不同土壤处理对东南景天吸取土壤中锌和镉效率的影响

通过盆栽试验，观察分析东南景天植物在未处理及若干用土壤添加剂处理的土壤介质上生长和累积锌、镉的状况。结果显示：除单独使用沸石粉外，所有土壤处理均有利于土壤改良和东南景天的生长。与对照处理相比，赤泥和城市污泥对东南景天累积锌起促进作用，而施用熟石灰却无助或甚至不利于东南景天累积锌。不过，尽管赤泥和城市污泥对东南景天累积镉的效果比熟石灰好，无论施用赤泥、城市污泥或熟石灰，东南景天植物干物质所含的镉均比对照处理高得多。总的来说，赤泥和城市污泥均为改良土壤、促使东南景天生长和超累积锌、镉的良好添加剂；而熟石灰或沸石粉单独使用则对东南景天超累积锌、镉的作用较小。在试验中，将15g污泥、15g沸石和6g赤泥与1000g土壤混和的T7处理对促使东南景天生长和超累积锌、镉最为有效。研究结果表明，在利用东南景天修复酸性锌、镉污染土壤时，通过加入合适的改良剂，调控土壤pH值和营养供给，可大大提高植物修复重金属污染的效果。     

Reduction of availability of trace metals in urban soils using inorganic amendments

Urban soils in medium- and large-sized cities generally have shown elevated contents of environmentally important trace metals (e.g. lead, copper, zinc). Such high concentrations in soils of green areas, mainly recreational areas, can be a source of potentially toxic elements and pose a risk for human health. Thus the availability of these contaminants is an essential control parameter, as it indicates potential plant uptake and their transfer to humans via inhalation of suspended dust, or direct ingestion (i.e. hand to mouth pathway), or consumption of contaminated foodstuff. Young children are the most sensitive segment of the population. Addition of amendments to the soil is a feasible technique to reduce the availability of trace metals. Accordingly, four urban soils of green areas of Seville (Spain), with relatively high lead contents and moderate copper and zinc contents, were amended in the laboratory with four inorganic materials [acid zeolite (AZ), sodium zeolite (SZ), Slovakite (SL), apatite (AP)], at two rates (1%, 5% w/w) and incubated for 1 year. Significant decreases in EDTA-extractable metal contents were observed in some of the treatments after adding the amendments even before the incubation begun, mainly for SL treatments. The amendment that produced the longest lasting immobilisation effect, compared to control treatments, was AZ at the higher rate. The effects of SZ and SL tended to decrease with time, while the AP effect was almost negligible after 3 months of ageing. This study confirms the feasibility of using certain inexpensive soil amendments to at least temporarily immobilise metals in urban soils for the purpose of protecting human health, especially that of young children.     

Effects of carbon nanotube and biochar on bioavailability of Pb,Cu and Sb in multi-metal contaminated soil

This study examined the effects of carbon nanotube and biochar on the bioavailability of Pb, Cu and Sb in the shooting range soils for developing low-cost remediation technology. Commercially available multi-walled carbon nanotube (MWCNT) and biochar pyrolyzed from soybean stover at 300 °C (BC) at 0.5, 1 and 2.5% (w w^?1) were used to remediate the contaminated soil in an incubation experiment. Both DTPA (bioavailable) and TCLP (leaching) extraction procedures were used to compare the metal/loid availability and leaching by the amendments in soil. The addition of BC was more effective in immobilizing mobile Pb and Cu in the soil than that in MWCNT. The BC reduced the concentrations of Pb and Cu in the soil by 17.6 and 16.2%, respectively. However, both MWCNTs and BC increased Sb bioavailability by 1.4-fold and 1.6-fold, respectively, in DTPA extraction, compared to the control. The toxicity characteristic leaching procedure (TCLP) test showed that the leachability of Pb in the soil amended with 2.5% MWCNT was 1.3-fold higher than that the unamended soil, whereas the BC at 2.5% decreased the TCLP-extractable Pb by 19.2%. Precipitation and adsorption via electrostatic and π–π electron donor–acceptor interactions were postulated to be involved in the interactions of Pb and Cu with surfaces of the BC in the amended soils, whereas ion exchange mechanisms might be involved in the immobilization of Cu in the MWCNT-amended soils. The application of BC derived from soybean stover can be a low-cost technology for simultaneously immobilizing bioavailable Pb and Cu in the shooting range soils; however, neither of amendments was effective in Sb immobilization.     

