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1.
Abstract

There is an increasing demand for organically grown pulses and cereal grains in Denmark, which is expected to cause a change in the typical organic farm structure away from dairy farming and towards arable farming. Spring field beans (Vicia faba) could be a popular break crop in organic agriculture. The black bean aphid (Aphis fabae) is generally considered to be a serious pest of spring-sown field beans in northern Europe, and field studies have shown that yield losses can exceed more than 50% due to attacks from the black bean aphid.

The use of insecticides in organically grown field bean crops is not permitted, but it has been known for a long time that the black bean aphid infests different varieties of beans to a very different extent. Therefore, partial resistance to the black bean aphid is one method of stabilizing yields. Another method of cultural pest control is intercropping and a third method could be a combination of both. Six field experiments involving the three methods were carried out. There was a significant difference between the number of aphids per plant on the three investigated bean varieties, where ‘Colombo’ was the most susceptible, ‘Quattro’ was intermediate, and ‘Caspar’ the most resistant variety. ‘Colombo’ intercropping with spring wheat and spring barley reduced the numbers of aphids per plant significantly, and also the number of plants infested. The harvesting of all crops took place during the last fourteen days of August.

It can be concluded that the growing of partial host plant resistant varieties of field beans or the intercropping of field beans with spring cereals separately will reduce the infestation with black bean aphids. If both methods are used, the reduction of infestation will be even higher and consequently also the yield.  相似文献   

2.
土壤施肥对烟粉虱生长发育、寄主选择及繁殖的影响   总被引：1，自引：1，他引：0  
为探讨土壤施肥对烟粉虱种群的影响,在室内采用盆栽方法测定了11种氮、磷、钾施肥组合处理和对照处理的黄瓜苗上烟粉虱的发育历期、存活率、若虫大小、寄主选择、繁殖力及寿命等生命参数。结果表明,烟粉虱的发育历期受施肥影响显著;施肥对卵和低龄若虫存活率无显著影响,但对高龄若虫存活率及各龄若虫大小影响显著;成虫较喜欢在氮肥施用量适中且不施用钾肥和磷肥的黄瓜植株上取食和产卵,而不喜好氮肥施用量大且施用钾肥和磷肥的植株;烟粉虱的寿命及繁殖力在单独施用磷肥的黄瓜植株上低于对照处理的植株,在其他施肥处理上均高于对照。在氮肥施用量大且施用钾肥和磷肥的植株上,一个世代后烟粉虱种群增殖最大,达74．4倍;在单独施用磷肥时增殖最小,仅17．2倍。  相似文献   

3.
Genetic variability of wild populations, closely related to domesticated species, constitute important genetic resources for plant breeding programs. In this paper, we analysed the variation of eight wild populations of Solanum lycopersicum var. cerasiforme in a common garden experiment for levels of plant infestation by whitefly, leaf trichome density as a defensive character preventing infestation by whitefly, and the effect of whitefly incidence into vegetative and reproductive plant characters. Number of adults of whitefly was recorded in the eight wild populations of S. lycopersicum var. cerasiforme, one population of the wild species S. habrochaites (C-360), and one of a cultivated variety of S. lycopersicum (Rio Grande). There were significant differences among the wild populations of S. lycopersicum var. cerasiforme in the average level of whitefly incidence and trichome density. Cultivated tomatoes had the higher incidence of whiteflies ( = 7.50 ± 0.14) followed by plants of S. lycopersicum var. cerasiforme ( = 2.02 ± 0.92) and plants of S. habrochaites with the lowest incidence ( = 0.36 ± 0.35). Whitefly incidence was negatively correlated with trichome density (r = − 0.38, p < 0.0001), suggesting that trichomes deter or limit the establishment of whiteflies. Additionally, a significant negative effect of whitefly incidence along the growing season upon plant growth rate (number of branches and height) and fruit production was detected.  相似文献   

