| Abstrakt: |
Both established and subsequently emerging weed species in ecofarming systems must be selectively controlled without tillage in order to better conserve soil and water in the semiarid region of the Great Plains. The objective of this research was to determine selective weed control methods for an oat (Avena sativaL.)‐soybean [Glycine max(L.) Merr.] ecofarming rotation in order to allow dryland soybean production to move further west in the Great Plains. Experiments were conducted at Concord, NE on a Colo silty clay loam (fine‐silty, mixed, mesic, Cumulic Haplaquoll) and at Lincoln, NE on a Sharpsburg silty clay loam (fine, montmorillonitic, mesic, Typic Argiudoll) during 1976 through 1979. Weed control must be effective during the entire crop rotation. There are several herbicide treatments that provide ample length and spectrum of weed control after oat harvest. During the subsequent soybean year, glyphosate [N‐ (phosphonomethyl)glycine] at 0.8 kg ha−1controlled established weeds prior to soybean planting, and there were several residual herbicide treatments that gave selective weed control in soybeans without cultivation. The low‐till farmer has several herbicide treatments available that will selectively and adequately control weeds without tillage in an oat‐soybean rotation. This low‐tillage method of growing crops in the Great Plains should improve soybean yields and yield stability while conserving soil, water, energy, and labor. |
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