Reservoir tillage for controlling runoff and saving energy

As energy costs have risen in recent years, sprinkler irrigation equipment has been designed to apply water at lower pressures. Some low pressure devices have been developed for use with set-move systems, but the most popular application has been on self-propelled systems such as center-pivot and linearmove systems. Although low pressure sprinkler systems reduce irrigation pumping energy requirements in most cases, their use can greatly increase the potential for runoff. Since the pattern diameter of low pressure sprinklers is less than that of high pressure sprinklers, water is applied over a smaller area. This increases the application rate, and can often exceed the soil water intake rate. (These relationships are explained in the BPA Irrigation Energy Efficiency sheet on "Irrigation Runoff Control Strategies.") If the water application rate exceeds the intake rate, surface ponding can occur. This surface water can move within the field from high areas to low areas. Runoff or wet and dry areas provide visual evidence of surface water movement, which results in crop variability and loss in crop production. These losses can be reduced by increasing intake rates and/or surface storage capacity of the soil so that all water is retained where it is applied

A comparison of low pressure center pivot irrigation systems

Center-pivot sprinkler irrigation is presently being used on about 1.7 million acres in the Pacific Northwest. This acreage is increasing as other types of sprinkler systems are converted to center pivots. As electric energy rates increase and labor becomes more scarce, there is more incentive to convert to low pressure center pivots. However, there are potential problems associated with low pressure systems of which the user should be aware, namely pressure regulation and potential runoff. (See the companion bulletin on reservoir tillage for controlling runoff.

Low pressure center pivot irrigation and reservoir tillage

In 1989 there were 4 million ha of cropland under center pivot irrigation in the 17 western states (irrigation Journal 1990). The largest areas under center pivot are in the High Plains with soils ranging from sands to clay loams, and the Pacific Northwest with predominately silt loam soils. Most center pivot systems in the semi-arid areas are designed with gross capacities near the peak seasonal evapotranspiration rate, or approximately 10 mm/d. The length of a typical center pivot lateral ls about 400 m, which evolved from standard field sizes in the western U. S. Application rates are highest near the outer end of the lateral and are determined by the system capacity, length of lateral, and the width of the water application pattern

Secondary Overtriage of Trauma Patients to a Central Hospital in Malawi

Introduction: Secondary overtriage (OT) is the unnecessary transfer of injured patients between facilities. In low- and middle-income countries (LMICs), which shoulder the greatest burden of trauma globally, the impact of wasted resources on an overburdened system is high. This study determined the rate and associated characteristics of OT at a Malawian central hospital. Methods: A retrospective analysis of prospectively collected data from January 2012 through July 2017 was performed at Kamuzu Central Hospital (KCH) in Lilongwe, Malawi. Patients were considered OT if they were discharged alive within 48 h without undergoing a procedure, and were not severely injured or in shock on arrival. Factors evaluated for association with OT included patient demographics, injury characteristics, and transferring facility information. Results: Of 80,915 KCH trauma patients, 15,422 (19.1%) transferred from another facility. Of these, 8703 (56.2%) were OT. OT patients were younger (median 15, IQR: 6–31 versus median 26, IQR: 11–38, p < 0.001). Patients with primary extremity injury (5308, 59.9%) were overtriaged more than those with head injury (1991, 51.8%) or torso trauma (1349, 50.8%), p < 0.001. The OT rate was lower at night (18.9% v 28.7%, p < 0.001) and similar on weekends (20.4% v 21.8%, p = 0.03). OT was highest for penetrating wounds, bites, and falls; burns were the lowest. In multivariable modeling, risk of OT was greatest for burns and soft tissue injuries. Conclusions: The majority of trauma patients who transfer to KCH are overtriaged. Implementation of transfer criteria, trauma protocols, and interhospital communication can mitigate the strain of OT in resource-limited settings

Resonance Raman and photophysical studies of transition metal complexes in solution and entrapped in zeolites

We have obtained convincing evidence for localization of the optical electron on a single-ring fragment of a chelated bipyridine-like'' ligand (ie., pyridylpyrazine or 4-Methyl-bipyridine). In addition we have completed studies of Ru(bipyrazine){sub 3}{sup 2+} in aqueous sulfuric acid (0--98% by weight) and find clear evidence for sequential addition of six-protons to the six peripheral nitrogen atoms. Studies of zeolite-entrapped complexes are continuing and a series of homo- and heteroleptic complexes have been prepared and characterized. Finally, the synthesis of zeolite-entrapped metallophthalocyanines has now been developed and the copper and cobalt analogues synthesized. The characterization of these materials is now in progress

A comparison of low pressure center pivot irrigation systems

Center-pivot sprinkler irrigation is presently being used on about 1.7 million acres in the Pacific Northwest. This acreage is increasing as other types of sprinkler systems are converted to center pivots. As electric energy rates increase and labor becomes more scarce, there is more incentive to convert to low pressure center pivots. However, there are potential problems associated with low pressure systems of which the user should be aware, namely pressure regulation and potential runoff. (See the companion bulletin on reservoir tillage for controlling runoff.

Low pressure center pivot irrigation and reservoir tillage

In 1989 there were 4 million ha of cropland under center pivot irrigation in the 17 western states (irrigation Journal 1990). The largest areas under center pivot are in the High Plains with soils ranging from sands to clay loams, and the Pacific Northwest with predominately silt loam soils. Most center pivot systems in the semi-arid areas are designed with gross capacities near the peak seasonal evapotranspiration rate, or approximately 10 mm/d. The length of a typical center pivot lateral ls about 400 m, which evolved from standard field sizes in the western U. S. Application rates are highest near the outer end of the lateral and are determined by the system capacity, length of lateral, and the width of the water application pattern