The influence of selected environmental factors on diuron toxicity to winter wheat

Previous work has shown that diuron (3-(3, 4- dichlorophenyl)-1, 1-dimethylurea) is less toxic to fall-planted wheat than to wheat planted in the spring. Diuron has been a significant factor in increasing yields of winter wheat grown in Oregon's Willamette Valley. The influence of several selected environmental factors on diuron toxicity to Nugaines winter wheat (Triticum aestivum L.) were observed. Glasshouse, field and growth chamber studies were conducted using Chehalis loamy sand. Wheat grown in water temperature baths indicated that soil temperature had an important influence on diuron toxicity. Plants grown at 20 C were injured more severely than at 5 C soil temperature. Two intensities were used to study the effects of light in a range from 400 to 1600 ft-c. In these experiments strict control of other environmental factors was not achieved, but evidence was obtained that increased injury from diuron occurs with increased light intensity. Injury symptoms occurred earlier and were more severe under the higher intensities. In another study, plants were kept under 1000 ft-c light until minor symptoms developed. When one-half of these plants were exposed to eight hours of full sunlight almost complete chlorosis was observed in diuron-treated plants. No visible change occurred in treated plants left in the growth chamber. This study indicated that sunlight has an effect other than its influence on transpiration rate in causing injury to wheat. Soil moisture at the time of diuron application was studied in a glasshouse. Treated plants grown in soil which was wet when sprayed were not different from those grown in soil which was dry when sprayed and then watered. Fertility experiments produced conflicting results. In one, increased fertility increased injury. In another, experimental plants receiving one rate of complete fertilizer had less injury than plants receiving twice this rate or those receiving no added fertility. Further studies are needed to clarify the relationship of fertility level to diuron toxicity. Wheat grown in a glasshouse in soil maintained at field capacity was injured more by diuron than when the soil was maintained below field capacity. No difference in injury was found between plants grown in soil maintained at 70 or 85% field capacity. A field experiment was conducted to see what effect date of planting would have on pre-emergence applications of diuron to Nugaines wheat. Excessive injury occurred at all rates used. Less injury occurred to wheat following pre-emergence application of diuron in a late fall than in an early fall development. The resistance of Nugaines, a new variety, to diuron was compared in a glasshouse to the resistance of a standard variety, Druchamp. Nugaines was injured more by diuron than Druchamp. In a soil placement study, diuron was found to be taken up through the roots with little or no uptake through the emerging coleoptile. Herbicide effectiveness varied with closeness to seed. A narrow band of herbicide placed just below the seed produced more injury than when an untreated layer two-thirds inch thick was interspersed between the seed and. the treated layer. With the same total amount of diuron, more injury occurred from a narrow band than from a band twice as wide. Glasshouse studies indicated that depth of planting was the most important factor studied. Injury to wheat decreased while increasing depth of planting to one and one-half inches. No difference in diuron injury from applications in various stages of early development was observed. Stage of growth, at least up to three inches high, does not appear to be a major factor in folerance. An experiment using an infrared gas analyzer within a growth chamber revealed that wheat had not overcome two and three-hour exposures to a 10⁻⁵ M diuron solution 24 hours after treatment. Photosynthesis was completely inhibited prior to any visual diuron symptom development. No injury symptoms were evident when the plants were harvested 16 days after treatment although foliage yields were much reduced. On well-drained soils, diuron toxicity to wheat can be reduced by deeper plantings, lower light intensity and lower soil temperature. The results of these studies point out the need for seeding to the maximum practical depth with suitable commercial grain drills. Wheat should be planted in heavier soils which are adequately drained at a time when periods of low temperature and light intensity are likely to follow

An analysis of the reliability and design optimization of aluminium ribbon bonds in power electronics modules using computer simulation method

Ribbon bonding technique has recently been used as an alternative to wire bonding in order to improve the reliability, performance and reduce cost of power modules. In this work, the reliability of aluminium and copper ribbon bonds for an Insulated Gate Bipolar Transistors (IGBT) power module under power cycling is compared with that of wire bonds under power and thermal cycling loading conditions. The results show that a single ribbon with a cross section of 2000 μm × 200 μm can be used to replace three wire bonds of 400 μm in diameter to achieve similar module temperature distribution under the same power loading and ribbon bonds have longer lifetime than wire bonds under cyclic power and thermal cycling conditions. In order to find the optimal ribbon bond design for both power cycling and thermal cycling conditions, multi-objective optimization method has been used and the Pareto optimal solutions have been obtained for trade off analysis

The relationships of understory vegetation to stand composition, stand structure and soil series in the San Jacinto Experimental Forest of Texas

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Attitudes of Kaw Valley Residents toward Surface Water Quality

This report is based on an investigation of attitudes toward surface water quality in the Kansas (Kaw) River Valley. The purpose of the study is to help determine what actions Kaw Valley residents and farmers are willing to take to help improve surface water quality in the Kaw Valley. Specifically, the report uses results from focus groups and telephone surveys to address five questions: 1) What beliefs do residents have about the current state of surface water quality in the Kaw Valley? 2) How concerned are residents about the current state of surface water quality in the Kaw Valley? 3) What beliefs do people have about the impact of their personal actions on surface water quality in the Kaw Valley? 4) What behaviors would people be willing to change to improve the surface water quality in the Kaw Valley? 5) What would motivate people to make these changes

Kaw Valley Focus Groups on Local and Organic Produce

Environmentally-Identified Products (EIPs) refers to food products that are described as organic or sustainable, were grown using Integrated Pest Management (IPM), or are in other respects viewed as having a less-negative impact on the environment than directly competing products. This report summarizes findings from focus groups conducted in eastern Kansas to determine factors of consumer motivation for buying or not buying Environmentally-Identified Products. The findings were consistent with previous literature on demands for EIP foods