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Research Article

Competition among warm season C4-cereals influence water use efficiency and competition ratios

| (Reviewing Editor)
Article: 1011466 | Received 26 Oct 2014, Accepted 20 Jan 2015, Published online: 11 Feb 2015
 

Abstract

Water use efficiency (WUE) and competition ratio (CR) response of three warm season C4-cereals (grasses) viz. corn (Zea mays L., cv. Hybrid-5393 VT3), grain sorghum (Sorghum bicolor L. Moench, cv. Hybrid-84G62 PAT), and foxtail millets (Setaria italic, cv. German Strain R) in pure and mixed stands under low and high water levels was investigated. The experiment was conducted in pot experiment at Dryland Agriculture Institute, West Texas A&M University, Canyon, Texas, USA, during spring 2010. The objective of this study was to know whether the differences in the competitive ability of different crop species influence WUE or not? The planned mean comparison indicated that the corn WUE was 20, 11, and 6% higher in the mixed stand than in pure stand at 30, 60, and 90 days after emergence (DAE), respectively. The corn plants in pure stand had 91, 72, and 81% higher WUE than the average WUE of sorghum and millets in pure stand at 30, 60, and 90 DAE, respectively. Grain sorghum in pure stand had 70, 32, and 36% higher WUE than that of millets in pure stand at 30, 60, and 90 DAE, respectively. The WUE of three crops in mixed stand was 10 and 8% higher than the two crops mixed stand at the two early stages; but the WUE was 24% less in the three crops mixed stand than the two crops mixed stand at 90 DAE. Corn-mixed stand in two crops (average of corn + sorghum and corn + millets) had 78, 74, and 74% higher WUE than the mixed stand of sorghum and millets at 30, 60, and 90 DAE, respectively. Corn and millets mixed stand had 14, 10, and 26% higher WUE than the corn and sorghum mixed stand at 30, 60, and 90 DAE, respectively. The increase in water level decreased WUE at the two late growth stages in all three crop plants. At the early growth stage (30 DAE), WUE increased in all crops at the higher water level. On the basis of CR, corn was found the best competitor, while millets was declared the least competitor in the mixed stands (corn > sorghum > millets). It was concluded that the higher the compatibility of a species in a mixed stands, the greater will be total biomass accumulation (corn > sorghum > millets) and hence WUE (corn > sorghum > millets).

Public Interest Statement

Water use efficiency (WUE) and competition ratio (CR) response of three warm season C4-cereals (corn, grain sorghum, and millets) in pure (sole crop) and mixed crops under low and high water levels was investigated. The three warm season cereals responded differently in terms of WUE and CR when grown in pure and mixed stands. Among the three crops under study, corn plants had the higher WUE and CR due to the highest total dry matter accumulation (shoots + roots) and was considered the best competitor, followed by sorghum, while millets stands in the bottom due to its less WUE and CR in mixed stands. This indicates that corn plants captured most of resources above and below the ground over time because of its well-developed shoots and roots. The results further confirmed that plant species with higher completion ratio in mixed stand have higher water use efficiency.

Cover image

Source: Author.

Additional information

Funding

Funding. Financial support from the Higher Education Commission, Islamabad, Pakistan, and the partial support from the Dryland Agriculture Institute, West Texas A&M University Canyon, Texas USA for this research project are highly acknowledged.

Notes on contributors

Amanullah

Amanullah is working as an associate professor in Agronomy, The University of Agriculture, Peshawar, Pakistan. He did his PhD in agronomy from the University of Agriculture, Peshawar in 2004, and postdoctorate from the Dryland Agriculture Institute, West Texas A&M University, Texas, USA in 2010. His field of interests includes Crop Nutrition, Crop Physiology, Crop Competition, Dryland Agriculture, and Crop Management under Stressful Environments. He has added more than 120 publications to his name, including 60 papers in the international impact factor journals. He has won the two consecutive research productivity awards from the Pakistan Council of Science and Technology, Islamabad in 2011–2012 and 2012–2013. So far, he has produced two PhDs students and more than 15 MSc (Hons) students.