三唑类杀菌剂对苹果锈病的防效及作物安全性评价

以苹果锈病(Gymnosporangium yamadai)为试材,采用田间试验,研究了6种三唑类杀菌剂不同浓度不同施药时间对苹果锈病的田间防治效果及作物安全性的影响,以期为苹果锈病的安全高效防控提供参考依据。结果表明:腈菌唑的防治效果及安全性均表现优良,预防试验中,40%腈菌唑EC 2 000倍和4 000倍于幼果期第2次药后10 d保护苹果叶片不受G.yamadai侵染的防治效果均达98%以上,治疗试验中,果实膨大期第4次药后16 d抑制叶片病斑扩展的防治效果为90.89%和87.17%。作物安全性试验结果表明,供试药剂不同浓度于花芽露红期到果实膨大期施用,对苹果叶片、枝梢、花和果均无药害产生,果面无畸形和果锈。于花芽露红期到果实膨大期施药,只有10%苯醚甲环唑DC 2 000倍和40%腈菌唑EC 4 000倍的单果质量与对照差异不显著,其它各处理均下降9%以上。果实膨大期开始施药,供试药剂处理均未对果实生长产生显著影响。     

Einfluss verschiedener Ausdünnverfahren auf die Source: Sink-Verh?ltnisse und Fruchtqualit?t von Zwetschen

Chemical thinning agents for stone fruits are scarce. Hence, the objective of the present work was to improve fruit quality,viz size in plum, using mechanical and chemical thinning or combinations thereof; untreated, i.e., un-thinned plum trees of the same rows served as control. Plum trees of the medium-sized cv. ‘Ortenauer’ on dwarfing St. Julien GF 655/2 rootstock, with maximum flower intensity in 2009, were grown near Bonn, Germany. Trees were mechanically thinned in April 2009 with the blossom thinner developed by the University of Bonn with 300, 400 or 500?rpm at a tractor speed of 5?km/h. Half of the trees were additionally chemically thinned with both ammonium thiosulphate (ATS) (15?l/ha) at full bloom and an ethylene releasing compound (0.375?l/ha) 35 days after full bloom. The objective of 1/3 flower i.e. fruitlet removal was successfully achieved even with the slowest rotor speed of 300?rpm. The number of fruit per metre fruiting spur was reduced from 46 to 18–27, equivalent to a (source: sink) leaf: fruit ratio of 5:1. Mechanical thinning significantly enlarged fruit mass from 28?g in the un-thinned control to 30–32?g with rotor speeds of 400 or 500?rpm. Additional chemical thinning with ATS and an ethylene-releasing compound resulted in no further increase in fruit mass. Inner fruit quality (sugar) of the plums appeared unaffected by either mechanical or chemical thinning, except for fruit firmness. Plums thinned with an ethylene releasing compound were softer and ripened earlier than respective control fruit, possibly due to the ethylene release. The lesser fruit density per tree after thinning reduced the potential for fungal infections such asMonilia due to faster drying of the fruits after precipitation. Mechanical thinning reduced thinning by manual labour from 31?min. per tree in the un-thinned control to 24?min. by ca 25%, i.e., by 7?min. per tree; this is equivalent to a net financial gain of 400–500?€/ha, after expenditure (120?€/ha; 1.5?h/ha), for thinning. Overall, both efficacy of blossom removal and fruit mass enlargement scored best after mechanical thinning around 400?rpm, indicating that mechanical blossom thinning provides a suitable alternative for chemical and/or manual thinning or can be combined with either of those options. An additional advantage of mechanical blossom thinning is to overcome or avoid alternate/biennial bearing due to its early application at bloom time; a similar effect was observed with the ethylene-releasing compound applied 35 days after full bloom.     

