Phosphorus contamination of surface water is a growing problem associated with container production of nursery plants. Iron and iron compounds have the ability to adsorb phosphorus and render it immobile. Incorporating iron compounds into media at the base of nursery containers serves to filter out phosphorus from fertilizers while still allowing the plant to collect enough phosphorus to grow. Two experiments were devised. The first experiment examined how much phosphorus various iron compounds would adsorb. Metallic iron adsorbed the most phosphorus, followed by HCl reacted magnetite (a form of iron ore), Fe2O3, Fe3O4 and magnetite. In the second experiment, PVC tubes (4 cm inner diam.) were filled to a level of 5 cm with a phosphorus adsorbing layer containing growing media that was 25% or 50% by weight iron compounds. Compounds included metallic iron, HCl reacted magnetite and magnetite. Plain media was used as a control. A layer of 15 cm of media and slow-release fertilizer was applied above the adsorptive layer. One hundred milliliters of distilled water was applied to PVC tubes daily to simulate irrigation. Metallic iron reduced phosphorus leachate to almost 0 for over 2 weeks. HCl reacted magnetite was also effective in reducing phosphorus leachate. Magnetite only affected phosphorus leachate slightly.
Jeffrey H. Gillman and Carl J. Rosen
Carl J. Rosen and David E. Birong
Recent demand for high-quality garlic (Allium sativum L.) has prompted an interest in growing garlic as an alternative crop in the Upper Midwest. The overall objective of this study was to determine the effects of various amendments on garlic growth and selected soil quality indices in two contrasting soils. Garlic (Rocambole type) was planted in the fall of 1995 on a Kandota sandy loam (5% organic matter) and a Spartan loamy sand (1.5% organic matter). Three treatments replicated three times were tested: 1) a nonamended control, 2) manure compost, and 3) fertilizer application based on a soil test. Scapes were removed on half the plants in each plot and allowed to grow until harvest on the other half. Soil microbial biomass nitrogen (N) and carbon (C) were determined before planting and about 4 weeks after emergence. Within each site, the effect of soil amendments on garlic yield depended on scape removal. Garlic yield in nonamended soil was lowest when scapes were not removed. The effect of scape removal tended to diminish when compost or fertilizer was applied. Overall yields were 35% higher in the sandy loam soil compared to the loamy sand soil. Drought stress occurred during bulbing at both locations. Higher yields in the sandy loam soil were likely due to its higher water-holding capacity. Soil amendments did not consistently affect microbial biomass N and C; however, the sandy loam soil had 2 to 6 times higher biomass N and 3 to 4 times higher biomass C than the loamy sand soil and reflected the higher organic matter content of the sandy loam.
Carl J. Rosen, Mohamed Errebhi, and Wenshan Wang
An important aspect of establishing critical sap nutrient concentrations for diagnostic purposes is to determine the accuracy of the analytical method used. We compared a Cardy flat membrane NO3 electrode, a Hach portable NO3 electrode, and a Wescan N analyzer for their ability to determine NO3 concentrations in sap of potato (Solanum tuberosum L.) petioles. The Hach and Wescan instruments require diluted sap, while nondiluted sap can be used with the Cardy. Nitrate-N concentrations in nondiluted petiole sap measured with the Cardy electrode were 90 to 120 mg·L–1 higher than the other two methods. Using sap diluted with 0.075 m aluminum sulfate tended to lower Cardy NO3 readings to concentrations closer to the other methods, but made the procedure more complicated for practical use. We also compared a Cardy K electrode with flame emission spectroscopy for determining K concentrations in sap. Using nondiluted sap with the Cardy procedure resulted in K concentrations 200 to 2500 mg·L–1 lower than those determined by flame emission, depending on K concentration of the sap. Diluting sap with 0.075 m aluminum sulfate or deionized water for use with the Cardy electrode resulted in K concentrations similar to those determined by flame emission.
