The effects of subsoiling, in addition to ordinary plowing and disking on crop yields and moisture and organic matter content of the soil

This study was designed to determine the effects of shattering the subsoil below normal plowing depth on the yields of corn, wheat and red clover hay, the moisture content of the soil at critical periods during the growing season and the organic matter content of the subsoil as an evidence of increased root development in the subsoil. The longevity of these effects were also to be determined by repeating the crop rotation on the same plots without re-subsoiling. An evaluation of heavy-duty disking as a substitute for ordinary plowing in the initial preparation of a seedbed for corn was included in this study as a secondary objective

A quantitative description of the vocalizations and vocal activity of the Barred Owl

Barred Owls (Strix varia) are highly vocal and perform a diverse array of vocalizations. They are often monitored by acoustic surveys, yet Barred Owl vocalizations and vocal behavior are poorly described. We present a detailed analysis of Barred Owl vocal behavior with four goals: (1) to provide a quantitative description of Barred Owl vocalizations, including those given within duets, (2) to examine diel variation in vocal output for multiple vocalizations, (3) to explore the use of vocalizations inside and outside of duets, and (4) to identify sex-specific vocal characteristics and discuss their utility in identifying an owl\u27s sex. Adult Barred Owls produced 13 distinct vocalizations that could be assigned to call type on the basis of fine-structural measurements. Barred Owls vocalized throughout the day but were more vocal at night with peaks in vocal activity from 18:00 to 20:00 and 02:00 to 05:00. Most calls were produced throughout the night, but some (e.g., alarm calls) were more common at particular times. Two types of vocalizations were produced only within duets, and one type of vocalization occurred primarily outside duets. Calls of females were higher in pitch with longer terminal notes and more vibrato than those of males. Using these differences, cluster analysis assigned owls to two groups corresponding to predicted sex with 91% accuracy. We discuss possible functions of certain vocalizations and how understanding the vocal repertoire and sex differences of this species\u27 acoustic signals will benefit behavioral studies and monitoring, including Spotted Owl (Strix occidentalis) conservation. © The Cooper Ornithological Society 2010

Inconsistent geographic variation in the calls and duets of Barred Owls (Strix varia) across an area of genetic introgression

Much of our understanding of vocal geographic variation in birds is based on the dialects of oscine songbirds that learn their songs. Recent studies have revealed that nonoscine vocal behavior is more complex than previously thought, yet we still have a rudimentary understanding of how vocalizations of suboscine and nonpasserine birds are infuenced by genetic and geographic variation. We examined geographic variation in male calls, female calls, and duets of Barred Owls (Strix varia) among 10 locations across the southeastern United States. Recent molecular work revealed two genetically distinct clades of Barred Owl at either end of our transect, with substantial introgression in between. We predicted that calls would vary with genetic distance in a clinal pattern, but that duets and duetting behavior might exhibit dialects similar to that of learned bird song. Discriminant analysis did not reveal any components of vocalizations or vocal behavior that could be used to assign vocalizations to the correct recording location. There were no relationships between any aspect of vocal structure or behavior and geographic distance. Some characteristics of male and female calls and duets varied among locations, but there was no discernible geographic pattern. We suggest that such inconsistent geographic variation in vocalizations is not unexpected for non-song-learning species. The lack of geographic pattern in vocalizations may be due, in part, to high levels of individual variation, recent signal evolution, and local adaptations. We discuss the application of these results to the ontogeny and evolution of complex, coordinated vocal behavior in nonpasserines. © The American Ornithologists\u27 Union, 2012. Printed in USA

Eradication of Exotic Weeds in Australia: Comparing Effort and Expenditure

Weeds have many adverse impacts on agriculture and the environment and therefore are often targets of eradication attempts. Eradication attempts involve large commitments of labour and financial resources over significant periods of time. Using data from 12 Australian weed eradication attempts the authors compare work hours and expenditure on each attempt for various initial-infestation sizes. Analysis of a limited data set shows: (1) that while the eradication effort increases with the initial area of infestation, the effort applied per hectare actually decreases; (2) that application of a greater work effort was not the reason why completed eradications were successful; and (3) that the larger the initial infestation size, the smaller the amount of resources applied per hectare for eradication.weeds, eradication, work effort, expenditure, infestation size, Environmental Economics and Policy, Resource /Energy Economics and Policy,

Levels and Timing of Nitrogen Fertilizer Applications for Tall Fescue in Central Alabama

Tall fescue (Festuca arundinacea Schreb.), the most important cool season perennial pasture grass in the United States, is generally well adapted to the northern two-thirds of Alabama. Unfortunately, the most commonly grown tall fescue cultivar, Kentucky 31, is of northern origin and is dormant during the winter. To reduce this problem, AU Triumph was selected from Mediterranean germplasm. The Alabama Agricultural Experiment Station released this cultivar to growers in 1981. Compared to Kentucky 31, AU Triumph produces about 80 percent more forage during the winter and produces mature seed about 2 weeks earlier in the spring. Total annual forage production for the two cultivars is usually about the same

Levels and Timing of Nitrogen Fertilizer Applications for Tall Fescue in Central Alabama

Tall fescue (Festuca arundinacea Schreb.), the most important cool season perennial pasture grass in the United States, is generally well adapted to the northern two-thirds of Alabama. Unfortunately, the most commonly grown tall fescue cultivar, Kentucky 31, is of northern origin and is dormant during the winter. To reduce this problem, AU Triumph was selected from Mediterranean germplasm. The Alabama Agricultural Experiment Station released this cultivar to growers in 1981. Compared to Kentucky 31, AU Triumph produces about 80 percent more forage during the winter and produces mature seed about 2 weeks earlier in the spring. Total annual forage production for the two cultivars is usually about the same