Farmers Stock Peanuts Research Articles

Revised Thresholds for Runner Peanut Harvest Maturity Pertaining to Recent Cultivars in South Carolina

Revised Thresholds for Runner Peanut Harvest Maturity Pertaining to Recent Cultivars in South Carolina

Sound Splits as Influenced by Seed Size for Runner and Virginia Market Type Peanut Shelled on a Reciprocating Sheller

The objective of this study was to examine peanut (Arachis hypogaea L.) kernel percent sound splits as a function of sound mature kernel seed size when shelled on a reciprocating sheller. Data were compiled from a total of 139 field experiments conducted in the Virginia-Carolina region and Georgia from 2005 to 2020. Runner and Virginia peanut market types were graded according to United States Department of Agriculture (USDA) standards using standard sheller screens with upper grid sizes corresponding to the red pan from the pre-sizer of 10.3 × 19.1 mm (26/64 × 3/4 ″) and 13.5 × 25.4 mm (34/64 × 1 ″) with minimum bar grid clearances of 8.7 (11/32 ″) and 12.7 mm (1/2 ″), respectively. A subset of runner market type samples was graded using the Virginia sheller screen. Grade data per market type and sheller screen was analyzed separately. Among runner market types shelled with the standard runner-type screen, percent sound splits increased linearly with increasing seed size at the logit rate of 1.16 per sound mature kernel g (p < 0.001). Sound splits for Virginia and runner market types shelled on the standard Virginia-type screen did not significantly vary by kernel size (p = 0.939 and 0.687, respectively). Extra-large kernels (proportion) for Virginia types linearly increased with seed size at 1.91 per sound mature kernel g (logit scale) (p < 0.001). Runner market types sized 75 to 91 g/100 sound mature kernels (605 to 500 seed/lb) were estimated to have a 50% probability of a 2.3 to 4.5% or greater increase in sound splits when shelled with the standard runner-type screen compared to runner-type seed sized 55 g/100 sound mature kernels (820 seed/lb), respectively, equivalent to a potential deduction increase of 1.8 to 4.4 USD /1000 kg. For both Virginia and runner market types, seed weight linearly increased with pod weight at 0.169 and 0.195 g/g (p < 0.001), respectively. Results from this study may be used as a reference to suggest runner-type seed sizes above which larger reciprocating sheller screen utilization in line with USDA grading practices is warranted to reduce mechanically induced sound splits during grading and subsequent economic deduction penalties for corresponding farmer stock peanut.

In-shell Bulk Density as an Estimator of Farmers Stock Grade Factors

The objective of this research was to determine if bulk density of in-shell peanuts, called pod bulk density can be used to accurately estimate farmer stock grade factors such as total sound mature kernels and other kernels. Physical properties including pod or in-shell bulk density, pod size, and kernel size distributions are measured as part of the cooperative Uniform Peanut Performance Tests (UPPT). Using physical property data from three years (2002–2004) of UPPT, analysis of variance were performed to determine the effect of bulk density, location, year, peanut type, and cultivar on percent total sound mature kernels (TSMK), other kernels (OK), and farmer stock value (FSV). Results indicated that all effects in the model were significant in predicting both TSMK and FSV and accounted for most of the variation (R 2 50.80). Linear regressions of the UPPT (2002–2004) data (with pod bulk density as a single factor) showed that TSMK and FSV increased as pod bulk density increased with poor R 2 values (R 2 50.2). A second set of data collected during the 2005 peanut harvest by Federal State Inspection Service (FSIS) had similar results. Location and peanut type were highly significant factors in the variation of TSMK, OK, and FSV. Overall correlation of grade factors with pod bulk density, location, and type was poor (R 2 ,0.5). Based on these data, pod bulk density cannot be used to accurately estimate TSMK and OK for marketing farmer stock peanuts. Observed pod bulk density averaged for UPPT (all years) and FSIS was 316 kg/ m 3 for runner, 427 kg/m 3 for spanish, 491 kg/m 3 for valencia, and 258 kg/m 3 for virginia peanuts.