4.
A short-term experiment was conducted to investigate whether the effect of rootstock on plant response to salinity depends on the solanaceous species used as scion. Tomato cv. ‘Ikram’ and eggplant cv. ‘Black Bell’ were grafted onto two tomato interspecific hybrids (‘Beaufort’ and ‘He-Man’). Plants were grown in an open soilless cultivation system and supplied with two nutrient solutions: non-saline control and a saline solution (adding 15 mM Na2SO4, 3.7 dS m?1). Plant dry biomass production and partitioning were influenced by salinity, but its effect was depending on the rootstock/scion combination. ‘Beaufort’ eliminated the deleterious effect of salinity when tomato was used as scion, but reduced (?29.6%) the shoot biomass of eggplant. ‘He-Man’ had a different effect on scion growth under saline conditions: shoot biomass was less reduced in eggplant (?20.6%) than in tomato (?26.8%). Under salt stress, ‘Beaufort’ reduced the accumulation of Na+ in tomato leaves more than in eggplant, whereas no differences were observed between tomato and eggplant grafted onto ‘He-Man’. Stem Na+ accumulation followed a different pattern. The increase of Na+ in the stems was similar for tomato and eggplant grafted onto ‘Beaufort’, whereas stems of tomato accumulated more Na+ compared to eggplant grafted onto ‘He-Man’. The opposite response of the tested rootstocks to salt stress when the scion was either tomato or eggplant seems to be partially related to the capacity of the rootstock and scion to exclude Na+ from the shoot. However, the results of nutrient accumulation within plant tissues imply that other mechanisms in addition to ion competition are involved in the salt resistance of grafted plants.  相似文献   

5.
2017年1月9—12日和2月21—24日,在南平建瓯、三明将乐、三明三元、福州闽侯、龙岩新罗以及漳州龙海等6个地区,调查了大棚和露地烟粉虱越冬寄主及种群密度,以期明确福建省露地及设施蔬菜烟粉虱越冬规律,为烟粉虱的综合治理提供理论依据。共记录烟粉虱越冬寄主6科16种,主要包括栽培蔬菜花椰菜、番茄、茄子以及阔叶类杂草龙葵、小飞蓬、辣子草和胜红蓟。在露地花椰菜上,烟粉虱越冬虫口密度1月份显著高于2月份;花椰菜采后残株上的越冬虫口密度显著高于莲座期和花球形成期。在温室大棚中,休耕大棚中越冬虫口密度显著高于生产大棚。无论是蔬菜还是杂草,温室大棚中的越冬虫口密度显著高于露地。烟粉虱各虫态均可在各地温室大棚和漳州露地越冬,而在南平和三明等温度较低的地区以卵和伪蛹在露地越冬。在蔬菜上发现越冬烟粉虱有MEAM1隐种和MED隐种,温室大棚中两隐种数量分别为57只和111只,温室大棚可能有助于MED隐种定殖。室内耐寒性测定证实卵和高龄若虫比低龄若虫以及成虫更耐寒,烟粉虱在花椰菜、龙葵和辣子草上的世代存活率分别为83.7%、79.3%和81.6%,世代发育历期分别为18.9 d、16.7 d和18.8 d,龙葵和辣子草是烟粉虱适宜的越冬杂草寄主。综上,烟粉虱可在福建省露地越冬,温室大棚加重了烟粉虱的发生为害。  相似文献   

6.
Two tomato scions (cvs. ‘Raf’ and ‘Gorety’) were grafted on three different rootstocks: S. torvum, ‘Beaufort’ (Lycopersicum esculentum × Lycopersicum hirsutum) and intermediate grafting of eggplant ‘Cristal’ between tomato and S. torvum (double graft). Plants were grown in Mediterranean greenhouse conditions. The response to grafting was measured through growth parameters, Fv/Fm and leaf macronutrients analysis, and it was compared with non-grafted plants. The scions grafted on S. torvum in simple and double graft showed lower fresh and dry weight of leaves, number of commercial fruits, plant height, Fv/Fm and decreased their capacity to absorb several nutrients resulting in a lower mineral concentration in scions leaves, as a result of a thickened graft union. On the other hand, both scions showed a good response when grafted on the rootstock ‘Beaufort’, with which growth parameters, yield and photosynthetic capacity were similar to non-grafted plants.  相似文献   

