When a manure heap is subjected to rainfall, which nutrient is most likely to be lost in the greatest amount?

Explanation

Nitrogen is the nutrient that is most vulnerable to loss due to rain exposure on manure piles. This happens because nitrogen, particularly in the form of nitrates or ammonium, can be easily leached or volatilized when exposed to water, unlike calcium, magnesium, or sulfur which are less prone to such rapid losses.