Development and commercial use of afla-Guard®, an aflatoxin biocontrol agent

A biopesticide, afla-guard(®), has been developed for controlling aflatoxin contamination in peanuts. This product provides the means of introducing a competitive, non-aflatoxigenic strain ofAspergillus flavus into soils where peanuts are being grown. The introduced strain competitively excludes toxigenic strains naturally present from invading developing peanuts. The biocontrol technology was made commercially available in 2004 by Circle One Global, Inc., upon receiving U.S. Environmental Protection Agency section 3 registration of afla-guard(®) as a biopesticide. The product was applied to approximately 2000 ha of peanuts in Georgia and Alabama during the 2004 crop year. Application of afla-guard(®) changed the composition ofA. flavus soil populations from an average 71.1% toxigenic strains in untreated fields to only 4.0% in treated soils. Analyses of farmer's stock peanuts being delivered at seven different locations showed a consistent reduction in aflatoxin contamination in peanuts from fields treated with afla-guard(®). Over all locations, aflatoxin averaged 78.9 ng/g in untreated peanuts compared with 11.7 ng/g in treated peanuts, an 85.2% reduction. Peanuts from treated and untreated fields were stored together in separate warehouse bins at two different locations. Aflatoxin analyses at the Unadilla, GA location showed that 48.4% of shelled edible lots from untreated fields contained unacceptable levels of aflatoxin (>15 ng/g). At the Dawson, GA location, 15.8% of shelled lots from untreated fields contained >15 ng/g. At both locations, no shelled edible lots from treated fields contained >15 ng/g. Mean aflatoxin concentrations in edible peanuts from untreated and treated fields at Unadilla were 36.2 and 0.9 ng/g, respectively. At Dawson the respective means were 7.2 and 2.2 ng/g.

AERATING FARMER STOCK PEANUT STORAGE IN THE SOUTHEASTERN U.S.

A two-year study was conducted to determine acceptable aeration strategies for farmer stock peanuts stored inconventional warehouses with and without headspace ventilation. Farmer stock peanuts were stored in 1/10th scale modelwarehouses with various aeration and ventilation treatments. Peanuts were loaded into each warehouse in the fall and storedfor about 190 days. Peanuts stored with aeration generally cooled faster than those stored without aeration. Aflatoxin wasdetected in the initial samples from the 2002 crop, but aeration significantly reduced the further production of aflatoxin instorage. Aflatoxin contamination was not a factor in the 2003 storage season. Value change based on kernel size distributionwas not significantly affected by aeration. An aeration rate of 0.31 m3 min-1 t-1 was sufficient for proper aeration when usedwithout headspace ventilation. The reduced aeration rate of 0.10 m3 min-1 t-1 in conjunction with headspace ventilationcooled the center of the peanut mass sufficiently to reduce the risk of aflatoxin production in storage. Headspace ventilationwith aeration reduced the temperature difference between the top and bottom layers of peanut during storage.

A MODEL FOR TEMPERATURE AND MOISTURE DISTRIBUTION DURING CONTINUOUS MICROWAVE DRYING*

ABSTRACT A heat and mass transfer model of continuous drying of farmer stock (in‐shell, uncured) peanuts (Arachis hypogaea L.) in a planar microwave applicator was developed and investigated. Transport phenomena equations previously developed for batch‐type microwave drying were successfully adapted to account for the spatial variation of the electric field inside the applicator. The theoretical equations developed, together with experimental methods, were used to determine the effect of microwave power level and dielectric properties on the temperature profiles and reduction in peanuts’ moisture content (mc). The temperature profiles from the solution of these equations matched the experimental ones determined using fiber optic temperature probes inserted into drying peanut pods. An exact theoretical determination of mc reduction during microwave drying was not possible due to the dependence of dielectric properties on mc. The surface temperature distribution of the peanut bed measured using infrared pyrometry was well correlated with internal temperature profiles.