7.
ABSTRACT

To better understand the mechanisms responsible for differences in uptake and distribution of cadmium (Cd), nutrient-solution experiments were conducted with different varieties of rice (Oryza sativa), ‘Khitish’ and ‘CNRH3’. The plants were grown in a complete nutrient solution with different levels of pCd (-log free Cd+2 activity) and pFe [-log free iron (Fe+2) activity]. The required concentrations of chelating agent and metals were determined using a computerized chemical equilibrium model such as Geochem-PC. Experimental treatments included a combination of four pCd activity levels (0, 7.9, 8.2, and 8.5) applied as Cd (NO3)2 4H2O, and two pFe activity levels (17.0 and 17.8) applied as FeCl3. The application of both Cd and Fe in solution culture significantly affected plant growth, yield, and Cd accumulation in plant tissue. In general, yield of rice was decreased by an increase in amount of solution Cd; however, yield response varied among the cultivars. At the 7.9 pCd level, yields of rice cultivars ‘Khitish’ and ‘CNRH3’ were reduced to 69% and 65%, respectively, compared with control plants. Root Cd concentrations ranged from 2.6 mg kg?1 (control plants) to 505.7 mg kg?1 and were directly related to solution Cd concentrations. In rice plants, Cd toxicity symptoms resembled Fe chlorosis. Differential tolerance of varieties to phytotoxicity was not readily visible, but a significant interaction of substrate Cd and variety was obtained from dry-matter yields. Significant interactions indicated that response of tissue Cd concentration, plant Cd uptake, and translocation of Cd to the aerial parts were dependent on variety as well as substrate Cd. Uptake of Cd by roots was significantly higher than by shoots. Higher Cd uptake by rice plants decreased the uptake of other beneficial metals.

The effect of Cd and Fe on the rate of phytometallophore release was also studied in the nutrient solution. Among the rice genotypes, ‘Khitish’ was the most sensitive to Cd toxicity. In both genotypes, with the onset of visual Cd-toxicity symptoms, the release of phytometallophore (PM) was enhanced. Among the rice varieties, ‘Khitish’ had the highest rate of PM release. Treatments with the metal ions studied produced a decrease in chlorophyll and enzyme activity. A decrease in concentrations of chlorophyll pigments in the third leaf was observed due to the highest activity level of Cd (pCd 7.9). Activities of enzymes such as peroxidase (POD) and superoxide dismutase (SOD) are altered by toxic amounts of Cd. Changes in enzyme activities occurred at the lowest activity of Cd (pCd 8.5) in solution. Peroxidase activity increased in the third leaf. Results showed that in contrast with growth parameters, the measurements of enzyme activities may be included as early biomarkers in a plant bioassay to assess the phytotoxicity of Cd-contaminated solution on rice plants. Evidence that Cd uptake and translocation are genetically controlled warrants the selection of varieties that assimilate the least Cd and that translocate the least metal to the plant part to be used for human and animal consumption.  相似文献   

8.
Abstract

The distribution patterns of dry matter and P in field‐grown tomato ‘Campbell‐37’, ‘Knox’, and ‘Tipton’, (Lvcopersicon esculentum mill), were determined from 25 days after emergence to harvest. Dry weight accumulation was about the same for the 3 cultivars up to 55 days after plant emergence. From 55 to 75 days, ‘Knox’ accumulated more total plant dry weight than either ‘Tipton’ or ‘Campbell‐37’, largely due to an accelerated fruit accumulation rate during this period. In the 75 to 105 day interval, dry weight accumulation by ‘Knox’ was less than ‘Campbell‐37’ or ‘Tipton’. Fruit accumulation, as indicated by fruit number increase, was during the 45 to 75 day period for ‘Knox’, the 55 to 75 day period for ‘Tipton’, and the 55 to 85 day period for ‘Campbell‐37’. ‘Knox’ and ‘Tipton’ had a faster fruit ripening rate than ‘Campbell‐37’. The total ripe fruit yields, for single and multiple harvests, were 36.7% and 28.6% respectively, higher in ‘Campbell‐37’ than in ‘Knox’. Phosphorus concentration of stem, leaf, and cluster tissues decreased over the season for the 3 cultivars. Phosphorus concentrations of leaves decreased from 0.49% to 0.16% as plant development progressed from seedling stage to ripe fruit harvest. Phosphorus in the vegetative portion of the tomato plant at final harvest represented only about 10% of the total P accumulated. The plant efficiency with respect to P accumulation decreased from an early stage of plant development as the relative growth rate of the plant declined.  相似文献   

