A number of herbacious sun and shade plants were grown at different light levels to investigate their adaptations in morphology and growth to light intensity. All species examined respond to low light intensity strongly, but very much the same. It is concluded that shade tolerance is not based on different adaptations in morphology or growth rate.

Some herbaceous sun and shade plants were grown under two red/far-red ratios to investigate their adaptation in morphology, growth and net photosynthesis to the light quality component of shade light. All species reacted in the same way to a low red/far-red ratio, but the sun species reacted more, showing more stem elongation, a lower leaf weight ratio and a lower relative growth rate. It can be inferred that photosynthetic functions are not influenced by the red/far-red ratio, but dark respiration increases, and probably to a greater extent in sun species.

In a bio-based economy, chemicals, materials, biofuels, and other forms of energy will be produced from biomass. Pressure on agricultural land will thus increase, calling for highly effi cient solutions in terms of land use, with minimal environmental impacts. In order to gain better insight into the available options and their trade-offs, this perspective studies the production of polylactic acid (PLA), bioethanol, and bio-based polyethylene (PE) from wheat, maize, sugarbeet, sugarcane, and Miscanthus. While in current agricultural practice some plants are harvested and used as whole crop (e.g. Miscanthus), for others only part of the plant is used, with the remainder being returned to the fi eld (e.g. wheat straw). In order to obtain an understanding of the unused potential we assume as default case that all agricultural residues and processing co-products are used for energy purposes, thereby replacing non-renewable energy. We conclude that this agricultural practice would allow to substantially reduce non-renewable energy use (NREU). We also fi nd a clear difference in ranking depending on whether we study (i) NREU per (metric) tonne of product or (ii) Avoided NREU per hectare of land. The latter seems a suitable choice in a world where land availability is limited. In this case, we identify PLA as the preferred choice, irrespective of the type of crop. The production of ethanol for the replacement of fuels scores as the worst option for all crops. For each of the products studied, sugarcane offers the highest savings per hectare followed by sugarbeet

Emissions of CH4, N2O, and CO2 from soils are the result of a number of biological and physical processes, each influenced by several environmental and management factors exhibiting spatial variability. This study aimed to assess the spatial variability and spatial dependence of CH4, N2O, and CO2 emissions and their underlying soil processes and properties from grasslands on drained peat soil (Terric Histosol). Emissions and possible controlling factors were measured at a field location in Sweden. Measurements were done on two adjacent sites on peat soil on two successive days for each site. Spatial variability was analyzed with trend analysis and variograms. Both sites consumed small amounts of atmospheric CH4, i.e., 0.03 and 0.05 mg CH4 m−2 d−1, and emitted N2O and CO2, i.e., 5 to 19 mg N2O m−2 d−1 and 4 to 6 g CO2 m−2 d−1. Spatial variability of emissions was high, with coefficients of variation of 50 to 1400%. Emissions either showed a spatial trend or were spatially dependent with ranges of spatial dependence of 50 to >200 m. However, spatial dependence of emissions showed differences between sites and short‐term temporal variability. Variograms of emissions and soil processes, which are partly biological in nature and have a high degree of inherent variability, should be interpreted with care.

Ammonia emission into the atmosphere is of concern because of its potential impact on atmospheric aerosol chemistry and fertilizer N use efficiency. The purpose of this study was to evaluate the effects of N surplus and deficit on soil‐plant‐atmosphere NH3 exchange in a temperate humid grassland. Plant and soil N measurements were made along with NH3 fluxes using flux‐gradient techniques. Ammonia flux was related to the plant ammonia compensation point (NH3 CP), which was controlled by plant N concentration and management practices (such as harvest and fertilization). The measured fluxes were generally much larger during daytime than during nighttime. The daily variation in flux was apparently caused by higher diffusive resistance at night. Generally, there were no significant differences between daytime and nighttime NH3 CP. Ammonia was absorbed in dew and released during dew evaporation; however, nighttime absorption exceeded daytime release, with some of the N apparently being captured by the crop.