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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.

2020

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Sammendrag

A major cost component in livestock production is feed, which suggests improved feed efficiency as a promising strategy to improve both competitiveness and environmental sustainability. This study has investigated the technical and economic efficiency of using two alternatives to the standard feeds in livestock production in Norway. Data was generated from two controlled feeding experiments involving dairy cows and finishing pigs. In the dairy cow experiment, grass silage optimal in protein content was compared to silage lower in protein content in rations to moderately yielding cows. In the pig experiment, imported soybean meal was compared to rapeseed meal in diets to finishing pigs. From Data Envelopment Analysis, we did not find significant within group as well as between group differences in technical efficiency of animals under different feeding strategies. Under the assumptions of the study, however, a feeding regime based on low protein silage was found to be cheaper (–9% to –10%) for moderately yielding dairy cows, suggesting that Norwegian milk production could be based on the low protein silage fed ad libitum. On the other hand, despite reducing feed costs, a feeding regime based on rapeseed meal was less profitable, although statistically insignificant, than soybean meal for finishing pig production. Therefore, the nutritional value must improve and/or the price of rapeseed meal drop before it becomes an economically acceptable replacement to soybean meal.

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Sammendrag

Phosphorus is an essential plant nutrient, but primary resources are limited and overfertilization may cause eutrophication of freshwater. Our objectives were to examine temperature effects on (a) optimal P rate for turfgrass establishment, and (b) increasing rates of foliar vs. granular P for early spring growth of established greens. Two trials, both on USGA root zones and replicated in April−May over 2 yr, were conducted in daylight phytotrons at 7, 12 and 17 °C. Experiment 1 compared 5 P rates from 0 to 0.48 g P m−2 wk−1 for creeping bentgrass establishment on a sand containing 13 mg P kg−1 (Mehlich‐3). Results showed no temperature effect on the optimal P rate. Bentgrass coverage and clipping yield increased up to 0.12 and 0.24 g P m−2 wk−1, corresponding to 6 and 12% of the N input, respectively. The concentration of P in clippings was higher at 7 than at 17 °C indicating that temperature was more limiting to shoot growth than to P uptake. A higher root/top ratio showed that plants invested more in roots under P deficiency. Experiment 2 was conducted using intact cores from a 4‐yr‐old creeping bentgrass (Agrostis stolonifera L.) green with a Mehlich‐3 P level of 34 mg P kg−1. Results showed increased clipping yields up to 0.18 g P m−2 wk−1 and higher P uptake with granular than with foliar application, but there was no effect on turfgrass color and no interaction with temperature. Low temperatures did not justify higher P applications.