Carl J. Rosen, Mohamed Errebhi, and Wang Wenshan
An important aspect of establishing critical sap nutrient concentrations for diagnostic purposes is to determine the accuracy and precision of the analytical method used. We compared a Cardy flat membrane NO3 electrode, a Hach portable NO3 electrode, and a Wescan N analyzer for their ability to determine NO3 concentrations in sap of potato petioles. The Hach and Wescan instruments require diluted sap, while nondiluted sap can be used with the Cardy. Nitrate-N concentrations in nondiluted petiole sap measured with the Cardy electrode were 100 to 200 mg·liter–1 higher than the other two methods. Using sap diluted with 0.15 M Al2(SO4)3 tended to lower Cardy NO3 readings to concentrations closer to the other methods, but made the procedure more complicated for practical use. We also compared a Cardy K electrode with flame emission spectroscopy for determining K concentrations in sap. Using nondiluted sap with the Cardy procedure resulted in K concentrations 1000 to 1700 mg·liter–1 lower than those determined by flame emission. Diluting sap with 0.15 M Al2(SO4)3 for use with the Cardy electrode resulted K concentrations similar to those determined by flame emission. Implications for using the electrodes for diagnostic purposes will be discussed.
Chad E. Finn, Carl J. Rosen, and James J. Luby
Root sections of cranberry (Vaccinium macrocarpon Ait. cv. Searles) were microscopically examined to document the typical anatomy of cranberry roots and changes in root anatomy in response to N-form and solution pH. Cranberry cuttings were rooted, then established in hydroponic conditions with three N and two pH regimes. The three N regimes with equal N levels were 1) NH4-N alone, 2) NH4/NO3-N in combination, or 3) NO3-N alone. pH was maintained at 4.5 or 6.5. Root apical regions were examined using phase contrast, bright field, and epifluorescence microscopy. The cranberry root tip develops with a closed apical organization with the tetrarchal vascular cylinder, cortex, and root cap traceable to independent meristem cell layers. The most obvious treatment difference was an accumulation of unidentified “granules” in the subepidermal layer, readily visible with epifluorescence microscopy with NO3-N alone. Roots produced at pH 4.5 branched less than those at 6.5 and had more “quiescent” root initials; at pH 6.5, these developed more frequently into branch roots.
Carl J. Rosen, Deborah L. Allan, and James J. Luby
The effects of pH and N form on growth and nutrition of blueberry (Vaccinium corymbosum L. × V. angustifolium Ait. cv. Northblue) and cranberry (V. macrocarpon Ait. cv. Searles) were tested in separate greenhouse hydroponic experiments. A factorial treatment arrangement of two pH levels (4.5 and 6.5) and three N forms (NO3-N, NH4-N, and NH4-N/NO3-N) was used for each clone. Blueberry shoot growth and final dry weight were greatest at pH 4.5, regardless of N form. In contrast, cranberry fresh weight accumulation and final dry weight were higher with NH4-N/NO3-N or NH4-N than with NO3-N alone. Cranberry plants receiving NO3-N alone accumulated low levels of tissue N and grew relatively poorly at both pH levels. Differences in N response by these two species may be due partially to the environments in which they were selected. Soil from the site where `Northblue' blueberry was selected contained relatively high NO3-N and low NH4-N levels; soil from commercial `Searles' cranberry bogs had relatively low NO3-N and high NH4-N levels. Both species accumulated relatively high levels of root Fe, regardless of pH or N form. Levels of Fe in the root were as much as 100 times higher than in the shoot. Based on X-ray microanalysis of cranberry roots, most of the Fe appeared to be precipitated on the root surface as iron phosphate. Concentrations of Mn in shoots and roots depended on N form and pH. In general, root Mn was highest at pH 6.5 and apparently was precipitated with Fe.
Carl J. Rosen, Thomas R. Halbach, and Bert T. Swanson
Composting of municipal solid waste (MSW) has received renewed attention as a result of increasing waste disposal costs and the environmental concerns associated with using landfills. Sixteen MSW composting facilities are currently operating in the United States, with many more in the advanced stages of planning. A targeted end use of the compost is for horticultural crop production. At the present time, quality standards for MSW composts are lacking and need to be established. Elevated heavy metal concentrations in MSW compost have been reported; however, through proper sorting and recycling prior to composting, contamination by heavy metals can be reduced. Guidelines for safe metal concentrations and fecal pathogens in compost, based on sewage sludge research, are presented. The compost has been shown to be useful in horticultural crop production by improving soil physical properties, such as lowering bulk density and increasing water-holding capacity. The compost can supply essential nutrients to a limited extent; however, supplemental fertilizer, particularly N, is usually required. The compost has been used successfully as a sphagnum peat substitute for container media and as a seedbed for turf production. High soluble salts and B, often leading to phytotoxicity, are problems associated with the use of MSW compost. The primary limiting factor for the general use of MSW compost in horticultural crop production at present is the lack of consistent, high-quality compost.
