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1.
Effects of silicon (Si) on subcellular distribution and chemical forms of Cd in two contrasting peanut cultivars, Qishan 208 (low seed Cd cultivar) and Haihua 1 (high seed Cd cultivar), were investigated by a hydroponics experiment at low Cd level (0.2 μM CdCl2). Two cultivars differ in Cd translocation, subcellular distribution and chemical forms. In comparison to Qishan 208, Haihua 1 shows higher translocation factors (TFs); this may be resulted from higher Cd in the soluble fraction, and a larger proportion of inorganic Cd (extracted by 80% ethanol) and water-soluble Cd (extracted by d-H2O) in roots. Pretreatment with Si decreased Cd in the cell wall, and enhanced Cd in the soluble fraction for both cultivars. However, effects of Si on chemical forms and TFs are cultivar dependent. Si enhances Cd translocation and the d-H2O extractable Cd in Haihua 1. Positive correlations were observed between TF and Cd in the soluble fraction (r = 0.71, P < 0.05), and between TF and d-H2O extractable Cd in root (r = 0.89, P < 0.001). Therefore, larger proportion of d-H2O extractable Cd may be responsible for high TF in Si pretreated plants of Haihua 1.  相似文献   

2.
Abstract

To clarify the effect of soil type on changes in sugar beet (Beta vulgaris L.) productivity since 1980 in Tokachi District (Hokkaido, Japan), we analyzed yield data from 121 settlements from 1980 to 2002 using maps of parent materials and surface organic matter contents in a geographical information system. The soil types were Brown Lowland soils, Andosols with an alluvial subsoil, Wet Andosols and Andosols. The sugar beet yields were highest in the Andosols and moderate in Andosols with an alluvial subsoil. Yields in Brown Lowland soils in the 1980s were similar to those in Andosols, but decreased below the yields in the Andosols by the 1990s. The yields in Wet Andosols were the lowest in the 1980s, but have been similar to those in Andosols with an alluvial subsoil since 1990. Thus, productivity appears to have varied over time in Brown Lowland soils and Wet Andosols. The correlation coefficients between yields and cumulative daily mean temperature from late April to mid-July since 1990 were highest in the Andosols (r = 0.67), lowest in the Brown Lowland soils (r = 0.50) and intermediate in the other soil types (r = 0.54–0.60). However, the magnitude of the correlation between the yield and the cumulative precipitation since 1990 was lowest in the Andosols (r = –0.22), highest in the Brown Lowland soils (r = –0.58) and intermediate in the other soil types (r = –0.44 to –0.45). These results suggest that the present soil water environment in the Andosols is superior to that in the other soil types.  相似文献   

3.
Das Cadmiumaneignungsvermögen von Lupinus albus L., Lupinus angustifolius L. und Lolium multiflorum Lam. Mehrere Pflanzenarten mobilisieren Bodenphosphate (P) und Kationen wie Fe und Al durch die Exsudation organischer Anionen und Protonen. Deshalb untersuchten wir das Cd‐Aneignungsver‐mögen von P‐, Fe‐, Al‐mobilisierenden Arten (Lupinus albus L., Lupinus angustifolius L.) im Vergleich zu einer nicht mobili‐sierenden Pflanzenart (Lolium multiflorum Lam.). Die Pflanzen wuchsen in zwei stark unterschiedlichen Böden (saurer Humuspodsol, karbonathaltiger Lössunterboden). Die Cd‐Aufnahme in die Sprosse war bei Weidelgras 5 bis 10 mal höher als bei Blauen bzw. Weißen Lupinen. Dieses Ergebnis hat mehrere Ursachen: 1. Das Wurzellängen/Sprossmasseverhältnis des Weidelgrases ist 2—3 mal größer als das der Lupinenpflanzen. 2. Bei Weidelgras wird ein größerer Teil des aufgenommenen Cd in die Sprosse verlagert. 3. Die Cd‐Aufnahme bei Lupinen ist im sauren Boden (Podsol) und bei P‐Mangel auch im Kalkboden niedriger als bei Weidelgras. Während im Podsol die Cd‐Konzentration der Bodenlösung unter Lupine geringer war als in der Kontrolle (Gefäße ohne Pflanzen), war sie im Kalkboden höher. Bei den Lupinen war der Efflux organischer Säureanionen, vor allem Citrat und Malat, um den Faktor 10—100 höher als bei Weidelgras. Diese Exsudation kann zu einer hohen Cd‐Komplexierung, insbesondere durch Citrat, in der Rhizosphärenbodenlösung führen (˜ 85%). Diese Ergebenisse deuten darauf hin, dass das komplexierte Cd von den Wurzeln schlechter aufgenommen wird als das freie Cd.  相似文献   

