Advantages of Orchard Fertilization

Orchard fertilization management is of great importance for proper, efficient nourishment of the trees. It’s necessary to address the specific species of orchard and sometimes the different varieties of fruit trees fertilization management differs considerably between deciduous trees and evergreen orchards (subtropical, citrus, olive trees and bananas,  etc.)
Fertilization management relates to providing nutrient elements efficiently throughout the season according to the tree’s consumption, assuming that we know the quantity of nutrient elements necessary for orchard fertilization and taking into consideration the species of plant, Its expected yield and perform soil/leaf analysis
In Israel all orchards are irrigated by drip, micro sprinklers, or micro-jets. This enables fertigation which delivers the nutrient directly to the rooting system
Fertilizer can be selected with different concentrations and combinations of nitrogen phosphorus: potassium proportions, including supplemental micro element and bio-stimulants in variable doses, according to the tree’s stages of development along the season
The process seems to be simple and logical, but in fact is not easy to execute due to several basic reasons
1information about uptake of element nutrients in different species of orchards trees is incomplete. Research to estimate plant uptake is complex and expensive
Evaluation of the nutrient content of the trees implies the destruction of sample trees from which laboratory tests are performed to determine the amount / concentration of each nutrient element in the various organs of the tree, during different growth stages and at different ages. Furthermore, studies take several years for each species, so that, worldwide the number of studies is small, dealing with a few species
 2It’s relatively easy to measure the amount of nutrient removed from the orchard. The weight of harvested fruit his known, the fruit’s nutrient content can also be analyzed in a laboratory, just as it’s possible to estimate the weight of tree pruning removed during the season, also be analyzed in a laboratory for of nutrient contents. Multi-year average for quantities of nutrient removed constitutes a basis for estimating the quantity of fertilizer required by a given orchard. In practice, recommendations for nitrogen, phosphorus and potassium are twice or more than the amount removed from the plot
Alternate fruit bearings, as well as, non-uniform pruning from year to year, make it hard to estimate precisely the amount of nutrients required
 3Very few studies have been performed on the transport of nutrient elements from roots to the consuming organs in the canopy (new branches, leaves and fruit). There isn’t adequate information about the tree’s reaction time to element nutrients absorbed from soil solutions into the plant roots and transported to the canopy. The rate of absorption and transport of nutrients is highly important for determining fertilization management during the different growth stages

 4In recent years the number of experiments for control of orchard tree nutrition, has increased with the use of the lysimeter. This is an expensive experimental system in which a tree is grown in a container, so that it is possible to measure precisely the volume of water for irrigation, the amount of drainage and the quantity of nutrients contained in it. Using such data, it is possible to compute exactly daily and seasonal nutrient uptake. The lysimeter system does not allow determination of nutrient transport to the different organs of the tree from the moment they are absorbed by the root
As a consequence, fertilization management is based on a few well based studies. Recommendations are based primarily on insight gained from experience and observation of orchard fertilization over the years
The uptake of nutrient by deciduous trees, citrus and subtropical trees begins at a slow rate from the beginning of root growth in early Spring, with an increasing rate of uptake as the canopy and fruit develop, until the leaf shedding stage. During this period fertilization management has to be optimal as to composition of and quantity of nutrient elements. The remaining questions is, when to start decreasing their rate and when to conclude the fertilization For deciduous trees determining optimal fertilization management is complex, and accordingly, and accordingly, there are various professional approaches 
For nitrogen fertilization it is usual to apply about 50-70% of the seasonal dose of fertilizer up to 2 – 3 weeks prior to harvest. The remainder nitrogen being applied after harvesting until late autumn. The main problem is in early-ripening varieties in which blossoming, and plant growth begins while the root system is not yet active, due to low ground temperatures. Nevertheless, the standard recommendation to begin fertilization early on with “technical irrigation application” for only purpose is fertigation, even if the orchard’s soil is sufficiently wet
This method is undoubtedly inefficient, since root activity is minimal and late spring rains may leach the nitrogen deep into the soil to the where the root system is still dormant
In several studies, carried out primarily on apples, it was found that 80% of the nitrogen in the tree’s developing parts until the budding stage, and sometimes even later stages (in June), came from stored nitrogen from the previous season, that accumulated primarily in the roots,and only 20% of the nitrogen in the young organs originated from current uptake 
We may conclude from this that nitrogen fertilization is extremely important until the later stage of leaf shedding, in order to charge the root system with nitrogen for the following season, primarily in early ripening varieties
Nitrogen fertilization after the harvest does indeed encourage more vigorous plant growth that requires more labor for pruning. However, it contributes significantly to charging the roots with nitrogen to be utilized during blossoming at the beginning of the following season

Phosphorus fertilization of deciduous trees has less influence on the tree’s canopy development, contributing to vigorous radicle development at the beginning of the season when being absorbed by the roots. Phosphorus influences the intensity of blossoming and budding but Fall fertilization with phosphorus has no known advantage
Potassium fertilization of deciduous trees has less influence on tree development
It is usual to fertilize with potassium according to the annual amount removed. Due to its limited movement in silt and clay soils, it is not immediately available to the root system at the depth at which the most active roots are found. Continuous potassium fertilization throughout the season increases the odds of being transported to the depth of the
cross-section. Fall potassium fertilization is recommended as part of seasonal fertilization management
In evergreen orchards (subtropical, citrus and bananas), fertilization management is
simple, but there are varying professional approaches
For nitrogen fertilization it’s customary to give the initial dose of nitrogen at beginning of spring and onwards, till several weeks prior to harvest, according to the species. It’s not customary to do Fall, except for mangoes whose harvest during the summer Suspending fertilization prior to harvest is recommended in order to quicken the change in color and promote earlier ripening of citrus trees, or in order to prevent surplus nitrogen that shortens the fruit’s shelf-life
For orchards irrigated with wastewater, there is no actual break in fertilization, and no essential differences were found at harvest time or in fruit shelf-life
For species fertilized in the autumn that continues up to the start of the rainy season
Even during the winter, the trees continue to develop their canopy and fruit to growth, so that currently there is tendency is to apply fertilizer to avocado trees and bananas during the winter as well
Root system have limited activity due to low temperatures, and it is reasonable to assume that the primary supply of nitrogen is from the nitrogen stores in the roots, and a bit from the trunk
Phosphorus fertilization in evergreen orchards, similar to deciduous orchards, contributes to vigorous development of radicles at the beginning of the season when being absorbed by the root. Phosphorus influences the vigor of blossoming and budding
Potassium fertilization in evergreen orchards is similar to the deciduous orchards. Fall potassium fertilization is recommended as part of seasonal fertilization management