Page 102 - Nutrient Management Planning Guide

97

Chapter 3.3

Soil sampling for nutrient management •

purposes should occur immediately before seeding, just prior to active growth or in the fall after soil temperatures drop below 5 to 7 o C. Sampling strategies include random •

sampling, directed random sampling, benchmark sampling, directed benchmark sampling and grid sampling. Benchmark sampling is the recommended sampling method for most situations, while grid sampling is the most intensive. To accurately assess nutrient levels, samples •

should be collected from the 0 to 15 cm, 15 to 30 cm and 30 to 60 cm soil depths. For best management, samples should be •

collected and analyzed annually. AOPA regulations require that all fields receiving manure must have a soil analysis that is not older than three years.

Make sure samples are handled •

appropriately based on laboratory guidelines to ensure reliable test results. Moist samples should be kept cool and sent to the lab immediately. Samples that cannot be immediately shipped should be dried or frozen. Recommended analyses for samples include •

tests for: extractable NO

3

- , available P, available K, extractable SO

4

-2 , pH and salinity (electrical conductivity). Soil samples submitted for analysis should •

be accompanied by information regarding legal land location, a realistic yield goal, production and management system information, and prior manure or fertilizer application history.

summary