Reducing Nitrate Accumulation and Fertilizer Use in Lettuce with Modified Intermittent Nutrient Film Technique (NFT) System

Lettuce (Lactuca sativa L.) is a leading greenhouse-grown vegetable. However, nitrate (NO3) accumulation in leaves remains a major issue. The aims of this research were: (i) to test the modified intermittent Nutrient Film Technique (NFT) in the cultivation of soilless lettuce in which plants are grown on peat blocks in trays and supplied with an intermittent flow of nutrient solution, and (ii) to calibrate the fertilization scheme to increase yield performance, while keeping NO3 concentration under control. Two greenhouse trials were performed between autumn 2013 and spring 2014. Results showed that a 30-day cycle is the optimum duration in terms of fresh biomass yield, both for autumn and spring cultivation. Reducing N fertilization in the last cropping days never aected NO3 concentration in leaves during autumn trial, due to unfavourable growing conditions. Conversely, suspension of fertilization 2 days before harvest had a consistent eect during the spring trial, when NO3 concentration in leaves was highly reduced (from 20 to 36%) without yield penalties. Thus, suspending fertilization 2\u20134 days before harvesting in intermittent NFT may reduce, on average, NO3 accumulation by 29\u201358% and the fertilization rate by 7\u201316%, respectively. Yet, growing conditions are crucial to make this system eective

Climate-wise models of biomass productivity for hybrid poplar clones in Europe

Renewable bioenergy has the potential to contribute sustainably to the energy sector. Forestry is the main source of biomass for energy in Europe, and poplar (genus Populus) is widely used for short rotation coppice (SRC). Many studies have assessed poplar clones’ productivity but there is a lack of regional studies and links with the climate. We investigated the biomass productivity of twenty hybrid poplar clones for SRC. Clones were planted in sixteen locations across nine countries in Europe, although not all clones were replicated in all locations. In each location, clones were planted in three replicated plots. All plots were harvested after four years, and the aboveground dry biomass estimated. We fitted clone-specific linear mixed models of total aboveground dry biomass production at plot level as function of climatic variables. For many clones (eight) only annual heat moisture deficit negatively affected productivity, in few cases (3) together with a quadratic term for a smoother relationship. In some other clones (five) only the mean summer precipitation positively and linearly affected productivity. On average, the variance explained by the fixed effects in those models was 56%. For the remaining clones (seven), no climate variables resulted significant. Our study explicitly investigated the quantitative link between water availability and poplar SRC productivity, one of the most important known factors but not often studied with a modelling approach. Further, we show the most productive clones in dried conditions. We also highlight the need to larger scale regional experiments to produce models that can be used in climate change scenarios

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Fiber Morphology, Chemical Composition, and Pulping of Nine Introduced Poplar Clones Grown in Beijing, China

Evaluating the wood properties of poplar clones to be used in fast-growing and high-yield plantation and select superior clones are critical to increase both quantity and quality of wood production. This study determined the fiber morphology, chemical composition and pulping of nine introduced poplar clones after six growing seasons and assessed their suitability for pulping and papermaking. Results showed that the fiber morphological differences among nine clones were not obvious. Fiber with length less than 1.0 mm accounted for 91.7% of the total fibers which were mainly short. Taro had longer and thinner fibers with the largest length-width ratio, followed by Bellatto, whereas Lambro owned the shortest and thickest fiber with a small length-width ratio. Neva had the Runkel ratio much high as 1.0, which was larger than that of other eight clones. From the point of view of chemical composition, Taro contained low content of ash, cold/hot water-soluble content, benzene ethanol-soluble content, and lignin, but higher content of holocellulose. 1% sodium hydroxide-soluble and pentosan contents were 20.47% and 22.62% respectively, on average; thus Taro can be suggested as good-quality industrial material applied in pulping and papermaking. On the contrary, Bellotto got imperfect overall performance, which was considered comprehensively before selection.