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1.
土壤薄板层析测定苯并（α）芘（ＢａＰ）的Ｒｆ值小于０．１，在土壤中ＢａＰ属于不迁移性有机化合物，土壤中ＢａＰ被降解成极性化合物（占总＾１４Ｃ－ＢａＰ２３．５％）水溶形式（占１．７％）和非极性形式（占３８．４％）。土壤＾１４－Ｂａｐ组合态占３６．４％。土壤表层（０～１ｃｍ）＾１４Ｃ－ＢａＰ为０．１％，水稻苗期对ＢａＰ吸收速度快，且数量大，拔节期间吸收转缓，分蘖期后吸收达平衡。水稻体内＾１４Ｃ－ＢａＰ 相似文献
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14C－PP333在土壤及作物中的残留 总被引：1，自引：0，他引：1
研究了＾１４Ｃ－ＰＰ３３３在小麦、水稻、芹菜中的残留。结果表明，＾１４Ｃ－ＰＰ３３３在作物中的残留水平随土壤中滞留水平的提高而提高。小麦籽粒残留水平为１．３１￣０．７５ｐｐｍ，水稻籽粒为０．２２ｐｐｍ，芹菜为０．０１３￣０．０３２ｐｐｍ。＾１４Ｃ－ＰＰ３３３在水稻植株中残留水平由高到低为穗梗〉叶〉茎〉谷壳〉根〉米；小麦为叶〉籽粒〉穗其余部分〉根〉茎；芹菜为叶〉根〉茎。施入＾１４Ｃ－ＰＰ３３３１３个 相似文献
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利用＾１４Ｃ－ＰＰ３３３研究了它在不同土壤７０％田间最大持水量及淹水情况下的降解动态。结果为两种处理的＾１４Ｃ－ＰＰ３３３均按指数衰减，半衰期分别为１２８－１６１ｄ和１４４－２２４ｄ。降解半衰期与土壤ｐＨ值呈负相关，在淹水情况下与土壤物理粘粒含量呈显著正相关。 相似文献
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高效唑的化学名称为（Ｅ）－１－（４－氯苯基）－４，４－二甲基－２－（１，２，４－三唑－１－基）戊烯醇－３。其＾１４Ｃ标记化合物制备方法：先由Ｂａ＾１４ＣＯ３制成＾１４Ｃ－甲酸钠，后者在真空多支管中转移制成＾１４Ｃ－甲酸，再与重碳酸氨基遥反应得＾１４Ｃ－氨基三唑，经脱氨得＾１４Ｃ－１，２，４三唑，进而＾１４Ｃ－唑酮，进而＾１４Ｃ－Ｅ－Ｅ烯酮，后者转位制成＾１４Ｃ－Ｅ烯酮，再经还原而得＾１４Ｃ－高效唑 相似文献
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本通过室内培养试验和田间小区试验探索了磷石膏农用的机理及其利用的途径。室内培养试验过程中，土壤ｐＨ值、碳酸氢根含量下降明显，土壤速效磷水平有明显的提高。田间试验表明，磷石膏在降低土壤中ＨＣＯ３＾－、ＣＯ３＾２－及Ｃｌ＾－、Ｎａ＾＋含量的同时，提高了Ｃａ＾２＋、ＳＯ４＾２－的含量。以磷石膏为主的水稻壮苗剂对水稻秧苗生长有明显的促进作用。在石灰性土壤地区，改良盐碱土、生产调酸壮苗剂及研制改土肥是磷石 相似文献
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不同施氮水平对茶树^14C—同化产物积累与分配的影响 总被引：4，自引：0，他引：4
用＾１４Ｃ示踪技术，研究了不同施氮水平对茶树＾１４Ｃ－同化产物积累与分配的影响。结果表明，适宜的施氮水平有利于＾１４Ｃ－同化产物的积累；施氮可增加光合产物在绿色器官的分配，同时降低了在非绿色器官的分配；秋季施氮过多，对茶树向根系运输养分不利，使＾１４Ｃ－同化产物过多地滞留在绿色器官中。 相似文献
11.