Natural and synthesised iron-rich amendments for As and Pb immobilisation in agricultural soil

The immobilisation of heavy metals in contaminated soils is a promising alternative to conventional remediation techniques. Very few studies have focused on the use of iron-rich nanomaterials and natural materials for the adsorption of toxic metals in soils. Synthesised iron-rich nanomaterials (Fe and Zr–Fe oxides) and natural iron-rich materials (natural red earth; NRE) were used to immobilise As and Pb in contaminated agricultural soil. Total concentrations of As and Pb in the initial soil (as control) were 170.76 and 1945.11 mg kg^?1, respectively. Amendments were applied into the soil at 1, 2.5 and 5% (w/w) in triplicate and incubated for 150 days. Except for the NRE-amended soil, soil pH decreased from 5.6 to 4.9 with increasing application rates of Fe and Zr–Fe oxides. With addition of Fe and Zr–Fe oxides at 5%, the ammonium acetate (NHO₄Ac)-extractable Pb was greatly decreased by 83 and 65% compared with NRE addition (43%). All subjected amendments also led to a decrease in NHO₄Ac-extractable As in the soils, indicating the high capacity of As immobilisation. Soil amended with NRE showed a lower ratio of cy19:0 to 18:1ω7c, indicating decreased microbial stress. The toxicity characteristic leaching procedure produced results similar to the NHO₄Ac extraction for As and Pb. The NRE addition is recommended for immobilising heavy metals and maintaining biological soil properties.     

Trace elements in wild grasses: a phytoavailability study on a remediated field

There have been significant efforts to establish a widely usable method for the prediction of trace element bioavailability in soil. In this work, we used extraction with 0.01 M CaCl₂ and 0.05 M ethylenediaminetetraacetic acid (EDTA) to estimate bioavailable concentrations of As, Cd, Cu, Pb, and Zn in a soil moderately contaminated with trace elements 1 and 2 years after the application of three amendments. The experiment took place in a field plot of a soil affected by the toxic spill of the Aznalcóllar mine. Four treatments were established: three with amendments (biosolid compost, sugar beet lime, and a combination of leonardite plus sugar beet lime) and a control without amendment. Trace element concentrations of two representative species in each year (Lamarckia aurea and Poa annua in 2004 and Lamarckia aurea and Bromus rubens in 2005) were analyzed. The results showed a positive effect of the amendments both on soil and vegetation. Trace element concentrations in plants growing in the amended subplots were lower than those in plants from nonamended subplots. As a rule, concentrations of CaCl₂-soluble Cd, Cu, and Zn in soil were positively correlated with trace elements in plants, whereas EDTA extraction was scarcely correlated with plant concentration. For species of grasses, especially L. aurea, CaCl₂ seems to be a more suitable extractant to predict trace element bioavailability in this contaminated soil.     

土壤改良剂对荧蒽、苯并[k]荧蒽提取和植物吸收的影响

在温室条件下,利用盆栽实验研究了三种土壤改良剂(骨炭、活性炭、泥炭)对荧蒽和苯并[k]荧蒽的提取和黑麦草吸收的影响.结果表明,添加骨炭、活性炭和泥炭后,土壤中可提取态荧蒽和苯并[k]荧蒽的量比对照处理分别降低了43.1%-63.8%和35.2%-57.6%,在高剂量骨炭、活性炭和泥炭处理的土壤中,可提取态荧蒽和苯并[k]荧蒽的量降低幅度均比相应低剂量处理的降低幅度大,并且各处理的效果与对照相比均达到了显著差异(p＜0.05);骨炭、活性炭和泥炭减少了荧蒽和苯并[k]荧蒽在黑麦草地下部分和地上部分的累积量,并且荧蒽和苯并[k]荧蒽在黑麦草地下部分和地上部分的累积量随着骨炭、活性炭和泥炭添加量的增加呈下降趋势.     

