Farm Progress

Objective estimate mirror's last season's production126,000 bearing acres of Navels in CaliforniaCitrus trade association thinks estimate is too high  

tfitchette, Associate Editor

September 15, 2014

4 Min Read
<p>California Citrus Mutual believes this year&#39;s NASS estimate on Navel oranges will prove to be too high because of drought impacts not factored into the survey.</p>

California Navel orange production for the 2014-15 season is projected to be 81 million cartons on 126,000 bearing acres; 78 million cartons will come from the Central Valley, according to the latest objective estimate by the National Agricultural Statistics Service.

While subject to revision, this is tentatively equal to production in the 2013-14 crop year.

The forecast is based on the results of the 2014-15 Navel Orange Objective Measurement (O.M.) Survey, which was conducted from July 13 to September 2, 2014. Estimated fruit set per tree, fruit diameter, trees per acre, bearing acreage, and oranges per box were used in the statistical models estimating production.

The varieties forecast in this report include conventional, organic, and specialty Navel oranges (including Cara Cara and Blood orange varieties).

Survey data indicated a fruit set per tree of 333, above the five-year average of 328. The average September 1 diameter was low at 2.205, below the five-year average of 2.256.

A sample of 575 Navel orange groves was randomly selected proportional to county and variety bearing acreage, and 534 of the groves were utilized in this survey. Once a grove was randomly chosen and grower permission was granted, two trees were randomly selected. The Navel orange sample included organic, Cara Cara, and Blood orange groves.

Terminal branch inspected

For each randomly selected tree, its trunk was measured along with all connected branches. A random number table was then used to select a branch, and then all connected branches from the randomly-selected branch were measured.

This process was repeated until a branch was reached with no significant limbs beyond it. This randomly-selected branch, called the terminal branch, was then closely inspected to count all fruit connected to it, as well as all of the fruit along the path from the trunk to the terminal branch. Since each selected path has a probability of selection associated with it, a probability-based method was then applied to estimate a fruit count for the entire tree.

In the last week of the survey period, fruit diameter measurements were made on the right quadrant of four trees surrounding the two trees of every third grove. These measurements were used to estimate an average fruit diameter per tree. Of the 534 utilized groves, 8 were in Madera County, 90 were in Fresno County, 309 were in Tulare County, and 127 were in Kern County.

California supplies about 85 percent of the nation’s fresh citrus.

A Navel Orange Objective Measurement Survey has been conducted in the Central Valley every year since the 1984-85 crop year, except for the 1991-92 season due to a lack of funding. The data from the first two years were used for research purposes in developing crop estimating models.

Citrus industry response

California Citrus Mutual (CCM) questions the accuracy of this year’s because of unknown variables related to the drought. While CCM believes the estimate is high, the trade association did not say by how much it believes the objective estimate is off.

According to CCM President Joel Nelsen, there is no way of knowing how much of the crop has been adversely affected by drought or the total acreage impacted by it.

“The statistical team relies upon specific acreage for fruit-set and limb count which, over the years, establishes a record for the average number of fruit per tree,” Nelsen said. “However, this year there is no way of knowing if that acreage has been affected by the drought, whether it has had a full complement of water, or if it has been removed. Additionally, the statisticians have no way of knowing how much of total acreage has been adversely affected.”

Some of CCM’s concerns relative the 2014-15 crop include fruit size, which it says can be impacted by too little water.

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“We know the lack of water has affected fruit size during the growth stages,” Nelsen said. “We also agree there is more fruit on the tree as compared to last year; however fruit size is a concern. All of this affects the number of cartons ultimately packed.

Nelsen is optimistic that fruit size for those with ample water and flavor issues because of the hot summer weather will bode well for some growers.

About the Author(s)


Associate Editor, Western Farm Press

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