System for quasi‐continuous simultaneous measurement of oxygen diffusion rate and redox potential in soil

Abstract

Oxygen diffusion rate (ODR) and redox potential (E H ) are quantitative indices representing oxygen availability and redox status in soils, which is valuable information for better understanding causes and effects of soil aeration. Because these indices are spatially and temporally highly variable, continuous measurements and adequate numbers of repetitions are essential for accurate in situ monitoring. Here, we present a new, fully automated recording system for in situ measurements where ODR and E H are measured at the same platinum electrode. The conflict between electrode polarization for ODR and the resulting biased E H readings is solved by reducing the polarization time and introducing a recovery interval between two consecutive measurement cycles. The shorter polarization time ensures accurate E H readings. It also results in moderately overestimated ODR readings, but this can be corrected before data analysis. The recovery interval restricts temporal resolution of the E H -ODR data pairs to 8 h. We illustrate the use of the system with measurements in a field experiment in Zü rich, Switzerland. ODR curves at different depths ran roughly parallel to the corresponding curves of O 2 concentration in soil air but ODR was much more sensitive to precipitation. Low ODR was a necessary but not a sufficient condition for declining E H . E H ran parallel to O 2 concentration in soil air rather than to ODR. The fully automated system allows for time series of replicate measurements in multifactorial field studies with reasonable labor requirements. It may be particularly suitable for studies examining the effects of soil tillage, compaction, and irrigation, where structure-related soil properties such as porosity, gas permeability, and soil aeration play a dominant role.

Limited resilience of the soil microbiome to mechanical compaction within four growing seasons of agricultural management

“…This supports earlier findings that compaction affects large pores, disrupts pore continuity, and strongly decreases fluid transport properties [ 65 ]. The decreased gas transport capacity of the soil can ultimately result in poorer aeration and lower levels of oxygen concentration in soil air [ 66 ]. In the fourth growing season, bulk density was still higher in the compacted plots of all agricultural management systems without mechanical loosening, i.e., PL and NT (Fig.…”

Tingkat Difusi Oksigen Selama Periode Blind Feeding Budidaya Intensif Udang Vaname (Litopenaeus vannamei)

“…Kelarutan gas oksigen dari udara menuju media perairan akan berpindah mengikuti derajat koefisien termal suhu di perairan (Ariadi et al, 2019;Varalda et al, 2019). Difusi oksigen bersifat dinamis mengikuti dinamika fluktuasi kualitas air dan tekanan hidrodinamis yang ada di perairan tambak (Reiser et al, 2020).…”

“…Tingkat difusi oksigen selama periode blind feeding budidaya udang vaname diketemukan rata-rata sebesar 0.020 mgO2/L/jam. Mekanisme difusi oksigen adalah faktor pembatas produksi oksigen di perairan yang secara matematis berpengaruh terhadap kuantitas serta beban kelarutan kadar oksigen secara keseluruhan pada suatu media perairan (Reiser et al, 2020). Secara umum, proses difusi oksigen di tambak dipengaruhi oleh beragam faktor.…”

Metabolt: An In-Situ Instrument to Characterize the Metabolic Activity of Microbial Soil Ecosystems Using Electrochemical and Gaseous Signatures

“…There are systems in place for continuous in-situ monitoring of CO 2 fluxes autonomously [25][26][27]. Reiser et al [28] combined the Eh measurements with the O 2 diffusion rate. Biogenic volatile organic compounds (VOCs) and gases released in soil are known to be linked to microbial activity that can be sensed with electronic nose (E-nose) technology [29].…”

“…The concept can be applied to a space qualified model for planetary exploration purposes. Our instrument Metabolt has been recently taken to a field campaign at an analogue for Moon and Mars cave exploration, demonstrating its applicability for fast, in-situ detection of the microbial activity in the ancient salt deposits of a subsurface mine [28]. In October 2017, the international astrobiology field campaign (MINAR 5) explored the Boulby salt mine (UK) in collaboration with the Spaceward Bound (NASA) and the Kalam Centre, India.…”