Thermal Profiles and Moisture Loss During Continuous Microwave Drying of Peanuts1

Experimental methods were used to investigate the effect of microwave energy level on temperature profiles and moisture reduction of farmer stock peanuts (in-shell, uncured) during continuous microwave drying using a planar applicator. Temperature profiles, measured using fiber optic probes, were determined to be dependent on peanut moisture content and microwave power level. Although the maximum temperature in the microwave applicator was a function of power level only, the rate at which that maximum was attained was a function of the dielectric properties and moisture contents of the peanuts. Thermal imaging demonstrated that the temperature of the peanut bed surface at the exit of the microwave curing chamber was uniformly distributed. This study quantifies the relationships among the various parameters that influence the continuous microwave drying process of peanuts. The results provide a foundation for development of optimum process conditions in microwave drying of peanuts and other agricultural commodities.

MEASURING AIRFLOW DISTRIBUTION IN PEANUT DRYING TRAILERS

A method to measure airflow distribution exhausted from a filled peanut drying trailer was developed. Six 6.4-m peanut drying wagons were loaded with dry farmer stock peanuts at a local peanut processing facility. Three wagons had floors with 23% O.A. and three had 40% O.A. Peanuts were leveled on each trailer and peanut depth ranged from 114 to 130 cm. A 76-cm diameter, 1750 rpm, four-blade vane axial dryer with a 91-cm long straightening inlet transition was connected to each peanut drying trailer. The rated airflow capacity of the dryer was approximately 510 m3 min-1 at 124 Pa. Total airflow was measured using a pitot tube traverse across the inlet transition. Static pressure was measured in the wagon plenum using a U-tube manometer. The top of the trailer was divided into 40 sections using a 5 8 cell grid. The airflow through each grid cell was measured using a vane anemometer mounted on a conical transition placed in the center of each grid cell. No significant differences in static pressure, total airflow, or airflow distribution due to the percent O.A. of the perforated drying floor were detected. The average static pressure observed for wagons with the 23 and 40% O.A. was identical at 120 Pa. Total airflow measured at the fan inlet averaged 367 m3 min-1 for the 40% O.A. trailers compared to 366 m3 min-1 for trailers with 23% O.A. The total of the air flow measured as it exhausted from the peanuts was 63% of the flow measured using the pitot tube at the fan inlet.

A Note on the Accuracy and Variability of Grading and Marketing High Moisture Farmer Stock Peanuts

Abstract Previous research has shown that the farmer stock grade, lot weight, and market value could be accurately determined at kernel moisture contents greater than 10.5% without negative impact on either the producer or purchaser. In the 1998 and 1999 crop years, 686 farmer stock lots consisting of runner, Virginia, and Spanish types were graded and weighed at high moisture content (HMC), cured, and graded and weighed at low moisture content (LMC). The results indicated that LMC grade, lot weight, and lot value could be accurately predicted from HMC grade, lot weight, and lot value for individual farmer stock lots. However, the research did not address variability between HMC and LMC grade, weight, and values. In crop year 2001, a study was conducted in Georgia on runner-type peanuts to address variability in HMC and LMC grade, weight, and values. As farmer stock lots entered the buying point each lot was graded and weighed six times at HMC. The prediction equations estimated from the 1998 and 1999 studies were applied to the HMC values to obtain predicted grades, lot weights, and lot values. The lot was cured and graded and weighed six times at LMC and compared to the six predicted grades, lot weights, and lots values. Thirty-two farmer stock lots were included in the study. There were no significant differences in mean grade, lot weight, or lot value between the predicted and actual LMC values. Sound mature kernels and sound splits (SMKSS) differed by 0.07%. Mean lot weight differed by 7.7 kg (0.13%). Mean lot value differed by $20.11 (0.53%). Variability between predicted and actual SMKSS, lot weight, and lot value was not significantly different.

Processing Costs and Derived Demand for Screened Versus Unscreened Farmer Stock Peanuts1

