Individual sections of a core may not be representative of the entire core. Always collect a continuous core to the desired sample depth. Time of Sampling Late fall or winter is a good time for soil sampling except for testing for nitrate-nitrogen in sandy soils. Fall sampling allows more time to get the results from the testing laboratory and avoids the busy laboratory schedule in the spring. To determine the remaining nitrate-nitrogen in the soil, additional samples should be taken.
Spring sampling prior to planting is preferred.
Delaying sampling until spring provides for soil moisture replenishment from fall, winter, and early spring precipitation. Thus, the soil test should reflect the nitrate-nitrogen distribution more accurately for when the crop is growing. Late spring or early summer sampling after the crop is growing may have value for predicting sidedress nitrogen needs of the crop. Late sampling cannot be used if anhydrous ammonia was applied in the fall or spring before sampling. Also, soil test values for nitrate-nitrogen from late spring sampling are still being calibrated for Nebraska soils.