9.
This study was conducted to examine the effect of inoculation of plant growth-promotion Rhizobacteria (PGPR) on phenological data, total yield and fruit quality characteristics of strawberry (Fragaria x ananassa Duch) cv. ‘Fern’ during 2006 and 2007. All bacterial root inoculations significantly increased yield per plant (1.98–20.85%), average fruit weight (3.05–19.26%) and first quality fruit ratio (10.30–32.05%) compared to control, whereas the bacterial inoculations did not affect leaf area, first flowering and harvest dates in strawberry cv. ‘Fern’. The bacteria also increased soluble solid content (SSC) and vitamin C in strawberry cv. ‘Fern’. The vitamin C contents of fruits ranged from 47.41 mg 100 g?1 (control) to 53.88 mg 100 g?1 (RC05), while SSC values varied between 10.16% (control) and 12.83% (RC01). Results of this study show that RC19 (Bacillus simplex), RC05 (Paenibacillus polymyxa), and RC23 (Bacillus spp.) have the potential to increase the yield and growth of strawberries.  相似文献   

10.
Three rice (Oryza sativa L.) varieties viz. ‘CR 683‘, ‘Budumoni’ “Budumoni”, and ‘Akisali’ were grown in sand culture in a greenhouse with three levels of iron (Fe) in nutrient solutions viz., 0.045 (control), 5.34, and 7.12 mM Fe to study the effects of iron on physiology of rice seedling growth. Shoot length, root, and shoot dry weights were reduced significantly by higher levels of Fe in the medium. Results of leaf bronzing have revealed higher bronzing score in the seedlings grown at 7.12 mM Fe in the growth medium. Occurrence of bronzing was severe in varieties ‘CR683’ and ‘Akisali’. Variety ‘Budumoni'maintained higher leaf chlorophyll content, nitrate reductase activity and total soluble protein in the leaves at 5.34 and 7.12 mM Fe. Higher concentration of iron in the nutrient medium exerted an inhibiting effect on the concentration and content of almost all the macro and micronutrients in the root and shoot. Higher Fe and nitrogen (N) contents and lower phosphorus (P), potassium (K), manganese (Mn), copper (Cu), and zinc (Zn) were determined in roots and shoots in plants grown in medium supplied with 7.12 mM Fe. The variety ‘Budumoni’ “Budumoni” performed relatively better in comparison to other tested varieties at 7.12 mM Fe in the growth medium. ‘Budumoni’ “Budumoni” can be considered a suitable rice variety to use in the rice-breeding programme for Fe toxicity tolerance in acid soils of Assam.  相似文献   

11.
A suitable application of the deep seawater for high quality eggplant (Solanum melongena L.) production was examined on vegetative growth and fruit yield with special reference to qualities of fruits. Mineral controlled deep sea water was prepared by electrodialyzing deep sea water with a selective membrane cartridge for the exchange of monovalent ions. Eggplant plants variety ‘Ryoma’ were grown in the NFT system with the applications of 2% mineral controlled deep sea water to the standard nutrient solution (mineral controlled deep sea water treatment-MDST) under greenhouse condition with four replications. With the treatment eggplant had larger vegetative growth rate than with the control. Furthermore, MDST showed that total fruit yield and marketable fruit yield was 14% and 23% higher than the control. In this study, a new methodology to produce high quality eggplants enriched in sugar, minerals, and dry matter was demonstrated by applying the natural resource.  相似文献   

