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1.
The study on the behaviour of potassium,phosphate and trace elements,Fe,Mn,Cu and Zn,in the rhizosphere of different varieties of flue-cured tobacco (Nicotiana tabacum L.)with high and low potassium application rate with rhizobag technique showed that soil available K,soil available P,and slow available K was in depletion status,whereas DTPA extractable Fe,Mn,Zn and Cu accumulated obviously in rhizosphere.The depletion and accumulation rates of mineral nutrients differed in degree with K application rate,soil type,and tobacco variety.The content of available K in both rhizosphere and bulk soil and K concentration in tobacco leaf increased significantly,and the available P in rhizosphere dropped with more K application.The DTPA-Fe content of red soil much lower in pH was higher than that of calcareous soil in bulk soil.But the DTPA-Fe content of calcareous soil was much higher than that of red soil in rhizosphere,which was considered perhaps to be mainly related to releasing of Fe phytosiderophore.Nitrate coule increase depletion of a vailable K in rhizosphere and also soil pH in comparision with ammonium.  相似文献   

2.
Abstract

It was hypothesized that supplying potassium (K) in concentrated complex fertilizer (CCF) form with nitrogen (N) (NK CCF) to all fertilizer microsites, rather than in NK‐blended fertilizer form to a fraction of the total fertilizer microsites, should enhance the rate of K uptake by perennial ryegrass. Two complementary pot experiments were conducted to test this hypothesis. The results demonstrated that plants fertilized with an NK CCF absorbed K at faster rates than those fertilized with an NK blend and that use of K2SO4 in place of KCl as the K source lowered the rate of K uptake by plants regardless of fertilizer form. Form of fertilizer (i.e., CCF or blend), however, had no effect on NH4 + or NO3 ? uptake. Unfortunately, the positive effects of the CCF on K absorption were only manifest during the second 2 weeks of regrowth and did not result in significant improvements in dry matter production by the end of the 5‐week regrowth periods.  相似文献   

3.
Zusammenfassung Untersuchungen an fruchtendem Material des LebermoosesRicciocarpus natans aus China ergaben, daß in einigen nicht unwesentlichen Punkten die in der Literatur zu findenden Angaben über die Art zumindest nicht generelle Gültigkeit haben.Ergebnisse der Chinesisch-deutschen Biologischen Sammelreise durch N und NO China 1956, Nr. 9.  相似文献   

4.
Two field experiments were carried out over two consecutive years (2010–2011) in the research field of the College of Agriculture, Shiraz University, Fars Province, southern Iran. The study was a factorial experiment based on a randomized complete block design with three replications: the first factor was the ratio of safflower (Carthamus tinctorius L. Pi cv.) to bean (Phaseolus vulgaris L. Saiad cv.) at five levels (safflower and bean sole cropping, and intercropping of safflower and bean at ratios of 1:3, 2:2 and 3:1); and the second factor was weed management at two levels: weed-free (complete weed control) and weedy (no weed control). The results showed that an intercropping system was the most appropriate method for decreasing the adverse effect of weeds on the performance of both crops. Intercropping was more suitable for weedy than weed-free conditions. According to the land equivalent ratio (LER) value, if the main crop was bean, the best intercropping treatment was one row of safflower and six rows of bean (S1B3) under both weedy and weed-free conditions. By contrast, if the main crop was safflower, the best treatment under weedy conditions was S1B3, whereas under weed-free conditions the best treatment was two rows of safflower and four rows of bean (S2B2). Overall, S1B3 can be introduced as the best intercropping method.  相似文献   