4.
A pot culture experiment was performed to study the effect of cadmium stress (Cd stress) on seedling growth, physiological traits, and remediation potency of Avena fatua, Lathyrus sativus, and Lolium temulentum. The seedlings of these native rangeland plant species were treated with 0, 2, 4, and 6 mM cadmium nitrate concentrations. Based on the results of analysis of variance (p < 0.05), the shoot height, shoot dry weight, root length, root dry weight, root: shoot ratio, total chlorophyll content, soluble sugars, and protein contentof A. fatua, L. sativus, and L. temulentum significantly decreased with increased cadmium concentrations. Generally, translocation factor (TF) and tolerance index (TI) decreased significantly as the concentration of cadmium increased. The maximum TF and TI of studied plants in various concentrations of Cd were observed in L. temulentum followed by L. sativus and A. fatua. The root concentration factor (RCF) values of all studied plants were higher than 1 under different cadmium concentrations. Our results indicate that Lolium temulentum could be labeled as an accumulator of Cd asthe values of TF and RCF are greater than 1. A. fatua and L. sativus showed a potential to be used in the phytoremediation of Cd-contaminated soils.  相似文献   

5.
Non-exchangeable potassium (Knex) contributes to soil K availability and several extractants are used to access its contribution. This study evaluated sodium tetraphenylboron (NaBPh4) as a soil test of K availability in 20 soils from Northern Greece. Winter wheat (Triticum aestivum L. var. ‘Yecora’) was sown in a greenhouse pot experiment and five cropping cycles were carried out until K-depletion. Soils were analyzed with NH4OAc and NaBPh4 (1 and 5 min incubation periods). Critical levels of K ranged between 130–140 and 330–340 mg K kg?1 of soil for NH4OAc and NaBPh4 (1 min incubation period), respectively, and between 32 and 35 g K kg?1 of wheat dry matter. NaBPh4-K (1 min) related better with K concentration and uptake compared to NH4OAc for each cropping cycle (r2 = 0.45–0.83 and 0.44–0.89) and for all soils (r2 = 0.58 and 0.51). Similar results obtained in soils low in exchangeable K (r2 = 0.41 and 0.39). Correlation between NH4Oac- and NaBPh4-extractable K was weaker among soils below the critical level (r = 0.70) compared to those above (r = 0.93). Inclusion of illitic K and cation exchange capacity in a multiple linear regression between NH4OAc- and NaBPh4-extractable K showed that they significantly contributed to NaBPh4-extractable K.  相似文献   

6.
Highly weathered soils of the tropics are known to have great affinity for phosphate sorption with reportedly high values for affinity constant, k. This study evaluated soil samples from profiles dug at Agbor, Kwale, and Otegbo which overly alluvium and coastal plain sand parent materials for their capacities to sorb phosphorus (P). The samples were equilibrated in 30 ml of 0.01 M calcium chloride (CaCl2) containing various amounts of P as monopotassium phosphate (KH2PO4) to give 0, 25, 50, 100, 150, 200, 400, 800, and 1000 μg/L P for 6 days at a temperature of 25 ± 2°C. The rate of P adsorption increased with increased concentrations of P and was generally low in the soils. Affinity constant k was also low and did not compare with values earlier obtained for well-drained soils. P adsorption capacity decreased in the order: Agbor > Otegbo > Kwale. Percent phosphorus sorbed was highest at Agbor with values of 11.33%, 10.8%, and 10.12% for 50, 100, and 150 mg/kg P added, respectively. The adsorption maxima (b) of the soils was significantly correlated with the soils organic carbon with r = 0.817, p < 0.05; r = 0.883, p < 0.05, and r = 0.886, p < 0.05 for Agbor, Kwale, and Otegbo soils, respectively. Proper management of the soils organic matter content coupled with the addition of rock phosphate is recommended for P improvement in these soils for sustained cultivation of crops such as Raphia hookeri that are adapted to hydromorphic environment.  相似文献   

