Shih-Hao Jien

Using EDDS and NTA for enhanced phytoextraction of Cd by water spinach

A greenhouse experiment was used to test the applicability of [S,S]-Ethylenediaminedisuccinic acid (EDDS) and nitrilotriacetic acid (NTA) at rates of 2.5 mmol kg(-1) and 5.0 mmol kg(-1), respectively, to increase the uptake of Cd by water spinach (Ipomoea aquatic Forsk) in soils with 2.5-30 mg Cd kg(-1). The addition of EDDS and NTA significantly increased water soluble Cd in soils. However, the Cd concentration in the root and shoot was higher in the NTA treatment than in the EDDS treatment. No instance of Cd hyperaccumulation was observed; however, the 5.0 mmol kg(-1) NTA treatment for soil with 30 mg Cd kg(-1) caused the Cd concentration to increase to 86 mg kg(-1), which is close to the critical concentration (100 mg kg(-1)) of a hyperaccumulator. The total Cd uptake in the treatments of EDDS and NTA for soils with 2.5, 5.0, and 10 mg Cd kg(-1) was acceptable, and was higher than the control. The level of 5.0 mmol kg(-1) EDDS was excessively high for enhanced phytoextraction in soils with 20 and 30 mg Cd kg(-1). Water spinach for Cd phytoextraction is a viable alternative to using herbaceous hyperaccumulators.

Geochemical Element Differentiation in Serpentine Soils From the Ophiolite Complexes, Eastern Taiwan

The vertical distribution of 14 geochemical elements (Si, Al, Ti, K, Na, Ca, Mg, Fe, Mn, Cu, Cr, Ni, Pb, and Zn) in nine serpentine pedons for three ophiolite complexes was investigated. The pedons are located at Wu-Mau, Tong-An, and Shih-Tao mountains in the Coastal Range, eastern Taiwan. The objective of this study was to discriminate the parent material inheritance and pedogenic factors by comparison of the element concentrations based on principal component (PC) analysis. From the experimental results, the relative abundance of major elements was as follows: Si > Fe > Mg > Al, with lesser concentrations of Ti, K, Na, and Ca. In addition, Cr, Mn, and Ni contents in these soils were higher than in soils formed from other parent materials, with considerable variation between pedons on different landscapes, which reflected the ophiolite differences and degrees in chemical weathering of the associative serpentinitic rocks. The contents of pairs of Si-Fe, Si-Mn, Si-Pb, and Si-Zn showed significantly (P < 0.05) positive correlations. The close relations among contents of Fe, Mn, Cr, and Ni were observed herein. According to the eigenvalue in PC analysis, the elements most responsible for separation along the PC-1 axis were Si, Fe, Mn, Zn, Mg, and Ca, whereas Cr and Ni were the trace metals responsible for separation along the PC-2 axis. This result reflected the parent material differences in igneous rock composition and the degree of serpentinization between ophiolite complexes.

Magnified Sediment Export of Small Mountainous Rivers in Taiwan: Chain Reactions from Increased Rainfall Intensity under Global Warming.

Fluvial sediment export from small mountainous rivers in Oceania has global biogeochemical significance affecting the turnover rate and export of terrestrial carbon, which might be speeding up at the recognized conditions of increased rainfall intensity. In this study, the historical runoff and sediment export from 16 major rivers in Taiwan are investigated and separated into an early stage (1970–1989) and a recent stage (1990–2010) to illustrate the changes of both runoff and sediment export. The mean daily sediment export from Taiwan Island in the recent stage significantly increased by >80% with subtle increase in daily runoff, indicating more sediment being delivered to the ocean per unit of runoff in the recent stage. The medians of the runoff depth and sediment yield extremes (99.0–99.9 percentiles) among the 16 rivers increased by 6.5%-37% and 62%-94%, respectively, reflecting the disproportionately magnified response of sediment export to the increased runoff. Taiwan is facing increasing event rainfall intensity which has resulted in chain reactions on magnified runoff and sediment export responses. As the globe is warming, rainfall extremes, which are proved to be temperature-dependent, very likely intensify runoff and trigger more sediment associated hazards. Such impacts might occur globally because significant increases of high-intensity precipitation have been observed not only in Taiwan but over most land areas of the globe.