5.
Polygonum odoratum Lour. has been reclassified as Persicaria odorata (Lour.) Soják [Wilson, K. L. Polygonum sensu lato (Polygonaceae) in Australia. Telopea 1988, 3, 177-182]; other synonyms currently used are Vietnamese mint or Vietnamese coriander and, in Malaysia, Daun Laksa or Laksa plant. The aerial parts of Laksa plant are highly aromatic, and they contain many organic compounds such as (Z)-3-hexenal, (Z)-3-hexenol, decanal, undecanal, and dodecanal that are typical for green, citrus, orange peel, and coriander odors. In addition to these aldehydes, 3-sulfanyl-hexanal and 3-sulfanyl-hexan-1-ol were discovered for the first time in this herb. The fresh leaves are pungent when they are chewed, although the active compound has never been identified. The pungency of Persicaria hydropiper (L.) Spach (formerly Polygonum hydropiper L., synonym water pepper) is produced by polygodial, a 1,4-dialdehyde derived from drimane terpenoids. We also identified polygodial as the active pungent compound in P. odorata (Lour.) Soják.  相似文献   

6.
Abstract

Field trials were established on a loamy fine sand and a silt loam using snapbeans and soybeans as test crops, respectively. Row fertilizer was placed with the seed (seed‐placed). Treatments were arranged in a 3×3×3 factorial experiment, and N, P, and K were applied in all combinations at three rates (0, 3.4, and 6.8 kg/ha). Ammonium nitrate (AN), monoammonium phosphate (MAP), concentrated superphosphate (CSP) and potassium chloride (KCl) were used as sources of N, P and K. Additional treatments compared MAP with diammonium phosphate (DAP) and KCl with potassium nitrate (KNO3).

The salt index of each treatment was inversely related to emergence, i.e. as the salt index increased, the emergence decreased. Level of N was more important than level of P or K in regards to reduction in emergence. Snapbeans grown on a loamy fine sand were extremely sensitive to damage from seed‐placed fertilizer, even at rates as low as 3.4 kg/ha of N, P or K. Soybeans planted on a silt loam soil were less sensitive than snapbeans planted on a loamy sand. The soybeans were able to tolerate up to 10.2 kg/ha of seed‐placed P plus K or 6.8 kg/ha of seed‐placed N plus P or N plus K without causing a significant delay in emergence.  相似文献   

7.
The present investigation was carried out at CSK Himachal Pradesh Agricultural University, Palampur, Himachal Pradesh, India, during 2009–2011 to economize inorganic phosphorus (P) and enhance profitability of okra (Abelmoschus esculentus)–pea (Pisum sativum) cropping system through arbuscular mycorrhizal fungi (AMF). A field experiment was replicated thrice in a randomized block design comprising 14 treatments involving AMF (Glomus mosseae) at varying inorganic P (50%, 75%, and 100% of recommended soil test-based P dose) and irrigation regimes (40% and 80% available water capacity] in a Himalayan acid Alfisol. In okra, AMF inoculation at varying P and irrigation regimes registered higher P response ratio (PRR), net returns (10–18%), and benefit:cost (B:C) ratio (17–49%) compared to “generalized recommended P dose (GRD)” and their non-AMF counterparts. Similarly in pea, AMF inoculation at varying P and irrigation regimes again registered higher PRR, net returns (14–23%), and B:C ratio (10–58%) compared to GRD and non-AMF counterparts. Higher system productivity (7–16%) and profitability in terms of net returns (9–23%) and B:C ratio (10–54%) were also registered in AMF-imbedded treatments compared to non-AMF counterparts. Further, “AMF + 75% soil test-based P dose” at either of these irrigation regimes registered statistically similar okra–pea system productivity and profitability as that obtained under “100% soil test-based P dose” at either of two irrigation regimes, thus indicating an economy of soil test-based applied P dose by about 25%. Overall, the current study suggests that practice of AMF inoculation has great potential in enhancing system productivity and profitability besides cutting down about 25% inorganic P requirement in okra–pea production system in the Himalayan acid Alfisol.  相似文献   