Deborah L. Allan, Bruce D. Cook, and Carl J. Rosen
The effect of N form and solution pH on the carboxylic and phenolic acid content of cranberry (Vaccinium macrocarpon Ait. cv. Searles) shoots and roots was determined in a greenhouse experiment. The predominant carboxylic acids measured were malate and citrate. Protocatechuic acid was the dominant phenolic acid detected. Total organic acid concentrations were unaffected by N form supplied. In shoots, higher total concentrations of organic acids were found at pH 4.5 than at 6.5 in the shoot, but there was little pH effect in the roots.
Vincent A. Fritz, Gyles W. Randall, and Carl J. Rosen
Sweet corn silage waste is ≈18% dry matter and contains 1.2% N and 0.26% P on a dry-weight basis. Silage waste in rates of 0 to 448 T·ha–1 was applied to a previously harvested sweet corn field in late summer. Beginning the following spring, soil samples were periodically collected to follow the rate of N mineralization. Field corn was planted to the site the following spring as the test crop. At harvest, grain, stover, and silage yields were recorded and N removal from the system was followed through grain and tissue sampling. Additional studies were also conducted to evaluate the impact of primary tillage method on subsequent N mobilization from sweet corn silage waste and to assess the residual N release potential beyond the first year following silage waste application. Results suggest that land application of sweet corn silage waste at 224 T·ha–1 would be environmentally responsible, provided that adequate nitrogen credit from the silage waste is integrated into the total nitrogen needs of the subsequent crop. Greater mineralization is achieved when the silage waste is moldboard plowed compared to chisel plowing. Chisel plowing could result in greater residual N carryover during the year following silage waste application. Seedling emergence rates were faster and grain yield was superior in some years in moldboard-plowed plots compared to chisel-plowed plots. Further calibration of additional N fertilizer on land that received silage waste is necessary for improved production efficiency and sweet corn silage waste use in production systems.
Peter M. Bierman, Carl J. Rosen, and Harold F. Wilkins
Poinsettia (Euphorbia pulcherrima Wind. ex. Klotzsch cv. Gutbier V-14 Glory) plants were grown under conditions simulating commercial stock plant production to investigate the effects of NH4-N: NO3-N fertilizer ratios, foliar Ca sprays, medium-applied Ca, and medium-applied Mo on leaf edge burn (LEB) and cutting production. Leaf edge burn expression was nearly 100% greater with NH4-N: NO3-N fertilizer ratios of 1:2 or 2:1 than with NO3-N only. However, cutting production was 28% lower with NO3-N as the sole N source. There was little difference in either LEB or cutting production between the two NH4-N levels. Weekly Ca sprays at 500 mg·liter-1 were effective in reducing LEB, while medium-applied Ca as gypsum was ineffective. Foliar Ca sprays reduced both the number of LEB leaves (90%) and symptom severity of individual leaves. Spraying plants with tap water (Ca at 25 to 30 mg·liter-1) plus wetting agent had an intermediate effect. Medium-applied Mo was ineffective in reducing LEB, despite greatly increasing leaf Mo levels. The Ca concentration in chlorotic, marginal leaf tissue was significantly lower than the Ca concentration in green leaf margins. There was also a strong, negative correlation between the Ca concentration in young leaves at the susceptible growth stage and the incidence of LEB in various treatment groups. Supplemental applications of Ca and Mo did not consistently affect cutting production. Leaf edge burn appears to be a localized Ca deficiency due to inadequate Ca uptake and/or translocation to the numerous axillary shoots simultaneously developing on poinsettia stock plants.