Spatial and temporal variation in soil inorganic N concentration, and soil test P and K, in red raspberry fields and implications for soil sampling strategies

Fertilizer is commonly applied as a band in red raspberry (Rubus idaeus L.) fields, resulting in complex spatial and temporal variation in soil inorganic N concentration, and in soil test P and K. The objectives of this study were to determine the spatial and temporal distribution of soil inorganic N in red raspberry fields receiving different N fertility treatments, to use the data to determine the most appropriate sampling strategies for estimating the quantity of soil inorganic N at various times during the growing season, and to evaluate the same sampling strategies for soil test P and K. Treatments were a control that received no manure or fertilizer N, 55 kg N ha-1 as urea or as Duration T60, a slow release N fertilizer, banded in mid-April, or 100 kg total N ha-1 as solid broiler manure broadcast or banded in early March, or banded in mid-April. Soil inorganic N was sampled at 10 inter-row locations 8, 23, 38, 53, 68, 83, 98, 113, 128, and 143 cm from the crop row, and for 0–15, 15–30, and 30–60 cm...