Agronomic and Economic Performance Characteristics of Conventional and Low‐External‐Input Cropping Systems in the Central Corn Belt
Autor: | Fabian D. Menalled, David N. Sundberg, Craig A. Chase, Lance R. Gibson, Paula R. Westerman, Adam S. Davis, Robert G. Hartzler, Andrew H. Heggenstaller, Philip M. Dixon, Matt Liebman |
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Rok vydání: | 2008 |
Předmět: | |
Zdroj: | Agronomy Journal. 100:600-610 |
ISSN: | 1435-0645 0002-1962 |
Popis: | We conducted a 9-ha field experiment near Boone, IA, to test the hypothesis that yield, weed suppression, and profit characteristics of low-external-input (LEI) cropping systems can match or exceed those of conventional systems. Over a 4-yr period, we compared a conventionally managed 2-yr rotation system {corn (Zea mays L.)/soybean [Glycine max (L.) Merr.]} with two LEI systems: a 3-yr corn/soybean/small grain + red clover [Trifolium pratense L.) rotation, and a 4-yr corn/soybean/small grain + alfalfa (Medicago sativa L.)/alfalfa rotation. Synthetic N fertilizer use was 59 and 74% lower in the 3- and 4-yr systems, respectively, than in the 2-yr system; similarly, herbicide use was reduced 76 and 82% in the 3- and 4-yr systems. Corn and soybean yields were as high or higher in the LEI systems as in the conventional system, and weed biomass in corn and soybean was low (≤4.2 g m -2 ) in all systems. Experimentally supplemented giant foxtail (Setaria faberi Herrm.) seed densities in the surface 20 cm of soil declined in all systems; supplemented velvetleaf (Atbutilon theophrasti Medik.) seed densities declined in the 2- and 4-yr systems and remained unchanged in the 3-yr system. Without subsidy payments, net returns were highest for the 4-yr system ($540 ha -1 yr -1 ), lowest for the 3-yr system ($475 ha -1 yr -1 ), and intermediate for the 2-yr system ($504 ha -1 yr -1 ). With subsidies, differences among systems in net returns were smaller, as subsidies favored the 2-yr system, but rank order of the systems was maintained. |
Databáze: | OpenAIRE |
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