Peppermint residue consists of the cooked leaves and stems of the peppermint plant after high-temperature distillation to extract oil. This residue has value as a soil amendment. It is often applied to fallow fields in the fall or sold as a soil amendment to gardeners. Research was conducted to determine...
As part of a participatory research project, where farmers and Oregon State University researchers collaborated, aspects of potato (Solanum tuberosum L.) growing systems were studied. It was determined through conversations with the farmers that quantification of certain growth parameters of potato was lacking, including dry matter accumulation, crop nitrogen (N)...
Compost maturity is an important determinant of end use for composted municipal yard debris, and generally refers to the effect the compost has on plants. The rate of microbial respiration is an indicator of compost stability. The objectives of this research were to: i) determine whether continuous aeration resulted in...
Highbush blueberry (Vaccinium corymbosum L.) is adapted to soils with high organic matter and acidic pH. Composts provide organic matter and nutrients for growing blueberry in mineral soils, but many composts are high in pH and soluble salts. Acidification with elemental sulfur (S°) can remedy high pH, but the process...
In order to properly utilize organic amendments as nitrogen sources, reliable methods
to estimate plant-available nitrogen (PAN) are needed. The objectives of this study
were to (1) evaluate the use of crop and soil responses in fertilizer N equivalence
(FNE) calculations, (2) examine the relationships between the C/N ratio, total...
Estimates of nitrogen (N) available from long-term application of organic
amendments are required to balance N inputs with crop N requirements. Two studies
were conducted to (1) determine N mineralized from organic amendments (manures
and composts) during year 2 after application, and (2) compare plant-available N
(PAN) determined via in...
Phytophthora cinnamomi is a soilborne pathogen that causes root rot disease of highbush blueberry (Vaccinium corymbosum L.). When new installations of susceptible blueberry cultivars are infected with P. cinnamomi, plants often fail to grow significant new tissue, greatly reducing yields over the life of the planting. Chemical fungicides are available...
Quantifying labile phosphorus (P) pools in biosolids is needed to manage biosolids for both agronomic and environmental purposes. Phosphorus indices originated in an effort to protect surface water quality from-non-point-agricultural P inputs. The objectives of this research were to: (1) evaluate soil test components of the western Oregon P index...
Ammonia (NH₃) volatilization and loss from nitrogen (N) fertilizer in agriculture negatively impacts crops, farm profitability, human health and surrounding ecosystems where it is deposited. A significant source of NH₃ volatilization occurs from surface application of urea on sandy soils with low pH buffering capacity such as those in the...
Although the potato (Solanum tuberosum L.) is a global crop, few growing regions rival the high yields of the Columbia Basin of Eastern Oregon and Washington. Two research projects were conducted in Hermiston, OR to contribute to best management practices for the region. The first project evaluated the efficacy of...
Ammonia (NH₃) volatilization can result in a substantial amount of surface applied nitrogen (N) being lost into the atmosphere, making it an environmental pollutant as well as reducing plant-available N. However, N can also be easily lost from the soil through leaching,
and nitrous oxide (NO₂). Enhanced efficiency N fertilizers...
Douglas-fir [Pseudotsuga menziesii (Mirbel) Franco] bark (DFB),
sphagnum peat moss, and pumice are the most common substrate components used
in the Oregon nursery industry. Despite the widespread use of these three
components, little information is available on the effect of physical and hydraulic
properties of peat moss and pumice on...
Computer simulation models provide insight into ammonia loss processes and the sensitivity of ammonia loss predictions to environmental and management variables.
As an example of how a simple computer simulation model can inform the Extension guideline development process, the ALFAM (Ammonia Volatilization from Field-Applied Animal Slurry) model was used to...
The worksheet is designed to show a municipal biosolids manager how many acres are needed for land application of biosolids at an agronomic rate, based on crop nitrogen (N) requirements.
The worksheet is based on a peer-reviewed Extension publication: PNW 511, Worksheet for Calculating Biosolids Application Rates in Agriculture authored...
This manual is designed to serve as a resource for those who organize and conduct training programs in biosolids management. It describes the process of organizing and conducting effective training sessions as well as the technical topics that should be covered.
Preplant compost application increased plant growth and visual appearance of a wide variety of perennial landscape plants. The positive plant growth response to compost was similar for com-post left on the soil surface or compost incorporated via rototilling. Compost application did not alleviate soil compaction. Plant growth response to compost...
Interest in measuring soil quality continues to increase worldwide in view of demands on land productivity and the necessity to preserve soil resources, yet identification of suitable indicators for soil quality assessment is still evolving. This study adapted 10 biological, physical, and chemical indicators of soil quality identified by the...