Micronutrients status of Florida soils under citrus production
ABSTRACT Micronutrient nutrition plays an important role in citrus production. Soil extraction techniques to measure the status of bio‐available micronutrients are extremely valuable in the diagnosis of deficient or toxic levels of micronutrients. Mehlich 3 (M3), Mehlich 1 (M1), ammonium bicarbonate‐DTPA (ABDTPA), and ammonium acetate, pH 7.0 (AA), extractants were evaluated for their ability to extract Cu, Fe, Mn, and Zn using 45 citrus grove soils, representing 20 soil series with widely varying physical and chemical characteristics and production practices. The mean concentrations of M3 extractable Fe, Mn, Cu, and Zn were 5.5‐, 2.2‐, 1.6‐, and 1.2‐fold greater, respectively, than those extracted by M1. ABDTPA was more efficient in the extraction of Fe, Cu, and Zn, as compared to the M1 extradant, by 3.3‐, 3.0‐, and 1.4‐fold, respectively. Among the four extractants, AA was extremely inefficient in extraction of all the four micronutrients. Evaluation of the data from all 45 citrus grove soils revealed significant pH effects on extractable Zn by M3, Ml, and ABDTPA extractants and Fe by M1 and ABDTPA extracts only. However, evaluation of the data from pH x Cu experiment on a Candler fine sand (0–15 cm depth soil; pH ranging from 4.5–6.9) showed a negative relationship between the Fe extracted by M3, Ml, and ABDTPA extradants and soil pH. Both extractable Mn and Zn were positively correlated to soil pH except for Mn extractable by ABDTPA. Good correlations (r > 0.52) were observed between M3 vs. Ml extractable Cu, Fe, Mn, and Zn and M3 vs. ABDTPA extractable Cu and Zn. Good correlations were generally found between M3 and AA extractable Cu, Mn, and Zn. However, poor extractability of all micronutrients by AA indicated that it is not a suitable extractant for micronutrient analysis of the soil studied. The results suggest that M3 is a suitable extractant for micronutrient analysis on sandy soils under Florida citrus production.
- 05/2007: pages 171-215;
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ABSTRACT: Organic amendments are sometimes applied to agricultural soils to improve the physical, chemical, and microbiological properties of the soils. The organic fractions in these soil amendments also influence metal reaction, particularly the adsorption and desorption of metals, which, in turn, determine the bioavailability of the metals and hence their phytotoxicities. In this study, a Quincy fine sandy (mixed, mesic, Xeric Torripsamments) soil was treated with 0 to 160 g kg(-1) rates of either manure, sewage sludge (SS), or incinerated sewage sludge (ISS) and equilibrated in a greenhouse at near field capacity moisture content for 100 days. Following the incubation period, the soil was dried and adsorption of copper (Cu) was evaluated in a batch equilibration study at either 0, 100, 200, or 400 mg L(-1) Cu concentrations in a 0.01M CaCl2 solution. The desorption of adsorbed Cu was evaluated by three successive elutions in 0.01M CaCl2. Copper adsorption increased with an increase in manure rates. At the highest rate of manure addition (160 g kg(-1) soil), Cu adsorption was two-fold greater than that by the unamended soil at all rates of Cu additions. With increasing rates of Cu additions, the adsorption of Cu decreased from 99.4 to 77.6% of Cu applied to the 160 g kg(-1) manure amended soil. The desorption of Cu decreased with an increase in rate of manure amendment. Effects of sewage sludge amendments on Cu adsorption were somewhat similar to those as described for manure additions. Likewise, the desorption of Cu was the least at the high rate of SS addition (160 g kg(-1)), although at the lower rates there was not a clear indication of the rate effects. In contrast to the above two amendments, the ISS amendment had the least effect on Cu adsorption. At the highest rate of ISS amendment, the Cu adsorption was roughly 50% of that at the similar rate of either manure or SS amendments, across all Cu rates.Journal of Environmental Science and Health Part B 02/2005; 40(4):687-96. · 1.21 Impact Factor
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ABSTRACT: The objective of this study was to determine how the extractant Mehlich 3 (M3) compared with other methods currently used in Ireland for determination of copper (Cu) and zinc (Zn) in soils. Samples from eight different mineral soil types, four of sandstone/shale and four of limestone origin, were analyzed for copper and zinc using M3 and conventional extractants. Herbage samples were taken from the soils and analyzed for Cu and Zn. Mehlich 3 results showed good correlation with ethylenediamine‐tetraacetic acid (EDTA)– and diethylenetriamine‐pentaacetic acid (DTPA)–extractable Cu and Zn. Inclusion of soil properties in multiple regression models improved the coefficients of determination. All extractants were equal in their ability to predict Cu and Zn herbage content. Differences between sandstone/shale and limestone soils in relation to herbage content were also found, with the better relationship found in sandstone/shale soils.Communications in Soil Science and Plant Analysis 07/2008; 39(13-14):1943-1962. · 0.42 Impact Factor