Phosphates for Pb immobilization in soils: a review

In its soluble ionic forms, lead (Pb) is a toxic element occurring in waters and soils mainly as the result of human activities. The bioavailability of lead ions can be decreased by complexation with various materials in order to decrease their toxicity. Pb chemical immobilization using phosphate addition is a widely accepted technique to immobilize Pb from aqueous solution and contaminated soils. The application of different P amendments cause Pb in soils to shift from forms with high availability to the most strongly bound Pb fractions. The increase of Pb in the residual or insoluble fraction results from formation of pyromorphite Pb₅(PO₄)₃X where X = F, Cl, Br, OH, the most stable environmental Pb compounds under a wide range of pH and Eh natural conditions. Accidental pyromorphite ingestion does not yield bioavailable lead, because pyromorphite is insoluble in the intestinal tract. Numerous natural and synthetic phosphates materials have been used to immobilize Pb: apatite and hydroxyapatite, biological apatite, rock phosphate, soluble phosphate fertilizers such as monoammonium phosphate, diammonium phosphate, phosphoric acid, biosolids rich in P, phosphatic clay and mixtures. The identification of pyromorphite in phosphate amended soils has been carried out by different non destructive techniques such as X-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, X-ray absorption fine structure, transmission electron microscopy and electron microprobe analysis. The effectiveness of in situ Pb immobilization has also been evaluated by selective sequential extraction, by the toxicity leaching procedure and by a physiologically based extraction procedure simulating metal ingestion and gastrointestinal bioavailability to humans. Efficient Pb immobilization using P amendments requires increasing the solubility of the phosphate phase and of the Pb species phase by inducing acid conditions. Although phosphorus addition seems to be highly effective, excess P in soil and its potential effect on eutrophication of surface water, and the possibility of As enhanced leaching remains a concern. The use of mixed treatments may be a useful strategy to improve their effectiveness in reducing lead phyto- and bioavailability.     

农田重金属污染原位钝化修复研究进展

污染土壤重金属原位钝化修复是通过向土壤中施加一些活性钝化修复材料,通过溶解沉淀、离子交换吸附、氧化还原、有机络合等反应来改变重金属在土壤中的赋存状态,降低土壤中重金属的有效浓度、迁移性和生物有效性。这种方法成本较低、操作简单、见效快且适合大面积推广,在重金属污染土壤修复中有着不可替代的作用。尤其对主要由污水灌溉、大气沉降等造成的农田土壤面源污染,一些具有吸附固定土壤中重金属离子特性的天然物质和工业副产品都可运用在实地的钝化修复中,且不同类型的钝化修复剂对重金属污染土壤的钝化修复效果各不相同。采用实验室评价和实地应用评价,一方面可以评估钝化修复材料对污染土壤中重金属离子的固定效率;另一方面可以评估钝化修复材料对土壤理化性状、养分状况和生物活性的影响。对重金属污染土壤原位钝化修复中不同来源的钝化剂进行了分类,目前广泛使用的钝化修复剂主要包括硅钙物质、含磷材料、有机物料、黏土矿物、金属及金属氧化物、生物碳及新型材料等,概述了它们各自对重金属污染土壤的钝化修复效果。从研究方法、评价指标、环境影响因子、钝化机制以及环境风险评价等方面分析了该领域的研究现状以及存在的主要问题,今后应重点关注钝化修复剂对土壤-作物系统的潜在环境风险以及钝化材料修复效果的田间长期稳定性评价。     

重金属污染高风险农用地水稻安全种植技术研究

在农田土壤污染较为严重的情况下生产安全高品质的稻米是目前农业生产面临的一大挑战。重金属低积累水稻品种,不但能有效降低水稻稻米中重金属的含量,而且有经济成本低、且环境友好等特点,但在重金属高风险污染区仅仅使用低积累品种无法达到安全生产的目的。以重金属污染高风险农田土壤为研究对象,开展重金属低积累水稻品种筛选和化学修复手段结合的农田安全利用技术研究。结果表明:通过对23个不同品种水稻在高风险重金属污染农田土壤中种植重金属含量比较分析,表明不同水稻品种对Cd吸收能力差异较大,五优321、广8优占、丰优428、粤晶丝苗2号、粤金银占、合美占等6个水稻品种对Cd吸收能力较弱,但在该地区土壤重金属含量水平下,Cd质量分数仍高于0.2 mg·kg^-1,Pb和As含量均不超标;在此结果基础上结合土壤污染特点,采取3种污染物控制技术降低稻米中Cd含量,五优321品种与石灰、石灰Se配施等配合施用均有较好的效果,可以作为此类污染区域重点推广品种;喷施Se叶面肥能显著增加稻米中Se含量,提升稻米品质,且Se与石灰配合施用,增Se效果要好于单独施Se肥。采用化学钝化剂联合低累积水稻品种,稻米中Cd含量降低40%-70%。该研究采用大田原位试验,其结果可以对当地污染农田土壤的安全利用更具指导意义。     

