Soil Survey & Remote Sensing

In a high intensity detailed soil survey, the observation frequency is typically 4 observations per hectare.

• per ha: Observation frequency used in standard low-intensity detailed soil surveys.
• in 25 ha: Observation density typical of semi-detailed soil surveys.
• in 100 ha: Observation density typical of reconnaissance soil surveys.
• per ha: High-intensity detailed surveys conducted on 1:5,000 scale or larger for experimental stations and precision farms require at least 4 observations per hectare.

• 100 meters spacing is used in high-intensity detailed farm soil surveys (scale 1:5,000 to 1:10,000).
• In semi-detailed soil surveys (scale 1:25,000 to 1:50,000) for district and watershed planning, the standard grid density requires field auger-hole observations spaced approximately 500 meters apart (roughly 4-8 observations per square kilometer).
• 800 meters is coarser than semi-detailed standards.
• 1000 meters (1 km) is characteristic of reconnaissance soil surveys.

• 10,000 is a standard large scale for detailed watershed soil maps.
• 8,000 is an enlargement scale adapted from revenue/cadastral village maps.
• 5,000 is used for high-intensity detailed farm planning and research station surveys.
• Detailed soil surveys are characterized by large mapping scales ranging between 1:5,000 and 1:10,000 (including 1:5,000, 1:8,000, and 1:10,000) to map individual soil phases, farm boundaries, and field management units.

• screw type auger features spiral helical flutes that effectively bore into, penetrate, and retrieve samples from compact, cohesive, and sticky heavy clay soils without becoming blocked.
• Tube augers compress clayey soils and often get jammed during extraction.
• Dutch augers are specially designed for wet, boggy, fibrous organic soils or rooted substrates.
• Post hole augers are designed for excavating wide shallow holes for posts and saplings rather than deep soil sampling.