Sign up for email alerts of new Fluid Journal issues!
Fluid Journal : Fluid Journal 2005-2007
FALL 2007 Fluid Journal 15 !∀ #! ∃∀ #! !∀∀∀ ∀∃ &∋()∗ !∀ +,-.+-∗ /0)∋ 1234& 5.6/ 70)∀+ 08 .66∋)9.+)0∀ :,.∀(∋., !∀ +,-.+-∗ /0)∋; 1234& !∀ !.6 :,.∀(∋- <=>> 15 !∀ #! !)9,06?0+0≅,.6? 08 Α ΒΧ )∀9(Δ.+-∗ !∀ ≅,.∀(∋- Ε0∀9,-+- ∋)Χ- 0(+-, /?-∋∋Φ /0)∋ Γ 6,-9)6)+.+-/ Figure 1. Mn XRF maps for fluid Mn and granular Mn treated in experimental cells. Fertilizer granule extracted from soils clearly shows the presence of concrete-like precipitate adjacent to the granule. with our previous experiments that showed that nearly 90 percent of the Mn in the granule dissolved and diffused out of the granule but was retained within 4 mm of the point of placement. Zinc. Most of the fertilizer Zn was retained in the granule whereas fluid Zn diffused away from the point of application (Figure 2). This observation is in agreement with our previous studies in the same soil where 85 percent of the Zn in the granular Zn fertilizer source remained in the granule after 4 weeks of incubation. X-ray diffraction Manganese. X-ray diffraction analysis of the original granular Mn showed that granules mainly contained Mn in the form of the mineral szmikite [MnSO4 (H2O)], the original form that Mn was introduced into the granule during manufacturing, Moreover, it appeared from the XRD pattern that some manganese hydrogen phosphate and hydroxylapatite were present in these Mn granules (data not shown). In the granules incubated in soil, Mn remaining in the granule stayed in these same minerals with little transformation to other forms. Both micro and bulk x-ray absorption spectra suggested that the majority of Mn in the soil adjacent to the granule was present as Mn-carbonate [MnCO3 or rhodochrosite] and Mn-oxide mixtures whereas the spectra for fluid-treated soil suggested the major form of Mn in the is soil was a Mn(II) phosphate mineral called hureaulite (Figure 3). Our calculations using solubility data showed that when P and Ca solubility are controlled by ∃∀ #! !∀∀∀ ∀∃ Η∀9,-./)∀≅ 90∀9-∀+,.+)0∀ &∋()∗ ∃∀ +,-.+-∗ /0)∋ 1234& 5.6 :,.∀(∋., ∃∀ +,-.+-∗ /0)∋ 1234& 5.6 70)∀+ 08 .66∋)9.+)0∀ ∃∀ #! !∀∀∀ ∀∃ Figure 2. Zn XRF maps for fluid Zn, granular Zn in in experimental cells. hydroxyapatite and calcite (typical in fertilized calcareous soils) and at typical CO2 concentrations, MnCO3 can be comparatively less soluble than hureaulite or various other Mn phosphates. Thus x-ray absorption spectroscopy analysis agreed with previous isotopic dilution techniques indicating that when Mn is added to the soil in liquid forms, more Mn remains in comparatively more soluble minerals. By contrast, granular Mn tends to transform into comparatively less soluble minerals. Zinc. X-ray diffraction analyses of the original granular Zn showed the major crystalline form of Zn in the granule was zincite (ZnO). No other crystalline forms of Zn were observed by the XRD analysis
Fluid Journal 2002-2004
Fluid Journal 2008-2009