Impacts of Biochar on Physical Properties and Erosion Potential of a Mudstone Slopeland Soil

Food demand and soil sustainability have become urgent issues recently because of the global climate changes. This study aims to evaluate the application of a biochar produced by rice hull, on changes of physiochemical characteristics and erosion potential of a degraded slopeland soil. Rice hull biochar pyrolized at 400°C was incorporated into the soil at rates of 2.5%, 5%, and 10% (w/w) and was incubated for 168 d in this study. The results indicated that biochar application reduced the Bd by 12% to 25% and the PR by 57% to 92% after incubation, compared with the control. Besides, porosity and aggregate size increased by 16% to 22% and by 0.59 to 0.94 mm, respectively. The results presented that available water contents significantly increased in the amended soils by 18% to 89% because of the obvious increase of micropores. The water conductivity of the biochar-amended soils was only found in 10% biochar treatment, which might result from significant increase of macropores and reduction of soil strength (Bd and PR). During a simulated rainfall event, soil loss contents significantly decreased by 35% to 90% in the biochar-amended soils. In conclusion, biochar application could availably raise soil quality and physical properties for tilth increasing in the degraded mudstone soil.

Elucidating the process of co-composting of biosolids and spent activated clay.

This study elucidates the co-composting of biosolids and spent activated clay (SAC) using physio-chemical, bioassay, and spectroscopic methods. A pilot-scale pile of blended limed biosolids, SAC, and rice husk was composted for 15weeks. The changes in temperature, pH, Fourier-transform infrared (FT-IR) spectra, C/N, and germination index (GI) of Chinese cabbage (Brassica chinensis) seeds with time support the goal of producing a mature compost with a decline in the SAC acidity of associated with biosolids. Cadmium, Cr, Cu, Ni, and Pb in the initial biosolids were converted from labile fractions into relatively immobile phases upon maturation. Temperature, moisture, pH, C/N, and GI were used to separate the composting process into three phases - initial, thermophilic, and cooling, based on a score plot of principal component analysis (PCA). The values of the parameters of interest reveal that the compost fulfills the requirements of compost maturity in the literature.

Relations between morphological color index and soil wetness condition of anthraquic soils in Taiwan

The unique hydrologic and soil morphological features of the lowland rice-growing areas of the Chungli Terrace in northern Taiwan derive from diluvium red soils. Soil morphological characteristics and monitoring data provide a long-term record of the hydrological period and are useful for identifying these soils as hydric soils. The objective of this study was to establish relationships between the soil morphology-based soil chroma index and soil wetness conditions, including annual duration of both saturation and reduction. Three transects of a toposequence ranging from 20 to 40 m were selected. Four soils (Plinthaqualfs and Plinthaquults) were located in the toeslope position (20 m), four soils (Plinthudults and Paleudalfs) in the footslope position (30 m), and three soils (Paleudults and Paleudalfs) in the backslope position (40 m) with different redoximorphic features. Because they are seasonally flooded for rice (Oryza sativa L.) production and have perched water tables from February to October, all of these soils are considered to be anthraquic. Seasonally high groundwater levels also occurred during the growing season. Soils in three transects were monitored for groundwater depth, matric potential, and redox potential. The analytical results revealed that the seven soils with A horizons ≤ 25 cm thick were all hydric soils based on redox potential monitoring data. The analytical results indicated significant correlations between the chroma index and saturation time of year at 50-100 cm depth (P < 0.05) and at 100-150 cm depth (P < 0.01). A significant correlation was also found between chroma index and duration of reduction at depths of 50-100 cm (P < 0.01) and 100-150 cm (P < 0. 01). However, no clear correlation existed for depths of <50 cm because of the disturbance associated with plowing and the accumulation of rice straw residual on the soil surface.

Sorption of paraquat on clay components in Taiwan's oxisol.

The sorption of herbicides in soils is mainly influenced by clay components. The objectives of this study were to evaluate the contribution of clay components on paraquat sorption. The surface soils (0–20 cm) of a Laopi pedon (Fine, mixed, Hyperthermic Typic Hapludox) were separated clays into whole (< 2.0 μm), coarse (0.2–2.0 μm), and fine (< 0.2 μm) fractions with the treatments of removals of organic matter (OM) and free Fe (Fed) oxides. Results indicated that sorption isotherm of paraquat was fitted by the nonlinear Freundlich equation with R2 values ranged in 0.79–0.96, respectively. The shape of paraquat adsorption isotherm on the fine fraction was H‐type, but their shapes on the whole and coarse fractions were L‐types. The fine clay fractions gave higher contribution on paraquat sorption than the coarse clay fractions identified by their Kf values. Organic matter associated with fine clay fraction had high CEC contributing to relatively high affinity for paraquat. The DCB treatment created high‐affinity sites for paraquat on the fine clay, but had little effect on paraquat sorption for the coarse clay. Chemisorption is the major mechanism for retention of paraquat on clay components, not ion exchange. However, the silicate clay had the highest affinity for paraquat and free Fe compound had the lowest.

