Sandy soils will settle quickly, clay soils will require an hour or more. Use a separate test strip for each sample. Shake off the excess solution and wait 60 seconds. Each color represents a NO 3 level. The test strip results must be converted to nitrate nitrogen.
Soil texture is divided into sand, loam, or clay.
Dr. Tim Jones, NMSU, Department of Agronomy and Horticulture has developed a procedure for determining soil texture in the field. Next decide if the soil is moist or dry. Table 1 lists the appropriate correction factors by texture and moisture. Quick Test Correction Factors by soil texture and soil moisture. Soil Sand 2.3 2.6 Loam 2.0 2.4 Clay 1.7 2.2 Table 2 lists the general recommendations for fertigation with nitrate nitrogen based on the corrected test reading scores.