Thomas F. Morris

Lead Uptake and Translocation by Willows in Pot and Field Experiments

Plant growth and lead (Pb) uptake by seven willow varieties were investigated in pot and field experiments to assess the suitability of willows for phytoremediation of Pb at heavily contaminated sites such as skeet ranges. Differences in uptake and translocation of Pb in Salix were observed between pot and field experiments. In the pot experiment, willows grown in Pb-contaminated field soil for 6 months showed tolerance to very high soil Pb concentration (21360 mg kg−1), and with the addition of EDTA were able to take up and translocate more than 1000 mg kg−1 Pb into above-ground tissues. In the field experiment, all willow varieties showed tolerance to heterogeneously high soil Pb concentrations. Plants were also able to take up and translocate Pb into above-ground tissues. However, after 4.5 months, the lead concentration in the above-ground tissues of willows grown in soil amended with EDTA was less than 200 mg kg−1. The results from the pot experiment suggest that Salix varieties have the potential to take up and translocate significant amounts of Pb into above-ground tissues using EDTA. However, to verify the phytoextraction abilities of Salix in the field, additional research is needed.

Effect of Trap Position, Habitat, and Height on the Capture of Pepper Maggot Flies (Diptera: Tephritidae)

Abstract Trapping results indicate that pepper maggot, Zonosemata electa (Say), flies occupy tree canopies adjacent to fields when not on host plants. Several in- and near-field trap positions were used to find a reliable monitoring system for adult pepper maggots. Traps baited with liquid ammonium hydroxide (Stills-style trap), hung in the canopy of trees on the edges of pepper fields, caught significantly more Z. electa flies than when positioned lower along the treeline or in the field. In a second experiment, significantly more pepper maggot flies were captured in sugar maples compared with choke cherry trees, which indicates a pest preference for certain nonhost habitats. The lowest trap height tested (2.1 m) failed to capture Z. electa flies in either tree species when the pest population level was low. These studies demonstrated that pepper maggot flies can be reliably detected with Stills-style traps positioned at ≈6.4 m height within the canopy of sugar maple trees adjacent to pepper fields. Fruit oviposition scars also are useful site-specific indicators of pepper maggot presence/absence and may aid in determining if insecticide applications are necessary and in timing sprays.

Spatial Variability of Soil Properties, Cotton Yield, and Quality in a Production Field

Abstract Successful precision agriculture requires an understanding of spatial variability of soil properties, crop growth, and their interactions. The objectives of this study were 1) to examine the spatial variability of soil properties, cotton lint yield, and fiber quality and 2) to evaluate the spatial variability within mapping units at a production‐field scale. This research was conducted on an irrigated 49‐ha cotton field in Texas from 1998 through 2000. Samples were collected from regular 1‐ha grids, triangular, and random points. Results indicated that soil properties had stronger spatial dependence than did cotton lint yields and fiber quality. Soil properties, except nitrate (NO3 −) nitrogen (N) and Olsen phosphorus (P), were strongly spatially dependent, whereas lint yield was moderately to strongly spatially dependent. Fiber quality was moderately spatially dependent. Spatial appearance of higher yield in drier years was associated with the distribution of soil properties favoring cotton growth, including lower pH and calcium (Ca) and higher P and sand content. There were differences in the means and spatial structure parameters of the selected measurements among the three soil mapping units, suggesting the need for careful sampling design to make reasonable estimation of soil properties under a nonstationary situation. Furthermore, the spatial variability of soil properties and cotton yield were intensified under limited water supply, implying that site‐specific cotton management may be appropriate for cotton producers in the Texas high plains. Contribution of the College of Agricultural Sciences and Natural Resources at Texas Tech University Scientific J. Series Paper Number T‐4‐572.

