Progress 10/01/08 to 09/30/13
Outputs
Target Audience: Targeted audiences for this period are scientists, other professionals, and commerical growers. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest? Results have been disseminated through a professional speech at a scientific meeting. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Most soils in Florida are very sandy with minimal holding capacity for water and nutrients, including phosphorus (P), and phosphorus applied in water soluble fertilizers that is not taken up by the plants is subjected to leaching loss into surface or ground water, causing environmental pollution. Alternate fertilization strategies such as slow release P fertilizers are greatly needed to minimize the impacts of agriculture on water quality. In this study, organic amendment made of biosolids-based compost (N-Viro) and dolomite phosphate rock (DPR), a byproduct from phosphate industry, was evaluated in greenhouse for its effectiveness in reducing nutrient loss and sustaining crop production on sandy soils. The DPR material was blended with N-viro at the proportions of 20, 30, 40, 50, 60, and 70% and the mixtures were moistened to 70% of water holding capacity and incubated for two months at room temperature prior to use. Subsamples were analyzed for nutritional values and relevant agrochemical properties. For greenhouse studies, a typical agricultural soil (Alfisol) in Florida was used and the tested crop plants included candytuft (Iberis umbellata) representing ornamental plant and lettuce (Lactuca sativa) a vegetable crop. It was observed that organic amendment containing adequate DPR materials appeared to be superior to the water soluble P fertilizer in the growth of candytuft and lettuce in the Alfisol, in terms of healthy root system, biomass yield, nutrient concentrations in plants, and less toxic metals in plant shoot. Elevation in pH and Ca in the soil after organic amendment could promote the retention of P, resulting in slow release property of P. Even though Mehlich 3 extractable metals (especially, chromium, nickel, and lead) increased in the soils after the application of organic amendment, the concentrations of these metals in the shoot of candytuft and lettuce were below their respective toxic limits.
Publications
- Type:
Journal Articles
Status:
Submitted
Year Published:
2014
Citation:
Peter. J. Stoffella and Zhenli He. 2013. The Use of Organic Amendment for Reducing Phosphorus Loss in Sandy Soils While Sustaining Crop Production. the II International Symposium of Organic Matter Management and Compost Use in Horticulture.
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Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: Most soils in Florida are very sandy, and water-soluble fertilizers (WSF) are subjected to leaching loss. Alternate fertilization is a promising practice to reduce such loss. Dolomite phosphate rock (DPR), which contains calcium, magnesium, and phosphorus, is potentially useful for agricultural production and landscaping plants. In this study, DPR fertilizers were developed from mixing of DPR material and N-viro soil. A typical agricultural soil (Alfisol) in Florida was used for greenhouse studies, and ryegrass and citrus seedlings were tested. The DPR fertilizers appeared superior to WSF for the growth of ryegrass based on dry-matter yield and nutrient concentrations in plant; however, it was not evident in citrus seedlings. The concentrations of copper, lead, and zinc in the plant tissues were less than toxicity limits. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
DPR fertilizers were effective in raising pH (by 3 units) and electrical conductivity of acidic sandy soils and increasing soil organic matter, total nutrients, and available nutrients.
Publications
- Yang, Y., Z. He, X. Yang, J. Fan, P. Stoffella, and C. Brittain. 2012. Dolomite Phosphate Rock-Based Slow-Release Fertilizer for Agriculture and Landscapes. Communications in Soil Science and Plant Analysis, 43:1344-1362
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Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: Calcium water treatment residue (Ca-WTR), an industrial by-product, was found to be effective in decreasing Cu availability in contaminated soils and transport to the environment. In this study, a greenhouse study was conducted to test the ability of Ca-WTR to reduce the toxicity and uptake of Cu by ryegrass (Lolium perenne L) and lettuce (Lactuca sativa L) as indicator crop plants in Cu-contaminated sandy soils. Eight weeks growing period was observed in Alfisol and Spodosol amended with different levels of Ca-WTR (5-100 g kg(-1) soil). Plant biomass yields increased with WTR application rates at the low levels (5-20 g kg(-1) for Alfisol, pH 5.45 and 5-50 g kg(-1) for Spodosol, pH 4.66), and decreased at the high levels (>20 g kg(-1) for Alfisol and >50 g kg(-1) for Spodosol). The maximum growth of ryegrass with Ca-WTR was 133% and 149% of the control (without Ca-WTR) for the original Alfisol and Spodosol (without spiked Cu), respectively, while the corresponding values for lettuce was 145% and 206%. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Copper concentrations in ryegrass shoots decreased significantly with increasing Ca-WTR application rates. For lettuce, Cu concentration decreased only at high Ca-WTR rates (>50 g kg(-1)). Ryegrass had a greater potential for Cu uptake and translocation than lettuce in both soils.
