|Sudduth, Kenneth - Ken|
|Sadler, Edward - John|
|Volkmann, Matthew - Matt|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2015
Publication Date: 3/1/2016
Citation: Yost, M.A., Kitchen, N.R., Sudduth, K.A., Sadler, E.J., Baffaut, C., Volkmann, M.R., Drummond, S.T. 2016. Long-term impacts of cropping systems and landscape positions on claypan-soil grain crop production. Agronomy Journal. 108(2):713-725. doi: 10.2134/agronj2015.0413.
Interpretive Summary: Claypan soils occupy roughly 10 million acres of land in the southern half of the Midwestern United States. These soils are highly prone to erosion and associated environmental concerns and likely require conservation practices such as diversified crop rotations, reduced or no-till, cover crops, and reduced agrichemical inputs to sustain grower profits and soil and water resources. Therefore, information on the long-term impacts of conservation practices on grain crop (corn, soybean, and wheat) production on claypan soils is crucial to sustaining and enhancing our nation’s food and feed supply. As a part of the Long-Term Agroecology Network, this study summarized 20 years of data from long-term research plots with different cropping systems and landscape positions. The results show that conservation cropping systems with no-till and reduced chemical inputs or with no-till, diversified rotations, cover crops, and integrative chemical inputs can sustain grain yields equal to a conventional system. Furthermore, the conservation systems increased yield, yield stability, and reduced crop yield variability over a conventional system on the most eroded and vulnerable backslope landscape positions. Results of this study will aid in the further acceptance and use of conservation practices by farmers and farm advisors on claypan landscapes. Increased use of conservation practices should maintain farmer’s long-term crop yields, reduce variability in their crop yield, and increase the stability of their yields across a range of growing conditions.
Technical Abstract: Sustainable grain crop production on vulnerable claypan soils requires improved knowledge of long-term impacts of conservation cropping systems (CS) with reduced inputs. Therefore, effects of CS and landscape positions (LP) on corn (Zea mays L.), soybean [Glycine max (L.) Merr.], and wheat (Triticum aestivum L.) yield, yield stability, and yield variability were evaluated from 1991 to 2010 on a claypan soil near Centralia, MO. Replicated treatments were three CS (2-yr mulch till corn-soybean [MTCS], 2-yr no-till corn-soybean [NTCS], and 3-yr no-till corn-soybean-wheat-cover crop [NTCSW]) and three LP (summit, backslope, and footslope). Corn yield was equivalent among systems on the summit, was 13% higher for the no-till systems on the backslope, and was 14% lower for NTCSW on the footslope than other systems. Soybean yield on the summit and backslope was 8 and 24%, respectively, higher in both no-till systems and 12% higher on the footslope in NTCSW than MTCS. Regression stability analysis showed that corn yield was stable in NTCSW and on the backslope, and was much more susceptible to environmental conditions in MTCS than NTCS. Soybean yield was stable in all three CS and at the summit and footslope, but was susceptible to environmental conditions on the backslope. The coefficient of variation (CV) of corn yield across years was 10 percentage points lower in NTCS and on the footslope, and of soybean yield was 10 percentage points lower at the footslope and summit than in other respective systems and at LP. Wheat production was not affected by LP. Results indicate that conservation systems (NTCS and NTCSW) often can maintain grain crop productivity equal to, increase yield stability above, and reduce yield variability below those of a conventional system (MTCS) on claypan soils.