Author
JANEGITZ, MONIKI - Sao Paulo State University (UNESP) | |
SCHAEFFER, SEAN - University Of Tennessee | |
Jin, Virginia | |
ROSELEM, CIRO - Sao Paulo State University (UNESP) | |
LI, LIDONG - University Of Tennessee |
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only Publication Acceptance Date: 7/28/2015 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Conservation soil management practices may influence the soil acidity. Surface application of lime may be required in no-till systems to ameliorate soil acidity and to improve crop yields. The application of lime may also increase microbial activity on soil. Specifically, the microbial activity of soil can be determined by C-loss via respiration. We evaluated microbial respiration after lime was applied to no-till cotton fields that have been under different agriculture practices for 31 years. Treatments consisted of: lime and no lime, nitrogen fertilizer rate application (0, 36, 72, or 108 kg/ha) and cover crop (no cover, vetch, or wheat). Soil samples were collected in Spring 2014 from 0-to-10 cm depth. We neutralized soil acidity using a pH buffer procedure to calculate doses for each plot. Soil samples were incubated at 25 ºC under laboratory conditions, and respiration was then measured at 0, 1, 3, 7 and 14 days after liming using an infrared gas analyzer (IRGA, LICOR-820). We found high fertilization rates and legume cover crops caused acidity in soil. Soil respiration was significantly higher in limed compared to un-limed soils. However, lime application with vetch resulted in higher respiration rates regardless of nitrogen rate. Soil pH data was positively correlated with respiration data; in the treatment with low pH, respiration rate was also low. Though some CO2 measured as respiration likely came from added lime, the observed increases in respiration were above that expected from a purely inorganic CO2-source. |