7.
Maize crop is grown mostly in tropical/subtropical environments where drought adversely affects its production. A field experiment was conducted on sandy loam soil for four years (1999 – 2002) to study the effect of wheat straw mulch (0 and 6 t ha?1) and planting methods (flat and channel) on maize sown on different dates. Maximum soil temperature without mulch ranged from 32.2 – 44.4°C in channel and 31.6 – 46.4°C in flat planting method. Mulching, however, lowered soil temperature by 0.8 – 7.0°C in channel and 0 – 9.8°C in flat planting. Mulching, on an average, improved leaf area index by 0.42, plant height by 14 cm, grain yield by 0.24 t ha?1 and biomass by 1.57 t ha?1, respectively. Mulching improved grain yield only in flat sowing. Interaction between sowing date and planting method was significant. Seasonal variation in biomass were significantly correlated (p = 0.05) with mean air temperature during 0 – 45 days after planting (DAP) (r = ?0.95), pan evaporation during 0 – 15 DAP (r = 0.79) and negative correlation with rainfall in entire cropping season (r = ?0.89), whereas biomass increase with mulch in different cropping seasons had negative relation (r = ?0.74) with amount of rain during 0 – 15 DAP.  相似文献   

8.
Abstract

To develop an advanced method for estimating nitrous oxide (N2O) emission from an agricultural watershed, we used a closed-chamber technique to measure seasonal N2O and nitric oxide (NO) fluxes in cornfields, grassland, pastures and forests at the Shizunai Experimental Livestock Farm (467 ha) in southern Hokkaido, Japan. From 2000 to 2004, N2O and NO fluxes ranged from –137 to 8,920 µg N m?2 h?1 and from –12.1 to 185 µg N m?2 h?1, respectively. Most N2O/NO ratios calculated on the basis of these N2O and NO fluxes ranged between 1 and 100, and the log-normal N2O/NO ratio was positively correlated with the log-normal N2O fluxes (r 2 = 0.346, P < 0.01). These high N2O fluxes, therefore, resulted from increased denitrification activity. Annual N2O emission rates ranged from –1.0 to 81 kg N ha?1 year?1 (average = 6.6 kg N ha?1). As these emission values varied greatly and included extremely high values, we divided them into two groups: normal values (i.e. values lower than the overall average) and high values (i.e. values higher than average). The normal data were significantly positively correlated with N input (r 2 = 0.61, P < 0.01) and the “higher” data from ungrazed fields were significantly positively correlated with N surplus (r 2 = 0.96, P < 0.05). The calculated probability that a high N2O flux would occur was weakly and positively correlated with precipitation from May to August. This probability can be used to represent annual variation in N2O emission rates and to reduce the uncertainty in N2O estimation.  相似文献   