12.
Abstract

A solution culture study was conducted to determine the effects of cadmium (Cd) application on Cd accumulation and growth of two durum wheat (Triticum turgidum L. var durum) cultivars. Arcola and DT618 were grown in nutrient solution for 13 days. Cadmium application to nutrient solution significantly (P ≤ 0.05) decreased root and shoot biomass, leaf area, leaf mass, total root length, and chlorophyll a and b concentration of the first leaf. The deleterious effects of Cd on plant growth were explained by a modified version of Weibull distribution function of the form, y = a.exp(b.√Cd), where ‘y’ is the growth parameter, ‘a’ is plant growth in the absence of Cd, and ‘b’ is reduction in growth with per unit increase in solution Cd. Total root length was decreased the most (80%) and chlorophyll b concentration of the first leaf decreased the least (9%) with per unit increase in solution Cd. Although the two cultivars were significantly different in some growth characteristics, both responded similarly to increase of Cd concentration in solution. Cadmium concentration in roots and shoots increased significantly (P ≤ 0.05) with Cd application, but due to concomitant decrease in growth the Cd content of plants remained constant at solution Cd concentrations of 5 μm or above. We concluded that seedlings of durum cultivars with different growth potential responded similarly to Cd application in nutrient solution.  相似文献   

13.
An experiment was conducted under greenhouse conditions to test the symbiotic performance and plant nutrient uptake of the twelve nationally registered chickpea cultivars (‘Çak?r’, ‘I??k-05’, ‘Can?tez-87’, ‘Hisar’, ‘Ya?a-05’, ‘Azkan’, ‘Küsmen-99’, ‘Gökçe’, ‘Damla-89’, ‘Diyar-95’, ‘Aziziye-94’, and ‘?zmir-92’) in Turkey. Inoculation with Mesorhizobium ciceri increased the average nodule number by 687%, nodule weight by 257%, plant height by 6%, shoot dry weight by 12%, root dry weight by 21%, chlorophyll content by 4.2%, nitogen (N)% by 7.9%, and total N by 22.7%. Averaged across chickpea cultivars, inoculation also significantly increased sulfur (S) by 14.4%, phosphorus (P) by 1.9%, magnesium (Mg) by 13.8%, potassium (K) by 6.2%, calcium (Ca) by 17.4%, copper (Cu) by 4.5%, iron (Fe) by 16.5%, manganese (Mn) by 10.9% and zinc (Zn) uptake by 9.4%. The macro- and micronutrient uptake of cultivars significantly correlated with their nitrogen content and the magnitude of response to inoculation in relation to nodulation, plant growth, nitrogen fixation, and nutrient uptake significantly varied among cultivars. Based on the amount of fixed N and plant nutrient uptake, ‘Azkan’, ‘Aziziye-94’, ‘Küsmen-99’, ‘Diyar-95’, and ‘Hisar’ were the genotypes with the most positive response to inoculation. Our data showed that nodulation, nitrogen fixation, plant dry matter production, and macro- and micronutrient uptake of the inoculated chickpea can be improved by selecting the best compatible cultivar.  相似文献   

14.
Potent bacterial strains effective against the whitefly, Bemisia tabaci, nymphs (second instar), were isolated from tomato cultivated fields at Fayoum governorate, Giza, Egypt. Of 72 isolates, 12 with the most morphologically distinct-looking bacterial colonies were selected and named A1, A2, A3, A6, A7, A9, A12, A13, A107, B37, B45 and B100. All isolates were preliminarily identified as members of the genus Bacillus based on morphological, physiological and biochemical characteristics. When tested for their pathogenicity against Bemisia tabaci, the 12 isolates revealed varying efficiencies with isolates A1 and A9 being superior, exhibiting maximum mortality of 92.2 and 90.8% on day 10, respectively. Isolate A7 recorded the lowest percentage at 18.3%. Further genetic characterization of the 12 isolates was performed using inter simple sequence repeat (ISSR), randomly amplified polymorphic DNA (RAPD) and 16S rDNA gene sequencing analysis. RAPD and ISSR results confirmed each other. The combined ISSR and RAPD phylogenetic tree showed two major clusters. With 16S rRNA gene analysis, isolate A1 and A12 sequences recorded 100% identity with Bacillus thuringiensis, while isolates A7 and B100 showed 95.7% and 95.6% identity with Bacillus cereus and Bacillus sphaericus, respectively.  相似文献   