Publications
- Fan, Jinghua, Zhenli He, Lena Q. Ma, Thiago A. R. Nogueira, Yanbo Wang, Zhanbei Liang, and Peter J. Stoffella. 2011. Calcium water treatment residue reduces copper phytotoxicity in contaminated sandy soils. JOURNAL OF HAZARDOUS MATERIALS Volume: 199 Pages: 375-382
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Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: Most soils in Florida are very sandy with minimal holding capacity for water and nutrients. Phosphorus (P) applied in water soluble fertilizers that is not taken up by the plants is subjected to leaching loss into surface or ground water. Alternate fertilization strategies such as slow release P fertilizers are greatly needed to minimize the impacts of agriculture on water quality. The objective of project was to develop technologies to convert dolomite phosphate rock (DPR), a byproduct from phosphate mining industry in central Florida, into a new type of controlled release fertilizers to supply multiple nutrients and being environmentally friendly. The specific objectives were: a) to develop formulas of DPR fertilizers vegetable crops; b) to evaluate the agronomic effectiveness of the developed DPR fertilizers; and c) to assess the environmental impact of the DPR fertilizers, as compared with water soluble P fertilizers. The DPR fertilizers were made from ground DPR material and N-viro soil with high organic matter and nitrogen (N) contents and micro-nutrients (Fe, Mn, Cu, Zn, Mo and B, etc.). The combination would make the DPR fertilizers more beneficial to agriculture, supplying not only P, Ca, and Mg but also N, K, S, and micro-nutrients. In addition, the breakdown of organic matter from N-viro soil helped release P from the DPR material. For greenhouse studies, a typical agricultural soil (Alfisol) in Florida was used; the tested crop was lettuce (Lactuca sativa). The tested DPR fertilizers had the DPR/N-viro ratio of 20%, 30%, 40%, 50%, 60%, and 70% and the control was water soluble P fertilizer (K2HPO4). All the plants received the same amounts of available nutrients regardless of fertilizer sources. DPR fertilizers made from DPR material and N-viro soil contain adequate amounts of P in a slow release nature and other nutrients and were promising for application in acidic sandy soils where P leaching is a problem. DPR fertilizers was superior to water soluble fertilizer for the growth of vegetable crops in term of both dry matter yield and nutrient concentrations in plant. Other benefits of DPR fertilizers over regular water soluble fertilizers include improvement of soil quality, such as raised pH of acidic soils, increased soil organic matter, total and available nutrients. Application of DPR fertilizers slightly increased the concentration of Mehlich 3 extractable metals such as Cr, Ni, and Pb in the soils, but the concentrations of these metals in plant tissue were reduced due to raised soil pH. The DPR fertilizer made from 50% N-viro soil plus 50% DPR material appears to be the best among the tested formula for both ornamental plant and vegetable crop production, based on both the agronomic effectiveness and effects on soil quality and heavy metals in plants. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
This is an on-going project. The results from greenhouse experiments indicate that the DPR fertilizers made from DPR materials and N-viro soil are as effective as water soluble fertilizers but more environmentally friendly and better for improving soil quality. This will open the possibility of developing phosphorus fertilizers of slow release nature. This type of fertilizers is not currently available in the market but much needed for agriculture in places like Florida where P leaching is a problem.
Publications
- Yang, Y.G., Z. L. He, Y. Lin, and P. J. Stoffella. 2010. Phosphorus availability in sediments from a tidal river receiving runoff water from agricultural fields. Agric. Water Management 97: 1722-1730.
- Wu, C. Y., L. L. Lu, X. E. Yang, Y. Feng, Y. Y. Wei, H. L. Hao, P. J. Stoffella, and Z. L. He. 2010. Uptake, translocation, and remobilization of zinc absorption at different growth stage by rice genotypes of different Zn densities. J. Agric. Food Chem.58: 6767-6773.
- Yang, X. E., Y. E. Chao, H. B. Ye, Z. L. He and P. J. Stoffella. 2010. Zinc and lead accumulation by two contrasting evcotypes of sedum alfredii Hance at different zinc/lead complex levels. Commun Soil Sci. Plant Anal.
- Chen, W.R., Z.L. He, X.E. Yang, S. Mishra and P. J. Stoffella. 2010. Chlorine nutrition in higher plants. J. Plant Nutrition 33:943-952.
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Control of downy (Pseudoperonospora cubensis) mildew on 'Sweet Dumpling' winter squash (Cucurbita maxima) was evaluated at the University of Florida, IFAS, Indian River Research and Education Center (IRREC) in Fort Pierce, Florida during the Spring of 2008. Five foliar spray fungicide treatments were evaluated against an untreated control. Downy mildew ratings (estimated percentage of foliage damage) and marketable yields (mt/ha) were measured. The first appearance of disease was 2 Apr, early. Plants in the untreated plots had significantly higher downy mildew ratings during the first two ratings. All fungicide treatments significantly reduced the downy mildew, some as much as 75%, until the final rating. The two Revus-based protocols and weekly applications of Previcur Flex + Manzate 75 DF were particularly effective. There were significant differences among treatments compared to the control for marketable yield. Marketable fruit was up to 1.5 times higher where effective fungicides were sprayed. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Selection of cultivars and pest management are major decisions. With the following information, producers should be able to select cultivars and pest management systems that will best suit their production constraints and consumer demands.
Publications
- Beany, A. H., K. Pernezny, P. J. Stoffella, and N. Havranek. 2009. Efficacy of foliar spray for management of downy mildew of winter squash. HortScience 44:579-580.
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