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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2020

Abstract

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.

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Abstract

It is commonly known that the pretreatment of complex substrates yields higher biogas production in anaerobic digestion (AD) by improving hydrolysis. However, it is still questioned whether all solubilized fractions after pretreatment can be used for CH4 production during AD. In this study, the relationship between increased solubilization and AD efficiency in response to different pretreatment conditions of lipid-extracted microalgae waste (LEMW) was investigated. The individual pretreatment (acid and ultrasonic) and combined pretreatment were applied to assess the solubilization of LEMW. A biochemical methane potential (BMP) test was subsequently performed to determine the AD efficiency. Combined pretreatment of LEMW (60 min of irradiation + pH 1) showed the highest performance, achieving CH4 production of 1245 ± 28 mL CH4/L with increased solubilization of 50.4%. However, it was found that increased solubilization did not proportionally increase CH4 productivity. The assessment of the origin of produced CH4 through biomass fractionation supports this finding in that the soluble fraction that does not contribute to CH4 production increased at more severe pretreatment conditions.