Effects of tillage intensity on nitrogen dynamics and productivity in legume-based grain systems |
| |
Authors: | Drinkwater LE Janke RR Rossoni-Longnecker L |
| |
Institution: | (1) Rodale Institute, 611 Siegfriedale Road, Kutztown, PA 19530, USA;(2) Present address: Department of Horticulture, Plant Science Building, Cornell University, Ithaca, NY 14853-5908, USA; Current address: Department of Horticulture, 2014 Throckmorton Plant Science Center, Kansas State University, Manhattan, KS 66506, USA |
| |
Abstract: | In 1988 an experiment was established at the Rodale Institute Experimental Farm to study weed control and nitrogen (N) management
in rotations with grain crops and N-fixing green manures under reduced tillage without the use of herbicides. Tillage intensities
ranging from moldboard plow (MP) to continuous no-till (NT) were compared. We present results for maize production in 1994,
the seventh year of the experiment. Our goal was to further investigate reduced tillage regimes that alternated no-till with
different forms of primary tillage in legume-based systems. In the chisel-disc (CD) and MP treatments comparable yields were
achieved under so-called organic (weeds controlled with cultivation and green manure N source) and conventional management
(weeds controlled with herbicides and mineral N fertilizer applied). Weed competition in these treatments was minimal and
the N status of maize plants was essentially the same regardless of the N source (fertilizer or green manure). Of the four
organic no-till maize treatments, only the mixed-tillage system with cultivation for weed control (CD-NTc) produced yields
comparable to conventional NT maize. The fate of vetch N as well as temporal N dynamics were largely determined by tillage
intensity and the handling of the vetch residues at maize planting. Treatments with primary tillage (CD and MP) had extremely
high levels of mineral N early in the season and had greater average net N-mineralization, even though N content of hairy
vetch in these treatments was equal to or lower than that in treatments with mow-killed vetch. In terms of soil mineral N
concentrations, the CD-NTc treatment was similar to the other mow-killed vetch/no-till maize treatments. However, N availability
in this treatment was greater, probably due to more complete decomposition of green manure residues. Cultivation for weeds
not only helped control weeds but also increased mineralization of the vetch residues, which in turn increased the N supply
during the period of maximum N demand by the maize. Carefully designed rotations combining tillage reductions with the use
of leguminous N sources can have multiple benefits, including improved timing of N availability, reduced herbicide applications,
and improved soil quality in the long term.
This revised version was published online in June 2006 with corrections to the Cover Date. |
| |
Keywords: | green manure mixed-tillage rotations nitrogen mineralization no-till organic agriculture vetch |
本文献已被 SpringerLink 等数据库收录! |
|