EVALUATION OF AIRLEG SORTING Kathy Kelley, Bill Olson, Steve Sibbett, Ron Snyder ABSTRACT To evaluate the possible economic benefit of on-farm dry side airleg sorting, 74 lots of walnuts comprising six cultivars collected from the Southern and Central San Joaquin Valley and the Sacramento Valley were submitted to airleg sorting, separating each lot into three sublots based on quality: number 1, number 2 and culls. Each sublot was weighed to calculate the percent in each category. The sublots, plus an original nonairlegged sample, were submitted for quality evaluation and value determination. OBJECTIVES Sorting walnuts with "airlegs," machines which remove lightweight nuts through exposure to an airstream or vacumm, is becoming more common in the on-farm walnut operation. The objective of this research was to determine whether or not the removal of poor quality nuts (weight loss) by use of a dry side airleg results in sufficient value increase (quality improvement) of the remaining lot to improve net profit of the load. PROCEDURE In this trial, 74 50-lb. samples of dry, in-shell, orchard run walnuts comprising six varieties: (11 samples), (8 samples), (12 samples), (10 samples), (16 samples) and (17 samples), were collected from the Southern and Central San Joaquin Valley and the Sacramento Valley. Thus, an array of qualities were obtained due to both district and harvest timing differences for each cuitivar. A two to five pound non-airlegged control sample of each lot was taken. The remaining sample was subjected to strong air velocity which separated the heaviest nuts. These were reserved as first quality "No.1. " The remainder of the sample was subjected to less air velocity and separated into a second quality, "No.2" and "culls." Each of these subsamples were collected, weighed to determine the percent in each category and submitted for quality analysis and value determination. In addition, quality and value determinations were also made after combining the No. 1 and No. 2 segments as if only a single separation was made, good nuts and culls. RESULTS For purposes of comparison, the data has been adjusted to represent one ton of walnuts thus allowing comparison of potential total value from similar, one-ton lots of walnuts either submitted to an airleg or left untreated. The airleg separated from 1 highest percent was removed to 5% of the weight as culls. from early leafing cultivars, The those -59-
that usually have blight and sunburn problems which result in shriveled, lightweight kernels. Value of these culls, if separated from one ton of walnuts, is shown in Table 1. Culls are of low value and substantial amounts would have to accumulate to justify delivery costs. For purposes of this study, they were considered discarded and not included in the value determinations. Doubte Airleg Separation The initial airleg (high air velocity) separated approximately 76-90% of the nuts into the No. 1 (highest quality) category. The remaining 9-20% remained as No. 2's, a category of only mediocre quailty. Percentages in each category and potential pounds per ton are shown in Table 2. As with culls, samples of early leafing cultlvars that suffer more from blight and heat contained more nuts in the No. 2 category than usually higher quality, late leafing cultivars, such as and. Separating lots of nuts into a No. 1 quality category did not result in a significant increase in value per pound for all tested cultivars except when compared to value of that cultivar's nonairlegged nuts. Value of the No.2 component was substantially less when compared to both No. 1 and nonairlegged control nuts (Table 3). To determine ultimate value of this practice, we assume a grower would have one ton of nuts with an option to utilize the airleg for double separation or leave them untreated. This benefit can be calculated by using weights in each category, No. 1 and No. 2 (Table 2), and values per pound (Table 3) for each separation and adding these together (Table 4). In all cases except, reduced value to the grower occurred by utilizing a double airleg separation. The