Pollen tube growth in styles of apple and almond flowers after spraying with pesticides

Summary

The timing of fungicide and antibiotic applications in fruit crops often overlaps flowering and pollination. Numerous studies report detrimental effects of chemical applications on pollination, fruit set and yield. However, field results can be quite variable even when similar compounds are tested on the same crop. Problematic is that field variables unrelated to the effects of pesticides on reproductive activities can mask results. In the current study, we specifically investigated the effects of selected pesticide sprays applied to stigmas, on subsequent pollen germination and tube growth. Using two model systems, apple and almond, sprays were applied to detached emasculated flowers under constant laboratory conditions using an electronically controlled robotic apparatus which simulated a field sprayer. flowers were pollinated at specific times after spraying, and pollen tube numbers and growth assessed using fluorescence microscopy. The pesticides evaluated were for apple: captan, myclobutanil and streptomycin; and for almond: azoxystrobin, myclobutanil, iprodione and cyprodinil. In apple, captan significantly reduced pollen germination, by 20% compared with water controls when pollination was conducted 18 h after treatment. The number of tubes that reached the basal part of the style within 20 h was not affected. In contrast, myclobutanil and streptomycin had no significant effect on pollen tube growth. With almond, none of the sprays significantly affected pollen germination or tube growth.     

The native pollinators of an apple orchard: variations and significance

Observations on native and domestic insect pollinators were carried out during the blossom period from 1978 to 1980 in a semi-dwarf apple orchard in Ontario. Weather conditions and numbers of blossoms per tree were also recorded. Apis mellifera was the most frequent pollinator for all years. The Anthomyiidae (Diptera) ranked second for 1978 and 1979, but in 1980 the Andrenidae and Halictidae were of greater importance than the Diptera. The efficiency of the pollinators was determined by analysis of the pollen carried on their bodies. Hymenoptera had more pollen on their bodies than the Diptera. Among the Hymenoptera, the Andrenidae and the pollen-gathering Large Andrenidae had the greatest amount of fruit pollen on their bodies. Among the Diptera, the Syrphidae had the greatest amount of fruit pollen. The effectiveness of the pollinators was evaluated by measuring fruit set, seed set and the effective pollination period. There was no significant difference in fruit set between years inspite of adverse weather in 1979. Native insects were important pollinators, particularly in unfavourable weather.     

Influence of Alternative Copper Fungicide Formulations on Copper Content in Apple Fruits

Field trials were carried out from 2008 to 2011 at Maribor, Slovenia to determine the effect of new copper fungicide formulations on the copper content in apple fruits, separated in peel and flesh, of seven cultivars at harvest. Apple trees were treated 12?C18 times per season with formulations based on copper oxychloride or sulphate (trial standards), copper hydroxide and their complexes or chelates with amino acids, peptides, EDTA, urea, and octanoic or gluconic acids at the same rate of 200?g of pure copper ions (Cu²⁺) per hectare irrespetive of the product. Copper formulations were applied with Teejet 800067 flat fan nozzles mounted on a vertical boom of the sprayer, which gave a droplet volume median diameter (VMD) of 120 microns and 130?C180 droplet impacts per square centimeter, as determined on water sensitive papers. The new formulations of copper in the form of salts of fatty acids or organic complexes or chelates had a higher penetration rate into apple fruit tissue than the traditional formulations based on Cu-hydroxide, Cu-oxychloride and Cu-sulphate. The copper content in the fruit depended on the ratio between copper solubility in the formulation, rate of penetration into the fruit and stability of the copper fungicide deposit on the fruit surface. Despite being applied at lower hectare rates, frequent applications led to the exceeding of the permitted EC maximum residue level of 5?mg/kg fresh mass (FM). MRL was most often exceeded with the application of formulations based on Cu-octanoate and Cu-gluconate and less often in case of the application of complexes of copper with amino acids, peptides or urea. A comparison of the copper content between different cultivars showed that cv. ??Jonagold??, ??Golden Delicious?? and ??Elstar?? accumulated more cooper than other cultivars. Copper concentrations in the peel exceeded that of the flesh at least twice. The potential effects of accumulation of copper in woody tissue of bearing shoots after long-term application of highly systemic copper formulations on growth and blooming of apples are discussed too. Some apple growers may not be aware of much higher penetration rate of these new copper products (fungicides, fertilisers or plant strengtheners) and should be warned about the necessity to adapt their spraying schedules despite applications of a low hectare rates of copper, i.e. the number of treatments and proper seasonal timing, to avoid exceeding of EU MRL of copper in fruit.     

