) according to the method in Appendix A of NY/T1121.3-2006. Quickly put the ring knife containing the soil sample into a wooden box and bring it back to the room, and weigh the mass of the ring knife and wet soil on the balance (m2).
5 Calculation of results
（m2-m）×1000
Bulk density, g/cm2=
VX(1000+W)
NY/T1121.4—2006
Wherein:
-Mass of ring cutter and wet soil, in grams (g): Mass of ring cutter, in grams (g);
Volume of ring cutter, in cubic centimeters (cm2), V=yuanr2h, where r is the inner radius of the end of the ring cutter with the cutting edge (cm), and h is the height of the ring cutter:
W——Soil moisture content, in grams per kilogram (g/kg). The measurement results are expressed as arithmetic mean, with two decimal places retained. Precision
The absolute difference of parallel measurement results is allowed to be ≤0.02g/cm2. 7 Notes
Bulk density can also be measured by drying the ring knife filled with soil sample in a constant temperature drying oven at 105℃±2℃ to a constant weight, and then weighing and measuring on a 1% precision balance.
Bulk density, g/em2 = soil sample mass (g) ring knife volume (cm2)
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