M. Richert S. Saarnio S. Juutinen J. Silvola J. Augustin W. Merbach 《Biology and Fertility of Soils》2000,32(1):1-7
Short-term (3–6 days) and long-term (27 days) laboratory experiments were carried out to determine the distribution of assimilated
C in the system Phragmites australis (common reed)-waterlogged fen soil after 14C pulse labelling. The investigated system of fen plants and anaerobic organic soil showed different patterns of assimilated
14C distribution when compared to systems with cultivated plants and aerobic mineral soil. Between 90% and 95% of the 14C in the system was found in the reed plants. A maximum of 2% of the assimilated plant 14C was released from the fen soil as CO2 and about 5–9% remained in the soil. The 14C remaining in the waterlogged fen soil of the reed plant had the same amount as that of a cultivated plant in mineral soil,
despite lower 14C-release (i.e. rhizodeposition and root respiration) from reed roots. Assuming that root respiration of fen plants is low,
this indicates that microbial C turnover in waterlogged fen soil is much slower than in mineral soil. The estimated quantity
of the assimilated C remaining in the soil was of an ecologically relevant order of magnitude.
Received: 8 July 1999 相似文献
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Shigekazu Yamamuro Hideto Ueno Hiroshi Yamada Yumiko Takahashi Yoko Shiga Syuko Miyahara 《Soil Science and Plant Nutrition》2013,59(6):787-795
Nitrogen and carbon dynamics in paddy and upland soils for rice cultivation and in upland soil for corn cultivation was investigated by using 13C and 15N dual-labeled cattle manure compost (CMC). In a soil with low fertility, paddy and upland rice took up carbon and nitrogen from the CMC at rates ranging from 0.685 to 1.051% of C and 17.6–34.6% of N applied. The 13C concentration was much higher in the roots than in the plant top, whereas the 15N concentration differed slightly between them, indicating that organic carbon taken up preferentially accumulated in roots. The 13C recovery in the plant top tended to be higher in upland soil than in paddy soil, whereas 15N applied was recovered at the same level in both paddy and upland soils. In the experiment with organic farming soil, paddy rice took up C and N from the CMC along with plant growth and the final recovery rates of 13C and 15N were 2.16 and 17.2% of C and N applied. In the corn experiment, a very large amount of carbon from the CMC was absorbed, accounting for at least 7 times value for rice. The final uptake rates of 13C and 15N reached about 13 and 10% of C and N applied, respectively. Carbon emission from the CMC sharply increased by 2 weeks after transplanting and the nitrogen emission was very low. It is concluded that rice and corn can take up an appreciable level of carbon and nitrogen from the CMC through roots. 相似文献
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The soil organic matter plays a key role in ecological soil functions, and has to be considered as an important CO2 sink on a global scale. Apart from crop residues (shoots and roots), left over on the field after harvest, carbon and nitrogen compounds are also released by plant roots into the soil during vegetation, and undergo several transformation processes. Up to now the knowledge about amount, composition, and turnover of these root‐borne compounds is still very limited. So far it could be demonstrated with different plant species, that up to 20 % of photosynthetically fixed C are released into the soil during vegetation period. These C amounts are ecological relevant. Depending on assimilate sink strength during ontogenesis, the C release varies with plant age. A large percentage of these root‐borne substances were rapidly respired by microorganisms (64—86 %). About 2—5 % of net C assimilation was kept in soil. The root exudates of maize were mainly water‐soluble (79 %), and in this fraction about 64 % carbohydrates, 22 % amino acids/amides and 14 % organic acids could be identified. Plant species and in some cases also plant cultivars varied strongly in their root exudation pattern. Under non‐sterile conditions the exuded compounds were rapidly stabilized in water‐insoluble forms and bound preferably to the soil clay fraction. The binding of root exudates to soil particles also improved soil structure by increasing aggregate stability. Future research should focus on quantification and characterization of root‐borne C compounds during the whole plant ontogenesis. Apart from pot experiments with 14CO2 labeling, it is necessary to conduct model field experiments with 13CO2 labeling in order to be able to distinguish between CO2 originating from the soil C pool and rhizosphere respiration, originating from plant assimilates. Such a separation is necessary to assess if soils are sources or sinks of CO2. The incorporation of root‐borne C (14C, 13C) into soil organic matter of different stability is also of particular interest. 相似文献
