SOIL AND PLANT ANALYSIS (1+1)

Sampling Depth

Sampling depth should be determined to represent the root zone that the plant will draw from, but should also be consistent with the sampling depth used in developing the calibration data set to be used for interpreting the soil tests.


Prescribed depth of soil sampling


Field crops	15-20 cm
Deep rooted crops	30-60 cm (Sampling at different depths or layers is ideal)
Forage or pasture crops	8-10 cm
For immobile nutrients (P, K, Ca and Mg)	Sampling at tillage depth
Nitrate, Sulfate	60 cm (when the biological activity is low)
Saline alkali soils	Salt crust should be sampled separately and the depth of sampling should be recorded