The gaseous losses of N from conventional-till (CT) and zero-till (ZT) crop fields were 3 to 7 and 12 to 16 kg N ha−1 y−1, respectively. In contrast, losses from CT and ZT fallow were severalfold higher, namely, 12 to 14 ...

A field study was conducted with treatments consisting of a factorial combination of N (0 or 100 kg N ha−1 as (NH4)2SO4, straw (0 or 3000 kg ha−1), and two tillage treatments. Ground straw was mixed with the plow layer of ...

Factors affecting the accuracy of the carbon-dating method of analysis have been discussed by several workers (1, 3, 13, 14). Since, however, these workers were interested primarily in archeological and geological applications ...

The organic fraction of soil is known to be composed of the soil biomass, partially decomposed plant and animal residues, and the materials commonly referred to as humic substances. Knowledge of the persistence of these ...

The radioactivity of naturally occurring C14 in soil humus when compared to the C14 activity of a standard of recent origin (carbon dating) can be used to estimate the mean residence time of the soil humus in studying ...