8.
The assessment of heavy metals in spinach (Spinacia oleracea) grown in sewage sludge–amended soil was investigated. The results revealed that sewage sludge significantly (P < 0.01) increased the nutrients and heavy metals such as cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), and zinc (Zn) in the soil. The contents of metals were found to be below the maximum levels permitted for soils in India. The most agronomic performance and biochemical components of S. oleracea were found at 50% concentrations of sewage sludge in both seasons. The contents of Cd, Cr, Cu, Mn, and Zn in S. oleracea were increased from 5% to 100% concentrations of sewage sludge in both seasons. The order of contamination factor (Cf) of different heavy metals was Mn > Cd > Cr > Zn > Cu for soil and Cr > Cd > Mn > Zn > Cu for S. oleracea plants after application of sewage sludge. Therefore, use of sewage sludge increased concentrations of heavy metals in soil and S. oleracea.  相似文献   

9.
ABSTRACT

Knowledge of the initial soil fertility status is very crucial to make the soil test-based fertilizer recommendations and therefore it is necessary to develop alternative techniques to predict the post-harvest soil test values than analyzing the soils after every crop. The study was done to develop multiple linear regression (MLR) models to predict soil available nitrogen, phosphorus and sulfur in the hybrid rice-wheat cropping sequence. The post-harvest soil test values were considered as the dependent variable and initial soil nutrients applied nutrient through fertilizer and farmyard manure and grain yield as independent variables. In general, the accuracy of prediction for the calibration and validation models using the single year and two-year data model was significant and had a coefficient of determination was ≥0.75. Although the performance of MLR model to predict post-harvest soil N, P and S after the individual crop was better than that after whole rice-wheat cropping sequence, predictions of the post-rice-wheat sequence of soil N, P and S also had acceptable levels of accuracy. Thus, the concept of the using the MLR-based models to predict the post-harvest soil test values could be used in hybrid rice-wheat cropping sequence to make the soil test-based fertilizer recommendations to the individual crops or whole cropping sequence.  相似文献   

10.
With the present understanding that decomposing straw may not only affect soil properties,but possibly greenhouse gas emissions as well,focus among cnvironmental researchers has gradually expanded to include understanding of decomposition rate and stability of straw of different plants in different soils under different management conditions.Against such a background,a short-term(60 days)greenhouse simulation experiment was carried out to study the effects of straw placement,external mineral N source and tillage on straw decomposition of maize and cotton in two contrasting soils,a red soil(Ferrasol)and a black soil(Acrisol).The treatments included straw addition only(T1);straw addition mineral N(T2);and straw addition tillage(T3).Straw was either buried in the soil or placed on the surface.Sampling was done every 15 days.Placement,addition of external mineral N sources(Urea,46% N),straw type,soil type and exposure duration(15,30,45 and 60 dyas)affected straw decomposition.Decomposition was more in buried straw than in surface-placed straw at all sampling dates in red soil.The addition of an external N source significantly increased decomposition.The study could not,however,fully account for the effect of tillage on straw decomposition because of the limited effect of our tillage method due to the artificial barrier to mechanical iaterference supplicd by the mesh bags.  相似文献   