Inducing Precocious Cropping On Young Dr. Jules Guyot Pear Trees with Gibberellic Acid

A single spray of gibberellic acid (GA) at blossom time doubled the final set and yield of 4-year-old Dr. Jules Guyot trees without reducing the fruit size. GA affected the fruit shape, but this was detrimental only at a high concentration (100 p.p.m.) ; it also hastened fruit ripening by about a week and increased the percentage of seedless fruits. Although a heavy spray at 50 p.p.m. had the most effect, a light spray at the same concentration was more effective in conserving the plants’ resources by avoiding the early development of an excessive number of fruitlets prior to the June drop.

The total shoot growth, the number of shoots and buds, and the girth increment were reduced by GA at 50 p.p.m. applied as a heavy spray but the mean length of shoots and internodes remained unaffected.     

Biology of Some Predatory Insects and Mites Associated With the Fruit Tree Red Spider Mite (Metatetranychus Ulmi (Koch)) in South-Eastern England: I. The Biology of Blepharidopterus Angulatus (Fall.) (Hemiptera-Heteroptera,Miridae)

Fungicide programmes, designed to control both scab and mildew, have been compared for phytotoxicity in several seasons on apple and pear varieties. Dodine acetate was found to cause russeting of the fruits of several apple and pear varieties. In one year, frost at a spraying time seemed to interact with dodine acetate application to produce unusual russet on Sunset apples. Crops of Conference and of Doyenne du Cornice pears were reduced in some years when dodine was applied.

The fungicide based on nitrated octylphenols, DNOPC, caused no undesirable effects on the apple varieties, but tended to reduce cropping on pears; the effects of the unesterified mixture, DNOP, were more serious.

Both dodine acetate and DNOPC caused reductions of fruit bud formation on Cornice, an effect already reported for organomercurial fungicides on Conference and for didecyldimethylammonium bromide (DDAB) on both varieties. It is suggested that freedom from this effect should be a criterion to be satisfied in the evaluation of any new pesticide for pears.     

两种钙的抑制剂对苹果幼果发育及果肉细胞超微结构的影响

以红富士苹果果实为试材,在盛花后30d以内,分3次向幼果中引入EGTA和LaCl3,研究了两种钙的抑制剂对果实细胞超微结构和果实生长的影响。结果表明,EGTA主要是在盛花后20d以前影响果肉细胞形态建成,导致细胞扭曲变形;而La3+是在盛花后20d以后,细胞开始扭曲变形,盛花后10d,质体上开始出现淀粉粒,盛花后30d,质体上淀粉粒明显增多。两种抑制剂对幼果发育有不同程度的影响。LaCl3处理,对幼果发育有抑制作用,其中,花后20d处理,抑制效应最强。花后20dEGTA处理,对果实的横径生长有一定的促进作用,其它两次处理,则表现出对幼果生长的抑制效应。     