Abstract Screening of farmer stock peanuts separates smaller, lower value pods from larger, higher value pods by mechanical separation. The returns to screening farmer stock peanuts depend on prescreened peanut quality. The purpose of this research was to examine the post-harvest processing costs and the resulting derived demand schedules between screened and unscreened lots. Screening increased value by $19.79/Mg in screened versus unscreened lots. Due to the removal of peanuts during the screening process, the farmer stock lot value and total value of 45 paired farmer stock lots comparing screened versus unscreened lots differed by only $2.45 (0.10%) and $109.98 (0.98%), respectively. Thus, the total purchase cost to shellers for screened lots is not significantly different from unscreened lots. Differences in shelled stock values on a per ton, per lot, and total basis were $38.86, $17.29, and $704.01, respectively, where processing cost differences were assumed to be zero. However, 16 shelled stock lots (20,287 kg) were rejected due to aflatoxin > 15 ppb in the unscreened peanuts compared to five rejected lots (5265 kg) in the screened peanuts. Estimates for blanching cost and product loss due to shrink and disappearance were applied to the unscreened and screened lots, respectively. For farmer stock lots in which at least one shelled stock lot was rejected, the added processing costs per Mg equate to $349.54 and $153.43 in the unscreened and screened lots, respectively. Deducting the added processing cost from the loan value ($677.73/Mg) resulted in net farmer stock values per Mg of $328.19 and $524.30 in the unscreened and screened lots, respectively. Thus, screening peanuts improved shelled stock peanut quality by reducing rejected lots and processing costs.

Cost of Aflatoxin to the Farmer, Buying Point, and Sheller Segments of the Southeast United States Peanut Industry

Abstract Aflatoxin in peanut imposes considerable economic cost to the southeast U.S. peanut industry. A federal marketing agreement administered by the Peanut Administrative Committee ensures the consumer that only edible quality peanuts are allowed entry into edible markets. The 1993-1996 crop years were analyzed to estimate the net cost due to aflatoxin to the farmer, buying point, and sheller segments of the southeast peanut industry. Farmer stock peanuts are examined for visible Aspergillus flavus, the mold primarily responsible for aflatoxin contamination in peanut. Detected lots with aflatoxin (Segregation III) are removed from edible channels because the lot is presumed to be at high risk for aflatoxin contamination and the value of farmer stock peanuts is reduced. The farmer segment net cost due to Segregation III lots averaged $2,595,937 per year. Segregation III lots are generally placed under loan in the Commodity Credit Corporation (CCC). Buying points are paid to handle peanuts for CCC, but at a lower rate per ton than commercial commissions; thus, a loss is incurred to the buying point segment. Buying point losses from handling Segregation III lots average $532,585 annually. The southeast peanut sheller segment incurred the highest cost associated with aflatoxin. The majority of the cost was due to the purchase of Segregation I farmer stock that required further processing due to the aflatoxin contamination found via chemical testing. The average net annual cost to the southeast sheller segment over the 4-yr period was $22,697,737. Segregation III lots and aflatoxin cost the farmer, buying point, and sheller segments of the southeast U.S. peanut industry $25,825,259 annually. On a total Segregation I farmer stock basis, aflatoxin cost the southeast peanut industry an average of $25.53/Mg and an average $69.34/ha.

Use of Plant Introductions in Peanut Cultivar Development

Abstract The genetic base of peanut (Arachis hypogaea L.) in the U.S.A. has at times been extremely narrow, particularly in specific production areas where a single cultivar may be grown in near-monoculture. Because peanut is not a native North American species, all U.S. cultivars necessarily trace their ancestry to plant introductions (PIs), but most of the genetic base of current cultivars rests on selections from farmer-stock peanuts of obscure origin. The objectives of this study were to (a) summarize and document the use of introduced genetic resources in cultivar development and (b) estimate the resulting economic impact. Different PIs were used as parents in early breeding programs. B.B. Higgins used Gambian line Basse as a parent of the GA 207 cross that gave rise to selections used in Georgia, Florida, and North Carolina as the basis for further improvement. PI 121067 was one of seven parents used by W.C. Gregory to initiate the program in North Carolina. A different set of PIs including PI 121070, PI 161317, PI 168661, and A. monticola Krapov. & Rigoni were used in the Texas and Oklahoma programs. Recycling of lines as parents and exchange of germplasm among breeding programs proliferated these PIs in the pedigrees of cultivars released since 1960. Over the past 20 yr, there have been concerted efforts to incorporate additional germplasm into U.S. breeding populations, usually with the purpose of improving resistance to diseases or pests, but also with the objective of broadening the genetic base. These efforts have had a significant economic impact on U.S. peanut farmers, the largest from the development of cultivars with resistance to Sclerotinia blight (Sclerotinia minor Jagger), root-knot nematodes (Meloidogyne spp.), and tomato spotted wilt virus. Use of these resistant cultivars has an economic impact of more than $200 million annually for U.S. peanut producers. In the runner and virginia market types, the average PI ancestry of all cultivars was 17.9%. There are several examples of successful cultivars with up to 25% ancestry from a single PI, including Georgia Green and NC-V11. In the spanish market type, most successful cultivars have derived 50% or more of their ancestry from PIs. Several recent or impending releases incorporate PI germplasm but have not yet been proven in the U.S. seed market.

