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

Subthreshold behavior and avalanches in an exactly solvable Charge Density Wave system

We present a toy charge density wave (CDW) model in 1d exhibiting a depinning transition with threshold force and configurations that are explicit. Due to the periodic boundary conditions imposed, the threshold configuration has a set of topological defects whose location and number depend on the realization of the random phases. Approaching threshold, these defects are relocated by avalanches whose size dependence on the external driving force $F$ is described by a record-breaking process. We find that the depinning transition in this model is a critical phenomenon, with the cumulative avalanche size diverging near threshold as $(F_{\rm th} - F)^{-2}$. The exact avalanche size distributions and their dependence on the control parameter $(F_{\rm th} - F)$ are obtained. Remarkably, the scaling exponents associated with the critical behavior depend on (1) the initial conditions and (2) the relationship between the system size and the pinning strength.Comment: 6 pages, 2 figures. Revised and extended versio

Cover Crop Selection and Management for Agronomic Farming Systems

Cover crops can extend the season of active nutrient uptake and living soil cover and thereby reduce nutrient losses in water and sediment. The conversion of the prairies or other native vegetation ecosystems to summer annual grain crops resulted in a shortening of the season of living plant cover and nutrient uptake. Summer annual grain crops, like corn and soybean, accumulate water and nutrients and provide living cover for only about four months (mid-May to mid-September), whereas in natural systems, some living plants are actively accumulating nutrients and water whenever the ground is not frozen (at least 7 months; April-October). As a result, soil nutrients in summer annual cropping systems are susceptible to losses in part because there are periods during each year when active plant uptake and soil cover are absent

The Somalia Operation: Report on Feeding and Nutrition in the Refugee Camps

Review of UNHCR operations in Somalia from 24 March to 6 April 1980. Studies of International relief organizations. (12) Disaster studies (Specific Disasters) (90) Administrative Case Studies. Relief Administration Case Studies. (199.1) Country Profiles. (801.4H)The digital Cuny Archive was made available in part through funding assistance from USAID.INTERTEC