A sustainable1nutrient management program in almonds calls for supplying enough of the required nutrients annually to keep the trees healthy and to replace the nutrients removed from the trees through development of the hulls, shells and nuts. Applying an insufficient amount of nutrients risks the health of the trees and the size and quality of the next crop. Oversupplying nutrients is inefficient, and may have implications for groundwater and surface water quality, as well as air quality.
1Sustainable almond farming utilizes production practices that are economically viable and are based upon scientific research, common sense and a respect for the environment, neighbors and employees. The result is a plentiful, nutritious and safe food product.
The Four R’s of Nutrient Management in Almonds
Maximizing the use efficiency of applied nutrients in almonds will result in improved yields, reduced input costs and less potential for off-site movement into ground and surface water. Efficient nutrient management can be accomplished by following the Four R’s:
- Applying at the right rate – Matching tree and crop demand with supply, taking into consideration the contribution of nutrients from all sources, including fertilizer, organic nitrogen, water and soil.
- Applying at the right time – Spoon-fed applications during the growing season to maximize uptake and minimize loss potential.
- Applying in the right place – To ensure delivery to the active root zone.
- Using the right source – To maximize uptake and minimize loss potential.
The Nutrient Management module of the California Almond Sustainability Program is designed as a grower practice self-assessment, but also contains valuable educational information about nutrient management in almonds. For more information on CASP, go to Almonds.com/Sustainability.
It is important to supply almond trees with as much nitrogen as they need at different stages of growth to optimize yields and quality. Almond trees need nitrogen to form proteins, which in turn form protein-dense nuts.
Research has shown that almonds can achieve nitrogen use efficiencies (NUEs) of more than 70%, making almonds among the most efficient nitrogen using crop1. Applying nitrogen fertilizers in amounts that exceed what the tree can take up, or at a time when no uptake can occur, is not only costly: nitrogen in the form of nitrates may then move through the soil beyond the root zone, potentially leaching into and contaminating groundwater.
Nitrates in groundwater is a regulatory issue governed by the Irrigated Lands Regulatory Program, which requires all growers in California to prepare a nitrogen management plan each year, starting in 2015. A nitrogen management plan takes into consideration the contribution of various sources of nitrogen other than fertilizer: nitrates in irrigation water, nitrogen in cover crops and nitrogen that is contributed by compost.
An updated in-season nutrient budget model, including early-season leaf sampling guidelines, has been developed under the leadership of Patrick Brown, UC Davis Department of Plant Sciences. These guidelines are given in the document “Almond Early-Season Sampling and In-Season Nitrogen Application Maximizes Productivity, Minimizes Loss.” The guidelines include a protocol for early-season tissue sampling and for applying nitrogen during the season based on crop load and fine-tuned by sampling results.
- New Nitrogen Management Protocol Helps Almond Growers Comply with Mounting Regulations
- New Protocol for Nitrogen Management: Hold Off on N Until Leaf-Out
- Nitrogen Use Efficiency in Almonds
- FREP (California Department of Food and Agriculture’s Fertilizer Research and Education Program) Almond Nitrogen Fertilization Guidelines
- USDA Funds New Pilot Project to Help Almond Growers Gain Greater Access to Greenhouse Gas Markets
1Silva, S.S., S. Muhammad, B. Sanden, E. Laca, P. Brown. Almond Early-Season Sampling and In-Season Nitrogen Application Maximizes Productivity, Minimizes Loss Protocol for Early-Season Sampling and In-Season Nitrogen Budgeting.
Using the in-season nutrient budget model developed under the leadership of Patrick Brown, UC Davis Department of Plant Sciences, Almond Board has simplified the process of budgeting nitrogen with the Nitrogen Calculator. This is a free, easy-to-use online tool that calculates nitrogen fertilizer needs throughout the season. The calculator takes into consideration yield estimates, leaf sampling results and nitrogen that comes from other sources. The calculator stores data by orchard block, making updates easy as information changes. It’s also completely private — information is not shared with anyone.
The Nitrogen Calculator is available at the California Almond Sustainability Program (CASP) website, SustainableAlmondGrowing.com. Information is entered on orchard configuration and production, along with nitrogen credits from nitrates in irrigation water, cover crops, compost and other sources. Data from leaf sampling in April, or correlated predicted July numbers is also entered. The calculator then provides a total nitrogen fertilizer recommendation, along with recommended amounts by crop growth stage.
Data entered into the Nitrogen Calculator can be saved and updated as necessary. Budget components can be cloned and applied to other orchards or used in subsequent years. All almond growers can use the online model to create budgets, but must be participants in CASP for the data storage aspect, which saves the need to reenter all the data when revising budgets during the growing season. Data can be printed or displayed as a PDF file, or exported into a database.
Contact CASP@Sureharvest.com for questions regarding the Nitrogen Calculator.