9.
Organics, biological, and inorganic fertilizers play a crucial role for improving crop yield and soil properties. Accordingly, we assessed their impact on yield, microbial activities, and transformations of carbon (C), nitrogen (N), phosphorus (P), and sulfur (S) in soils under a 12-year-old intensively cultivated rice (Oriza sativa L.), mustard (Brassica juncea L.), sesame (Sesamum indicum L.) system with sole inorganic (NPK); NPK + farmyard manure (NPKF); NPK + green manure (NPKG) (Sesbania sesban L.), and NPK + green manure + bio-fertilizer (NPKGB) (Azotobacter chroococcum+ pseudomonas putida) treatments in sub-tropical India. The system yield was much higher with NPKF (23%) and NPKGB (18%) than that with NPK. Organic supplementation had a favorable influence on soil microbial biomass C (Cmic), N (Nmic), and activities of extracellular enzymes. Results of principal component and multiple regression analyses showed significant influence of Cmic on system yield (R2 = 91, p = 0.001) and S availability (R2 = 62, p = 0.001). Similarly, mineralizable N and acid phosphatase could predict significantly soil available N (R2 = 85, p = 0.001) and P (R2 = 51; p = 0.001), respectively. Results thus indicated that integrated nutrient management (NPKF/G) improved system yield, nutrient accumulation, and microbial activities in soils.  相似文献   

10.
Soil organic matter (SOM) plays a key role in soil, and is used to determine soil quality. Conventional soil property analysis is relatively slow, expensive and laborious. Although using a spectrometer can quickly assess a large amount of organic matter content, it is an expensive, complex and undefined process. This article presents a potential simple method for estimating black-SOM that uses a digital camera that is cheaper and easier to operate than a spectrometer. RGB (red, green and blue) image-intensity values of the soil from a digital camera were measured, to research the relationship between black-SOM and RGB. The results show the red image-intensity values provide the greatest correlation with SOM, with a correlation coefficient (r) reaching 0.73. A comparison with spectrometer results for SOM predictions shows that the best prediction result for the digital camera (R2 = 0.72, root-mean-square error [RMSE] = 0.40) is slightly better than the spectrometer (R2 = 0.65, RMSE = 0.45) at certain band points. Thus, a low-cost digital camera that is easy to operate can be used as an alternative tool for the rapid and accurate estimation of black-SOM content.  相似文献   

11.
A field experiment was conducted to evaluate nine genotypes of sorghum grown for two consecutive cropping seasons in 2006 and 2007 under rain-fed conditions in a semiarid zone at the Research Farm of El Fasher Research Station, Sudan. The objective of the study was to assess genetic variability and heritability among sorghum genotypes using phenotypic morphological traits. A randomized complete block design with four replications was used for the experiment. The grain yield (kg ha?1), the number of heads/plant, followed by straw yield (kg ha?1) had the highest genotypic coefficients of variation in both seasons. High heritability (above 95%) was shown for plant height in both seasons. High genetic advance was reported in straw yield, 1000-grain weight and days to flowering in both seasons. Highly significant differences among genotypes were found for all characters. The high-yielding genotype was Adv-Edo-CWS (E-9) with grain yields of 2780.6 kg ha?1. Grain yield was significantly and positively correlated with straw yield (r = 0.91), number of heads/plant (r = 0.69), plant height (r = 0.53) and 1000-grain weight (r = 0.36). However, it was significantly and negatively correlated with days to 50% flowering (r = ?0.21). Based on their positive association with grain yield, the character’s straw weight, number of heads/plant, plant height and 1000-grain weight would be the preferable selection criteria for sorghum improvement program in the country.  相似文献   

12.
Chinese cabbage and surface soil samples (0–20 cm) from a periurban market garden in Yunnan Province (P.R. China) were collected to determine variations of cadmium (Cd) and zinc (Zn) contents in Chinese cabbage and the influence of soil factors. Mean Cd content was 0.49 mg kg?1 dry materials (DM) in Chinese cabbage, ranging between 0.23 and 1.34 mg kg?1 DM (n = 21 samples). Mean Zn content was 51.2 mg kg?1 DM, ranging from 34.9 to 157.5 mg kg?1 DM (n = 21 samples). The soil factors best predicting Chinese cabbage Cd and Zn contents were total and available Cd and Zn contents and cation exchange capacity (CEC). Soil samples and corresponding Chinese cabbage samples were divided into two groups: soils with low pH (<6.5, n = 10) and soils with high pH (>6.5, n = 11). Positive correlation between CEC with pH > 6.5 and Cd and Zn contents in Chinese cabbage were observed. Available trace element contents and CEC explained 77% and 69% of variation of Cd and Zn contents in Chinese cabbage, respectively. AEC (enrichment coefficient related to trace element availability) and BCF (bioaccumulation factors) could be used to understand Cd and Zn accumulation in Chinese cabbage.  相似文献   

