Investigating Root Density of Plum and Apple Trees Grafted on Low-Vigor Rootstocks to Improve Orchard Management

Plum and apple trees are the most widely spread fruit trees in south-eastern Europe. The main purpose of this paper is to characterize the spatial distribution of roots in medium and course textured soils to improve orchard management. ’Stanley’ plum cultivar grafted on Saint Julien A semi-dwarf rootstock and ’Topaz’ apple cultivar grafted on M.9 dwarf rootstock were studied in a temperate climate and medium and course textured soils. The trench technique was used. There was an intense concentration of roots near the trees and the roots did not occupy the whole soil space between tree rows. The finest tree roots in both species were prevalent. Root density was higher in tree rows versus inter-rows. Both the inter-row and in-row distances can be reduced to increase tree density if light penetration into canopy is sufficient. When a full irrigation regime is applied, a soil depth of 0.8?m would be sufficient for water application, and soil depths of 0.4 to 0.6?m would be recommended for deficit irrigation; water and fertilizers should only be applied over the surface area covering most of the roots. When a more strict control on root activity is desired, the tree roots could be cut vertically at 0.5–0.8?m distance from tree rows. The results could also be used in regions and countries with similar soil texture and climate conditions.     

An Evaluation of Blueberry Cultivars Grown in Plastic Tunnels in Douglas County,Oregon

Abstract

Growing fruits and vegetables in plastic tunnels is known to accelerate maturity and protect quality. There are several studies on highbush blueberry (Vaccinium corymbosum) that demonstrate the ability of row covers to advance or delay crop maturity depending on how they are manipulated. Accelerating or delaying harvest time can prove to be very lucrative for producers. However, before producers start putting plastic tunnels over their crops it is important to know how blueberry cultivars will behave when grown under plastic. Six cultivars of southern highbush blueberry and eight cultivars of northern highbush blueberry were grown in a high hoop plastic tunnel for two seasons. Blueberry plants were grown under plastic from February 1 until their harvest was completed each year. After harvest, the plastic covering over the hoops was removed to help the blueberry plants develop fruit buds and meet winter chill requirements. On February 1 the plastic covering was returned to the high hoop tunnel after chilling requirements were met. As expected, fruit maturity dates were 1-3 weeks earlier for all the highbush blueberries grown inside the tunnel versus the same cultivars grown outside. The difference in maturity dates between cultivars grown under plastic and outside did change from one year to the next because of variation in the weather. Despite potential for poor pollination of blueberries in plastic tunnels, yields were significantly enhanced for four cultivars when grown under plastic tunnels. ‘Toro’, ‘Nui’, ‘Legacy’, and ‘Misty’ showed yield gains ranging from 1 to 4 times when grown under a plastic tunnel. Seed numbers per fruit were not significantly impacted by growing plants inside our tunnel.     

