Christopher L. Butts

Determination of Maturity and Degree Day Indices and their Success in Predicting Peanut Maturity1

Abstract The ability to accurately assess and predict peanut maturity is a strong determinant of the economic return to the producer as it governs crop quality, flavor, and yield. However, the currently available methods used to predict peanut maturity are based on hull color determination and are somewhat labor-intensive and subject to the observers ability to finely discriminate color classes. The objectives in this study were: 1) create an index of maturity based on the distribution of peanut pods within the accepted maturity profile board classes that give the best quantifiable correlation with peanut yield, grade, and net value; and 2) test degree day models to determine their efficacy in predicting the optimum maturity index. Peanuts were harvested on 7 and 6 sequential dates in 2003 and 2004, respectively, at two sites in southwest Georgia, USA. Several maturity indices were calculated at each harvest based on the percentage of pods in each color class of the maturity profile board. For both sites...

ESTIMATING DRYING TIME FOR A STOCK PEANUT CURING DECISION SUPPORT SYSTEM

A decision support system to manage commercial peanut drying facilities was developed. Empirical equations to predict peanut drying time were developed using PNUTDRY, a bulk peanut curing model. Input data for the empirical model includes daily maximum/minimum ambient temperature, maximum allowable plenum temperature, maximum allowable temperature rise, initial and final pod moisture content, and airflow rate. Using kernel moisture content instead of pod moisture content, as required in the original simulation model, had minimal impact on predicted drying time. Regression equations comparing actual drying times to estimated drying times had an R2 of 0.72. When data from loads dried with ambient air were included, the R2 decreased to 0.48. The equations presented have been incorporated into a software module to manage peanut curing facilities, released as FarmSuite by the Peanut Foundation.

MOISTURE CONTENT DETERMINATION FOR IN-SHELL PEANUTS WITH A LOW-COST IMPEDANCE ANALYZER AND CAPACITOR SENSOR

Moisture content (MC) in peanuts is an important parameter to be measured and monitored at various stages in the peanut industry. In previous research, peanut MC was estimated by placing a sample between a set of parallel-plate conductors to measure capacitance and phase angle of the system with commercially available, expensive impedance analyzers. In this work, a low-cost impedance analyzer called the CI meter (Charis impedance meter) was designed and developed to measure impedance and phase angles at frequencies 1, 5, and 9 MHz using the parallel-plate sensor. The average MC values predicted by the CI meter for peanut samples harvested during two different years were compared with the standard air-oven values. In-shell peanut sample MC ranged between 6% and 23%. Over 90% of estimated in-shell MC values were within 1% of the air-oven values. Ability to determine the average MC of in-shell peanuts without shelling and cleaning them can be of considerable use in the peanut industry.

Economic Returns of Irrigated and Non-Irrigated Peanut Based Cropping Systems

Proper crop rotation is essential to maintaining high peanut yield and quality. However, the economic considerations of sustainable cropping systems must incorporate commodity prices, production costs, and yield responses of the crops within the cropping system. Research was conducted at the USDA/ARS National Peanut Research Laboratorys Multi-crop Irrigation Research Farm in Shellman, Georgia to determine the average net returns of irrigated and non-irrigated cropping systems consisting of peanut (Arachis hypogea L.), cotton (Gossypium hirsutum L.), and corn (Zea mays L.). Five replicated cropping systems provided data on yield responses from irrigated and non-irrigated rotation sequences defined as: continuous peanuts (PPP), cotton/peanuts/cotton (CPC), corn/peanuts/corn (MPM), cotton/cotton/peanuts (CCP), and cotton/corn/peanuts (CMP). The peanut yield in the PPP rotation was 3300 kg/ha in the non-irrigated treatment. Non-irrigated yields in CPC and MPM rotation sequences were 3940 and 3890 kg/ha, respectively and yields in CCP and CMP rotation sequences were 4770 and 4710 kg/ha, respectively. The peanut yield in the PPP rotation was 4080 kg/ha in the irrigated treatment. Irrigated yields in CPC and MPM rotation sequences were 5280 and 5230 kg/ha, respectively and yields in CCP and CMP rotation sequences were 5940 and 6010 kg/ha, respectively. The economic returns of the cropping systems were analyzed for 3 different price level combinations. Production costs (variable and fixed) were obtained from partial budgets. Returns were defined as the 3 year average net returns of each cropping system and were calculated for each price level combination which resulted in 57 comparable average net returns for the irrigated and non-irrigated treatments. Net returns were influenced by rotation sequence, price, and irrigation.

