Measurement of stability of soil aggregates by optical methods

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00027006%3A_____%2F22%3A10175833" target="_blank" >RIV/00027006:_____/22:10175833 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Measurement of stability of soil aggregates by optical methods

Original language description

The resistance of soil aggregates to destruction in water is an important parameter of soil quality. Procedures that quantify the soil aggregate stability (SAS) are based on either a direct approach that determines the weight loss of a predefined aggregate load during periodic movement of the screen with the aggregates in the water, or by the action of water droplets impinging on soil aggregates under predefined experimental conditions. Another set of methods is based on an indirect approach in which we observe and measure the area occupied by a soil aggregate crumbling after placement to water. However, these methods are burdened by the subjective error of the observer and provide rather indicative results.Soil slaking assessment using image recognition was proposed by Fajardo et al. (2016). A soil aggregate crumbling is recorded by a digital camera, and an image recognition software and subsequent image processing quantifies the water stability of soil aggregates and calculates &quot;slaking index&quot;. More stable aggregates give lower slaking index. The method was implemented into a mobile phone app SLAKES for Android and IOS platforms. We comprehensively tested the method and the app. We developed a supporting device that improves problematic aspects of the method arising from inappropriate light conditions. The improved measuring set consists of a mobile phone (with SLAKES app) and a LED panel, which backlights the bowl with soil aggregates during the measurement.Soil samples from 7 long-term field experiments were evaluated: experiment with different crop rotations (Hněvčeves), fertilization experiment VOP (Čáslav, Lukavec, Ivanovice), experiment with application of digestates ÚKZÚZ (Lípa, Svitavy and Jaroměřice), from spring and post-harvest samplings. The samples included various experimental treatments as well as permanent grasslands in the vicinity of the experiments. For SLAKES method, we used aggregates of a size 3-5 mm. The reference method for determining the stability of soil aggregates was the wet sieving method according to Kandeler (1994), using aggregates of a size 1 - 2 mm.The study showed a significant negative correlation between the two methods (R = -0.64). The correlation was higher (R = -0.76) for more stable aggregates (SAS above 40 %) and for sandy soils (Lípa and Lukavec, R = -0.8). Both methods indicated significant differences between treatments of field trials. The highest stability of soil aggregates was found in permanent grasslands (low values of slaking index, high values of SAS), the lowest on treatments fertilized only by mineral fertilizers and on the unfertilized treatments. Based on these experiences with the optical method of soil aggregate stability measurement, we developed a unique simple measuring device for aggregate stability assessment. The device is based on a photocells and enables simultaneous separate SAS measurement of 9 aggregates.It can be concluded that optical methods of soil assessment enable farmer and public users measure and evaluate quality of their soils. Slaking index provide a good indication of the soil aggregate stability in a variety of soils. The LED backlighting substantially increases measurement stability and reproducibility. Comparing with the apparatus for wet sieving, the set of a mobile phone with LED panel is inexpensive and can be used in home conditions. Innovation and the development of simple soil assessment methods can further increase interest in soil quality and health, and can increase farmers&apos; efforts to improve it.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

40106 - Agronomy, plant breeding and plant protection; (Agricultural biotechnology to be 4.4)

Project

<a href="/en/project/QK1810186" target="_blank" >QK1810186: Agrotechnical measures for improvement of soil structure stability and rainwater infiltration</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2022

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů