Application of electrical capacitance measurement for in situ monitoring of competitive interactions between maize and weed plants

Imre Cseresnyés,Krisztina R Végh,Éva Lehoczky,Anna Füzy,Tünde Takács

doi:10.5424/sjar/2016142-7562

Abstract

Applicability of root electrical capacitance (EC) measurement for monitoring of crop–weed competition was studied in a pot experiment. Maize (Zea mays L.) was grown both alone and with Echinochloa crus-galli or Abutilon theophrasti in different densities with regular measurement of root EC. Plants were harvested 42 days after planting to determine above- and belowground biomass. Depending on weed density, E. crus-galli-A. theophrasti interaction reduced the root EC of maize by 22–66% and 3–57%, respectively. Competitive effect of crop on weeds and intraspecific competition among weeds could also be detected by EC values: E. crus-galli was less sensitive both to the presence of maize and to intraspecific competition than A. theophrasti. Strong linear correlations between root dry mass and root EC for crop and weeds (with R2 from 0.901 to 0.956) were obtained by regression analyses at the end of the experiment. EC monitoring informed us on the emergence time of competition: E. crus-galli interfered with maize root growth a week earlier then A. theophrasti, and increasing weed densities accelerated the emergence of competition. In conclusion, the simple, non-destructive EC method should be considered a potential in situ technique for pot studies on crop–weed competition, which may partially substitute the intrusive techniques commonly used in agricultural researches.

Highlights

Excluding environmental variables, weed competition is the major constraint to crop production for many agroecosystems worldwide
electrical capacitance (EC) monitoring informed us on the emergence time of competition: E. crus-galli interfered with maize root growth a week earlier A. theophrasti, and increasing weed densities accelerated the emergence of competition
Higher densities of E. crusgalli corresponded to an earlier effect of competition: signal intensity in root EC for Z-E1, Z-E3 and Z-E5 groups became significantly lower on 20, 16 and 13 days after planting (DAP), respectively than those of maize control (Z-0)

Summary

Introduction

Excluding environmental variables, weed competition is the major constraint to crop production for many agroecosystems worldwide. The great advantage of EC method over other in situ techniques that it can study the functional aspect of the plant root system, providing information about the absorptive root surface area (Cseresnyés et al, 2013b) The aim of this methodological work presented was to test the applicability of EC measurement for in situ monitoring of root development and biomass loss of crop and weed plants subjected to competitive interactions in a pot experiment with two weeds native to southern Asia which (due to their broad ecological adaptation) have become widely distributed in various agricultural areas of the Northern Hemisphere during the last century. They are considered to be among the most troublesome yieldlimiting weeds in many temperate and tropical crops including maize, rice, cotton, sorghum, soybean, cassava and vegetables (Warwick & Black, 1988; Holm et al, 1991; Hyvönen & Ramula, 2014)

Material and methods

Statistical methods

Results

Discussion