EVALUATION OF AIRLEG SORTING

Kathy Kelley, Bill Olson, Steve Sibbett, Ron Snyder

ABSTRACT

To evaluate the possible economic benefit of on-farm dry sideairleg sorting, 74 lots of walnuts comprising six cultivars col-lected from the Southern and Central San Joaquin Valley and theSacramento Valley were submitted to airleg sorting, separatingeach lot into three sublots based on quality: number 1, number2 and culls. Each sublot was weighed to calculate the percentin each category. The sublots, plus an original nonairleggedsample, were submitted for quality evaluation and value determina-tion.

OBJECTIVES

Sorting walnuts with "airlegs," machines which remove lightweightnuts through exposure to an airstream or vacumm, is becoming morecommon in the on-farm walnut operation. The objective of thisresearch was to determine whether or not the removal of poor qualitynuts (weight loss) by use of a dry side airleg results in sufficientvalue increase (quality improvement) of the remaining lot to improvenet profit of the load.

PROCEDURE

In this trial, 74 50-lb. samples of dry, in-shell, orchard runwalnuts comprising six varieties: Ashley (11 samples), Payne(8 samples), Vina (12 samples), Serr (10 samples), Hartley (16samples) and Franquette (17 samples), were collected from theSouthern and Central San Joaquin Valley and the Sacramento Valley.Thus, an array of qualities were obtained due to both districtand harvest timing differences for each cuItivar. A two to fivepound non-airlegged control sample of each lot was taken. Theremaining sample was subjected to strong air velocity which separ-ated the heaviest nuts. These were reserved as first quality"No.1. " The remainder of the sample was subjected to less airvelocity and separated into a second quality, "No.2" and "culls."Each of these subsamples were collected, weighed to determinethe percent in each category and submitted for quality analysisand value determination. In addition, quality and value determina-tions were also made after combining the No. 1 and No. 2 segmentsas if only a single separation was made, good nuts and culls.

RESULTS

For purposes of comparison, the data has been adjusted to representone ton of walnuts thus allowing comparison of potential totalvalue from similar, one-ton lots of walnuts either submitted toan airleg or left untreated.

The airleg separated from 1highest percent was removed

to 5% of the weight as culls.from early leafing cultivars,

Thethose

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that usually have blight and sunburn problems which result inshriveled, lightweight kernels. Value of these culls, if separatedfrom one ton of walnuts, is shown in Table 1. Culls are of lowvalue and substantial amounts would have to accumulate to justifydelivery costs. For purposes of this study, they were considereddiscarded and not included in the value determinations.

Doubte Airleg Separation

The initial airleg (high air velocity) separated approximately76-90% of the nuts into the No. 1 (highest quality) category.The remaining 9-20% remained as No. 2's, a category of only mediocrequaIlty. Percentages in each category and potential pounds perton are shown in Table 2. As with culls, samples of early leafingcultlvars that suffer more from blight and heat contained morenuts in the No. 2 category than usually higher quality, late leafingcultivars, such as Hartley and Franquette.

Separating lots of nuts into a No. 1 quality category did notresult in a significant increase in value per pound for all testedcultivars except Franquette when compared to value of that culti-var's nonairlegged nuts. Value of the No.2 component was substan-tially less when compared to both No. 1 and nonairlegged controlnuts (Table 3).

To determine ultimate value of this practice, we assume a growerwould have one ton of nuts with an option to utilize the airlegfor double separation or leave them untreated. This benefit canbe calculated by using weights in each category, No. 1 and No.2 (Table 2), and values per pound (Table 3) for each separationand adding these together (Table 4). In all cases except Hartley,reduced value to the grower occurred by utilizing a double airlegseparation. The differences, however, are not significant whensubmitted to statistical analyses.

Single Airleg Separation

Quality and value of the airlegged samples were combined as onelot to compare value of a nonairlegged control with a similarlot submitted to an airleg adjusted to remove only culls.

Average value per pound of nuts was not significantly improvedby only removing culls (Table 5). Although value per pound wasgenerally, but not significantly increased, still, no significantimprovement in value per ton occurred.

CONCLUSIONS

Data collected from this experiment indicate that price gain byquality improvement did not usually offset value lost by weightreduction. Removal of cull nuts has no significant effect onultimate value of the .load. Further, separation into qualitycategories also does not improve value. As shown in Tables 4and 6, there appears to be as much chance of having a negativeeffect as a positive one. In both single and double separation,value of cull nuts is lost. Although, their value, if deliveredseparately, is minimal it can be substantial when their weight

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-- - - - ----

is eliminated from a relatively valuable load.

An airleg can increase value if a small amount of material isremoved and a significant increase in value of the remainder isobtained as might occur if an in-shell premium is received followingremoval of a minimal amount of nuts.

Where quality is poor and high cullage expected, a negative impactcould occur. Table 7 provides a guide to determine value neededfor remaining nuts to be equivalent to original value under varyingremoval and values/ton.