Soil remediation using in situ immobilisation techniques

The main objective of this study was to investigate the efficiency of different substrates to reduce the extraction of heavy metals concentration in a heavily contaminated soil. Two contaminated soils by Cu and Zn were used to evaluate the effectiveness of eight substrates (calcium carbonate, bentonite, kaolinite, charcoal, manganese oxide, iron oxide, zeolite, phosphate) to reduce metal availability and to study the change of metals speciation in different forms using sequential extraction technique (single step). Sequential extraction technique (single step, 0.11 M acetic acid, HONH₃Cl, H₂O₂+NH₄OAc, Aqua regia) was applied on contaminated soils after and before treatment to evaluate metals speciation. Results indicate that the most effective treatments in decreasing available metal concentrations were calcium carbonate, zeolite and manganese or iron oxide. Metal sequential fractionations indicate that the exchangeable fraction of Cu and Zn in contaminated soils can be transformed into unavailable forms after chemical remediation.     

Effects of rape straw and red mud on extractability and bioavailability of cadmium in a calcareous soil

Screening of cost-effective soil amendments is important to develop “in situ” remediation techniques for cadmium (Cd) contaminated soils. In this study, different soil amendments, including red mud, a by-product of the alumina industry, and acid-treated, nano-treated by nano-particle milling, nano and acid-treated red muds, zeolite, corn straw, and rape straw, were evaluated to immobilize Cd in two added levels (2 and 5 mg Cd·kg^-1 soil) in a calcareous soil by single and sequential extractions and by cucumber (Cucumis sativus L.) pot experiments. Results indicated that cruciferous rape straw significantly decreased the concentrations of water soluble, extractable Cd in soils, and Cd in cucumber plants, and it was more effective than gramineous corn straw. Also, red mud generally decreased the extractability and bioavailability of Cd added to calcareous soils more effectively than zeolite. Furthermore, the efficiency of red mud could be increased by the treatment of nano-particle milling due to the increase in specific surface area of red mud. It is potential to use rape straw and red mud as soil amendments to develop a cost-effective and efficient “in situ” remediation technology for Cd mildly contaminated calcareous soils.     

Response of roselle (Hibiscus sabdariffa) to heavy metals contamination in soils with different organic fertilisations

The response of green roselle (Hibiscus sabdariffa) to Cu/Pb contamination and manure application in soil was investigated using pot experiments. Subsamples of a mineral soil were treated with increasing doses (0–500 mg kg^?1) of Cu/Pb only and/or amended (at 10% w/w) with poultry or swine manure. Roselle plants were grown, monitored for changes in growth rate and post-harvest aboveground dry biomass and tissue Cu/Pb concentrations were determined. The plants were typically greenish with linear growth profiles at all metal doses, indicating some level of tolerance. Dry biomass yields decreased as metal dose increased. Poultry manure enhanced roselle biomass yields better than swine manure. Tissue Cu/Pb concentrations increased linearly as metal doses increased in unamended soils; whereas nonlinear responses were observed in manure-amended soils. Soil-to-plant transfer factors, T _f (%) indicated that Cu (13≤T _f (% )≤60) was more phytoavailable to roselle than Pb (11≤T _f (% )≤20). Tissue metal concentrations were modelled from soil pH, organic matter, plant available and pseudototal metal; but the models appeared more reliable with plant available metal as a covariate than with pseudototal metal content. These observations may become useful whenever phytoextraction is the remedial option for soils moderately contaminated by toxic metals.     

利用美洲商陆修复锰尾渣污染土壤对后茬植物的影响

采用盆栽法研究用锰超富集植物美洲商陆(Phytolacca americana)修复锰尾渣污染土壤对后茬植物大豆(Glycine max)和绿豆(Phaseolus radiatus)的影响.经美洲商陆修复锰尾渣污染土壤后,后茬植物大豆和绿豆的镉、铅、锌和锰含量降低,污染土壤的毒性减弱,有利于这2种植物生长.经美洲商陆修复2～3 a,可显著减弱污染土壤对大豆的毒性.由此可见,在经美洲商陆修复的污染土壤上栽培大豆,可以增加含氮量,促进其他植物生长,从而维持锰尾渣污染区植被持续发展.     