Verfrühung von Süßkirschen im Folienhaus

Early ripening sweet cherry cvs ‘Burlat’, ‘Earlise’, ‘Samba’, ‘Souvenir des Charmes’ and clone M, which are all characterised by large fruit size and dark red fruit, on GiSelA 5 rootstock were forced – by closing a polytunnel from 24 March to 20 April 2006 – at Klein-Altendorf research station of Bonn University. A portable gas heater was used for automated frost protection in April. An adjacent uncovered planting at the same spacing of 3.8?m?×?1.75?m served as control. Forcing resulted in a 16–18 days earlier flowering in April relative to the 12–16 days earlier harvest at the beginning of June, resulting in a 2–4 days longer fruit development and retarded ripening. PAR was reduced in the polytunnel by 40% on sunny and 30% on overcast days with a concurrent drop in the humidity to 30% on sunny and 40% on overcast days and nearly 100% relative humidity at night. Polytunnel air temperatures on sunny days were increased – during ventilation – by up to 6?°C relative to the outside, e.g. 33?°C versus 27?°C outside. Forced cherries saved one spray application against aphids compared to those outside. Fully-grown cherry leaves contained 40–60?mg chlorophyll/g FM sufficient for photosynthesis with commensurate chlorophyll contents when grown in the polytunnel compared with those outside, and were deficient in calcium (0.5% DM) and magnesium (0.2% DM), but with a surplus in both nitrogen (3.5% DM) and phosphorus (0.42% DM). The surplus leaf nitrogen was due to excessive nitrogen mineralization in the rich soil under the higher temperatures in the polytunnel which caused the vigorous vegetative growth despite the dwarfing rootstock. Great fluctuations in fertilisation – despite strong flowering and sufficient pollination with honey bees – of between 4–71% may be due to the combination of S-alleles of the cherry varieties, infrequent water supply, nutrient imbalance and microclimate. Trees of cv. ‘Burlat’, ‘Earlise’ and clone M in their fourth leaf yielded an average of 2.5–7.5?kg fruit with 15?kg/tree in one case. Fruit of forced cvs. ‘Burlat’, ‘Souvenir’ and ‘Samba’ were larger compared with those of cv. ‘Earlise’ and clone M, which were smaller as a result of increased fruit load on the tree than those from uncovered control trees. For all five cvs tested, except forced cv. ‘Earlise’, a fruit mass of between 10?g (28?mm ) and 12?g (30?mm) and a sugar content of 12–17% with sugar:acid ratios of 20–37:1 made their fruit suitable for marketing as superior or premium fruit at higher farm-gate prices of 4.5–8?€/kg. Fruits were sufficiently dark red or black and firm for short distance transport and rapid sale. An economic evaluation showed financial gains, when yields exceed 8?kg fruit per tree per year at a farm-gate price of 4.50?€/kg.     

Temporary immersion and stationary bioreactors for mass propagation of true-to-type highbush,half-high,and hybrid blueberries (Vaccinium spp.)

True-to-type propagules in half-high, highbush, and hybrid blueberries (Vaccinium L. spp.) were produced using stationary (SB) and temporary immersion bioreactor (TIB) systems containing a liquid medium. Multiple shoots were produced in vitro from nodal segments of blueberry cultivars ‘St. Cloud’ and ‘Polaris’, and of six blueberry hybrids obtained from crossing between half-high/highbush and lowbush blueberries. Shoot proliferation was best in a liquid medium containing 4.6 µM zeatin in both TIB and SB systems, but the performance was genotype dependent. Shoot proliferation was better in hybrids than in cultivars. Although SB produced longer shoots with more leaves per shoot in most of the genotypes, TIB-derived shoots were more vigorous and rooted better under ex vitro condition. Liquid culture-derived elongated shoots were rooted ex vitro by treating with indole-3-butyric acid (39.4 mM) before planting on a 3 peat:2 perlite (v/v) medium. Micropropagules were acclimatized and maintained in a greenhouse with 80?90% survival rate of rooted plantlets. Expressed sequence tag (EST)-polymerase chain reaction (PCR) and EST- and genomic-simple sequence repeat (SSR) marker assay formed a homogenous monomorphic banding pattern in the in vitro-derived and donor control plants proving the clonal fidelity of liquid-culture-derived micropropagated plants.     

Spatial distribution of Malus root systems in irrigated,trellised orchards

Summary

Root distribution was determined for apple trees [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf. ‘Fuji’/’M.26’ (syn. M. domestica Borkh. non Poir.)] 1, 2 and 3 years after planting in trellised orchards in central Texas. Using a soil-coring method, measurable differences were detected in root-length density (RLD; root length per unit volume of soil) by tree age, soil depth, radial distance from the tree, and spatial bearing within and across rows (P ≤ 0.05). For fine roots (root diameters < 1 mm), mean RLD values were 0.1028, 0.1139 and 0.2911 cm cm^–3 for 1, 2 and 3 year-old plantings, respectively. For coarse roots (root diameters 1–5 mm), mean RLD values were 0.0006, 0.0009 and 0.0015 cm cm^–3 for 1, 2 and 3 year-old plantings, respectively. Mean RLD values declined for both fine and coarse roots of all ages with increasing soil depth and radial distance from the trunk (P ≤ 0.05). Similar patterns were observed for the number of soil cores containing measurable roots. The percentage of samples with no roots increased with increasing soil depth and distance from the trunk (P ≤ 0.05). When examining fine roots by spatial bearing from the tree, the greatest RLD was found along the drip irrigation lines for the two youngest plantings and along drip irrigation lines and beneath shaded trellises for the oldest planting (P ≤ 0.05). For coarse roots, the greatest RLD was found along the drip irrigation lines for all plantings (P ≤ 0.05). This information is important for predicting the rates and locations of new root growth in orchards after transplanting, so that management techniques (e.g., fertilisation, irrigation, control of soilborne diseases) can be properly targeted and effectively implemented.     

