Environmental Taxes and Agriculture in the European Union and the Netherlands

This paper analyzes the introduction of environmental taxes in the EU and Netherlands and their effects on agriculture, with a special focus on the background of the introduction of environmental tax systems, their design concepts and effects on agriculture, the effects of fertilizer taxes in promoting sustainable agriculture, policy packages between environmental tax and environmental agreements, effects on globalization and global competitiveness, and conversion to renewable energy based on biomass resources.

Experimental Research on Monomial Cooling Measure of Greenhouse in Summer

This paper describes several main monomial cooling methods of greenhouse in summer, including natural ventilation, mechanical ventilation, wet curtain cooling, external sun-shading etc., as well as analyzes the change law of the environment on temperature and humidity in greenhouse. The result shows that the four cooling methods stated above make the temperature gradients between internal and external respectively 1.1℃, 0.4℃, -2.6℃ and -1.2℃,so it is obvious that the cooling effect of wet curtain cooling is the optimum;and the internal and external humidity difference is respectively: -13%, 6%, 8% and 1%.

The circadian clock contributes to diurnal patterns of plant indirect defense in nature

The plant circadian clock regulates the rhythms of plant metabolism.Many herbivore-induced plant volatiles(HIPVs)fluctuate,diurnally,but the role of the circadian clock in the emission of HIPVs and their ecological consequences remains largely unknown.Here,we show that the timing of herbivore attack can alter the outcome of tri-trophic interactions,and this is mediated by the circadian clock,under both field and glasshouse conditions.Although most HIPV emissions did not have a circadian rhythm,the circadian clock modulated HIPV emissions in a time-dependent manner.HIPVs mediate tri-trophic interactions,and the circadian clock may affect these interactions by modulating HIPV emission in nature.

The importance of ecotype diversity on duckweed growth with and without salt stress

The pollution of freshwater ecosystems is threatening freshwater plant species diversity worldwide.Freshwater plants,such as the common duckweed(Lemna minor),are potentially sensitive to novel stressful environments.To test if ecotype diversity could increase resistance to stressful environments,I used seven L.minor populations and measured their growth rates with and without moderate salt stress across an ecotype diversity gradient.The L.minor populations were grown over 5 months in 92 experimental mesocosms,either in ecotype monocultures or in polyculture with either one or three conspecific ecotypes(23 unique compositions).After growing the duckweed in unperturbed conditions(phase 1),the cultures were subjected to moderate salt stress(50 mmol/L NaCl)for several weeks(phase 2).The experiment was conducted in the presence of the natural epimicrobial community associated with the different ecotypes.In phase 2,a subset of these algae added an unintentional second stressor to the experiment.The ecotypes differed in their growth rates,the fastest growing at twice the rate of others.The diversity context further shaped the ecotype growth rates.Ecotype polycultures showed higher abundances towards the end of the experiment,thus over time,as the environment deteriorated,ecotype diversity gained in importance.These findings show that within-species variation in growth rates can translate to a positive effect of ecotype diversity on population abundance.Exposure of L.minor to moderate salt levels did not significantly impact growth rates,although the effect may have been masked by reduced algal stress in the saline environments.