Nutrient / Fertilizer Application BMPs
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Soil, Tissue and Water Testing
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Base N fertilizer amount and timing on crop needs and production goals.
Before applying N early in the growth cycle, assess the amount of nitrate already present by soil (or soil solution) sampling and analysis.
Use plant tissue sampling for mid- and late season fertilizer decisions.
Measure nitrate levels in the irrigation water and adjust N fertilizer rate accordingly.
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Application Timing
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Almond trees absorb nitrogen from the soil much more efficiently during the growing season. Dormant season applications are inefficient due to poor uptake during dormancy, leaching from winter rains and frost protection irrigations and denitrification.
Highest uptake of N occurs between the onset of the spring flush of growth (usually in March) until the loss of leaf function in late October.
Applications are more economic when applied through the irrigation system as long as the irrigation is uniform in its application.
Do not apply excessive single amounts of fertilizer N during the rainy season.
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Fertilizer Placement
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Place N fertilizer materials where maximum plant uptake will occur. N applied through the irrigation system is the most effective.
Incorporate manures and other organic amendments into soil with consideration of the timing of conversion of manure N to other forms.
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Irrigation
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Adopt drip / micro-sprinkler irrigation.
Collect surface water runoff for recirculation or reuse in other fields using a tailwater return system.
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Application Practices
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Clean-up fertilizer spills promptly.
Shut off fertilizer applicators during turns and use check valves when possible.
Maintain proper calibration of fertilizer application equipment.
Whenever injecting fertilizer into irrigation water, ensure backflow does not occur.
Rinse water from fertilizer tanks should be evenly spread throughout a field. Fertilizer tanks and equipment should be cleaned by rinsing in the field or at a properly designed wash facility. Rinse water and/or sludge should be evenly spread across a field using good agronomic practices.
When equipment is parked, use care to prevent material from leaking into storage area. If equipment is known to be in disrepair, completely remove fertilizer material before parking equipment.
When transferring fertilizer into on-farm storage or into a fertilizer applicator, take care not to allow materials to accumulate on the soil. Good housekeeping practices should be implemented to prevent contamination of groundwater and/or surface water.
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Cover Crops
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If conditions permit, grow a cover crop to use any excess nitrogen and prevent leaching during the rainy season. |
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