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United States Department of Agriculture

Agricultural Research Service

Research Project: CHARACTERIZATION AND ENHANCEMENT OF PLANT RESISTANCE TO WATER-DEFICIT AND THERMAL STRESSES Title: Allelopathic influence of a wheat or rye cover crop on growth and yield of no-till cotton

Authors
item Li, Yue -
item Chen, Junping
item Hou, Fujiangi -
item Brown, Phillip -
item Green, Paul -
item Allen, Vivien -

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 9, 2013
Publication Date: N/A

Interpretive Summary: Interpretive Summary No-till planting cotton into small grain cover crops has many benefits including reducing soil erosion and allelopathic suppression of weeds. Studies conducted under controlled environments also suggested the potential impact of allelopathy on cotton plants. However, little is known about the actual effects of allelochemicals from small grain cover crop on the growth and yield of the following cotton plants. In this study, we investigated the effects of rye and wheat cover crops or no cover crop on the growth and yield components of no-till planted cotton in field conditions in 2007 to 2009; examined soil samples for the presence of major allelochemicals and their dynamic changes in soil throughout the season and compared the allelochemical species found in soils with those detected in wheat and rye tissues. In all 3 years of experiments conducted, significant amounts of major allelochemicals were detected in cover crop fields throughout the season but the amounts varied due to specific cover crop and sampling date. Cottons no-till planted in no cover crop field was relatively greener (measured at mid-season) and significantly taller (end-season height) than those planted into cover crop fields. Cotton yield was also reduced by cover crops but the magnitude of allelopathic effect on yield varied by year. Our results show that the reductions in the growth and yield of cotton no-till planted in cover crop field are associated with allelochemicals of wheat and rye plant released into soils. Furthermore, allelochemicals studied in this experiment appeared to persist for up to 2 year in semi-arid and underground irrigated fields, much longer than that reported in laboratory studies. Further studies are needed to determine the long-term persistence of these chemicals and allelopathy under varying field and environmental conditions in order to better manage agricultural resources and sustain crop production.

Technical Abstract: TECHNICAL ABSTRACT No-till planting cotton into small grain cover crops has many benefits including reducing soil erosion and allelopathic suppression of weeds. It is suggested that the potentials of allelopathy on cotton plants. Nevertheless, little is known about the actual effects of allelochemicals of small grain cover crop on following cotton plants. In this study, we investigated the effects of rye and wheat cover crops or no cover crop on the growth and yield components of cottons no-till planted in the field from 2007 to 2009. Presence of allelochemicals in soil and their dynamic changes throughout the season was examined by HPLC analysis and compared with the allelochemical species found in wheat and rye tissues. Significant amounts of major allelochemicals were detected in soil samples of cover crop fields throughout the season. However, the amounts found varied between the 2 cover crop fields and different sampling dates. Cotton leaf chlorophyll content of cotton plants grown in no cover crop field was relatively greater (measured at mid-season) that those of plants grown in cover crop fields. Cotton in no cover crop field was taller than those in cover crop field (end-season plant height). Cotton lint and seed yields were reduced by cover crops but the magnitude of allelopathic effect on yield varied by year. Our results show that the reductions in the growth and yield of cotton no-till planted in cover crop field are associated with allelochemicals of wheat and rye plant released into soils. Furthermore, allelochemicals studied in this experiment appeared to persist for up to 2 year in semi-arid and underground irrigated fields, much longer than that reported in laboratory studies. Further studies are needed to determine the long-term persistence of these chemicals and allelopathy under varying field and environmental conditions in order to better manage agricultural resources and sustain crop production.

Last Modified: 11/27/2014
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