Effects of Storage Environment on Farmers Stock Peanut Grade Factors in an Aerated Warehouse in West Texas

Abstract Temperature and relative humidity (RH) in an aerated warehouse in west Texas were monitored during storage of 1994 and 1995 crop farmer stock (FS) peanuts. Temperature and RH were measured at various positions throughout a vertical cross section of the peanut mass in the overspace and outside the warehouse. Data were collected at 1-hr intervals throughout storage. Peanut mass temperatures averaged 9.6 C during storage for the 1994 crop and 10.3 C for the 1995 crop. Relative humidity for the 1994 crop storage averaged 68.3 and 57.9% for the 1995 crop storage. Farmer stock grades were collected at warehouse loading and unloading for 10- to 12-t lots of peanuts stored in the warehouse (Wpnuts) and for samples (Spnuts) positioned at temperature and RH sensor locations. Wpnuts, in approaching equilibrium moisture with ambient RH, lost 2% moisture content both storage years. Spnuts lost 1.4% moisture content during storage of both crops. Percentage sound mature kernels (SMK) from Wpnuts decreased by 3.3% during 1994 crop storage and 6.6% during 1995 crop storage. Percentage SMK from Spnuts decreased 2.2 and 6.2% for the two storage years. Percentage sound splits (SS) for the Wpnuts increased 2.2% during 1994 crop storage and 4.2% during the 1995 crop storage. Percentage SS for Spnuts increased 2.4 and 6.1%, respectively. Changes in other grade factors were not consistent comparing percentage values for Wpnuts and Spnuts. Data indicate that maintaining grade and quality during FS peanut storage in west Texas will require knowledge of moisture content of peanuts placed into the warehouse and environmental monitoring in order to determine storage length. For 3- to 5-mo storage, it is recommended that FS peanuts have a moisture content close to 10% when placed into storage for peanuts to be above 7% when unloaded from the warehouse.

Feasibility of Purchasing Screened Farmer Stock Peanuts: The Sheller's Perspective

Abstract Mechanical screening to separate foreign material, loose shelled kernels (LSK), and smaller, lower value pods (thrus) from larger, higher value pods (overs) increased the value of peanut lots compared to unscreened lots. The average value of overs was $29.15 per Mg higher than unscreened peanuts. Marketing overs translates into higher purchase cost to shellers. The percentage of LSK in unscreened peanuts was a key factor in whether shellers would prefer to purchase screened lots because, as LSK of unscreened lots increases, the value per Mg of farmer stock (FS) peanuts decrease. The value of unscreened lots with 1% LSK was $12.33 per Mg less (not significant) than the resulting value of lots after screening, while the value of unscreened lots with 10% LSK was $57.57 per Mg less (P = 0.01) than the resulting value of lots after screening. LSK in screened lots were generally reduced to less than 1% limiting the availability of LSK for shellers to recover and use in edible channels. However, removal of high risk components (LSK and small kernels) should reduce aflatoxin levels in overs lots compared to unscreened lots. Significant increases in jumbo and medium outturn and decreases in No. 1 outturn were associated with shelling screened lots. Gross shelled stock value increased $32.37 per Mg for screened lots with no LSK recovery and $10.82 per Mg for unscreened lots with total LSK recovery. The differences in dollar returns from purchasing and shelling screened lots were compared to unscreened lots for different levels of LSK in unscreened lots and varying LSK recovery levels into edible channels.