13.
The usefulness of Mehlich 3 (M3) reagent was evaluated as a method to extract numerous elements from coalmine soils in As Pontes (Spain) showing a wide range of physicochemical properties. Critical levels (deficiency and/or toxicity) were established for plant available elements extracted by this reagent. The M3 method was compared to 1M NH4Cl, Olsen, acid oxalate, and DTPA methods as extractants for exchangeable Ca, Mg and K, available P, non-crystalline aluminium, and available heavy metals, respectively. The M3 method correlated significantly to NH4Cl for Ca, Mg and K (r=0·76, 0·84 and 0·87, respectively), to Olsen P (r=0·77) and to oxalate Al (r=0·77). Significant correlations were found between Fe, Cu, Zn and Cd extracted by M3 and DTPA; for Mn, Ni, Co and Pb different relationship between methods were obtained for acid and alkaline samples, so that critical levels were established for M3 metals as a function of soil pH. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

14.
The effect of soil organic matter (SOM) on sorptive parameters under different soil management practices in Rendzic Leptosol was studied. In 2006, an experiment of different management practices in a productive vineyard was established in the locality of Nitra-Dra?ovce (Slovakia). The following treatments were established: (1) control (grass without fertilization), (2) T (tillage), (3) T + FYM (tillage + farmyard manure), (4) G + NPK3 (grass + 3rd intensity of fertilization for vineyards), (5) G + NPK1 (grass + 1st intensity of fertilization for vineyards). Soil samples were collected every month during the year 2010. Obtained results showed increased hydrolytic acidity (by 23%), sum of basic cations (by 37%) and decreased total cation exchange capacity (CEC) (by 36%) with higher doses of fertilization in comparison to control. Application of farmyard manure had a positive effect on the increase in the SOM cation sorption capacity. Positive correlations between pH and sum of basic cations (SBC) (r = 0.493, p ≤ 0.001), CEC (r = 0.498, p ≤ 0.001) and cation sorption capacity of SOM (r = 0.391, p ≤ 0.01) were observed. Higher values of labile carbon:potentially mineralizable nitrogen (CL:Npot) ratio corresponded with lesser CEC, SBC and base saturation values in the soil. With increased humus quality (higher values of humic acid:fulvic acid (CHA:CFA) ratio), cation sorption capacity of SOM significantly increased (r = 0.329, p ≤ 0.01). The results of this study proved that the application of farmyard manure had a positive effect on the increase of SOM sorption capacity, but higher doses of mineral fertilizers added to soil had a negative effect.  相似文献   

15.
This study was carried out with the objective of evaluating the effect of citrate concentration on the extraction efficiency of some micronutrients from soil. Composite surface soil samples (0–20 cm) were collected from Eastern Harage Zone (Babile and Haramaya Districts), Wolaita Zone (Damot Sore, Boloso Bombe, Damot Pulasa and Humbo Districts) and Dire Dawa Administrative Council in purposive sampling. The treatments were arranged in completely randomized design (CRD) with three replications. A greenhouse pot experiment with soybean plant was conducted to determine the correlation between soil test methods and the selected micronutrients, such as iron (Fe), copper (Cu), manganese (Mn) and zinc (Zn) in the leaves of the plant. The results showed that, among the different citrate concentrations with strontium chloride (SrCl2) tested for the determination of available Fe, Mn and Zn, the highest correlation coefficients (r = 0.82, p < 0.05), (r = 0.96, p < 0.001) and (r = 0.98, p < 0.001) were found between the diethylenetriamine pentaacetic acid (DTPA) method and 0.02 M strontium chloride (SrCl2)-0.025 M citric acid extractant, respectively. Therefore, 0.02 M SrCl2-0.025 M citric acid extractant is considered to be the most effective for the determination of Fe, Mn and Zn in soils of the studied areas. Similarly, high correlation coefficients (r = 0.97, p < 0.001) were found between DTPA and 0.02 M SrCl2-0.05 M citric acid and (r = 0.88, p < 0.01) between DTPA and 0.02 M SrCl2-0.025 M citric acid extractants for the determination of available Cu from soils. Hence, the 0.02 M SrCl2-0.05 M citric acid extractant was shown to be the best for the determination of Cu in soils of the studied areas. However, considering the use of universal extractant, the 0.02 M SrCl2-0.025 M citric acid extractant could easily be adopted as a procedure for the determination of Fe, Cu, Mn and Zn for both agricultural and environmental purposes. The greenhouse experiment confirmed the result.  相似文献   