Geomorphological and paleoclimatic implications of soil development from siliceous materials on the coral-reef terraces of Liuchiu Island in southern Taiwan

Liuchiu Island is an uplifted coral-reef island located off southwestern Taiwan. A total of four soil pedons, labeled as LC-1 and LC-2 from the Holocene terraces and LC-3 and LC-4 from the Pleistocene terraces, were sampled on the island for this work. These soils were siliceous, and were characterized by enrichment of clay and free iron (Fed). According to Soil Taxonomy, pedons LC-3 and LC-4 were classified as Paleudults and pedons LC-1 and LC-2 were Dystrudepts. The soil properties showed progressive changes from pedon LC-1 to pedon LC-4 in morphology, physical and chemical properties, and clay mineralogy. The contents of total Fe and dithionite-citrate-bicarbonate extractable Fe were significantly higher in pedons LC-3 and LC-4 with high weathering degree than in pedons of LC-1 and LC-2 with less weathering degree. Enrichment of kaolinite and gibbsite in pedons LC-3 and LC-4 also suggested high chemical weathering degree of the soils. The estimated soil ages for all studied pedons were consistent with their degrees in pedogenesis, where pedons LC-3 and LC-4 were located at older terraces and pedons LC-1 and LC-2 were located at younger terraces. Namely, it complied with the geologic interpretation of the continuous and simultaneous uplift and tilt of the island over time. Instead of the in situ weathering from the underlying coral reef limestone, all soils developed from siliceous parent materials deposited onto the surfaces. The SiO2/Al2O3 ratios of soils indicated a component of loess may have been incorporated from continental China as part of the parent material, which confirmed a climate change of strong monsoons or severe dust storms occurred before the Holocene. However, soil development increased by the subsequent warm and humid climates of the interglacial stage over time.

Relationships between soil mass movement and relief in humid subtropical low-elevation mountains.

Well-developed and undeveloped soils are present in tropical and subtropical mountainous landscape. The soil types and mass movement were determined by geomorphological processes. We studied the relationships between soil mass wasting and soil distribution and relief in a subtropical low-elevation mountain in central Taiwan. Five soil profiles located on different landscape sites with 5% to 30% slopes along two transects were selected to evaluate soil mass wasting episodes by estimating absolute soil ages according to predictive equations. From the estimated absolute soil age, the soils in this mountain may have formed in the early Pleistocene (ca. 1200∼1500 ka). However, the soils of this era were mass wasted during mid-Pleistocene (ca. 200∼900 ka) and were preserved only in the footslope areas as buried soils. The geomorphological surface of the mid-Pleistocene was covered with colluvial material in the backslope areas and exposed at the footslope sites. In recent era, soils on the ridge were mass wasted and accumulated on the backslope areas, which led to a new soil genesis direction; therefore, soils located on the ridge and backslope are classified as Inceptisols or Cambisols and those on the footslope area as Typic Hapludults or Acric Nitisols. The variety of soil development and distribution based on relief in this mountain forest in Taiwan show the key features of unstable K-cycle phases and are best illustrated in the alternating (backslope) and accreting (footslope) zones of the K-cycle. This study also presents that the activity ratio (Feo/Fed) and the crystallinity ratio of free iron oxides (Fed − Feo/Fet) are good indices to infer or predict soil ages in this area.

Erosion potential estimation by network measurement of soil properties in coastal areas after clearcutting

Invasive white leadtrees (Leucaena leucocephala (Lam.) de Wit) are contributing to the destruction of coastal ecosystems and biodiversity in humid subtropical and tropical regions. Sudden clearcutting of invasive tress can lead to substantial soil loss, which subsequently reduces the efficiency when indigenous vegetation is restored. Soil samples ( n = 142 ) were collected using the grid method to measure soil properties and to spatially analyze the soil erosion potential in the studied area after clearcutting of the invasive trees. Results indicated that the soil erosion rates ranged from 21 to 249 tons ha−1 yr−1, and the eroded soil depths ranged from 0.30 to 3.40 cm yr−1 after clearcutting. The network measurements for determining the mortality ratio of the restored indigenous vegetation demonstrated that Ficus benjamina L., Macaranga tanarius, and Scaevola taccada (Gaertner) Roxb were likely to be susceptible to damage from the substantial amount of soil loss and low SOC content. During the period between clearcutting and establishing the next stand of plants for reforestation, the network measurements for determining the soil properties and estimating the spatial heterogeneity of soil erosion potential are regarded as a major issue of concern regarding the efficiency of subsequent restoration efforts.