Use of Loose Shelled Kernels to Estimate Aflatoxin in Farmers Stock Peanut Lots1

Abstract Loose shelled kernels (LSK) are a defined grade component of farmers stock peanuts and represented, on the average, 33.3% of the total aflatoxin mass and 7.7% of the kernel mass among the 120 farmers stock peanut lots studied. The functional relationship between aflatoxin in LSK taken from 2-kg test samples and the aflatoxin in farmers stock peanut lots was determined to be linear with zero intercept and a slope of 0.297. The correlation between aflatoxin in LSK and aflatoxin in the lot was 0.844 which suggests that LSK taken from large test samples can be used to estimate the aflatoxin concentration in a farmer's lot. Using only LSK allows large test samples to be used to estimate the lot concentration since LSK can be easily screened from a large test sample. If LSK accounts for 7.7% of the lot kernel mass, a 50-kg sample will yield about 3.9 kg of LSK which can be easily prepared for aflatoxin analysis. Increasing the test sample size from 2 to 50 kg reduced the coefficient of variation associated with estimating a lot with 100 parts per billion (ppb) aflatoxin from 114 to 23%, respectively. As an example, a farmers stock aflatoxin sampling plan with dual tolerances (10 and 100 ppb) that classified lots into three categories was evaluated for two test sample sizes (2 and 50 kg). The effect of increasing test sample size from 2 to 50 kg on the number of lots classified into each of the three categories was demonstrated when measuring aflatoxin only in LSK.

Economic Feasibility of Screening Farmer Stock Peanuts Prior to Marketing

Abstract Screening farmer stock peanuts prior to marketing provides a method to increase the per-ton value of peanuts. The mechanical separation of larger, higher value pods (overs) from smaller, lower value pods—which includes foreign material (FM) and loose shelled kernels (LSK) (thrus)—results in significant changes in farmer stock grade. Based on data from 394 runner lots in the Southeast, the percentage of sound mature kernels and sound splits (SMKSS), LSK, FM, and other kernels (OK) was changed by +0.61, −4.31, −2.32, and −0.3 between overs and unscreened lots, respectively. The average value of farmer stock peanuts was $29.15/ Mg higher in the screened lots (overs) compared to the unscreened lots. Although the average per-ton value of screened peanuts is increased, economic feasibility of screening is dependent upon several factors. Two specific marketing scenarios for farmers are analyzed including production of quota poundage only and production in excess of quota poundage where additional peanuts are used to replace peanuts removed during the screening process. Thus, opportunity cost must be included. Typical investment in high capacity (minimum 18 Mg/hr) screening equipment is approximately $150,000. Amortized at 10% rate of interest over a 6-yr period with depreciation allowances and labor and energy cost included, a minimum of 4536 Mg/yr must be screened to effectively ldquo;spread” fixed cost, thus indicating that only exceptionally large farmers, groups of farmers, or buying points have sufficient volume for screening. Further, the quality of peanuts prior to screening also impacts economic feasibility. These factors will be incorporated to estimate probability decision thresholds to determine if individual lots can be profitably screened prior to marketing.

Feasibility Tests for a Two-Stage Batch Dryer for Curing Farmer Stock Peanuts1

Abstract A two-stage batch dryer for farmer stock peanut was developed by a commercial grain dryer manufacturer and tested at a commercial peanut buying point during the 1996 and 1997 harvests. A 7.3-m diameter grain bin provided the superstructure for two peanut curing chambers. Each chamber had an approximate capacity of 18,000 kg of in-shell peanuts. Comparisons between conventional peanut curing wagons and the bin dryer were conducted. Recorded data included temperature and relative humidity in both type dryers, drying time, moisture content throughout curing, farmers stock grades, milling quality, and seed germination. A total of 451,717 kg were cured in the two-stage dryer and 215,460 kg in conventional dryers. The initial moisture content of peanuts averaged 19% wet basis and dried at an average moisture removal rate of 0.45%/hr. The moisture removal rates for the two dryers were not significantly different. The final moisture content averaged 11%. Moisture content at the time of grading averaged 9%. Farmers stock grades and milling quality were not significantly different. The average quota support price, including LSK for peanuts cured in conventional dryers, was $630.47/1000 kg compared to $636.08/1000-kg peanuts cured in the two-stage dryer. Seed germination averaged 75.8 and 76.1% for conventional and bin-dried peanuts, respectively. The twostage batch dryer was comparable to the current wagon-drying system. A single batch in the two-stage dryer was equivalent to three peanut wagons.

