After collecting soil samples for nitrate-nitrogen tests, what should be done immediately?

After collecting soil samples for nitrate-nitrogen tests, it is crucial to chill or freeze the samples as soon as possible. This is because nitrates in the soil can convert into other nitrogen forms if the samples are not stored properly. By chilling or freezing the samples, you effectively halt biological activity that could alter the nitrate content, ensuring the accuracy and integrity of the test results. Proper preservation is vital for maintaining the chemical composition of the samples until they are analyzed.

Chilling or freezing prevents any further microbial activity that might happen if the samples were stored at room temperature, which could lead to erroneous results in the nitrate-nitrogen testing. Ensuring that the samples are kept in optimal conditions directly contributes to the reliability of nutrient management practices, making it a fundamental step after sampling.