Phosphorus Availability from Phosphorus-Amended Water Treatment Residual

Abstract Water treatment residual (WTR) is a by-product generated from drinking water treatment facilities that often contains considerable amounts of aluminum (Al) or iron (Fe). Application of WTR to agricultural land can cause deficiencies in soil phosphorus (P). Amendment of WTR with P before application to agricultural land may eliminate the problem of P deficiencies in plant growth. The objective of this field study was to estimate the amount of P required to make WTR a supplier of P to plants. A Fe-based WTR that contained a cationic polymer was collected from a sand-bed lagoon of a Connecticut water treatment facility in the spring of 1996 and 1997. The WTR was amended with P at rates of 19.4, 38.8, 62.0, and 77.4 g P kg−1 WTR in 1996, and 0.0, 4.9, 9.7, 14.6, 19.4, 38.8, and 62.0 g P kg−1 WTR in 1997. Fertilizer P was applied at rates of 0–486 kg P ha−1 for the calculation of fertilizer P equivalents of the P-amended WTR. Sorghum-sudangrass (Sorghum sudanenese “Ciba FP-5”) was planted in 1996 and 1997 in a Paxton fine sandy loam soil (coarse-loamy, mixed, mesic, subactive oxyaquic Dystrudepts). The experimental design was a randomized complete block with four replications. A P rate between 14.6 and 19.4 g P kg−1 WTR was sufficient to make this WTR a supplier of P. The rate of P addition to the WTR was much less than predicted based on the amount of P adsorbed by the WTR in a laboratory study. The rate likely was less than predicted due to the release of P from the cationic polymer used in the coagulant. Amendment of WTR with P when the WTR contains a cationic polymer may provide a beneficial use for the WTR.

A comparative study of neural network and mechanistic models for surface complexation

Abstract This paper demonstrates the use of a feed-forward neural network model to quantify the partitioning of phosphate onto water treatment residual (WTR) as a function of pH. Reasonably good results were obtained with a limited amount of experimental data. The neural network models were essentially as good as the specific mechanistic model used. Comparison of the neural network models with simple models obtained from statistical regression shows the neural network models to be superior. Quantification of the distribution of phosphate in this system may allow accurate prediction of available phosphate in a land application scenario. In surface complexation studies where mechanistic models are not available, it is recommended that neural network models be used.

Soil sample bag effects on pre‐sidedress soil nitrate test concentrations

Abstract Most soil testing laboratories require soil samples collected for the pre‐sidedress soil nitrate test (PSNT) to be dried before shipment. Shipment of field‐moist samples would make it easier to use the test. The objective of this study was to measure the effect of bag type on changes in soil nitrate in samples collected for the PSNT. Soil samples were collected from the surface foot of soil when corn (Zea mays L.) plants were 15‐ to 30‐cm tall. Four fields with a history of manure applications were sampled. The bulk sample was subsampled in the field and the subsamples were kept cool during transport to the laboratory and were immediately air dried after arrival at the laboratory. Field‐moist subsamples from each bulk sample were placed into either cloth bags or plastic‐lined paper bags after arrival at the laboratory. Four replications of the subsamples were incubated at 30°C for 1, 2, 3, and 4 days. After removal from the incubator, the subsamples were immediately spread to air dry. The soils i...

Alternative Health Practices for Livestock

Contributors. Introduction. Section one: Science of alternative methods. 1. Evaluation of an Alternative Therapy for Subclinical Mastitis in Lactating Holstein Cows -Sheila M. Andrew and Robin R. Rastani. 2. Potential Role of Amazonian Medicinal Plants for Health Maintenance in Livestock -Mark J.S. Miller. 3. Botanicals for Pigs -Palmer J. Holden. 4. Evaluation of Homeopathic Nosodes for Mastitis and Calf Scours: Lessons from the Vermont Nosode Project -Lisa McCrory and John Barlow. 5. Livestock Self-Medication -Cindy Engel. 6. Alternative Methods of Controlling Parasites in Small Ruminants -Robert Godfrey and R.E. Dodson. 7. Brief Overview of Research Methods on Medicinal Plants for Livestock with a Focus on Plants for Endo- and Ecto-parasites -Jennifer K. Ketzis. Section two: Historical review of alternative methods. 8. Forage Quality and Livestock Health: A Nutritionists View -Jerry Brunetti. 9. Livestock Treatments: Links from the Past to Holistic Alternatives of the Present -Hubert J. Karreman. 10. Herbs and Alternatives in Equine Practice -Joyce C. Harmon. Section three: Concerns about conventional therapies. 11. The Ecology of Antimicrobial Resistance and Use of Alternatives to Antimicrobials in Food Animal Production in the United States -Stephen DeVincent. 12. Use of rBST and Cow Health in the Dairy Industry -Alan H. Fredeen. Section four: Ideas to promote alternative methods. 13. Funding for Testing Alternative Livestock Methods -Randy Kidd. 14. Economics of Niche Marketing in Alternative Livestock Farming -Gary Valen. Index