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Full-Text Articles in Life Sciences
Pig Vocalizations Under Selected Husbandry Practices, Hongwei Xin, James A. Deshazer, D. W. Leger
Pig Vocalizations Under Selected Husbandry Practices, Hongwei Xin, James A. Deshazer, D. W. Leger
Hongwei Xin
Acoustical characteristics of vocalizations of sows, piglets, and nursery pigs under selected husbandry practices were analyzed with a digital signal processing system. The duration (D) and major energy-resonance frequency (P) for each call were determined as follows: a) processing of piglets (D = 0.81 s and f* = 3 700 Hz); b) food anticipation of breeding-gestation sows (2.50 s and 3 000 Hz); c) isolation of piglet (0.34 s and 500, 3 500 Hz); d) startling of nursery pigs (0.29 s and 900 Hz); e) sows in heat (3.07 s and 1 375 Hz); f) farrowing (0.10 s and 3 …
Phosphorus Fertilization Through Drip Irrigation, Robert Mikkelsen
Phosphorus Fertilization Through Drip Irrigation, Robert Mikkelsen
Robert Mikkelsen
Although P fertilization through drip irrigation systems has not been widely recommended, a review of currently available literature indicates this fertilizer application technique can offer many advantages when performed properly. Using drip irrigation to apply P fertilizer allows nutrient placement directly into the plant root zone during critical periods of nutrient demand. Less P fertilizer is generally required to achieve sufficient tissue P concentrations and equivalent yields when it is drip-applied than with other application methods. The distribution of drip-applied P in soil depends on soil properties, the source of P fertilizer, the rate of application, and the amount of …
Factors Affecting Selenium Accumulation By Agricultural Crops, Robert Mikkelsen, Albert L. Page, Frank T. Bingham
Factors Affecting Selenium Accumulation By Agricultural Crops, Robert Mikkelsen, Albert L. Page, Frank T. Bingham
Robert Mikkelsen
The accumulation of selenium by plants is of concern worldwide. Many regions grow crops that contain insufficient Se to meet animal nutritional requirements. In these locations with low Se, efforts have been made to increase tissue Se concentrations. Other areas have problems with excessive Se found in vegetation grown on seleniferous soils. Plant species vary in their ability to accumulate and tolerate Se. Selenium accumulator plants can accumulate extremely high Se concentrations (several thousand mg Se kg-1) when grown in seleniferous soils, whereas typical agricultural crops have a much lower Se tolerance (<50 mg Se kg>-1 ). It has been suggested that …
Sheep Preference For Perennial Glandular-Haired And Eglandular Medicago Populations, Andrew W. Lenssen, E. L. Sorensen, G. L. Posler, L. H. Harbers
Sheep Preference For Perennial Glandular-Haired And Eglandular Medicago Populations, Andrew W. Lenssen, E. L. Sorensen, G. L. Posler, L. H. Harbers
Andrew W. Lenssen
Erect glandular-haired Medicago species and hybrid populations have been developed that possess a high degree of resistance to the alfalfa weevil [Hypera postica (Gyllenhal)] and potato leafhopper [Empoasca fabae (Harris)]. Trials were conducted at the North Agronomy Farm, Manhattan, KS, in June and August 1986 to determine if erect glandular hairs on diverse perennial Medicago populations affect forage preference of sheep (Ovis aries). Glandular-haired (+) and eglandular (−) populations were selected from each of the following: diploids M. prostrata Jacq. and M. glandulosa David (KS94) and tetraploids M. glutinosa Bieb. (KS108), M. sativa L. ✕ M. prostrata (KS159), and M. …
An Expert System For Tractor Selection, Steven A. Freeman, P. D. Ayers
An Expert System For Tractor Selection, Steven A. Freeman, P. D. Ayers
Steven A. Freeman
A user friendly expert system to assist the farmer in tractor selection was developed based on the evaluation procedure developed by Rider et al. (1979). This evaluation procedure utilizes Nebraska Tractor Test data from 1980 to 1986 along with information provided by the farmer to make selection decisions. The expert system provides the farmer with a list of tractors that are best suited for a specific operation. However, it is only designed to aid the farmer in the tractor selection process, not to provide a definite solution.
Texture, Climate And Cultivation Effects On Soil Organic Matter Content In U.S. Grassland Soils, Ingrid C. Burke
Texture, Climate And Cultivation Effects On Soil Organic Matter Content In U.S. Grassland Soils, Ingrid C. Burke
Ingrid Burke
Soil organic C content, a major source of system stability in agroecosystems, is controlled by many factors that have complex interactions.The purpose of this study was to evaluate the major controls over soil organic carbon content, and to predict regional patterns of carbon in range and cultivated soils. We obtained pedon and climate data for 500 rangeland and 300 cultivated soils in the U.S. Central Plains Grasslands, and statistically analyzed relationships between C and soil texture and climate. Regression models of the regional soils database indicated that organic C increased with precipitation and clay content, and decreased with temperature. Analysis …