Five Years of Subsurface Drip Irrigation on Peanut: What Have We Learned?1

Abstract Long term peanut yield with various crop rotations and irrigated with subsurface drip irrigation (SDI) is not known. A subsurface drip irrigation system was installed in 1998 on a Tifton loamy sand (Fine-loamy, kaolinitic, thermic Plinthic Kandiudults) with five crop rotations, two drip tube lateral spacings, and three irrigation levels. Crop rotations ranged from continuous peanut (Arachis hypogaea L.) to four years between peanut rotated with either cotton (Gossypium hirusutum L.) and/or corn (Zea mays L.). Laterals were installed underneath each crop row (narrow) and alternate row middles (wide). Crops were irrigated daily at 100, 75 and 50% of estimated crop water use. Continuous peanut yields averaged 3107 kg ha−1 while peanut in rotation averaged 4031 kg ha−1. Yield of peanut in any rotation and with narrow spaced drip tube laterals averaged 4883 kg ha−1 and wide spaced laterals averaged 4592 kg ha−1. Peanut in any rotation and irrigated at 75% had the same pod yield as the 100% irrigated i...

IMPROVING PEANUT YIELD AND GRADE WITH SURFACE DRIP IRRIGATION IN UNDULATING FIELDS

A surface drip irrigation system was developed to irrigate peanut in two experimental fields: one with very little topographic variation on Greenville fine sandy loam soil, and one with undulating terrain containing 2.4% slope on Faceville fine sandy loam soil. Pod yield, kernel size distribution, and total sound mature kernels (TSMK) were evaluated with two peanut varieties, two planting patterns, and two drip tape lateral spacings. Test results were compared with the adjacent non-irrigated area planted with the same varieties of peanut. Soil temperature and volumetric water content were measured at different locations to monitor soil temperature and water movement from drip tapes. Maximum soil temperature in the irrigated area was substantially lower than in the non-irrigated area. For both 13 and 25 mm irrigations, about 16 h were required for water to move laterally 46 cm to reach the peak water content level. No significant difference (p < 0.05) was observed in yields between 0.9 m and 1.8 m drip tape lateral spacings. Peanut yields with drip irrigation were 1.4 times those of the non-irrigated yield. The irrigation water use efficiency from surface drip irrigation was 10 kg/ha-mm during the two growing seasons. Yields tended to slightly decrease as the land elevation decreased for both irrigated and non-irrigated zones. Compared to the non-irrigated areas, the drip-irrigated area produced a greater portion of larger kernels than smaller kernels. In the undulating area, the average TSMK was 73.7% and 64.9% for drip-irrigated and non-irrigated treatments, respectively. Average gross revenue was

Nondestructive NIR Reflectance Spectroscopic Method for Rapid Fatty Acid Analysis of Peanut Seeds

2,093 per ha with drip irrigation and

Pod Yield and Mineral Concentration of Four Peanut Cultivars Following Gypsum Application With Subsurface Drip Irrigation

1,253 per ha with no irrigation.

APPLICATION OF NIR REFLECTANCE SPECTROSCOPY ON DETERMINATION OF MOISTURE CONTENT OF IN-SHELL PEANUTS: A NON-DESTRUCTIVE ANALYSIS

Near Infrared Reflectance Spectroscopy (NIRS) was used to rapidly and nondestructively analyze the fatty acid concentration present in peanut seeds samples. Absorbance spectra were collected in the wavelength range from 400 nm to 2500 nm using NIRS. The oleic, linoleic and palmitic fatty acids were converted to their corresponding methyl esters and their concentrations were measured using a gas chromatograph (GC). Partial least square (PLS) analysis was performed on a calibration set, and models were developed for prediction of fatty acid concentrations. The best model was selected based on the coefficient of determination (R 2 ), Root Mean Square Error of Prediction, residual percent deviation (RPD) and correlation coefficient percentage between the gas chromatography measured values and the NIR predicted values. The NIR reflectance model developed yielded RPD values of three and above for prediction of the three fatty acids, indicating that this nondestructive method would be suitable for fatty acid predictions in peanut seeds.

Effects of Irrigation Method and Tillage Regime on Peanut (Arachis hypogaea L.) Reproductive Processes

Abstract A 2-year study (2004 and 2005) was conducted where gypsum was applied to four peanut (Arachis hypogaea L.) cultivars and irrigated with subsurface drip to determine pod yield and mineral concentration of peanut plants and kernels. Gypsum rates were none, 560 and 1120 kg/ha. Peanut cultivars were C99R, Georgia Green (GG), NCV-11 (NCV), and GA-O2C (O2C). Irrigation was applied daily with subsurface drip irrigation except when precipitation exceeded the estimated daily water requirement. Average soil Ca and S concentrations increased as gypsum was applied, 5% and 20%, respectively, compared with the non-treated control. The average soil calcium to potassium (Ca∶K) ratio increased to 9.8∶1 compared with 7.6∶1 prior to applying calcium. When averaged across calcium rates, peanut leaves had 3 and 14 times higher calcium and 1.4 times higher S concentrations compared with pegs and pods, respectively. The cultivars GG and NCV had the same pod yield. Cultivars C99R and O2C had the same yield as NCV but we...