1,849 research outputs found
Midwest Cover Crops Council Surveying Soybean Growers and Agronomists
A team from the Midwest Cover Crops Council is conducting surveys of North Central Region soybean growers and CCAs/Agronomists to learn more about the use and challenges of including cover crops before and after soybeans from a farmer’s perspective
Winter rye cover crop effect on corn seedling pathogens
Scientists conducted laboratory and field studies to find out what effects cereal rye cover crops might have on corn yield under different contidions and different management tactics
Residue Removal When Planting No-Till Corn
Plant residues from the previous crop are very effective in reducing soil erosion. However, if not properly managed, surface plant residues increase the risk of poor stand establishment for com (Zea mays. L.) and reduce yield potential of com when grown, especially following com, with conservation tillage production systems. A series of field studies evaluated residue management when planting com in no-tillage systems. Com planted by use of planters with residue clearing attachments emerges more rapidly than com planted with use of rolling coulter attachments. Row cleaners not only reduce plant residue above the seed row, but also result in less residue being placed into the seed zone. Removing residue from a 3- to 6-in band over the seed row allows rapid seedling emergence and good crop yields, while maintaining adequate residue cover for erosion control
Automated tension infiltrometer
An automated tension infiltrometer including a soil contacting base to which is mounted a porous plate for interfacing the infiltrometer with the soil to be analyzed. A Marriotte column is positioned in the base so that its open bottom end abuts the porous plate. A bubble tower is also positioned in the base and has a bubbling tube operatively connected between its interior and interior of the Marriotte column. The bubble tower is adjustable to provide variable tension to the Marriotte column. First and second transducers are positioned at the upper and lower parts of the Marriotte column and continuously measure pressure changes at those positions while water from the column infiltrates into the soil. By correlating these measurements, improved precision in measuring water level is achieved, which in turn allows improved results regarding deriving soil characteristic information
Connecting the World of Embedded Mobiles: The RIOT Approach to Ubiquitous Networking for the Internet of Things
The Internet of Things (IoT) is rapidly evolving based on low-power compliant
protocol standards that extend the Internet into the embedded world. Pioneering
implementations have proven it is feasible to inter-network very constrained
devices, but had to rely on peculiar cross-layered designs and offer a
minimalistic set of features. In the long run, however, professional use and
massive deployment of IoT devices require full-featured, cleanly composed, and
flexible network stacks.
This paper introduces the networking architecture that turns RIOT into a
powerful IoT system, to enable low-power wireless scenarios. RIOT networking
offers (i) a modular architecture with generic interfaces for plugging in
drivers, protocols, or entire stacks, (ii) support for multiple heterogeneous
interfaces and stacks that can concurrently operate, and (iii) GNRC, its
cleanly layered, recursively composed default network stack. We contribute an
in-depth analysis of the communication performance and resource efficiency of
RIOT, both on a micro-benchmarking level as well as by comparing IoT
communication across different platforms. Our findings show that, though it is
based on significantly different design trade-offs, the networking subsystem of
RIOT achieves a performance equivalent to that of Contiki and TinyOS, the two
operating systems which pioneered IoT software platforms
Magnetic interaction of Co ions near the {10\bar{1}0} ZnO surface
Co-doped ZnO is the prototypical dilute magnetic oxide showing many of the
characteristics of ferromagnetism. The microscopic origin of the long range
order however remains elusive, since the conventional mechanisms for the
magnetic interaction, such as super-exchange and double exchange, fail either
at the fundamental or at a quantitative level. Intriguingly, there is a growing
evidence that defects both in point-like or extended form play a fundamental
role in driving the magnetic order. Here we explore one of such possibilities
by performing {\it ab initio} density functional theory calculations for the
magnetic interaction of Co ions at or near a ZnO \{100\} surface. We
find that extended surface states can hybridize with the -levels of Co and
efficiently mediate the magnetic order, although such a mechanism is effective
only for ions placed in the first few atomic planes near the surface. We also
find that the magnetic anisotropy changes at the surface from an hard-axis
easy-plane to an easy axis, with an associated increase of its magnitude. We
then conclude that clusters with high densities of surfacial Co ions may
display blocking temperatures much higher than in the bulk
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