|Blank, Robert - Bob|
Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/12/2006
Publication Date: 2/12/2007
Citation: Blank, R.R., Burnham, J., Chambers, J., Mazzola, M., Morris, C., Lindgren, A., Nowak, R., Shaff, S. 2007. The effect of sucrose application on soil nutrient availability [abstract]. Society for Range Management. Paper No. 80. Interpretive Summary:
Technical Abstract: Soil nutrient availability is a principal factor constraining the invasiveness of exotic weeds such as cheatgrass (Bromus tectorum L.). The soil microbial community is generally C limited; thus, providing a labile C source can cause microbes to proliferate and immobilize soil nutrients, particularly N. We applied the labile carbon source, sucrose, at the rate of 1,500 kg ha-1, to reduce soil nutrient availability and facilitate restoration of cheatgrass-invaded rangelands in Idaho, Utah, Nevada, and Oregon. Efficacy of nutrient reduction was gauged by use of resin capsules placed at 15 cm depth. Experimental plots were treated with Roundup in the spring of 2003 and sucrose was applied as a separate treatment in the fall of 2003 and spring of 2004. Resin integration periods were approximately the following: 10/03-4/04, 4/04-10/04, 10/04-4/05, 4/05-10/05, 10/05-5/06. As expected, sucrose application significantly reduced resin-available nitrate, but the magnitude of reduction was influenced by integration period and state. Ortho-P availability also was reduced by sucrose application, but the magnitude of reduction was less than that of nitrate and more influenced by site specific characteristics. Sucrose application significantly increased availability of Mn on some sites possibly due to elevated microbial production of Mn-chelators. Overall, nutrient availability was greatest during the 1st integration period, likely due to the effect of herbicide application. Caution is warranted on large scale rangeland herbicide application because elevated nutrient availability may temporarily increase site invasibility. Sucrose application does reduce nutrient availability, but the window of lowered availability is short and influenced by site conditions.