This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Two experiments were designed to study efficacy and uptake and translocation of an ester formulation of triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) in four solvents, aromatic solvent, aliphatic solvent, vegetable oil, and kerosene following stem applications to red maple (Acer rubrum), white oak (Quercus alba), and Virginia pine (Pinus virginiana). Another objective was to explore correlations between efficacy and uptake and translocation. Additional objectives included examining the influence of concentration, dose, and stem diameter on efficacy and the influence of bark thickness and season of treatment on uptake and translocation. Concentration ranged from 0.25 to 1 lb a.e./gallon in the efficacy study and was 1 lb a.e./gallon in the uptake study. Dose ranged from 0.4 to 2 ml/cm of stem diameter in the efficacy study and was 0.15 ml/cm of stem diameter in the uptake study. Efficacy evaluations were made 14 months following treatment in June. C¹⁴- triclopyr was used to determine uptake and translocation. Saplings in the uptake study were harvested three weeks following treatments in February, May, and July. Aliphatic solvent, vegetable oil, and kerosene treatments resulted in excellent crown volume control, largely independent of concentration, dose, and stem diameter. Aromatic solvent gave poorer results, dependent on concentration, dose, and stem diameter, except among the maples. Herbicide uptake with the vegetable oil treatment was greatest. The other solvents provided similar levels of uptake. Uptake was greatest among the maples, the thinnest-barked species, and about equal in the oaks and pines. Discrepancies between solvent differences in the efficacy and the uptake studies may have been, in part, a consequence of smaller doses used in the uptake study along with conditions which likely promoted greater solvent evaporation than those under which the efficacy study was performed. Faster evaporation of the kerosene and aliphatic solvents may have reduced their penetration of the outer bark while slower evaporation of aromatic solvent and vegetable oil likely had less influence on their penetration. Stem diameter correlated negatively with crown volume control, despite basing dose on stem diameter, suggesting that the square of diameter, or stem volume, may be a more appropriate basis for determining doses. Uptake correlated negatively with bark thickness. Uptake did not vary significantly among seasons but translocation did. Movement to the leaves occurred following the May and July treatment but virtually none to leaves or buds following the February treatment. The high degree of sprouting which occurred among saplings in the May treatment compared with none among saplings in the July treatment would suggest that downward translocation of herbicide was greater in July. / Master of Science

Pre-harvest glyphosate is often applied to cereal crops, such as oats, to insure uniform grain ripeness at harvest. However, some buyers have claimed that this practice negatively affects oat end product quality. Oat samples were grown in two different growing locations for each of two crop years, and glyphosate was applied at the soft dough, physiological maturity, or not applied. Groat quality and starch quality parameters were analyzed, and rolled oats were produced to analyze end product quality. Groat hardness, groat percentage, and percent plump groats were significantly (P<0.05) affected by glyphosate application at the soft dough stage. However, application of glyphosate at physiological maturity did not appear to detrimentally affect groat starch or end product quality. Therefore, pre-harvest glyphosate application isappropriate for oats providing it occurs after plants reach physiological maturity.

