Author
 |
Calderon, Francisco |
|
Reeves Iii, James |
|
McCarty, Gregory |
|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only Publication Acceptance Date: 7/19/2004 Publication Date: 10/31/2004 Citation: Calderon, F.J., Reeves III, J.B., McCarty, G.W. 2004. Infrared spectroscopy of cattle manure after soil application. Agronomy Abstracts. Presented at the 2004 ASA-CSSA-SSSA International Annual Meeting. Oct. 31-Nov. 4, 2004. Seattle, WA. CD-ROM #3781. Interpretive Summary: Technical Abstract: The capacity to predict manure mineralizable N is important for ensuring an adequate supply of N to crops, while avoiding over-application. However, a fast and accurate standardized method is yet to be developed. Fourier-transformed infrared spectroscopy (FT-IR) shows potential because it is sensitive to N functional groups in forages, and analyses can be performed quickly. We carried out a nine week field incubation of manure in order to measure manure decomposition. There were three manure treatments: Dairy cow manure, dairy heifer manure, and a control. We included 3 site treatments (low mid, and high soil C content). The manures were placed inside nylon mesh bags in order to be able to scan the manure for spectroscopy before and after being buried. Each bag received an equivalent to 100 kg ha-1 manure N. Besides the FT-IR, we measured the soil microbial biomass, the manure C/N ratio, soil CO2 and N2O fluxes, soil mineral N and manure mineral N. Soil and manure samplings were carried out at time zero, week 1, week 4, and week 9. Our results show that the spectra of the manures changed chronologically during decomposition in soil, indicating that spectroscopy is a sensitive technique for monitoring compositional changes in manure after soil application. The effects of manure on soil gas fluxes and soil N pools varied with the field sites, showing that field variability is an important determinant of manure nutrient dynamics |