A Screening Attachment for an Amadas Peanut Combine1

Abstract Some farmers mechanically screen farmer stock (FS) peanuts after combining to remove undesired materials for value and quality improvement. Screening is accomplished with low capacity, portable screens at the field after combining or with high capacity cleaners or screens at buying points. An alternative method for FS peanut screening has been developed cooperatively by Amadas Industries and USDA-ARS, National Peanut Research Laboratory utilizing an experimental combine screening attachment. The attachment is a hydraulically driven, rotating cylindrical screen (trommel) with an axis inclined less than 10° from horizontal during operation. Peanuts are screened with the trommel prior to entering the combine basket, and smaller, unwanted materials are returned to the soil. Thirty-eight lots of FS peanuts averaging 3.27 t/lot were combined throughout all U.S. peanut-producing regions to examine performance. Foreign materials for the screened lots averaged 2.15% less than the unscreened lots (P = 0.05). Hulls were 0.62% less in the screened lots (P = 0.05). None of the other grade factors or market values per hectare were significantly different for runner peanuts. Foreign materials for screened virginia peanuts were 2.44% less than in unscreened (P = 0.01). Loose shelled kernels were 0.44% higher (P = 0.05), hulls 0.67% lower (P = 0.10), and damage 0.56% higher in screened peanuts than in unscreened. None of the other grade factors or market values per hectare were significantly different for Virginia peanuts. Although most grade factors and values per hectare were not significantly different for screened and unscreened peanuts tested, foreign materials were reduced significantly providing needed quality improvement. Possible cleaning costs also could be reduced with the attachment.

Correcting Current Moisture Calculations for Purchasing High Moisture Farmers Stock Peanuts1

Abstract The U.S. peanut industry may eliminate the 10% moisture content threshold for purchasing peanuts to facilitate implementing continuous flow drying systems and to increase the efficiency of the postharvest processing system. Equations based on the theoretical definition of wet basis moisture content were proposed to determine the weight of various components in a load of farmers stock peanuts. These equations more accurately describe and account for the distribution of moisture within a load of peanuts. Accurate descriptions of the amount of loose shelled kernels, foreign material, and in-shell peanuts would enable improved tracking of losses during storage. Compared to the current price structure, the proposed equations predict reduced payments to growers no more than $30 per 5-mt load of peanuts. The maximum reduction of $30 occurred if peanuts were delivered and marketed at 30% w.b. moisture content. A reduction of approximately $8.50 would occur for a 5-mt load delivered at 15% moisture content. The cumulative economic impact warrants adjustment of the peanut support price schedule if accurate accounting of moisture is implemented.

A Triple Deck, Parallel Belt Screen for Farmer Stock Peanuts1

Abstract Belt screens currently used in the peanut industry separate farmer stock peanut materials into two size categories based on diameter. Utilizing belt screens for obtaining more than two size categories requires two or more screens with different spacings between belts for each screen. A modification of the belt screen design was developed incorporating three screen decks into a single machine. The three decks provide the ability to separate small foreign materials, large vegetative foreign materials, and loose shelled kernels and small pods from farmer stock peanuts. The machine was equipped with fixed spacings appropriate for screening farmer stock peanuts (cv. Florunner) for performance testing. Round belts (1.27 cm dia.) for the three decks were spaced on sheaves to provide 0.64-, 1.03-, and 2.54-cm openings between belts. Screen capacity and separation performance were evaluated by varying material feed rates and belt speeds. Belt speeds evaluated were 105.2, 117.3, 130.0, 140.7, and 152.4 cm/sec and feed rates varying from 5170 to 27,210 kg/hr. An average of 91.55% of the sample weights was divided into the 10.3-mm < diam. < 25.4-mm separation. Compared to prescreening sample composition, the average LSK percentage was reduced by 6.39% and FM by 7.36% in the 10.3-mm < diam. < 25.4-mm separation. Within the ranges tested, derived equations indicated that feed rate and belt speed had limited effects on separations. The openings between the belts appeared to influence material separation more than feed rate and belt speed.