11.
The present investigation was carried out at CSK Himachal Pradesh Agricultural University, Palampur, India, during 2009–2011 to economize inorganic phosphorus (P) and water needs of an okra (Abelmoschus esculentus)–pea (Pisum sativum) cropping system through vesicular arbuscular mycorrhizal (VAM) fungi (Glomus mosseae) in a Himalayan acid Alfisol. The field experiment was replicated three times in a randomized block design comprising 14 treatments consisting of 12 treatment combinations of two VAM levels [0 and 12 kg ha?1], three phosphorus levels [50, 75, and 100% of recommended soil-test-based nitrogen (N)–P–potassium (K)], and two irrigation regimes [40 and 80% of available water-holding capacity of field soil (AWC)], in addition to one treatment with “generalized recommended NPK dose with generalized recommended irrigations (GRD)” and one treatment based on “farmers’ practice of plant nutrition and irrigation management in the region.” This article presents crop productivity and P dynamics studies during the second crop cycle of okra–pea sequence (2010–2011) and statuses of different P fractions in the soil after the second pea crop harvest during 2010–2011. Crop productivity and P uptake data in okra–pea sequence indicated that application of VAM + 75% P dose at either of two irrigation regimes did not differ significantly than GRD treatment and VAM + 100% P dose. It suggests an economy of about 25% inorganic P dose through VAM fungi. The treatments imbedded with VAM inoculation enhanced the P uptake in okra–pea system, on an average by 21% over the GRD and non-VAM-inoculated counterparts. Further, integrated application of P, VAM, and irrigation regimes evaluated in okra–pea sequence for 2 years led to greater status of water-soluble P (21%), sodium bicarbonate (NaHCO3)–inorganic phosphorus (Pi) (11%), sodium hydroxide (NaOH)–Pi (9%), hydrochloric acid (HCl)–extractable–P (20%) over non-VAM-inoculated counterparts and low status of organic P (NaHCO3-Po and NaOH-Po), all of which appreciably contributed to available P supply to plants in the present study in an acid Alfisol. The correlation coefficient reveals that contribution of inorganic P forms is highly correlated to crop productivity and total P uptake in okra and pea crops besides soil available P in the present study. Overall, it is concluded that VAM inoculation in okra–pea cropping system significantly enhanced the P availability to plants by way of enriching the labile-P pool such as water-soluble P and P loosely bound to aluminium (Al-P) and iron (Fe-P) on adsorption complexes and by P mineralization from organic matter in an Himalayan acid Alfisol.  相似文献   

12.
For the onset of symbiosis process between soybean (Glycine max (L.) Merr.) and Bradyrhizobium japonicum, signals should be exchanged. Salinity has inhibitory effects on the symbiosis between the two partners. Hence, a greenhouse experiment was planned to: (1) determine the stressful effects of salinity on soybean and B. japonicum symbiosis, hypothesizing that they can inhibit the signal exchange process between the two partners, and (2) determine if the addition of genistein (a nod gene inducer) to B. japonicum (strain 532C) inocula could overcome the stressful effects of salinity on the Bradyrhizobium – soybean symbiosis. Three levels of salinity (control, 36 and 61 mmolar or 3.6 and 6.1 mmhos/cm) and three levels of genistein (0, 5 and 20 μM) were combined in a factorial fashion in four replicates. Soybean plants were harvested at three different times including 20, 40 and 60 days after inoculation (DAI). Genistein enhanced soybean nodulation and growth, and such effects became greater with time under high salinity levels. For example, at 60 DAI the enhancing effects of genistein on the symbiosis process in soybean was more pronounced at the highest level of salinity. The significant interaction effect between genistein 5 μM and salinity 61 mmolar may reveal the direct role of genistein 5 μM in overcoming the stressful effects of salinity on the symbiosis between B. japonicum and soybean, and hence, plant growth. This novel finding may be very useful to increase soybean yields in salty croplands.  相似文献   

13.

Production of varieties of the medicinal plants Mentha  相似文献   

14.
印度芥菜(Brassica juncea L.)重金属耐性机理研究进展   总被引：4，自引：0，他引：4  
印度芥菜可富集/忍耐Cd、Zn 等多种重金属, 是研究植物修复技术的一种模式植物。高浓度的重金属离子会改变植物的基因表达、细胞形态、细胞结构, 最终使植物生长受抑, 甚至死亡。印度芥菜高效的抗氧化系统、损伤修复系统以及对重金属的螯合、区域化可部分解除重金属的毒性, 缓解重金属离子的毒害作用。利用基因工程技术在印度芥菜中导入重金属耐性及运输相关基因可大幅度提高其重金属富集能力, 在重金属污染修复方面具有广阔的应用前景。  相似文献   