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TABLE 1. QUALITY AND VALUE OF CULL WALNUTSSEPARATED BY AN AIRLEG

VarietyAshleyPayneVinaSerrHartleyFranquette

% Cull5.03.52.93.51.41.3

Lbs/TonRemoved

100.969.258.169.127.826.0

!/ Averages of sample,s, from each cultivar

g/ Total value = (value/lbs) (lbs/ton removed)

~/ Potential value/ton = (~alue/lbs) (2000 lbs/ton)

Total valueYof Culls1.23.35

1.674.52.74.74

Potential

Value~Per Tonit24.40

10.0057.40

130.8053.0053.00

TABLE 2. SEPARATION OF WALNUTSWHENSUBMITTED TO A DOUBLEAIRLEG - 198f/

VarietyAshleyPayneVinaSerrHartleyFranquette

No. 1

YLbs/Ton

155316491543153316831790

Separation

!/ Averages of samples from each cultivar.

g/ Lbs/ton = (%) (2000 lbs/ton)

-- -- -- -- ---

%77.7%82.4

77.176.684.1

89.5

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17~3%14.120.020.314.09.2

No. 2

Lbs(TonY3 5282399407280183

TABLE 3. VALUE PER LBS. OF NO.1, NO.2 AND NONAIRLEGGED(NAL) NUTS

bJJValue/Lbs

VarietyAshleyPayneVinaSerrHartleyFranquette

NAL$ .3078

.2968

.3152

.3528

.3061

.3345

No. 1&>. 3235

.3224

.3379

.3686

.3217

.3440

No.2'$.2158

.2088

.2645

.2370

.2538

.2353

Averages of each cultivar - includes in-shell premium if applicable,

Values not significantly different using paired "T" testexcept Franquette, 95:1.

TABLE 4. VALUE PER TON OF NONAIRLEGGED(NAL) AND AIRLEGGED (DOUBLE SEPARATION)NUTS

value/Tonl,3,4/

VarietyAshleyPayneVinaSerrHartleyFranquet te

NArJ:./$615.68

593.58630.33705.62612.13668~60

No. 1&2$577.23

592.20626.58657.81615.31662.55

Difference-$38. 45- 1. 38

3.7547.81

+ 3. 186.05

!/ Value/ton = value/lbs (Table 3) x Ibs/category (Table 2)

2/ NAL= nonairlegged

11 Averages of samples from each cultivar - includes in-shell premium ifapplicable

.!!./ Values not significantly different using paired "T" test

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TABIE 5. VALUE PER IN-SHELL POUND OF WALNUTS EITHER AIRIEGGED (AL) OR

NONAIRIEGGED(NAL) - SINGIE SEPARATION- 198:fJ

value/LbV

VarietyAshleyPayneVinaSerrHartleyFranquette

NAL~ . 3078

. 2968

.3152

.3528

.3061

.3345

AL~ .3031.3065.3243

.3654

.3180

.3406

!/ Averages of each cultivar, in-shell premium included if appropriate

2/ Differences not signifiqant using paired "1'11test

TABIE 6. VALUE PER TON OF NUTS (INCLUDING IN-SHELL) AS INFLUENCED BY AN

AIRIEG - SINGIE SEPARATION - 1983!/

1/ Averages of samples from each cultivar

'5/ Differences not significant using paired "1'11test

l/ NAL = nonairlegged, AL = airlegged

~/ Value/ton = (value/lbs *Table 5* x lbs/category *Table 2)

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-- --

2,4/Value Per Ton

Variety NAy)./ Ar)./

Ashley 615 .68 577.66Payne 593.58 592.34Vina 630.33 629.73Serr 705.62 703.61Hartley 612.13 627.11 +

Franquette 668.60 670.82 +

,-

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TABLE 7. VALUE (rt) INCREASE NEEDED PER REMAINING POUND OF WALNUTS AFTER A

PORT ION OF THE CR OP IS REMOVED WITH AN AIRLEGY

Value Per Dry Ton

%Removed 400 500 600 700 $800 900 1000 1100 1200

I" .20 .25 .30 .35 .40 .45 .50 .55 .602 .41 .51 .61 .71 .81 .91 1.10 1.12 1.223 .62 .77 .93 1.08 1.24 1.39 1.55 1.70 1.864 .83 1.04 .,.1. 25 1.46 1.67 1.88 2.08 2.29 2.505 1.05 1.32 " 1.58 1.84 2.11 2.37 2.63 2.89 3.126 1.28 1.60 1.91 2.23 2.55 2.87 3.19 3.51 3.837 1.51 1.88 2.25 2.63 3.01 3.39 3.76 4.14 4.528 1.74 2.17 2.61 3.04 3.48 3.91 4.35 4.78 5.229 1.98 2.47 2.97 3.46 3.96 4.45 4.95 5.44 5.9310 2.22 2.77 3.33 3.88 4.44 5.00 5.55 6.11 6.6611 2.47 3.09 3.71 4.33 4.94 5.56 6.18 6.80 7.4212 2.73 3.41 4.09 4.77 5.45 6.14 6.82 7.50 8.1813 2.99 3.74 4.48 5.23 5.98 6.72 7.47 8.22 8.9714 3.26 4.07 4.88 5.70 6.51 7.33 8.14 8.95 9.7715 3.53 4.41 5.29 6.18 7.06 7.94 8.82 9.71 10.06

Y Example: Nonairlegged ton of walnuts worth $800 per ton. If airleg removes

5% then remaining nuts must be worth 2.11rt/lb more to be equivalent to $800in total value.