differences, however, are not significant when submitted to statistical analyses. Single Airleg Separation Quality and value of the airlegged samples were combined as one lot to compare value of a nonairlegged control with a similar lot submitted to an airleg adjusted to remove only culls. Average value per pound of nuts was not significantly improved by only removing culls (Table 5). Although value per pound was generally, but not significantly increased, still, no significant improvement in value per ton occurred. CONCLUSIONS Data collected from this experiment indicate that price gain by quality improvement did not usually offset value lost by weight reduction. Removal of cull nuts has no significant effect on ultimate value of the.load. Further, separation into quality categories also does not improve value. As shown in Tables 4 and 6, there appears to be as much chance of having a negative effect as a positive one. In both single and double separation, value of cull nuts is lost. Although, their value, if delivered separately, is minimal it can be substantial when their weight -60- -- - - - ----
is eliminated from a relatively valuable load. An airleg can increase value if a small amount of material is removed and a significant increase in value of the remainder is obtained as might occur if an in-shell premium is received following removal of a minimal amount of nuts. Where quality is poor and high cullage expected, a negative impact could occur. Table 7 provides a guide to determine value needed for remaining nuts to be equivalent to original value under varying removal and values/ton. -61- - -- - ---
TABLE 1. QUALITY AND VALUE OF CULL WALNUTSSEPARATED BY AN AIRLEG % Cull 5.0 3.5 2.9 3.5 1.4 1.3 Lbs/Ton Removed 100.9 69.2 58.1 69.1 27.8 26.0 Total valuey of Culls 1.23.35 1.67 4.52.74.74 Potential Value ~ Per Ton it24.40 10.00 57.40 130.80 53.00 53.00!/ Averages of sample,s, from each cultivar g/ Total value = (value/lbs) (lbs/ton removed) ~/ Potential value/ton = (~alue/lbs) (2000 lbs/ton) TABLE 2. SEPARATION OF WALNUTSWHENSUBMITTED TO A DOUBLEAIRLEG - 198f/ Separation % 77.7% 82.4 77.1 76.6 84.1 89.5 No. 1 Lbs/Ton 1553 1649 1543 1533 1683 1790 Y 17~3% 14.1 20.0 20.3 14.0 9.2 No. 2 Lbs(TonY 3 5 282 399 407 280 183!/ Averages of samples from each cultivar. g/ Lbs/ton = (%) (2000 lbs/ton) -62- -- -- -- -- ---
TABLE 3. VALUE PER LBS. OF NO.1, NO.2 AND NONAIRLEGGED(NAL) NUTS bjj Value/Lbs 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" test except, 95:1. TABLE 4. VALUE PER TON OF NONAIRLEGGED(NAL) AND AIRLEGGED (DOUBLE SEPARATION) NUTS value/tonl,3,4/ Franquet te NArJ:./ $615.68 593.58 630.33 705.62 612.13 668~60 No. 1&2 $577.23 592.20 626. 58 657.81 615.31 662.55 Difference -$38. 45-1. 38 3.75 47.81 + 3. 18 6.05!/ 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 if applicable.!!./ Values not significantly different using paired "T" test -63- - - - - ----
TABIE 5. VALUE PER IN-SHELL POUND OF WALNUTS EITHER AIRIEGGED (AL) OR NONAIRIEGGED(NAL) - SINGIE SEPARATION- 198:fJ value/lbv NAL ~. 3078. 2968.3152.3528.3061.3345 AL ~.3031.306 5.3243.3654.3180.3406!/ 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!/ 2,4/ Value Per Ton NAy)./ Ar)./ 615.68 577.66 593.58 592.34 630.33 629.73 705.62 703.61 612.13 627.11 + 668.60 670.82 + 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) -64- -- --
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".20.25.30.35.40.45.50.55.60 2.41.51.61.71.81.91 1.10 1.12 1.22 3.62.77.93 1.08 1.24 1.39 1.55 1.70 1.86 4.83 1.04.,.1. 25 1.46 1.67 1.88 2.08 2.29 2.50 5 1.05 1.32 " 1.58 1.84 2.11 2.37 2.63 2.89 3.12 6 1.28 1.60 1.91 2.23 2.55 2.87 3.19 3.51 3.83 7 1.51 1.88 2.25 2.63 3.01 3.39 3.76 4.14 4.52 8 1.74 2.17 2.61 3.04 3.48 3.91 4.35 4.78 5.22 9 1.98 2.47 2.97 3.46 3.96 4.45 4.95 5.44 5.93 10 2.22 2.77 3.33 3.88 4.44 5.00 5.55 6.11 6.66 11 2.47 3.09 3.71 4.33 4.94 5.56 6.18 6.80 7.42 12 2.73 3.41 4.09 4.77 5.45 6.14 6.82 7.50 8.18 13 2.99 3.74 4.48 5.23 5.98 6.72 7.47 8.22 8.97 14 3.26 4.07 4.88 5.70 6.51 7.33 8.14 8.95 9.77 15 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 $800 in total value.,- -65-