Assessment of Potential Organic Pollenicides as Apple Blossom Thinners

Abstract

The potential of six products to act as pollenicides on apple pollen both in vivo and in vitro was evaluated. The six candidate pollenicides used were lime sulphur (LS) (1.15% solution), ammonium thiosulphate (ATS) (0.75% solution), Surround? WP (S) (59.2 g/L), biodiesel (BD) (5% emulsion), sodium chloride (NaCl) (8 g/L) and Horticultural-Vinegar (HV) (2% solution). It was found that ‘Golden Delicious’ blossoms that were treated with ATS, LS, S or NaCl had significantly fewer pollen grains that germinated in vivo than the treatment receiving no spray. The effect of the six candidate pollenicides was also investigated in vitro by spraying ‘McIntosh’ pollen with the candidate pollenicides and examining pollen germination, pollen tube growth length and the proportion of unviable pollen grains. All of the treatment sprays significantly reduced pollen germination compared with the control, with ATS and LS resulting in considerable reduction in pollen tube germination and HV completely hindering germination. Among those treatments that allowed some germination, only LS, ATS and BD effectively reduced the mean length that the pollen tubes grew in vitro. These laboratory results are compared with those generated in a parallel field trial to assess what stage of pollination the candidate pollenicides are targeting. Taken together these results indicate that ATS reduces pollen viability and germination on pollinated stigmas and on germination medium and is an effective blossom thinner in the field. Lime sulphur has a greater effect on pollen tube germination and growth on germination medium and is a good thinner in the field and that NaCl reduces pollen germination on pollinated stigmas and is an effective mild thinner in the field. Finally, this research suggests that while BD was an effective thinner in the field, it has less pollenicidal and greater phytotoxic effects than the Other products tested.     

Biology and control of the apple canker fungus Neonectria ditissima (syn. N. galligena) from a Northwestern European perspective

A review of apple canker caused by Neonectria ditissima is presented for Northwestern Europe with a focus on the Lower Elbe region (Northern Germany). Whereas conidia released by rainsplash are produced mainly from spring to autumn, the liberation of wind-borne ascospores peaks in autumn and/or early spring. Infection occurs via natural as well as pruning-induced wounds, some of which are present throughout the year. Autumnal leaf scars are the most frequent entry point for N. ditissima. Wounds on tree trunks, especially bark cracks in the crotch regions, are potentially even more serious because cankers on trunks and leader shoots commonly cause the total loss of a tree. Surface moisture is a prerequisite for leaf scar infections but possibly not for an entry through other wounds. Irrespective of the entry route, successful infection of a wound requires a mass inoculum of at least 50–100 conidia or ascospores. Infections of trees originating in nurseries may enter a state of latency from which they can break out up to 3 years after the trees have been explanted into the production orchard. Streaks of brown wood discolourations can be caused both by systemic colonisation of the xylem by N. ditissima and by winter frost damage. Apple varieties may show pronounced differences in their sensitivity to canker. For highly susceptible varieties, this disease can be a major production-limiting factor. Flower infections by N. ditissima commonly lead to a pre-harvest rot at the blossom end of the fruit, whereas infections of the growing fruit before harvest lead to a storage rot. Rigorous pruning is an essential canker control measure. Chemical control during the growing season is achieved by apple scab fungicides such as dithianone, captan or dodine. At leaf fall and in winter, copper fungicides are indispensible for controlling canker on highly susceptible varieties in Northern Germany.     

抗病诱导剂与杀菌剂混合处理对马铃薯晚疫病的防治效果

采用菌丝生长速率法和孢子囊萌发抑制法测定β- 氨基丁酸（BABA）、苯并噻二唑（BTH）、水杨酸（SA）和茉莉酸甲酯（MJ）4 种抗病诱导剂对马铃薯晚疫病菌菌丝生长和孢子囊萌发的影响,通过盆栽试验筛选出最佳药剂和适宜浓度,将抗病诱导剂与杀菌剂混合进行大田试验。结果表明：离体条件下,4 种抗病诱导剂对马铃薯晚疫病菌的菌丝生长和孢子囊萌发无抑制作用;盆栽试验中,4 种抗病诱导剂处理能够导致马铃薯植株晚疫病病情指数下降和产量增加,且随浓度增加,晚疫病抗性增强,其中BABA 诱导抗病效果最好,适宜浓度为50 μg · mL-1,防效为64.83%。田间试验结果显示,与单独使用化学杀菌剂相比,BABA与杀菌剂混合处理效果更好,晚疫病最终防效高达81.28%,产量为2 911.08 kg ·（ 667 m²）^-1。以上结果说明：BABA 能够较好地诱发马铃薯对晚疫病的抗病性,田间防治推荐将化学杀菌剂与抗病诱导剂BABA 联合使用。     