16.
Two cultivars of wheat (Triticum aestivum L.) with differential salinity tolerance were compared by evaluating the growth attributes, pigment composition and accumulation of Na+, K+, Zn2+, Fe 2+, Mn 2+ and proline. Wheat cultivars Al-Moiaya (AM) (salt tolerant) and Habbe-Druma (HD) (salt sensitive) were subjected to four levels of salinity (1.21 dS m?1, 4.4 dS m?1, 8.8 dS m?1 and 13.2 dS m?1) in factorial combinations with three drought stress (FC 30%, FC 60% and FC 90%) treatments in a randomized complete block design. Plant dry weight, leaf area ratio (LAR), soluble protein and total chlorophyll (Chl) content were higher in AM than HD. Salt-tolerant AM maintains a higher K+/ Na+ ratio and thereby is able to grow better than the salt-sensitive HD under both the stresses. The lower foliar Na+ in AM resulted in retention of higher Chl content, reflected in the strong positive correlations between plant ion status and Chl contents (Na+-Chl r2 = 0.83; Chl- Fe2+ r2 = 0.76; Zn2+ r2 = 0.93 and Mn2+ r2 = 0.88). In conclusion, our results suggested that the K+/Na+ ratio, exclusion of Na+ and ion homeostasis play much more important roles in the tolerance to salinity and drought stress than the compatible osmolyte, proline.  相似文献   

17.
Risk assessment of cadmium (Cd) contamination in soils requires identifying the bioavailable portion of the total Cd, a portion that is determined by environmental conditions such as pH and calcium (Ca) level in soils and by the physiological processes going on in the plant roots. Growth tests in solutions were conducted to develop a terrestrial biotic ligand model to describe uptake and rhizotoxicity of Cd to pea (Pisum sativum L. cv. Lincoln). Inhibition concentration associated with a 50% reduction in root elongation (IC50) values were found to vary with external Ca2+ and H+ activities. Root-bound Ca was found to reach a plateau of about 63 µmol g?1 (dry weight) although Ca treatment increased from 0.04 to 2 mmol L?1. When experimental treatments (e.g., pH 6, Ca 0.2 to 2 mM) resulted in sufficient Ca supply, dose–response curves relating root elongation to root-bound Cd could be modeled with Weibull equations; IC50 values were expressed in terms of root-bound Cd concentration. When the treatments (e.g., pH 4 or 5, Ca 0.04 mM) suggested a low Ca supply, root elongation was more sensitive to Ca content and root-bound Ca concentration became the dominant predictor variable. Cd accumulation was modeled by treating the pea roots as an assemblage of biotic ligands with known site densities (Q Lj ) and proton binding constants (K HLj ). The logK Ca and logK Cd values were established using measured root-bound ion concentrations and solution chemistry. The logK Ca values were negatively correlated to root Ca contents. The logK Cd values were positively correlated to logK Ca values. Explanations for the changing of constants are discussed.  相似文献   