几种固定剂对镉污染土壤的原位化学固定修复效果

在野外现场条件下,开展了硅肥、钙镁磷肥、石灰和骨炭粉等多种材料对镉污染土壤的固定修复研究.结果表明,施用这几种固定剂后不同程度地抑制了玉米(Zea mays L.)对Cd的吸收,其中骨炭粉和石灰的效果最好,在0.5%的施用量下,这两种固定剂可使玉米可食部位Cd含量降低到安全限量标准水平.而其它处理在本研究条件下未能使作物Cd含量降低到安全范围.固定剂抑制植物吸收Cd的效果从大到小顺序依次为:骨炭粉≈石灰>硅肥≈钙镁磷肥>高炉渣≈钢渣.形态提取分析表明,施用固定剂处理使土壤Cd的水溶态、可交换态和碳酸盐结合态减少,而有机结合态和残渣态增加,说明促进Cd从有效态向缓效/迟效态转化是固定剂抑制植物吸收Cd的重要机制.     

Immobilising of Cd,Pb, and Zn contaminated arable soils close to a former Pb/Zn smelter: a field study in Austria over 5 years

Numerous smelter sites are surrounded by rural land. The entrance of non-essential metals such as lead or cadmium into the food chain is very likely as well as phytotoxicity effects of zinc. Finding a realistic solution for these large-scale contaminations was one aim of this study. Previous results from pot experiments showed a high potential for the reduction of metals entering the food chain via crops grown on smelter-contaminated soils from Arnoldstein, Austria, by the use of amendments for immobilisation. A further aim was to optimise a field experiment for overcoming the gap between pot and field experiments and to look for long-term efficiency of the treatments [lime (CA), red mud (RM), gravel sludge + red mud (GS + RM)]. Field experiment results were obtained for 5 years. Besides soil and soil pore water samples, the following harvests were yielded: spring barley (Hordeum distichon ssp. L.) (2004–2005), narrowleaf plantain (Plantago lanceolata L.) (2006–2007) and velvet grass (Holcus lanatus L.) (2007–2008). The long-term efficiency of GS + RM led us to conclude that their application seems to be a realistic and practical measure for extensively contaminated land, best in combination with metal excluding cultivars.     

Ameliorants to immobilize Cd in rice paddy soils contaminated by abandoned metal mines in Korea

The cadmium (Cd) content of rice grain grown in metal-contaminated paddy soils near abandoned metal mines in South Korea was found to exceed safety guidelines (0.2 mg Cd kg?1) set by the Korea Food and Drug Administration (KFDA). However, current remediation technologies for heavy metal-contaminated soils have limited application with respect to rice paddy soils. Laboratory and greenhouse experiments were conducted to assess the effects of amending contaminated rice paddy soils with zerovalent iron (ZVI), lime, humus, compost, and combinations of these compounds to immobilize Cd and inhibit Cd translocation to rice grain. Sequential extraction analysis revealed that treatment with the ameliorants induced a 50-90% decrease in the bioavailable Cd fractions when compared to the untreated control soil. When compared to the control, Cd uptake by rice was decreased in response to treatment with ZVI + humus (69%), lime (65%), ZVI + compost (61%), compost (46%), ZVI (42%), and humus (14%). In addition, ameliorants did not influence rice yield when compared to that of the control. Overall, the results of this study indicated that remediation technologies using ameliorants effectively reduce Cd bioavailability and uptake in contaminated rice paddy soils.     

