Abstract
A study was conducted at Akron, CO, USA, on a Weld silt loam in 2004 to quantify the effects of water deficit stress on corn (Zea mays, L.) root and shoot biomass. Corn plants were grown under a range of soil bulk density and water conditions caused by previous tillage, crop rotation, and irrigation management. Water deficit stress (Dstress) was quantified by the number of days when the water content in the surface 0.3 m deviated from the water content range determined by the Least Limiting Water Range (LLWR). Root and shoot samples were collected at the V6, V12, and R1 growth stages. There was no significant correlation between Dstress and shoot or root biomass at the V6 growth stage. At the V12 and R1 growth stages, there were negative, linear correlations among Dstress and both root biomass and shoot biomass. The proportional decrease of shoot biomass was greater than the proportional decrease in root biomass, leading to an increase in the root:shoot ratio as water deficit stress increased at all growth stages. Determining restrictive soil conditions using the LLWR may be useful for evaluating improvement or degradation of the soil physical environment caused by soil management.
Highlights
There are mixed reports in the literature on the effects of water deficit stress on crop production, and how different plants respond to water deficits by changing root:shoot ratios
The objective of this study was to determine the effects of deficit water stress on corn root distribution, corn root surface area density, and root:shoot ratio using the Least Limiting Water Range (LLWR) as the criteria to evaluate water deficit stress
Lower ρb in the chisel tillage system (CT) plots was evident at all sampling times
Summary
There are mixed reports in the literature on the effects of water deficit stress on crop production, and how different plants respond to water deficits by changing root:shoot ratios. Amos and Walters [1] summarized the effects of several soil environmental variables on corn root:shoot ratios. Allmaras and Nelson [2] and Allmaras and Nelson [3] showed little difference in corn root distribution caused by differences in soil matric suction in a Nicollet soil in southwestern Minnesota, but the differences in matric suction were minimal among treatments. In their studies, the hydraulic head was greater than −40 kPa for all observations and only varied between −40 and −10 kPa during the two years of the study. Gregory [5] concluded that dry soils induce plants to develop a more extensive root system and include deeper rooting, greater total weight, and greater total root length when compared with well-watered plants
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
