Bill Jokela, Sid Bosworth, and Don Meals..
bill.jokela@uvm.edu
Duration: 1993-1995
Animal
manure is an important source of crop nutrients on livestock farms, but
it can also contribute to water quality problems. We conducted a 2-yr field
study in Chittenden County to evaluate the effects of different application
methods for liquid dairy manure on corn silage yields, potential for nitrate
leaching, and loss of phosphorus (P) and nitrogen (N) in surface runoff.
Manure was applied either pre-plant with disk incorporation (8000 gal/acre)
or at sidedress (5500 gal/acre; 12 to 18-inch plant height), either directly
incorporated with spreader-mounted s-tine cultivators or surface applied.
In the first year, while there were strong trends, there were no statistically
significant differences in yields among treatments; however, the surface
sidedressed manure yielded approximately the same as the no N control,
suggesting substantial loss of N via ammonia volatilization. In the second
year, all manure or fertilizer treatments yielded considerably more than
the control. The most marked water quality effect was a dramatic reduction
in runoff volume from the cultivated sidedress manure treatment, presumably
because of increased infiltration due to cultivation. This resulted
in a reduction in cumulative total P runoff loss of 60 to over 90% during
the mid-summer to fall period of both years. Nitrate leaching potential,
as indicated by soil sampling to four feet, appeared to be greatest in
the pre-plant broadcast manure and fertilizer N treatment, while that of
the sidedress cultivated manure was only slightly greater than the control.
This site is maintained by Sid.Bosworth@uvm.edu, Plant & Soil Science Department, University of Vermont.
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Last modified May 26 2004 12:55 PM