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Information on the input, distribution and fate of photosynthesized carbon (C) in plant–soil systems is essential for understanding their nutrient and C dynamics. Our objectives were to: 1) quantify the input to, and distribution of, photosynthesized C by rice into selected soil C pools by using a C14 continuous labelling technique and 2) determine the influence of the photosynthesized C input on the decomposition of native soil organic carbon (SOC) under laboratory conditions. The amounts of C14 in soil organic C (SOC14) were soil dependent, and ranged from 114.3 to 348.2 mg C kg−1, accounting for 0.73%–1.99% of total SOC after continuous labelling for 80 days. However, the mean SOC14 concentrations in unplanted soils (31.9–64.6 mg kg−1) were accounted for 21.5% of the rice-planted soils. The amounts of C14 in the dissolved organic C (DOC14) and in the microbial biomass C (MBC14), as percentages of SOC14, were 2.21%–3.54% and 9.72%–17.97%, respectively. The DOC14 and MBC14 were 6.72%–14.64% and 1.70%–7.67% of total DOC and MBC respectively after 80-d of rice growth. At 80-d of labelling, the SOC14 concentration was positively correlated with the MBC14 concentration and rice root biomass. Rice growth promotes more photosynthesized (newly-derived) C into soil C pools compared to unplanted soils, reflecting the release of root exudates from rice roots. Laboratory incubation of photosynthesized (plant-derived) C in soil decreased the decomposition of native SOC (i.e. a negative priming effect), in some, but not all cases. If this negative priming effect of the new C on native SOC also occurs in the field in the longer term, paddy soils will probably sequester more C from the atmosphere if more photosynthesized C enters them. 相似文献
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The degradation of14 C-Carbofuran was studied in sterilized, unsterilized and green manure amended clay soil under moist and flooded conditions overa period of 30 days. The14 C mass balance showed that carbofuran did not undergo any degradation in sterilized moist soil. In sterilized flooded soil bound residues were formed to the extent of about 47% of the applied radioactivity at the end of 30 days. Carbofuran underwent considerable degradation in unsterilized moist and flooded soils. In moist soil about 48% of the applied14 C activity was recovered as bound activity while in flooded soil, about 23% of the activity was bound. Green manure amendment resulted in formation of more bound residues under moist conditions while it enhanced the degradation of carbofuran under flooded conditions. In flooded amended soil about 44% of the appliedl4 C-activity was recovered as against about 54% in the unamended flooded soil. The notable degradation products formed under flooded soil conditions were 3-keto carbofuran and 3-hydroxy carbofuran. 相似文献
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Carbon (C) distribution in a sweet sorghum‐soil system was studied by 14CO2 pulse‐labeling of shoots at three dates during the growth cycle in order to assess the contribution of the crop to carbon storage in the soil. Soil and plant samplings were performed 24 h after the 14C‐labeling and at final harvest (October) to determine the assimilate allocation and estimate the amount of plant‐derived soil carbon. Approximately 4‐16% of the 14C present in the sorghum‐soil system was located in the soil fine fraction (< 2 mm) over a 24 h period. At final harvest, the proportion of 14C in the soil accounted for 7‐9% of the 14C present in the sorghum‐soil system. The plant‐derived soil carbon was estimated at 0.10‐0.12 g C plant‐1 day‐1. The total amount of carbon captured by sweet sorghum was estimated at 1.44 kg C m‐2 over the whole growth cycle: 0.82 kg C m‐2 in the above‐ground biomass, 0.52 kg C m‐2 in the below‐ground biomass and 0.10 kg C m‐2 in the soil carbon pool. No significant increase in soil 14C was detected over the next 14 months. 相似文献
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[triazine-ring-14C] simazine and [benzene-ring-14C] bentazon were added to the epipedon of a Luvisol from loess with and without maize shoots or roots (2 g/100 g soil) and mineralization proceeded in accordance with the standardized BBA degradation method at 50% of the maximum water holding capacity of the soil and at 22°C. The same degradation study was conducted using maize shoots (simazine) and maize roots (bentazon) which had taken up either 14C-simazine or 14C-bentazon from soil application. After 93 days of incubation 6.6% (simazine) or 7.2% (bentazon) of this plant incorporated 14C was mineralized to 14CO2. This was 4–10 times greater than the mineralization of active ingredients applied to the soil and 4–6 times higher when compared to variants which in addition received maize shoots (simazine) or roots (bentazon) as an additional energy source for microbial development. Apparently as a consequence of the more intensified degradation processes, the bound residue fractions were higher by a factor of 2 when the residual radiocarbon reached the soil already incorporated into plant material. 相似文献
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Hamid Reza Boostani Ailsa G. Hardie Mahdi Najafi-Ghiri 《Archives of Agronomy and Soil Science》2020,66(6):730-742
