Gas exchange in maize as a function of aeration porosity in a cohesive soil

Edilaine Da Silva Marques,Ricardo Espíndola Romero,Jaedson Cláudio Anunciato Mota,Francisca Gleiciane Da Silva,Claudivan Feitosa De Lacerda

doi:10.5935/1806-6690.20210035

Edilaine Da Silva Marques, Ricardo Espíndola Romero + Show 3 more

Open Access

https://doi.org/10.5935/1806-6690.20210035

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Journal: Revista Ciencia Agronomica	Publication Date: Jan 1, 2021
Citations: 1	License type: cc-by

Affiliation: Universidade Federal do Ceará

Abstract

Due to their physical characteristics, cohesive soils of either low or high aeration porosity can intensify limitations on plant cultivation. With the hypothesis that moist cohesive horizons where the soil has not yet reached a hard to extremely hard consistency may present a level of aeration porosity that affects gas exchange in maize plants, the aim of this study was to understand the influence of a cohesive horizon at different levels of aeration porosity on gas exchange in maize. The experiment was conducted in Fortaleza in the state of Ceara in a screened and covered environment, in a completely randomised block design with five levels of aeration porosity (AP) (0.04, 0.06, 0.09, 0.11 and 0.13 m3 m-3) and six replications, giving a total of 30 experimental units. The variables under analysis were intrinsic permeability (Kair) and gas exchange. Increases in AP afforded an increase in Kair. The AP of 0.04 and 0.13 m3 m-3 reflected in lower values for the photosynthetic rate (A) (24.54 and 25.50 μmol CO2 m2 s-1 respectively) and internal CO2 concentration (140.72 and 118.66 µmol mol-1 respectively). With the increase in AP, stomatal conductance and transpiration were reduced by 18% and 13.6% respectively, while the increase in instantaneous carboxylation efficiency was 19%, and intrinsic water use efficiency, 21%. It was concluded that variations in aeration porosity in cohesive soils affected gas exchange in maize plants. The AP of 0.04 and 0.13 m3 m-3 reduced the value of A due to non-stomatal and stomatal limitations respectively.

Highlights

Coastal tablelands can be found along almost the entire coast of Brazil (REZENDE, 2000)
This has a direct effect on the growth of crops, since when the soil water content is high, hypoxia or anoxia can occur and as a result, the photosynthetic process may be affected due to both stomatal and not-stomatal limitations (TIAN et al, 2019)
The data on the variation in area available to the flow of air in the soil, represented by the intrinsic soil air permeability (Kair), showed a positive linear correlation, indicating that with the increase in aeration porosity there was an increase in the area available for gas exchange between the soil and the atmosphere (Figure 1)

Summary

Introduction

Coastal tablelands can be found along almost the entire coast of Brazil (REZENDE, 2000). In the soils of this geomorphological unit, agricultural crops generally show lower productivity due, among other factors, to the presence of cohesive horizons (REZENDE, 2000). One of the main characteristics of cohesive soils is the compact arrangement of the particles, with blocked and less-functional pores, which hinder the aeration process in the soil (MENEZES et al, 2018). This has a direct effect on the growth of crops, since when the soil water content is high, hypoxia or anoxia can occur and as a result, the photosynthetic process may be affected due to both stomatal and not-stomatal limitations (TIAN et al, 2019)

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Conclusion