Potential use of hyper-spectral and multi-spectral remote sensing imagery to enhance management of peanut (Arachis hypogaea L.)

Experiments were conducted during 2003 and 2004 to determine if peanut yield and market quality factors differed when paraquat was applied 24 to 28 days after emergence or when 2,4-DB was applied in mid August to peanut seeded during the early, mid-, and late May and during early June. In other experiments conducted from 2003-2004, peanut was planted with or without aldicarb in the seed furrow to control tobacco thrips (Frankliniella fusca Hinds) followed by paraquat. In a final set of experiments conducted during 2005, treatments consisted of seeding with or without aldicarb followed by no paraquat or paraquat applied 24 to 28 days after emergence. Peanut yield and percentages of extra large kernels, total sound mature kernels, and farmer stock fancy pods were affected by planting date and pesticide treatment independently. Pod yield was higher in one of two years when peanut was planted in early and mid-May compared with late May and June. In the other year peanut yield was higher when seeded in mid-May compared to planting in early or late May or early June. In three of nine experiments pod yield was reduced when aldicarb was not applied and tobacco thrips were not controlled. In five experiments pod mesocarp color was used to determine if damage from tobacco thrips or paraquat delayed pod development and maturity. No differences in percentages of pods considered ready for digging were noted even though significant tobacco thrips damage and injury from paraquat was observed early in the season. Several differences in canopy reflectance were noted when hyperspectral imaging was used within 1 week of digging and inverting vines but they were not associated with pod maturity.; Experiments were conducted in North Carolina from 2003-2005 to determine if reflectance of the peanut canopy could be used as an indicator of pod maturity. The cultivars VA 98R and NC-V 11 were planted beginning in early-May through early-June during each year and reflectance was measured in mid- to late-September and was compared with the total percentage of pods with brown and black mesocarp color. In other experiments, the cultivars Gregory and NC 12C were dug weekly from mid-September through mid-October. Reflectance was determined at two dates spaced approximately 2 weeks apart for the cultivar Gregory. Experiments were also conducted to determine if differences of reflectance characteristics existed between the cultivars Gregory and Georgia Green and between the cultivars VA 98R and Perry seeded in single and twin row planting patterns were compared. Pod yield was affected by planting date with optimum yield occurring when peanut was planted in mid-May. Although pod yield differed among experiments, percentages of extra large kernels (%ELK) and total sound mature kernels (%TSMK) increased as digging was delayed. Pod yield of the cultivars Georgia Green and Gregory was similar in four of six experiments; yield of Georgia Green exceeded that of Gregory in two experiments. Planting peanut in twin rows resulted in higher yields than planting in single rows regardless of year or cultivar. Reflectance characteristics differed in only 1 of 3 years for the cultivar VA 98R and there were no differences for the cultivar NC-V 11 even though the percentage of mature pods ranged from 15 to 69% when assessed in mid- to late-September. Differences in reflectance characteristics were noted when the cultivars Gregory and Georgia Green were compared but not between the cultivars VA 98R and Perry. Reflectance characteristics of peanut did not differ when row pattern plantings were compared.; Experiments were conducted during 2004 and 2005 to develop spectral signatures of peanut with visual symptoms of nitrogen (N) deficiency, injury from a combination of low pH and Zinc (Zn) toxicity, drought stress, early leaf spot ( Cercospora arachidicola Hori) and web blotch (Phoma arachidicola Marasas et al.) lesions, and following application of acifluorfen, bentazon, cletho...