Nitrogen Management, Then and Now


As an industry, we have made significant advances in the last 20 years in nitrogen management. Twenty years ago, the state average yield was 1,200 to 1,300 pounds per acre. To achieve this yield, growers reportedly applied about 200 pounds of nitrogen per acre, resulting in a “nitrogen use efficiency" (NUE, or the percentage of N applied actually removed in the crop) of about 44%. In those days (I was considerably younger then, but I still remember reasonably well), many growers broadcast or banded nitrogen materials, often in large doses, once or twice a season in the fall, winter or early spring. Irrigation by flood or sprinklers followed, and a portion of the N applied that was not lost to volatilization was moved below the active root zone. Drip and microsprinkler systems were just getting popular in areas with high water costs.

Fast forward to today, and things look considerably different. The cost of nitrogen has increased by a factor of 2.5. Irrigation methods have improved dramatically in terms of uniformity of application, and, thanks to research funded by the Almond Board, we now have the ability to schedule applications to meet crop demands. Yields have doubled statewide. Almond growers have become more sophisticated and knowledgeable, and our fertilization practices much more accurately match the needs of the orchards. Soil and tissue sampling give us better clues about the nutritional status of our trees, though improvement will be welcome in this area.

In a recent trial in our Belridge ranches at Paramount Farms, research funded by the Almond Board and others has documented NUEs of 75% to 85%, the highest recorded in any crop. Losses from deep percolation averaged less than 5%. Volatilization of N was less than 1%.

State-of-the-art irrigation and nutrient management practices will not only ensure minimal environmental impact on groundwater quality (see Nitrate Levels in Groundwater), but also save money and increase yields. Growers can further assure the sustainable future of the California Almond industry by filling out sustainability workbooks on irrigation management and nutrient management. These workbooks are designed as both educational tools and as a way to document what growers are already doing to protect and preserve natural resources.

We can be proud of what we have achieved as an industry in these areas. We have made progress that clearly demonstrates our commitment to applying the results of production and environmental research that advances our farming practices. We have shown a willingness to use the tools we have developed to improve our efficiency for the benefit of our own operations, the environment, our neighbors and our communities. I have no doubt that we will continue this trend.

Sincerely,
Joe MacIlvaine, Chair
Production Research Committee

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