Nitrogen Fertilizer

To get the most out of fertilizers with nitrogen, use them wisely. Otherwise, especially if there is excessive fertilization, the result may be a significant decrease in yield rather than an increase. First, take into account the following: Liquid fertilizing products are most effective when applied during active plant growth, as plants readily absorb them. However, improper or excessive application may lead to leaks and scorching of the plant roots.

Dry or pelleted fertilizing products are best suited for less nutrient-hungry periods. But they might rest on the ground, making their volatile compounds more likely to evaporate. Before you apply nitrogen-based fertilizers, consider some other key considerations.

Matching the timing of fertiliser application to coincide with your crops' changing demand will maximise crop N uptake and minimise your fertiliser costs. Always aim to avoid applying fertiliser when soils are waterlogged or likely to become so, for example, before forecast heavy rain. Consider that:

Crops usually only use small amounts of N in early growth stages so if you apply most of the crops projected N needs at or close to planting, N losses are more likely sample soils and, if you're able to, apply 'in-crop' N fertiliser rather than 'up-front' N to better match your crops' demand. Supplying N fertiliser at crop development stages during high N uptake periods can increase N uptake by the crop, provided sufficient follow up rainfall occurs. Most crops require less than 20% of their total N requirement by first flowers2.

If you're converting long-term pasture to crops, minimise the length of fallow, especially in irrigated crops. Long fallows lead to rapid build-up of N in the nitrate form and subsequently, much higher N2O losses compared to short fallows before cropping. Avoid conversion in high rainfall years — for example, when La Niña is forecast.