Sandy soils tend to drain better than clay soils. However, a sandy soil may be underlaid by clay layers, which will affect drainage. In addition to these particles, soils also contain varying amounts of organic matter. Slide 9 Soil structure refers to how particles stick together. This is important because it can affect infiltration as well as pore space which influences root growth, drainage, and soil aeration.
Organic matter can help to improve structure of soil, especially clay soils.
However, heavy clay soils are not good orchard sites. Slide 10 Soil testing is a good starting point for determining soil fertility. Your county agent has the bags and directions for taking soil tests. Be sure to make a composite sample from each area where you want to plant. Your local NRCS office has soil maps which will tell you the soil types on your farm and describe their characteristics.