Application of ammonium thiosulfate for blossom thinning in apples

The efficacy of ammonium thiosulfate (ATS) in blossom thinning was investigated as a function of concentration, drying time and flower development stage at the time of treatment. In 2-year-old crabapple trees, flower damage caused by ATS, applied at a concentration of 10 g/l, increased as the drying time of the ATS spray increased. Approximately 40% of flowers were damaged when the ATS spray dried in 30 min, significantly less than the 80% damage observed when the drying time was 71 min. Application of ATS at 2% resulted in high levels of flower damage regardless of drying time. Fully developed open flowers were more susceptible to ATS damage than closed flowers. Ethylene does not appear to have a major role in mediating the thinning activity of ATS, as the levels of flower and leaf damage were unaffected by the use of an ethylene inhibitor. In ‘Jonagold’ apples, ATS at either 5 or 10% provided excellent thinning but was phytotoxic unless washed off the trees. The effects of drying time and flower development stage on ATS activity can be countered by applying ATS at a concentration of 5% at petal fall then washing the tree with water within 1 h of application to avoid excessive thinning and leaf damage.     

Effect of crop load,fruit position and shoot vigour on yield and quality of Annona atemoya × Annona squamosa in India

The effect of crop load, position of the fruit on the shoots and vigour of the shoots on yield and quality of Annona atemoya × A. squamosa hybrid ‘Arka Sahan’ was investigated in India over two years. The trees were hand-pollinated and thinned to 20, 40, 60, 80 or 100 fruit after fruit set. Information was collected on total and marketable yield, yield efficiency, average fruit fresh weight, peel weight, the number of seeds per 100 g of pulp, pulp content in the fruit, total soluble solids (TSS) and total titratable acidity. In other experiments, fruit were harvested from weak, medium or vigrous shoots, or from basal, middle or apical nodes. Total yield increased up to 60 or 80 fruit per tree and marketable yield increased up to 60 fruit per tree. Average fruit weight and peel weight increased as cropping increased. These results suggest that optimum productivity and quality is associated with 60 fruit per tree or 0.17 to 0.19 kg cm² trunk-cross sectional area. The quality of the fruit in different positions on the shoots or on the different types of shoots was highly variable and generally not affected by the various treatments.     

Influence of leaf blight on yields in geranium Pelargonium graveolens

Summary

Experiments were conducted during 1993 and 1994 at Bangalore, India, to estimate the reductions in yield of essential oil caused by leaf blight (Colletotrichum gloeosporioides (Penz.) Sacc.) on three geranium (Pelargonium graveolens (L.) Herit) clones. Leaf blight resulted in smaller reductions in oil yield in an Algerian-type (Kd) clone than a Reunion-type (Lo) and an Egyptian-type (Eg) clone. The results indicate that even expensive disease management practices can be recommended for management of leaf blight on the Lo and Eg clones in regions where leaf blight is prevalent, because increases in severity of leaf blight may cause considerable economic loss. Such measures, however, may not be economically viable for the Kd clone.     

The relationship between different spray combinations of certain fungicides with calcium nitrate and the incidence of bitter pit and fungal diseases of apple

Two apple cultivars, Cox’s Orange Pippin and Worcester Pearmain, were sprayed at high volume for scab control in two seasons with either captan or thiram, with dinocap to control mildew. On Worcester, it was confirmed that thiram reduced crop and increased fruit russet and bitter pit incidence; the proportion of misshapen fruits was also increased. On Cox, thiram reduced crop number, without any compensatory increase in weight, and provided inferior scab control as well as increasing fruit russet.