Efficacy of woody biomass and biochar for alleviating heavy metal bioavailability in serpentine soil

Crops grown in metal-rich serpentine soils are vulnerable to phytotoxicity. In this study, Gliricidia sepium (Jacq.) biomass and woody biochar were examined as amendments on heavy metal immobilization in a serpentine soil. Woody biochar was produced by slow pyrolysis of Gliricidia sepium (Jacq.) biomass at 300 and 500 °C. A pot experiment was conducted for 6 weeks with tomato (Lycopersicon esculentum L.) at biochar application rates of 0, 22, 55 and 110 t ha^?1. The CaCl₂ and sequential extractions were adopted to assess metal bioavailability and fractionation. Six weeks after germination, plants cultivated on the control could not survive, while all the plants were grown normally on the soils amended with biochars. The most effective treatment for metal immobilization was BC500-110 as indicated by the immobilization efficiencies for Ni, Mn and Cr that were 68, 92 and 42 %, respectively, compared to the control. Biochar produced at 500 °C and at high application rates immobilized heavy metals significantly. Improvements in plant growth in biochar-amended soil were related to decreasing in metal toxicity as a consequence of metal immobilization through strong sorption due to high surface area and functional groups.     

Comparative growth response of two varieties of <Emphasis Type="Italic">Vigna radiata</Emphasis> L. (var. PDM 54 and var. NM 1) grown on different tannery sludge applications: effects of treated wastewater and ground water used for irrigation

This study evaluates the possibility of using contaminated soil by treated tannery wastewater and the use of tannery sludge in agriculture. The plants of Vigna radiata var. PDM 54 grown on contaminated soil and irrigated with ground water have not shown the translocation of toxic metal (Cr) in the upper part. The biomass of the plant increased when irrigated with treated tannery wastewater compared to ground water, whereas no significant change was observed in chlorophyll and protein contents. In both the varieties (var. PDM 54 and var. NM 1) of V. radiata grown on tannery sludge amendments, the growth parameters exhibited a pronounced positive growth response up to 35% tannery sludge amendments compared with the plants grown on garden soil. Despite the Cr accumulation at lower amendments, no toxicity symptoms were observed in both the varieties of the plants. Higher amendments affected various growth parameters, NR activity, and carbohydrate content of the plants. The results suggest that the plants of V. radiata (var. PDM 54) may be grown on contaminated soil or lower sludge amendments and irrigated with ground water. No translocation of toxic metal Cr was found in the seeds of the plants grown in up to 25% tannery sludge. However, periodical monitoring is required before the consumption of seeds. Overall, the results showed that plant growth patterns were influenced to some extent by the level of soil contamination and the water used for irrigation.     

改良剂对土壤-芦蒿系统中镉行为的影响

开展了硅肥、钙镁磷肥、石灰和骨炭粉等对镉污染土壤的固定修复研究,结果表明,施用固定剂后不同程度地缓解了芦蒿吸收Cd,其中硅肥和钙镁磷肥的效果最好,在1%的施用量下,两种固定剂可使芦蒿可食部位的Cd含量降低到卫生限量标准水平以下,而其它处理在本研究条件下未能使芦蒿Cd含量降低到安全范围,固定剂抑制芦蒿吸收Cd的效果从大到小的顺序依次为:硅肥≈钙镁磷肥＞石灰≈骨炭粉＞高炉渣≈钢渣,形态提取分析表明,施用固定剂处理使土壤Cd的水溶态、可交换态和碳酸盐结合态减少,而有机结合态和残渣态增加,说明促进Cd从有效态向缓效/迟效态转化是固定剂抑制芦蒿吸收Cd的重要机制.     

Diffusive gradient in thin-film (DGT) models Cd and Pb uptake by plants growing on soils amended with sewage sludge and urban compost

Food contamination by Cd and Pb is of increasing concern because contaminated composts and sewage sludges are used as soil fertilizers. Indeed, Cd and Pb from sewage sludge and compost can be transferred to plants and, in turn, to food. Predicting the quantity of metals transferred to plants is difficult and actual models are unable to give accurate concentrations. Therefore, new techniques are needed. For instance, diffusive gradient in thin-film (DGT) is commonly used to measure metal bioavailability in waters, sediments and soils, but DGT has not been well studied for metal uptake in plants. Moreover, actual models for soil–plant transfer are too complex and require many soil parameters. Here, we simplified the modelization of metal uptake by plants by considering only DGT fluxes and roots surfaces. We grew durum wheat in a greenhouse on sandy soils amended with urban compost or sewage sludge. Results show that Cd uptake was slightly underestimated when whole roots were considered as an absorbing surface. For Pb, the best estimation was found by using root tip surface. Overall, our model ranks correctly the samples but underestimates Pb uptake by 15 % and Cd uptake by 45 %. It is nonetheless a simpler way of modelling by using only DGT fluxes and root system morphology.