Can no-till cropping alleviate water and heat stress?

摘要

No-till cropping systems,which include zero tillage with standing stubble and continuous cropping,are known to reduce soil erosion,improve soil quality and increase soil C sequestration compared to conventional practices.They are also generally associated with greater amounts of soil water and higher water use efficiencies,often resulting in a yield advantage.Recent studies found that no-till can buffer the extremes in soil temperatures reducing the damage caused by frost or heat stress.The warming trend associated with climate change could cause more frequent and severer water and heat stress in arid and semi-arid areas.We hypothesized that no-till cropping systems may provide an effective practice to reduce water and heat stress to cope with the climate change.A mini-rhizotron field study was conducted in the semiarid Brown soil zone of southern Saskatchewan with heavy surface residue and no residue treatments for spring wheat(Triticum aestivum L.),dry pea(Pisum sativum)and canola(Brassica napus).Results showed that surface residue improved near soil surface moisture in the early growing season and reduced near-surface soil temperature over the entire season,thus reducing water and heat stress.The improved near-surface soil environment increased total root length at the 0-50 cm soil depth for wheat and canola,but not for dry pea.Under the heavy residue treatment all the crops were taller than those under the no residue treatment.Grain and straw yield were increased for all crops,but were only significant for straw in canola.Although further studies are needed,this study supported the hypothesis that a no-till cropping system could improve plant performance in this area under the current and future climates.