The application of commercial calcium nitrate (C.C.N.) four times between mid-June and mid-August led to a considerable reduction in the incidence of bitter pit and storage rots in fruits from trees sprayed with captan and dinocap; it also partially offset the greater incidence of bitter pit associated with thiram treatments. In contrast to this, the application of a similar total amount of calcium, either in the form of a standard lime sulphur programme or by adding C.C.N, to the organic fungicide programmes for scab control, i.e. from April to mid-July, failed to reduce the incidence of bitter pit on either cultivar. Neither C.C.N, programme affected cropping, fruit russeting or scab control on either cultivar.

The ratio of potassium to calcium was higher in leaves and fruits from Worcester trees receiving thiram than in those from trees receiving captan; the application of C.C.N, in the summer reduced this ratio in fruits from trees receiving captan but not in those from trees receiving thiram, although it reduced the incidence of bitter pit associated with both fungicide programmes.

Results on Cox show that fungicide deposition and control of scab were independent of fungicide formulation and of the presence or absence of C.C.N. ; mildew control was not affected when C.C.N, was applied as the recommended summer programme.     

Effect of tebuconazole-tolerant and plant growth promoting Rhizobium isolate MRP1 on pea–Rhizobium symbiosis

Seed dressing with fungicides adversely affects the structure and function of beneficial soil microbial communities and consequently crop yield. This study was aimed to evaluate the impact of technical-grade fungicide tebuconazole on plant growth promoting potentials of tebuconazole-tolerant Rhizobium isolate MRP1. The performance of the isolate MRP1-inoculated pea plants grown in tebuconazole treated soils was also assessed. Generally, the three concentrations [100 (recommended dose), 200 and 300 μg kg⁻¹ soil] of tebuconazole when used alone, adversely affected the growth, symbiosis, grain yield and nutrient uptake by pea plants. Concentration dependent phytotoxicity of tebuconazole was observed for all the measured parameters. On the contrary, fungicide tolerant Rhizobium sp. MRP1 in the presence of fungicide increased the measured parameters at all tested concentrations. As an example, when inoculant MRP1 was also used with 300 μg tebuconazole kg⁻¹ soil, it substantially increased the root nitrogen, shoot nitrogen, root P, shoot P, seed yield and grain protein by 20, 19, 50, 31, 15 and 7%, respectively, when compared with uninoculated plants grown in fungicide-treated soils. The study suggests that the plant growth promoting Rhizobium sp. MRP1 can be used as bacterial inoculant to increase the production of pea in soils polluted with fungicides.     

The influence of fungicides and gibberellin (A4+7) applications on russet control of ‘Golden Delicious’ apple fruit

Summary

Various fungicides, gibberellins (A₄₁₇) and their mixtures were tested for the control of russet of ‘Golden Delicious’ apple fruit in the major apple-growing area in Israel. Four foliar applications of captan, metiram, the strobilurins kresoxim-methyl, trifloxystrobin, azoxystrobin, or the polyoxin B compound Polar from the green tip stage to the end of the petal fall stage gave similar reductions in russeting, compared with the controls, but none eliminated it. Tank mixtures of the gibberellins (A₄₁₇) Regulex and Perlan with captan, each at full rate, did not improve russet control, compared with each component alone at the same rate. Similarly, both captan and trifioxystrobin, and the gibberellin (A₄₁₇) Cytolin or their mixtures at full rates provided similar significant level of control of russet on fruit. Fruit in the upper part of the tree had significantly more russet than fruit in the lower part of the tree, regardless of treatment applied. In addition, russet was more severe on fruits of trees grown in the west side of the row, than those of trees grown on the east side. Data suggest that factors other than fungicides, which may act by reducing russet-inducing microorganisms, may be involved in russet development.     

Comparison of sampling strategies for determining fruit mineral concentrations in ‘Hass’ avocado (Persea americana Mill.)

