Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/12/2004
Publication Date: 9/23/2005
Citation: Lamb, M.C., Blankenship, P.D., Whitaker, T.B., Butts, C.L. 2005. Accuracy and variability of grading and marketing high moisture farmer stock peanuts. Peanut Science. 30:94-99
Interpretive Summary: Current regulations require that the kernel moisture content of farmer stock peanuts must be less than 10.5% before grading. This regulation mandates that individual loads of farmer stock peanuts be identity preserved till grading which increases handling costs and prohibits investment in more efficient curing equipment. A study was conducted in 1998 and 1999 on 686 farmer stock lots to develop equations to predict low moisture content grade, lot weight, and lot value from high moisture content grade factors and lot weight. At the request of the US peanut industry, a study was conducted in 2001 to analyze the accuracy and variability of grading peanuts at high moisture content versus low moisture content peanut grading. Thirty-four farmer stock lots were included in the study and each was graded six times at high moisture content and six times at low moisture content. Mean farmer stock grade factors, lot weight, and lot value when predicted from high moisture content did not significantly differ from the low moisture content grade factors, lot weight, and lot value. Coefficients of variation indicated that variability was not increased between high moisture content and low moisture content grading.
Technical Abstract: Previous research has shown that the farmer stock grade, lot weight, and value could be accurately determined at kernel moisture contents greater that 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 of this research 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-four farmer stock lots were included in the study. There were no significant differences in mean grade, lot weight, and lot value between the predicted and actual LMC value. Sound mature kernels and sound splits (SMKSS) differed by 0.10%. Mean lot weight differed by 11 pounds (0.12%). Mean lot value differed by $12.74 (0.50%). Variability between predicted and actual SMKSS, lot weight, and lot value was not significantly different.