15.
Abstract

A field experiment was conducted during two consecutive growing seasons (2013 and 2014) to evaluate the effects of inoculations with Rhizobium and Azotobacter on the growth and yield of two chickpea (Cicer arietinum L.) varieties under saline (5.8 dS m?1) arid condition. The single treatment of either Rhizobium or Azotobacter exhibited to promote the growth of chickpea to some level, however, co-inoculation produced more effects and increased the shoot dry weight (30.3 and 26.4%), root dry weight (17.5 and 26.3%), nodule number (79.1 and 43.8 piece per plant), nitrogen content in roots (9.62 and 10.9%), in shoots (12.6 and 8.3%) and seed protein (7.1 and 4.3%) in both Flip06-102 and Uzbekistan-32 chickpea varieties compared to the control. Our studies showed that the highest yield response of 429 (27.9%) and 538 (23.9%) kg?ha?1 over the control was revealed by the co-inoculation with Rhizobium and Azotobacter inoculants in Flip 06-102 and Uzbekistan-32, respectively. A new introduced Flip 06-102 chickpea variety was more salt tolerant and had higher root nodulation than the local Uzbekistan-32 chickpea variety. Nitrogen (N), phosphorus (P), and potassium (K) contents in the shoots and roots were significantly (p?Rhizobium plus Azotobacter could be applied to improve the vegetative growth and yield of chickpea and to alleviate the effects of salt stress.  相似文献   

16.
Most beetroot (Beta vulgaris) cultivars in South Africa are exotic and were specifically bred for root-knot (Meloidogyne species) nematode populations in their countries of origin. Due to the widespread distribution of different Meloidogyne species and races, exotic cultivars should be matched with nematode populations in importing countries. The objective of this study was to determine the interrelations between exotic beetroot cultivars ‘Detroit Red Dark’ and ‘Crimson Globe’ with Meloidogyne species in the predominant beetroot-producing regions in South Africa. Different inoculum series of M. incognita and M. javanica were used on the two beetroot cultivars. At 56 days after initiating the treatments, roots of both cultivars had small undeveloped root galls, with the reproductive factor values of M. incognita on ‘Detroit Dark Red’ being above and below unity at low (≤125 inoculation) and high (≥250 inoculation) nematode levels, respectively. Growth of ‘Detroit Dark Red’ was significantly stimulated and inhibited at low and high nematode infection levels, respectively. In contrast, RF values for M. javanica on ‘Crimson Globe’ were below unity, without any significant effects on plant growth. In conclusion, ‘Detroit Dark Red’ was tolerant to M. incognita, whereas ‘Crimson Globe’ was resistant to M. javanica.  相似文献   

17.
The identification of suitable crop varieties that respond best to organic management is the key to achieving better crop yields. A field experiment was conducted during the winter season of 2005–2006 and 2006–2007 at Almora (Indian Himalayas) to evaluate the performance of five varieties of garden pea (Pisum sativum L.) and changes in the soil properties under organic and integrated nutrient management (INM) systems. The yield reduction under organic management was 14.4% in 2005–2006 and 10.1% in 2006–2007 compared with INM. Among the garden pea varieties ‘Vivek Matar 9’, ‘Vivek Matar 8’ and ‘Azad pea 1’ produced similar but significantly higher pod yield compared to other varieties. The soil pH, organic carbon, and microbial activities in terms of dehydrogenase and phosphatase (acid and alkaline) were higher in the plots under organic management compared to INM. The latter, however, had higher activity of urease, and N, P, and K contents in soil. We conclude that at least 15–20% price premium for organic garden pea may be required to offset the higher cost of cultivation and low yields under organic production system. Among the garden pea varieties, ‘Azad pea 1’, ‘Vivek Matar 8’ and ‘Vivek Matar 9’ were found suitable for organic cultivation.  相似文献   

18.
Urban land disturbance degrades physical, chemical, and biological soil properties by removing topsoil and compacting the remaining subsoil. Such practices create a soil environment that is unfavorable for vegetation establishment. A 3-year field study was conducted to compare the effects of various one-time compost application treatments on soil properties and re-vegetation of a disturbed soil. A disturbed urban soil received the following treatments: (1) inorganic fertilizer; (2) 2.5-cm-depth surface-applied compost; (3) 2.5-cm-depth incorporated compost; (4) 5.0-cm-depth incorporated compost; (5) inorganic fertilizer plus 0.6-cm compost blanket; and (6) inorganic fertilizer plus straw mat cover. The plots were seeded with a mixture of tall fescue Festuca arundinacea Shreb.: ‘Magellan,’ ‘Coronado Gold,’ ‘Regiment,’ and ‘Tomcat,’ perennial ryegrass Lolium perenne L. ‘Linn’, and Kentucky bluegrass Poa pratenis L. ‘Baron.’ Soil chemical and physical attributes and plant growth and quality parameters were measured during 840 days following study establishment. Soil C, N, P, K, Ca, and Mg, and turfgrass growth and quality were increased and soil bulk density was reduced by amending with composts. Incorporation of compost into soil improved soil and plant attributes more than unincorporated surface application, but the differences diminished with time. Compost benefits increased with time. One-time applications of compost can provide immediate and long-term benefits to soil and plant attributes, but there may be no need to incorporate the compost into soil, particularly if the soil has recently been loosened by tillage.  相似文献   

