http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Lime requirement for coastal plain soils
xxii, 193 leaves : illustrations ; 28 cm.
A diverse group of forage crops grown in acid soils in Texas, range from highly pH sensitive alfalfa to relatively pH insensitive bermudagrass. Although the chemical attributes of East Texas Timberlands and their lime responsiveness have been well documented, there is little published information on appropriate lime application rates to overcome acidity problems. Adoption of any currently available laboratory methods for making lime recommendations in Texas has been delayed due to lack of critical evaluation of these methods. Our objectives were to 1) Study the effect of lime on soil parameters and crop yields; 2) Compare and evaluate the LR methods in the laboratory; 3) Calibrate the. laboratory LR methods against LR obtained from field incubation. Applied limestone increased soil pH in all the soils but the pH response to liming changed over the course of the study when the experiment was continued for more than one season/year. Lime rates >2.24 Mg ha- I decreased 0.01M CaCI2 and IM KCI extractable Al to < I mg kg-'. Lime treatments with 100% effective calcium carbonate equivalent (ECCE) produced a higher soil pH than 62% ECCE limestone because of its increased surface area and therefore, greater reactivity. Lime rates applied to the soils, which have pH values of 4.2 to 4.9, were sufficient to neutralize all of the exchange Al and raise the pH values to range of 5.3 to 6.7. Coastal bermudagrass did not respond to lime at half of the locations because it is tolerant to a wide range of soil properties. Marshall ryegrass was more responsive to lime due to its moderate tolerance to Al. Increased clover yields were negatively correlated with exchangeable Al and exchange acidity at all sites. Wheat (TAM 200) was responsive to lime only at one location. The SMP-single, SMP-double and Yuan double buffers were well and about equally suited as methods to predict LR to achieve pH 6.5 and 7.0 in the laboratory and field experiments. The double buffers had greater accuracy at lower LR values. The LR calculated using extractable Al did not correlate with incubation LR to pH 5.5, the pH where extractable Al is neutralized to negligible amounts. The LR determined by all methods was poorly correlated with soil pH measured in water. The buffer methods overestimated the LR in the most cases based on the laboratory methods but underestimated the actual field LR. The quantities of liming material needed to attain target pH values were greater in the field than in the laboratory because heterogeneity of mixing limestone in the field and the presence of slow reacting large particles cause incomplete neutralization of soil acidity in the field. Therefore, accurate lime recommendations can be made based on the field studies by adopting the SMP-double buffer as LR test method and incorporating a factor to correct incomplete neutralization of the acidity in the field.
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