and into the surrounding soil. These containers readily decompose after being directly installed in the landscape ( Evans et al., 2010 ). In contrast, compostable biocontainers do not decompose quickly enough to allow roots to physically break through
Youping Sun, Genhua Niu, Andrew K. Koeser, Guihong Bi, Victoria Anderson, Krista Jacobsen, Renee Conneway, Sven Verlinden, Ryan Stewart, and Sarah T. Lovell
M. Gabriela Buamscha, James E. Altland, Dan M. Sullivan, Donald A. Horneck, and John P.G. McQueen
to promote decomposition. Composted bark is rarely used in Oregon container nurseries due to the additional costs associated with its preparation. Physical and chemical properties of DFB as they pertain to use in nursery container substrates have only
Michael R. Evans, Matt Taylor, and Jeff Kuehny
on the root ball and planted into the field, landscape bed, or final container. They are designed to allow roots to grow through the container walls and to decompose after being planted into the field or final container. Compostable biocontainers are
Kevin R. Kosola and Beth Ann A. Workmaster
fitness in the native peat bog habitat of cranberries, where organic matter decomposition and N mineralization is usually quite limited ( Malmer et al., 2003 ; Svensson, 1995 ). Despite the extensive literature on cranberry-ERM associations based on
Clinton C. Shock, Erik B.G. Feibert, and Lamont D. Saunders
Long-day onion (Allium cepa L.) `Vision' was submitted to four soil water potential (SWP) treatments using subsurface drip irrigation in 1997 and 1998. Onions were grown on two double rows spaced 22 inches (56 cm) apart on 44-inch (112-cm) beds with a drip tape buried 5 inches (13 cm) deep in the bed center. SWP was maintained at four levels by automated, high frequency irrigations based on SWP measurements at an 8-inch (20-cm) depth. The check treatment had SWP maintained at -20 cbar (kPa) during the entire season. The other three treatments had SWP maintained at -20 cbar until 15 July, then reduced to -30, -50, or -70 cbar. Reducing the SWP level after 15 July below -20 cbar failed to reduce onion bulb decomposition in storage, but reduced colossal onion yield in 1997, and marketable and total yield in 1998.
Kathryn E. Fine, Janet C. Cole, and Chad J. Penn
mineralization rates for meals adequately supplied N for plant growth ( Snyder et al., 2009 ). Gale et al. (2006) examined decomposition and availability of N released from manure, compost, and specialty products (pelleted organic fertilizer, feather meal, and
Iris Cole-Crosby, Liang Huam, Jesse Harness, Patrick Igbokwe, Suresh Tiwari, and Om P. Vadhwa
Plant growth and residue decomposition values are needed by the Soil Conservation Service for developing data bases for selected fruit and vegetable crops. These data bases will be used for predicting soil loss using improved erosion prediction technology. The plant growth parameters under investigation are canopy cover leaf area index, plant height plant weight, root weight, stem diameter and vegetative dry matter. The climatic parameter are daily base temperature rainfall and growing degree days. The following is a list of the residue decomposition parameter: 1. Residue weight and harvest 2. Initial carbon-nitrogen ratio, and 3. Percent residue cover at harvest. The results are being used in the WEPP model to predict soil erosion. Data collection afor these parameters start 15 days after planting for vegetables and continue at 7 day intervals through maturity.
Michael R. Evans and Douglas Karcher
When the substrate surface and drainage holes of feather fiber, peat, and plastic containers were sealed with wax, hyperbolic growth curves were good fits to cumulative water loss on a per container and per cm2 basis, with R 2 values ranging from 0.88 to 0.96. The effect of container type was significant as the differences in asymptotic maximum water loss (max) values for all container pairs were significant at P < 0.05 for both water loss per container and water loss per cm2. The predicted total water loss for peat containers was ≈2.5 times greater than feather containers, and the predicted water loss per cm2 for the peat container was ≈3 times greater than feather containers. Vinca [Catharanthus roseus (L.) G. Don.] `Cooler Blush' and impatiens (Impatiens walleriana Hook f.) `Dazzler Rose Star' plants grown in feather and peat containers required more water and more frequent irrigations than those grown in plastic containers. However, plants grown in feather containers required less water and fewer irrigations than plants grown in peat containers. The surface area of containers covered by algal or fungal growth was significantly higher on peat containers than on feather containers. No fungal or algal growth was observed on plastic containers. Additionally, primarily algae were observed on peat containers whereas most discoloration observed on feather containers was due to fungal growth. Dry feather containers had a higher longitudinal strength than dry plastic containers but a lower longitudinal strength than dry peat containers. Wet feather containers had higher longitudinal strength than wet peat containers but a similar longitudinal strength as wet plastic containers. Dry feather and plastic containers had similar lateral strengths and both had significantly higher lateral strength than dry peat containers. Wet feather containers had significantly lower lateral strength than wet plastic containers but had higher lateral strength than wet peat containers. Dry and wet plastic containers had higher punch strength than wet or dry peat and feather containers. Dry peat containers had significantly higher punch strength than dry feather containers. However, wet feather containers had significantly higher punch strength than wet peat containers. Decomposition of peat and feather containers was significantly affected by container type and the species grown in the container. When planted with tomato (Lycopersicum esculentum L.) `Better Boy', decomposition was not significantly different between the peat and feather containers. However, when vinca and marigold (Tagetes patula L.) `Janie Bright Yellow' were grown in the containers, decomposition was significantly higher for feather containers than for peat containers. Therefore, containers made from processed feather fiber provided a new type of biodegradable container with significantly improved characteristics as compared to peat containers.
Wei Qiang Yang*
In a 2-year study, the decomposition rates (changes in carbon to nitrogen ratio) of two kinds of sawdust used for blueberry production were determined. The effects of sawdust age and nitrogen application rates on carbon to nitrogen ratio (C:N ratio) of two sawdust types were evaluated. When nitrogen was not applied, the C:N ratio in fresh and aged sawdust decreased 30% and 10% respectively over a 1-year period, indicating fresh sawdust decomposed faster than aged sawdust when used as a surface mulch. However, the C:N ratios between soils amended with aged and fresh sawdust were similar when no nitrogen was added, suggesting the age of sawdust does not affect the decomposition rate once the sawdust is incorporated into the soil. It was found that two nitrogen application rates (150 kg·ha-1 vs. 50 kg·ha-1) had an equal affect on the C:N ratio of both sawdust types. Nitrogen application had no affect on the C:N ratio of both sawdust types when both sawdust were used as soil amendments. Clearly, the decomposition rates of the sawdust were influenced by sawdust age and nitrogen application rates.
Chenggang Wang, Rolf Färe, and Clark F. Seavert
In this paper we analyze the sources of variation in revenue per unit of trunk cross-sectional area (TCA) across a 0.87-ha block of 272 pear (Pyrus communis L.) trees in 2003. Revenue capacity efficiency associated with TCA provides an overall measure of nutrient deficiency and revenue inefficiency caused by environmental constraints in the fruit production process. Data envelopment analysis (DEA) is adopted to estimate revenue capacity efficiency and its components. The deficiencies of macro- and micronutrients are measured and optimal nutrient levels computed for each individual tree. These measures are aggregated for comparing between grids and between rootstocks.