19.
ABSTRACT

Growth responses of potted ornamental crops to municipal biosolids in the semiarid southwestern USA are not adequately known. In 10- to 11-wk greenhouse pot studies, we evaluated the effects of dried biosolids-amended growing media on four ornamental crop species: Garden chrysanthemum (Dendranthema Xgrandiflorum ‘Megan’), butterfly bush (Buddleia davidii ‘Nanho Blue’), Japanese honeysuckle (Lonicera japonica ‘Purpurea’), and blanket flower (Gaillardia Xgrandiflora ‘Goblin’). The biosolids were composted without bulking agents (100% sewage sludge) and incorporated into growing media at rates ranging from 0 to 593 kg m?3, or 0 to 72% by volume. Biosolids increased substrate pH from 5.8 to 7.2 and electrical conductivity (EC) from 2.6 to 47.3 dS m?1. Any addition of biosolids (≥30 kg m?3) reduced total plant dry matter (DM) of chrysanthemum. Conversely, shoot DM of blanket flower and butterfly bush increased by four- to five-fold at biosolids rates of 59 to 148 kg m?3 (7 to 18% by volume) with corresponding increases in shoot N and P concentrations. Biosolids rates higher than 148 kg m?3 reduced top growth of the latter two species and of Japanese honeysuckle. For all species, growth reductions with excessive biosolids rates likely resulted from osmotic stress and specific NH4 toxicity. However, based on the substantial growth stimulations at moderate biosolids rates, xeric and salt-adapted species, such as blanket flower and butterfly bush, may be ideally suited for expanding the use of highly saline biosolids at semiarid nursery production sites.  相似文献   

20.
ABSTRACT

The effect of salinization of soil with Na2SO4, CaCl2, MgCl2, and NaCl (70:35:10:23) on the biochemical characteristics of three wheat (Triticum aestivum L.) cultivars (‘LU-26S,’ ‘Sarsabaz’ and ‘Pasban-90’) was investigated under natural environmental conditions. Twenty-day-old seedlings of all three cultivars were subjected to three salinity treatments: 1.3 (control), 5.0, and 10 dSm?1 for the entire life period of plants. After 120 d of seed sowing, plant biomass production decreased by 49% and 65%, respectively, in response to 5 and 10 dSm?1 salinity levels. Addition of salts to growth medium also had a significant adverse effect on plant height. Increasing salinity treatments caused a great reduction in nitrate reductase activity (NRA) of the leaf. The inhibitory effect of salinity on nitrate reduction rate was more pronounced at the reproductive stage than at the vegetative stage of plant growth. Wheat cultivars ‘LU-26S’ and ‘Sarsabaz’ showed less reduction in NRA due to salinity compared with ‘Pasban-90.’ Ascending salinity levels significantly reduced potassium (K+) and calcium (Ca2+) accumulation in shoots, while the concentration of sodium (Na+) was increased. Salts of growth medium increased the shoot nitrogen (N) concentration, whereas phosphorous (P) concentration of shoots was significantly reduced due to salinity. Wheat cultivars ‘LU-26S’ and ‘Sarsabaz’ proved to be the salt-tolerant ones, producing greater biomass, showing less reduction in NRA, maintaining low sodium (Na+), and accumulating more K+ and Ca2+ in response to salinity. These two cultivars also showed less reduction in shoot K+/Na+ and Ca+/Na+ ratios than in ‘Pasban-90,’ particularly at the 10 dSm?1 salinity level.  相似文献   

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