ABSTRACTRecently, the use of biochars for stabilization of soil heavy metals has been expanded due to their adsorption characteristics, low cost and carbon storage potential. A factorial experiment was performed to investigate the effects of two plant residue biochars (licorice root pulp and rice husk biochar each applied at 2.5% (w/w)) produced at two temperatures (350 and 550 °C), and three Ni application rates (0, 150 and 300 mg Ni kg?1) on bioavailability and chemical fractions of Ni in a calcareous soil after spinach cultivation. Application of all the biochars significantly reduced Ni bioavailability factor (5–15%) and spinach Ni concentration (54–77%) in Ni-treated soil. The biochars produced at 550 °C were more effective at reducing Ni mobility and Ni uptake by spinach than those produced at 350 °C, attributed to higher CaCO3 and lower acidic functional group content, which resulted in greater enhancement of soil pH. When comparing the biochars produced at the same temperature, the rice husk biochars were the most effective in reducing Ni bioavailability, likely due to their lower acidic functional group content and higher nano-silica content which resulted in higher soil pH values and potentially promoted the formation of Ni-silicates and hydroxides.Abbreviations : Ni: Nickel; RHB: rice husk biochar; LRB: licorice root pulp biochar; WsEx: water soluble and exchangeable; CARB: carbonate form; RES: residual; MnOx; manganese oxides bound; AFeOx; amorphous iron oxides bound; CFeOx: crystalline iron oxides bound; OM: organic bound. 相似文献
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Wolfgang Merbach Edith Mirus Günther Knof Rainer Remus Silke Ruppel Rolf Russow Andreas Gransee Joachim Schulze 《植物养料与土壤学杂志》1999,162(4):373-383
The root-borne C- and N-flux in the plant/soil system was studied by determining the 14C- or 15N-balances in pot trials with soil as a substrate (14CO2- or 15NH3-application to the shoots, comparison of sterile and nonsterile treatments for quantification of root-borne substances). The following results were obtained: 1. The amount of (primary) root-borne carbon compounds released into soil was (besides root respiration) 11—20% of net-CO2-assimilation or 13—32% of the 14C incorporated into the plants (= 1 t C · ha—1). 5—6% of 15N assimilated by the plants were released as root-borne N compounds (= 15 kg N · ha—1). 2. A considerable portion of the root-borne C (about 6% = 600 kg C · ha—1) was found in the rooted soil zone at the end of the experiments (rhizodeposition). 3. (Primary) root-borne C and N compounds found in immediate vicinity of the roots (about 60—80%) were mainly water soluble, whereas most of the C and N compounds found in a greater distance were water insoluble. The water soluble exudates consisted mainly of neutral (carbohydrates) and acid fractions (organic acids). The basic fraction (amino acids) made up a small portion only. 4. The root-borne C and N compounds influenced the nutrient balance of soil and plant directly and/or indirectly via microbes (depending on species, variety and nutritional status of plants). 5. Microbes stimulated the release of C- and N-compounds, but rapidly respired 65—85% of the root-borne C-compounds, thereby putting a burden on the C-budget of the “host” plant. 6. It could be shown by the example of hup+ Rhizobium meliloti strains (tested by 3H2-incorporation) and the wheat-Serratia-association, that energy efficient microbenplant systems can improve plant performance. 相似文献
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Christiane Kramer 《Soil biology & biochemistry》2006,38(11):3267-3278
In this study we used compound specific 13C and 14C isotopic signatures to determine the degree to which recent plant material and older soil organic matter (SOM) served as carbon substrates for microorganisms in soils. We determined the degree to which plant-derived carbon was used as a substrate by comparison of the 13C content of microbial phospholipid fatty acids (PLFA) from soils of two sites that had undergone a vegetation change from C3 to C4 plants in the past 20-30 years. The importance of much older SOM as a substrate was determined by comparison of the radiocarbon content of PLFA from soils of two sites that had different 14C concentrations of SOM.The 13C shift in PLFA from the two sites that had experienced different vegetation history indicated that 40-90% of the PLFA carbon had been fixed since the vegetation change took place. Thus PLFA were more enriched in 13C from the new C4 vegetation than it was observed for bulk SOM indicating recent plant material as preferentially used substrate for soil microorganisms. The largest 13C shift of PLFA was observed in the soil that had high 14C concentrations of bulk SOM. These results reinforce that organic carbon in this soil for the most part cycles rapidly. The degree to which SOM is incorporated into microbial PLFA was determined by the difference in 14C concentration of PLFA derived from two soils one with high 14C concentrations of bulk SOM and one with low. These results showed that 0-40% of SOM carbon is used as substrate for soil microorganisms. Furthermore a different substrate usage was identified for different microorganisms. Gram-negative bacteria were found to prefer recent plant material as microbial carbon source while Gram-positive bacteria use substantial amounts of SOM carbon. This was indicated by 13C as well as 14C signatures of their PLFA. Our results find evidence to support ‘priming’ in that PLFA indicative of Gram-negative bacteria associated with roots contain both plant- and SOM-derived C. Most interestingly, we find PLFA indicative of archeobacteria (methanothrophs) that may indicate the use of other carbon sources than plant material and SOM to a substantial amount suggesting that inert or slow carbon pools are not essential to explain carbon dynamics in soil. 相似文献