15.
【目的】研究土层、季节和树龄对宁夏枸杞土壤细菌群落结构的影响,对揭示枸杞种植区域土壤质量变化规律具有重要意义。【方法】以宁夏枸杞之乡—宁夏回族自治区中宁县为研究区,采用高通量测序分析了不同土层、季节和树龄条件下枸杞土壤细菌生物量及细菌群落结构和丰度的变化趋势。【结果】随着枸杞树龄增加,与幼龄 (种植当年,< 1 年) 枸杞土壤相比,春季和夏季 0—20 cm 中龄 (6 年) 和老龄 (12 年) 土壤总有机碳 (total organic carbon,TOC) 及 0—40 cm 土壤总有机氮 (total organic nitrogen,TON) 含量先增加后减少;春季不同树龄 0—20 cm 土壤微生物生物量碳 (microbial biomass carbon,MBC)和微生物生物量氮(microbial biomass nitrogen,MBN)一直增加,但春季和秋季 20—40 cm 则呈相反趋势。夏季中龄植株表层土壤 MBC 最高,但 MBN 却最低。随着树龄增加,枸杞表层土壤细菌多样性普遍呈先增加后减小的趋势。枸杞土壤变形菌门 Proteobacteria、放线菌门 Actinobacteria、拟杆菌门 Bacteroidete 在细菌群落中占绝对优势。相同季节老龄土壤 Proteobacteria 相对丰度普遍高于幼龄和中龄,幼龄土壤 Planctomycetes 和绿弯菌门 Chloroflexi 丰度高于中龄和老龄。变形杆菌中黄色单胞菌 Xanthomonadales、红杆菌 Rhodobacterales 和根瘤菌 Rhizobiales 占主导地位,尤其是在秋季中龄和 3 个季节的老龄枸杞土壤。土层、季节和树龄对土壤微生物数量影响不同。【结论】随着树龄增加,宁夏枸杞表层土壤微生物生物量和细菌多样性呈先增加后降低的趋势。老龄植株土壤 Xanthomonadales 数量相对最多。土层对枸杞土壤碳分布有极显著影响,树龄主要显著影响土壤氮源和细菌群落多样性,季节对枸杞土壤碳源、微生物量碳氮均有极显著影响。  相似文献   

16.
松嫩草地由于自然及人为因素的影响,出现了严重的次生盐碱化现象。盐碱化与次生盐渍化导致草地生物量急剧下降,许多优质牧草(如羊草等)消失,严重影响该区域畜牧业的发展,因此改良盐碱土,发展人工草地已成为该区域畜牧业可持续发展的重要途径。鉴于吉林西部草地的气候与土壤特点,本研究选择砂土改良之后建植的人工草地,开展了土壤盐碱化对紫花苜蓿生物学特征影响的研究。采用大地电导率仪(EM38)将研究区域分成3个盐碱程度(轻度、中度与重度);测定土壤(1.0m深度)盐碱指标,并对紫花苜蓿生物学特征进行长期调查。结果显示,紫花苜蓿的生长速率、生物量、鲜干比(FWR)、Na/K和叶绿素(SPAD)与土壤盐碱化程度呈负相关关系。随着土壤盐碱程度的增加,紫花苜蓿第一茬的生长速率由1.70cm·d^-1显著降低到0.40cm·d^-1(P<0.05),而第二茬的生长速率则由1.40cm·d^-1降低到0.45cm·d^-1;SPAD由62.3下降到53.2;Na/K由1.49减小到0.78;生物量(干重)由1.88t·hm^-2降低到0.20t·hm-2;鲜干比由2.59降低到1.80;而随着土壤盐碱化程度的增加,紫花苜蓿的茎叶比由1.72增加到了2.61。因此,土壤盐碱化降低了紫花苜蓿产量与品质。本研究结果可为盐碱化土地的利用以及盐碱化人工草地生产力提升提供理论依据。  相似文献   

