Excessive rainfall and denitrification can result in loss of applied nitrogen. There are many factors that affect soil nutrient levels, including soil type, fertilizer application and topography. One option to estimate the amount of nitrogen remaining is soil sampling. Soil analysis is a valuable tool to the nutrient status of a given field and, in turn, the inputs required for efficient and economic production.
A proper soil test will help ensure the application of enough fertilizer to meet the requirements of the crop while taking advantage of the nutrients already present in the soil.
There are different types of sampling, but regardless of what type is used, numerous samples should be taken to give an accurate average.
Grid sampling can be useful when there is limited prior knowledge of the field’s history. Grid-cell sampling randomly collects samples throughout the cell for a composite sample. Grid-point soil collects one or more samples around a certain point within the grid or at grid intersections.
If sampling is done by the farmer, the samples can be taken to an agronomist for results. When collecting samples, it is important to use clean, stainless steel or plastic tools to avoid contaminating the samples.