Summary

Spatial and temporal variation in mineral and dry matter (DM: % dry weight) concentrations were examined in ‘Hass’ avocado (Persea americana Mill.) fruit to identify sampling strategies for examining fruit mineral, DM and fruit quality relationships. Calcium (Ca), magnesium (Mg), potassium (K), and DM concentrations were compared from different parts of the same fruit, from fruit harvested from different shoot types and locations within the same tree, and at different stages during the growing season, from fruit set to commercial harvest. The main source of variation within fruit was longitudinal, with K and DM concentrations being higher at the distal end of the fruit. Sampling methods based on equatorial plugs of tissue provided the best estimates of whole fruit values for DM and mineral nutrients. While there was much variability in the internal distribution of minerals within the fruit, the distribution was the same for fruit from both the northern and southern aspects of the tree. During the first 4 months after fruit set, fruit from determinate floral shoots (i.e., with a flower in the terminal position) had higher Ca and Mg concentrations than fruit from indeterminate shoots (i.e., with a shoot in the terminal position). After this time, fruit Mg and Ca concentrations were higher on indeterminate shoots, possibly because of changes in sink-strength and increased transpirational flow associated with new leaf growth on indeterminate shoots. The data showed that shoot type was a source of fruit-tofruit variability in an avocado crop, and that care should be taken in sampling fruit tissues for nutrient analyses.     

Effects of grafting height of MM106 rootstock on growth,lateral shoot formation and yield in apple trees

Summary

Between 2004 and 2008, the effects of different grafting heights on sylleptic shoots were tested in the apple (Malus domestica Borkh.) cultivars ‘Granny Smith’ and ‘Gloster’, and cumulative fruit yields were evaluated. MM106 apple rootstocks were grafted 10, 20, 40, or 60 cm above soil level in August 2004. The results showed that an increased grafting height significantly decreased tree height in both cultivars. The tallest and shortest trees were observed at grafting heights of 10 cm (153.0 and 170.0 cm) and 60 cm (141.3 and 143.5 cm) in ‘Granny Smith’ and ‘Gloster’, respectively.Among the various grafting heights tested, 60 cm in ‘Granny Smith’ and 20 cm in ‘Gloster’ gave the largest stem diameters (17.6 mm and 16.8 mm, respectively). The number of lateral shoots increased significantly with increased grafting height in both cultivars. The largest numbers of lateral shoots in ‘Granny Smith’ (10.75) and ‘Gloster’ (2.00) were obtained from a grafting height of 60 cm, while 2.55 and zero lateral shoots occurred at 10 cm grafting height in ‘Granny Smith’ and ‘Gloster’, respectively. Shoot lengths decreased significantly by increasing the grafting height. Grafting heights of 10 cm and 60 cm resulted in the tallest and shortest shoots in both cultivars. Cumulative fruit yields were significantly affected by grafting height in both cultivars. The highest yield was found for a 60 cm grafting height in both ‘Granny Smith’ (11.295 kg tree^–1) and ‘Gloster’ (4.818 kg tree^–1).The results of this study suggest that grafting heights of 40 cm and 60 cm have the potential to promote branching and early bearing for apple fruit production in sustainable and organic agricultural systems.     

荔枝年生长周期内N、P、K营养动态规律与施肥管理体系

通过3年大田试验探索荔枝年生长周期内N、P、K营养规律,验证由高氮、高磷钾、高钾复合肥组成的荔枝平衡施肥管理措施的适用性。结果表明,荔枝年生长周期内,收获期N、P、K营养水平降至最低,随后因施肥而迅速恢复,在秋梢老熟到花芽分化期达年周期内最大值,此后随着开花结果N、P、K营养水平逐渐下降,至新的收获期又降至最低水平。秋梢和果枝的N、P、K水平因生长期的不同而明显变化,然而肥料用量(3～5kg/树)和N∶P∶K比例对树体N、P、K水平的影响较小。每个生育期结果母枝的N、P、K含量依次为N>K>P。收获期到开花前是树体营养恢复阶段,开花到果实生长发育期是消耗体内贮藏态N、P、K的过程。在荔枝年生长周期内,分别在收获期、秋梢老熟期和坐果期施用高氮复合肥、高磷钾复合肥和高钾复合肥能保障年周期内荔枝树体N、P、K营养水平处于最佳状态。