17.
This study was carried out to investigate the interaction of maize and Aspergillus niger as influenced by arbuscular mycorrhizal fungi (AMF). Three quality protein maize (QPM) genotypes (ILE1-OB, ART-98-SW5-OB and ART-98-SW6-OB) and two market accessions (Ilishan and Shagamu) were evaluated in a pot experiment conducted under natural environment conditions at the Research and Teaching Farm of Babcock University, Ogun State, Nigeria. AMF (Glomus deserticola) in mixtures of soil and root fragments was inoculated at the rate of 15 g per plant, while maize was artificially infected with A. niger (15 cfu ml?1) in each designated pots. The coefficient of emergence (COV), percentage emergence (% E) and disease severity were determined using standard methods. Generally, plants treated with AMF only produced the highest cumulative cob yield (18 g), followed by plants treated with AMF and A. niger (15 g) and then control (12 g), while the least was recorded for only A. niger-treated plants (4 g).  相似文献   

18.
The rDNA PCR–RFLP of foxtail millet (Setaria italica) germ-plasm collected throughout Eurasia and from a part of Africa was investigated with five restriction enzymes according to our previous study. Foxtail millet germ-plasms were classified by length of the rDNA IGS and RFLP; clear geographical differentiation was observed between East Asia, the Nansei Islands of Japan-Taiwan-the Philippines area, South Asia and Afghanistan-Pakistan. We also found evidence of migration of foxtail millet landraces between the areas. We calculated diversity index (D) for each region and found that center of diversity of this millet is East Asia such as China, Korea and Japan.  相似文献   

19.
The aim was to quantify medium term litter type and litter mixture effects on the translocation and transformation dynamics of root and leaf litter C during decomposition. Partitioning of 13C-labeled root or leaf litter C (beech – Fagus sylvatica L., ash – Fraxinus excelsior L.) to CO2, water-extractable organic C (WEOC), microbial biomass C (CMB) and light (LF) and heavy soil fraction (HF) was determined in a laboratory decomposition experiment of 206 days. The proportions of C mineralized from ash leaf (34%) and root litter (29%) were higher than those from beech leaf (24%) and root litter (23%). In mixture with beech, the mineralization of ash leaf litter was enhanced. Mineralization was positively correlated with litter-derived WEOC until day 29. Water-extractable organic C declined with time, until <0.1% of litter C remained in this fraction. Litter-C recovery in CMB was higher for ash (0.7–1.0%) than for beech (0.2–0.4%). The litter C recovery in HF (4–12%) was positively correlated with that in WEOC (days 9 and 29) and CMB, but did not differ between treatments. Ash leaf litter mineralization showed different behavior in mixed treatments from pure treatments. Thus, the ability to transfer results from pure to mixed treatments is limited. The litter differed in chemical composition and in mineralization dynamics, but differences in partitioning to HF, WEOC and MB were finally of minor importance.  相似文献   

20.
Volatile compounds of cajá and taperebá fruits, both classified as Spondias mombin, but from different geographic origins, were extracted (and analyzed) using solid phase microextraction (SPME) and simultaneous distillation and extraction (SDE). Forty-eight compounds were identified in taperebá and 47 in cajá by SPME using a DVB/CAR/PMDS fiber. (E)-Caryophyllene (18.7%), ethyl butyrate (10.0%), and ethyl hexanoate (7.0%) were the most abundant components in taperebá volatiles extracted by SPME, whereas myrcene (41.1%) and beta-phellandrene (8.5%) were the major compounds in cajá. In the taperebá SDE extract, 46 substances were identified, and (Z)-caryophyllene (13.2%) and limonene (9.5%) were predominant. From the 42 substances found in the SDE extract of cajá, the major components were myrcene (38.0%) and p-cymene (6.2%). The two fruits showed similar chromatograms upon the use of SDE and SPME. These methods made it possible to determine 30 identical components in both fruits by using SDE and 32 by using SPME.  相似文献   

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