18.
In temperate regions, cultivation of Robinia pseudoacacia L. has recently received considerable attention because it is a fast-growing species for biomass and bioenergy production, while acting as a potential carbon (C) sink to counterbalance carbon dioxide (CO2) emissions and an alternative to agricultural crops on marginal sites. The objective of our work was to compare total organic carbon (TOC), total nitrogen (TN), and organic C fractions in postlignite mining soils under different development stages of R. pseudoacacia. Soil samples from three different depths (0–3, 3–10 and 10–30 cm) were taken in plantations 2, 3, 4, and 14 years old (R2, R3, R4, and R14, respectively). The TOC and TN contents increased with increasing tree age in all layers (P < 0.01). In the top 30 cm, TOC and TN stocks ranged from 11.7 to 59.8 Mg C ha?1 and from 0.30 to 2.61 Mg N ha?1 at R2 and R14, respectively. The rate of C sequestration was calculated to be 4.0 Mg C ha?1 year?1. Microbial biomass C and N were strongly correlated to TOC (r2 = 0.96 – 0.81; P < 0.001) and TN contents (r2 = 0.92 – 0.91; P < 0.001). The light fraction C (CLF) accounted for 15–30% and the heavy fraction C for 70% of TOC in all layers. In the 0- to 3-cm layer, CLF increased by 0.5 g kg?1 year?1. The results indicate that plantations of R. pseudoacacia are an attractive alternative to increase soil C contents in reclaimed lignite mining soils. In the short term, microbial biomass C and light fraction C are sensitive and provide an appropriate measure to assess soil C changes caused by cultivation of R. pseudoacacia.  相似文献   

19.
Triticum monococcum L., Triticum dicoccum Schrank and Triticum spelt L. nowadays offer an alternative to Triticum aestivum L. We analyzed grain and straw yield, yielding parameters, chemical composition and bakery quality of these species and compared them with modern T. aestivum at three sites with different soil-climate conditions. The average grain yield varied from 0.41 t ha?1 (T. monococcum) to 5.17 t ha?1 (T. aestivum), straw yield varied from 1.50 t ha?1 (T. dicoccum) to 5.83 t ha?1 (T. aestivum). The yielding parameters and chemical composition of the grain were significantly influenced by soil-climate conditions and wheat species. The highest average crude protein content was recorded in T. spelta (20.55%), while the lowest in T. aestivum (11.20%). The Zeleny’s sedimentation test ranged from 9.0 ml (T. monococcum) to 34.5 ml (T. aestivum) and the value of the Gluten index varied from 7.45 (T. dicoccum) to 89.75 (T. aestivum). According to the results, ancient wheat species provides lower grain and straw yields, higher protein content and mineral concentrations. Concentration of proteins and grain’s baking quality strongly depends on wheat species and soil-climate conditions.  相似文献   

20.
Soil organic matter and its components play a key role in the stabilization of soil aggregates. This study aimed to investigate the distribution of organic carbon (OC), total nitrogen (TN), hot-water extractable (HWE) and dilute acid extractable (DAE) carbohydrates and CaCO3 in water-stable aggregates in histosols of Shahrekord, Iran. Additionally, correlations between aggregate stability (mean weight diameter (MWD) values) and mentioned characters were also examined. Results showed that at all depths in all 18 profiles, larger aggregates contained more OC, TN and carbohydrate content than the smaller aggregates, whilst CaCO3 had the opposite trend. OC, TN and carbohydrate fractions followed a consistent similar trend by aggregate size. The positive correlation between OC and TN within the aggregates was considerable. OC, TN, carbohydrate fractions and MWD significantly (P < 0.01) decreased with depth. Average concentration of CaCO3 was almost the same in aggregates <4 mm at all depths. We observed very low values of ratios HWE:OC and DAE:OC in the study site. OC, TN and carbohydrate fractions each gave highly or very highly significant correlations with aggregate stability. We obtained significant, but weak negative correlation of CaCO3 with aggregate stability (P = 0.05; r = ?0.23), implying that CaCO3 is a disaggregating agent in these histosols.  相似文献   

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