Previously this week, I wrote an article discussing nitrogen needs within the almond orchard. Application of nitrogen, as briefly discussed, varies in efficiency based upon techniques of application and irrigation/fertigation systems. Below are some tips to maximize efficiency and reduce losses for many common fertilizer application strategies.
1. Apply N only when leaves are present and the tree roots are active. Avoid dormant season applications.
2. Efficiency can be increased by applying N in small doses more frequently than large doses less frequently.
3. Apply a uniform irrigation that is adequate to carry the N into but not past the root zone.
4. Because young fruit trees have a fairly constant N uptake, apply multiple applications of N throughout the growing season.
5. Mature trees need most of the N in the spring, around 70-75% of the nitrogen budget.
6. Late summer/postharvest applications, 25-30% of the budget,will help with flower bud differentiation and formation for next year’s crop.
7. Fertigation has generally been very efficient in N applications.
8. Analyze leaves in July each year to fine tune N level to the orchard. Maintain the level in the adequate range.
1. If fertilizer is surface applied, disc or irrigate N into the root zone shortly after application.
2. Fertilize the tree, not the covercrop. Evaluate how best to bypass the covercrop. This may be by applying the fertilizer to the herbicide sprayed strip, mowing, or cultivating the covercrop.
3. Don’t over irrigate. Nitrogen is soluble and moves with water. Excessive runoff of tail water or leaching will remove N.