Sampling Procedure

When taking samples, follow these steps:

• If the soil in the area to be sampled is fairly uniform and the area is not very large, one composite sample will suffice. If the field is large, divide it into two or more blocks of approximately equal size and take one composite sample from each block. The sample area should not be more than one acre in size.
• In each field to be assayed, take a sample from each area that has a common cropping history and that will be planted to a single crop. For example, if a one-acre field is to be planted to peaches next year and if one-half of the field was in apples last season and the remainder in woods, collect a sample from each of the areas. If the soil in the area to be sampled is variable, such as having a heavy clay soil in one portion and a sandy soil in another portion, take one composite sample from each soil type.
• Preferably using a 1-by-12-inch sampling tube (or a trowel, small shovel, or similar tool, if a sampling tube is unavailable), take at least 20 cores of soil from each sampling area. Samples should be taken to a depth of 9 to 12 inches.
• Take soil samples from the area in which the roots were growing. Feeder roots, found at varying depths, usually are most abundant in soil at the dripline, directly below the outer leaf canopy. Do not sample from dead or nearly dead plants; rather, sample from adjacent plants.

Since nematodes generally are not uniformly distributed in a field, a carefully prescribed sampling procedure must be followed to obtain root and soil samples representative of the area surveyed. Furthermore, the samples must be properly handled and shipped to assure that they remain alive until they are processed in the laboratory. Samples can be taken any time from May to November, as long as the soil is moist and the temperature is above 40°F. If there has been a prolonged dry spell or if the soil has been saturated with water for an extended period, wait for 4 to 6 weeks of normal soil moisture conditions before sampling.