In full-season-soybean weed management experiments, the addition of glyphosate [N-(phosphonomethyl)glycine], paraquat (1,1'-dimethyl-4,4'-bipyridinium ion), or HOE-0661 [ammonium (3-amino-3-carboxypropyl)methylphosphinate] to chlorimuron [2-[[[[(4-chloro-6-methoxy-2-pyrimidinyl)amino] carbonyl]amino]sulfonyl] benzoic acid] plus linuron [N'- (3,4-dichlorophenyl)-N-methoxy-N-methyl urea] was required for effective weed control, especially of eastern black nightshade (Solanum ptycanthum Dun.). In double-crop experiments over 4 years including 10 experimental sites and 8 different weeds, chlorimuron plus linuron provided good control of vegetation at planting and residual weed control without glyphosate, paraquat, or HOE-0661. Cyanazine [2-[[4-chloro-6-(ethylamino)-1,3,5-triazin- 2-yl]amino]-2-methylpropanenitrile] and 2,4-D [(2,4- dichlorophenoxy)acetic acid] were the most effective herbicides for horseweed (Conyza canadensis (L.)Cronq.) control prior to establishing full-season no-till soybeans (Glycine max (L.)Merr.). In greenhouse experiments, emergence of tobacco (Nicotiana tabacum L.) seedlings was severely inhibited by all chlorimuron-containing treatments and by the highest rates of imazaquin [2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid]. Growth of tobacco transplanted into a treated potting mixture was severely reduced by all rates of chlorimuron-containing herbicides, and to a lesser extent by imazaquin. Postemergence applications of chlorimuron alone or imazaquin did not significantly affect tobacco growth. In the greenhouse, 'Vance' and 'Forrest' soybean varieties were more sensitive to chlorimuron than were 'W-20' (a sulfonylurea-resistant variety), 'Essex', or 'Hutcheson'. Herbicide injury increased with increasing soil pH. Under simulated rainfall conditions, chlorimuron movement in soil increased with increasing pH and rainfall. Soybean injury may be more directly related to chlorimuron in the soil water solution than to the amount of chlorimuron present in the soil profile. Laboratory experiments indicated that tolerance of pitted (Ipomoea lacunosa L.) and entire leaf (Ipomoea hederacea var. integriuscula Gray) morningglories to chlorimuron may be due to reduced herbicide uptake. Sensitivity of 'Vance' soybeans may be associated with the inability to rapidly metabolize chlorimuron herbicide. / Ph. D.

The primary objective of this research project is to develop a system for precision spraying of herbicides in a corn field. Ultimately, such a system would permit real-time image collection, processing, weed identification, mapping of weed density and sprayer control using a tractor-mounted digital camera and on-board computer. The initial hypotheses underlying this project were (1) that it is possible to train an artificial neural network (ANN) to distinguish weeds from a crop species (corn in this study); (2) that it is possible to differentiate between weed species; and (3) that precision spraying can significantly reduce the quantity of herbicide needed to protect crop yields, thus reducing both the costs and environmental impacts of such applications. Thus, development of an ANN for this purpose was the main focus of the research project. / Since the success of ANN development is primarily dependent on the type of information that it is provided, much of the work involved investigation of different approaches to extracting information from the digital images of field sections and individual objects (weeds or corn plants), as well as analysis of the type of information extracted. The applicability of a given image processing method was evaluated in terms of the image recognition accuracy, as well as the computer time and memory requirements for processing and obtaining ANN output, since speed is of the essence in real-time applications. The greenness method based on a pixel-by-pixel analysis of red-green-blue intensity value of the original images was the most successful and was used in further work. / As it turned out, ANN development for this purpose was difficult. While the success rate for recognition of corn plants was high (80% or greater), the success rate for recognition of weeds tended to be low. Improvements in weed recognition were met with decreases in the success rate of corn recognition. Differentiation between weed species was less than desirable. Differentiation between corn and a given weed species was also not as good, particularly when the weed species was similar in appearance to the young corn plant. / Therefore, another strategy was developed to recognize weeds in the field by taking images between the corn rows. Previously, the images were taken randomly in the field. The images were processed to obtain percent greenness in each image and this information was used to create weed coverage and weed patchiness maps. Based on these maps, herbicide spraying was decided and spraying amounts were determined. In terms of real-time, it was possible to process the equivalent of one metre of row per second. Although this is slow compared to tractor speed in the field, the computer was not operating under dedicated conditions as one would require for the real-time application. Thus, the results were considered encouraging. / The final stage of the work involved an evaluation of the potential herbicide savings from a precision spraying system. This was done by using the weed coverage and weed patchiness maps as inputs to a simulated fuzzy logic controller, and integrating the output of the controller over the field area corresponding to the input images. The simulations with different fuzzy rules and membership functions indicated that the precision spraying approach could reduce the amount of herbicide needed for weed control in a corn field by up to 15%.

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