Table 1.

Selected works observing at the use of DGT to assess nutrient mobility in soil and relations with different crops

Analyte	DGT type	Experimental conditions	Crops	Main findings	References
P	DGT-P/Fe–ZrO-Chelex resin gel to simultaneously measure labile P and Fe; Zr-oxide DGT to measure soil labile P fluxes	DGT was used to in situ assess P availability in rhizosphere, resupply, and release risk to the environment from soil amended with biochar	Rice	Biochar addition to the soil significantly reduced the P availability in rice rhizosphere	Chen et al. (2022)
P	Ferrihydrite hydrogel as binding gel	DGT was used for the assessment of P availability in soil of the Ultuna long-term field experiment	-	P resupply from the solid fraction of soil solution provided a better prediction on the P uptake than the equilibrium-based extractions	Jarosch et al. (2018)
P	0.4-cm-thick precipitated zirconia-based binding gel 0.75 cm polyacrylamide diffusive gel	DGT was used for the assessment of P mobility in 75 topsoil samples from a plastic-covered greenhouse vegetable production form China	-	The DGT accurately predicted the P mobility in acid-neutral and alkaline soils	Kalkhajeh et al. (2018)
P	DGT with a ferrihydrite binding layer	DGT determinations were compared to frequently used chemical soil extraction methods (ammonium lactate, NaHCO3, ammonium acetate) and with the transfer rates to crops	Spring barley	All four extraction methods might predict P concentrations in the youngest fully emerged leaf of unfertilized plants, harvested after 30 days of plant growth. DGT soil test showed the best correlation with plant uptake (0.83). For longer growth periods (56 days), the correlation had disappeared.	Mundus et al. (2017)
P	P-DGT form DGT research	DGT was used for the assessment of P mobility and lability in fertilized soil, in pot experiments. Different P application strategies were used	Maize	Different P application strategies affected the soil available P. The CDGT-P correlated well with the water-soluble P. The P uptake by the maize plant was better correlated with the CDGT-P than the P concentrations in soil, measured by other methods	Kang et al. (2021)
P	P-DGT ferrihydrite-based binding gel	Large-scale study on 218 soil samples from five countries in Europe, analyzed by DGT and other 4 chemical extraction methods; DGT deployment: soil saturation at WHC, 2–48 h	Different crop species	All tests were positively correlated to the P in crops; however, the oxalate extraction was generally poor	Nawara et al. (2017)
P	P-DGT Fe-oxide resin gel and open pore diffusive gel	P available fraction in fertilized soils was assessed by four methods, including DGT; DGT deployment: soil saturation at WHC, 24 h	-	Fertilizer application increased the available inorganic P and favored the available inorganic O relative to the organic P	Nobile et al. (2018)
P	P-DGT ferrihydrite-based binding gel	DGT measurement combined with X-ray absorption near edge structure (XANES) spectra in soil	-	The association between P and different minerals in soil were reported. The DGT concentration of P in the soil solution was highly variable, depending on the soil type	Tuntrachanida et al. (2022)
P and K	DGT with a binging gel containing mixed amberlite and ferrihydrite (MAF)	Elution efficiency was tested by placing DGT with tested gels in solutions with known amounts of analyte for 24 h. The diffusion coefficients were measured by deployment of DGT devices in boxes of 3 L containing known concentration of analyte	-	Elution efficiencies of the resin gel were 90% for K and 96% for P, respectively. The diffusion coefficient of K through the diffusive gel was calculated as 1.30 × 10−5 cm2 s−1 at 22 °C	Zhang et al. (2013)
Se	Ferrihydrite hydrogel as binding gel for Se, and polyacrylamide (0.78 mm thickness) diffusion gel	DGT was used to measure Se bioavailability in soil supplemented with selenite and organic amendment (cow and chicken manures) in pot experiments	Brassica juncea	Simultaneous amendment with manure and selenite can result in the reduction of Se mobility in the soil. DGT predicted well the accumulation of Se in B. juncea	Dinh et al. (2021)
Se	DGT form DGT research—for Se	DGT was used to measure Se bioavailability in soil amended with P and S in pot experiments	Pak choi	CDGT-Se was not significantly correlated with the Se content of pak choi since DGT cannot reflected the competitive relationship between P, S, and Se at the plant root uptake sites	Jiang et al. (2022)
Se	DGT form DGT research—for Se	Pot experiments on soil with Se concentrations varying between 0.12 and 20.62 mg kg−1 (average of 2.01 mg kg−1). Sequential chemical extractions and DGT were used to assess the Se fractionation in soil	-	Soluble and exchangeable Se fractions with high mobility in soil represent about 0.7% and 5.1% (respectively) of total Se; the DGT-determined concentration of Se was generally resulting from the soluble and exchangeable Se fractions	Lyu et al. (2021)
Se	DGT form DGT research—for Se ferrihydrite hydrogel; polyacrylamide diffusion gel	Soil spiked with Se at a concentration of 1 mg kg−1 with selenite and selenate. Soils were aged until 100 days, and analyzed to assess changes in Se availability	Pak choi	DGT may evaluate the fluctuations of Se availability in soil and predict the Se uptake by pak choi crop in aged soils	Peng et al. (2019)
Se	DGT form DGT research—for Se ferrihydrite hydrogel; polyacrylamide diffusion gel	Chemical extractions and DGT technique were used to assess Se content and mobility in soils amended by selenite or selenate	Purple cabbage, broccoli, wheat, and mustard	The soil amended with selenate and cultivated with wheat has a very high CDGT-Se compared with soil amended with selenite. Purple cabbage and broccoli changed most obvious change Se mobility with wheat and mustard	Peng et al. (2017)
Se	DGT form DGT research—for Se ferrihydrite hydrogel; polyacrylamide diffusion gel	Soil spiked with selenite and selenite. Chemical extractions and DGT technique were compared and correlated with accumulation by crop	Pak choi	DGT technique better predicted plant uptake of Se(IV) than the chemical extraction methods, while KH2PO4–K2HPO4 extraction better predicted the Se(VI) uptake	Peng et al. (2020)
NO3–N and NH4–N	A520E anion exchange resin and the PrCH cation exchange resin for resin gel Agarose diffusive gels	Experiments assessed the ability of the DGT with A520E anion exchange resin and the PrCH cation exchange resin to measure mobile NO3–N and NH4–N	-	The mass of NO3–N and NH4–N accumulated by the DGT device linearly increased on domains of concentrations in soil from 5 to 300 mg kg−1 NO3–N and from 5 to 300 mg kg−1 NH4–N; Concentrations measured by DGT and by extraction in 2 M KCl were significantly correlated	Kodithuwakku et al. (2023)