A thick cloud of Neptune Trojans and their colors

The dynamical and physical properties of asteroids offer one of the few constraints on the formation, evolution, and migration of the giant planets. Trojan asteroids share a planet's semimajor axis but lead or follow it by about 60 degrees near the two triangular Lagrangian points of gravitational equilibrium. Here we report the discovery of a high-inclination Neptune Trojan, 2005 TN(53). This discovery demonstrates that the Neptune Trojan population occupies a thick disk, which is indicative of "freeze-in" capture instead of in situ or collisional formation. The Neptune Trojans appear to have a population that is several times larger than the Jupiter Trojans. Our color measurements show that Neptune Trojans have statistically indistinguishable slightly red colors, which suggests that they had a common formation and evolutionary history and are distinct from the classical Kuiper Belt objects.     

Repeated application of anaerobic digestate,undigested cattle slurry and inorganic fertilizer N: Impacts on pasture yield and quality

The growth of on‐farm anaerobic digestion (AD) has generated significant quantities of digestate for use as a soil amendment. However, relative to other organic and inorganic fertilizers, only limited field trial data exist on the effect of repeated applications of digestate to temperate grasslands. Here, we compare yields and grass quality (protein and digestibility) from a field trial of a mixed pasture ley (ryegrass and clover), following the application of five different fertilizer types (liquid digestate generated from anaerobically digested slurry, dry fibre digestate, undigested slurry, ammonium nitrate and an NPK compound fertilizer) in comparison with a no‐fertilizer control. Application rates were normalized in terms of nitrogen (N) and were added as a split dose, with 100 kg N/ha added prior to the first harvest and an additional 50 kg N/ha supplied after the first harvest, every year for 3 years. Overall, our results showed that applying both forms of digestate or undigested slurry gave grass yields that matched those obtained with one compound inorganic fertilizer, and better than those from a straight N inorganic fertilizer. No differences were found with regard to digestibility or sward N‐content (hence calculated protein) between any treatments. Although the trial was conducted at only one site, the results indicate that inorganic fertilizers can potentially be replaced by digestate without compromising grassland productivity.