The optimum nitrogen fertilizer rate for maize in the US Midwest is increasing.

Fertilizing maize at an optimum nitrogen rate is imperative to maximize productivity and sustainability. Using a combination of long-term (n = 379) and short-term (n = 176) experiments, we show that the economic optimum nitrogen rate for US maize production has increased by 2.7 kg N ha yr from 1991 to 2021 (1.

Nitrogen Deposition Weakens Soil Carbon Control of Nitrogen Dynamics Across the Contiguous United States.

Anthropogenic nitrogen (N) deposition is unequally distributed across space and time, with inputs to terrestrial ecosystems impacted by industry regulations and variations in human activity. Soil carbon (C) content normally controls the fraction of mineralized N that is nitrified (ƒ), affecting N bioavailability for plants and microbes. However, it is unknown whether N deposition has modified the relationships among soil C, net N mineralization, and net nitrification.

Prospects for reducing group mean differences on cognitive tests via item selection strategies.

Cognitive ability tests are widely used in employee selection contexts, but large race and ethnic subgroup mean differences in test scores represent a major drawback to their use. We examine the potential for an item-level procedure to reduce these test score mean differences. In three data sets, differing proportions of cognitive ability test items with higher levels of difficulty or subgroup mean differences were removed from the tests.

Facile Mechanochemical Functionalization of Hydrophobic Substrates for Single-Walled Carbon Nanotube Based Optical Reporters of Hydrolase Activity.

Single walled carbon nanotubes (SWCNT) have recently been demonstrated as modular, near-infrared (nIR) probes for reporting hydrolase activity; however, these have been limited to naturally amphipathic substrate targets used to noncovalently functionalize the hydrophobic nanoparticles. Many relevant substrate targets are hydrophobic (such as recalcitrant biomass) and pose a challenge for modular functionalization. In this work, a facile mechanochemistry approach was used to couple insoluble substrates, such as lignin, to SWCNT using l-lysine amino acid as a linker and tip sonication as the mechanochemical energy source.