The fate of applied nitrogen under field conditions

Non-Peer Reviewe

Effect of moisture on nitrogen mineralization in some Saskatchewan soils

Non-Peer ReviewedThe ever-increasing cost of N fertilizer dictates the need for more efficient use of this nutrient in the future. This then demands that an accurate assessment be made of the N supply that can be expected from a soil. The latter depends on a soil's innate capacity or potential to supply N, as well as such intensity factors as moisture and temperature. At Swift Current, we have begun a study to determine rates of N mineralization in a representative cross section of Saskatchewan soils as influenced by cultivation, soil moisture, and temperature. This paper reports on some of our preliminary findings

Temporal changes in microbial biomass and N mineralization under simulated field cultivation

Intact soil cores from a perennial pasture were incubated under controlled environment conditions to examine the effect of simulated cultivation on microbial biomass C and N and associated nitrogenous products. Microbial biomass C increased by an average of 34% to 3184 μg C g soil during the first 17 days after addition of a glucose-sodium acetate-(NH)SO solution, but was not affected by cultivation. Microbial biomass N (average 343 μg N g soil) was not affected by either amendment or cultivation treatments. Cultivation promoted the oxidation of recently-synthesized microbial metabolites and enhanced substrate depletion, with an additional 16 μg NO-N g soil (equivalent to 0.5% of total organic N) being produced in the 105 days following disturbance. A 36% reduction in potentially mineralizable N in the disturbed vs undisturbed treatments suggests the rapid depletion of the labile organic component on cultivation may retard the subsequent decomposition of more resistant organic material

Eye pull, eye push:moving objects between large screens and personal devices with gaze and touch

Previous work has validated the eyes and mobile input as a viable approach for pointing at, and selecting out of reach objects. This work presents Eye Pull, Eye Push, a novel interaction concept for content transfer between public and personal devices using gaze and touch. We present three techniques that enable this interaction: Eye Cut & Paste, Eye Drag & Drop, and Eye Summon & Cast. We outline and discuss several scenarios in which these techniques can be used. In a user study we found that participants responded well to the visual feedback provided by Eye Drag & Drop during object movement. In contrast, we found that although Eye Summon & Cast significantly improved performance, participants had difficulty coordinating their hands and eyes during interaction