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Publikasjoner

NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

2012

Sammendrag

The use of velvet bentgrass (Agrostis canina L.) on putting greens is limited by sparse knowledge on optimal maintenance. Our objective was to determine the effects of N (75 or 150 kg N ha–1 yr–1), topdressing (0.5 or 1.0 mm biweekly), and mechanical-biological treatment (grooming, vertical cutting, spiking, and Thatch-less) on turfgrass visual quality, playability, winter survival, and thatch formation. The study was conducted at a coastal location in Norway (Landvik, 58°N) from August 2007 to May 2010 on sandbased root zone (United States Golf Association specifications) seeded in late spring 2007 with velvet bentgrass ‘Legendary’. Only the higher N rate gave acceptable quality during the first 2 yr after sowing. The higher N rate reduced moss and winter injuries from disease compared with the lower Nbut decreased surface hardness by 21% and reduced ball roll distance by 6 to 14%. Significant interactions reflected an increase in mat organic matter with increasing N rate under light but not under heavy topdressing. Compared with grooming only, grooming plus vertical cutting significantly reduced mat organic matter from 64 to 53 g kg–1. Grooming plus spiking improved water infiltrationrate by 51% compared with grooming alone. Thatch-less increased hardness of the otherwise soft plots receiving grooming plus spiking but had no effect on mat depth or organic matter content.

Sammendrag

We calculate entropy and complexity of runoff time series and artificially generated series with long-range correlations. Entropy and complexity of data series may be represented against each other in a two-dimensional diagram which we will refer to as Complexity-Entropy Causality Plane, or CECP. We use a recently developed framework for these two indicators based on order statistics. It is well-known that runoff, as all other environmental time series actually measured, is a mixture of deterministic (signal) and stochastic (noise) parts, the latter due to noise inherent in the measurement process and externally induced by natural processes. The distinction between signal and noise is notoriously difficult and subject to much debate. In our approach, the observed series are compared to purely stochastic but long-range correlated processes, the k noise, where k is a parameter determining the strength of the correlations. Although these processes resemble runoff series in their correlation behavior and may be even tuned to any runoff series by changing the value of k, the CECP locations and in particular the order pattern statistics reveals qualitative differences between runoff and k noise. We use these differences to conclude on the deterministic nature of the (short-term) dynamics of the runoff time series. The proposed methodology also represents a stringent test bed for hydrological models.