The Response of Soilless Grown ‘Michele Palieri’ (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.) Grapevine Cultivar to Deficit Irrigation Under the Effects of Different Rootstocks

Global warming, altering the physiology and irrigation demand of grapevines, has already been perceived in certain premium viticulture regions across the world. Selection of proper rootstocks for especially new cultivars has vital role for a sustainable viticulture under water-deficit conditions. The grapevine cultivar ‘Michele Palieri’ has been finding a good reception on the global markets. The objective of this study was to determine the response of ‘Michele Palieri’ cultivar to deficit irrigation using different rootstocks with distinct genetic origins. Two irrigation regimes (Full Irrigation [FI] and Deficit Irrigation [DI]) were applied to the vines of different grafting combinations of ‘Michele Palieri’ with Kober 5 BB, Richter 99, Richter 110, 140 Ruggeri, 44–53 Malégue or grown on own roots. Two years old vines were cultivated in 60?L pots containing sterile peat under controlled glasshouse conditions. Irrigations were regulated according to soil water matric potential (Ψm) levels using tensiometers. The volume of the irrigation water that has to be applied to attain 100% field capacity was performed as FI, while 50% of FI was considered as DI. The water was transported directly into the pots by micro-irrigation systems consisting of individual spaghetti tubes. The vines of DI treatment showed visible symptoms of mild water stress (e.?g., loss of turgor in shoot tips), but no defoliation or leaf necrosis occurred. DI treatment reduced the gs of ‘Michele Palieri’ scion cultivar in varying levels depending on the rootstock. DI treatment also affected vegetative growth of the scion cultivar in different levels. For example, the greatest decrease (26.7%) in shoot length resulting from DI was determined in ‘Michele Palieri’/5 BB grapevines, followed by own rooted vines (13.1%), while the lowest change (2.4%) was found in vines grafted on 110?R. Overall findings of this study imply that the rootstocks originating from V. berlandiery?×?V. rupestris hybrids (110?R, 99?R, 140?Ru and 44–53?M) better performed in a similar genetic aptitude under deficit irrigation regime while the rootstock 5 BB (V. berlandiery?×?V. rupestris) showed more susceptible responses. On the other hand, the general response of own rooted vines were better than those grafted on 5 BB. Therefore, the use of one of V. berlandiery?×?V. rupestris hybrids may be a better choice for viticulture under semiarid regions.     

Einfluss selektiver mechanischer Fruchtbehangsregulierung auf Ethylensynthese als Stressindikator sowie Ertrag und Fruchtqualität bei Kernobst

The overall objective of this work was to improve fruit quality, break alternate bearing and reduce hand thinning using fewer chemicals in fruit crops. A device was constructed for mechanical thinning, which consisted of three independent horizontal rotors with ropes and freely adjustable angles on a frame, mounted on a front three point hitch and powered by the tractor hydraulics. This can be adapted to any fruit tree trained as spindle, Solaxe, (tall) vertical axis or fruit wall (le mur fruitier) irrespective of rootstock employed. Rotor speed varied from 300 to 460?rpm at either 5 or 7.5?km/h tractor speed. Eight-year-old or twelve-old apple trees cvs. ‘Gala’ and ‘Golden Delicious’ were mechanically thinned in 2007 between pink bud and full bloom (flower bud stages 6–8 or F1–F2) near Bonn, Germany; non-thinned and hand-thinned apple trees of the same block and variety served as control. Mechanically thinned flowering branches showed a similar amount of ethylene efflux (0.4–0.6?ppm C₂H₄/branch) as non-thinned flower branches, preventing potentially unexpected subsequent fruit drop, except for those removed by the rotors. The impact of the horizontal rotors on the branches was from the upper side and removed excessive flowers right to the tree trunk viz. the centre of the tree canopy, where fruits of lesser quality are expected leaving 2–3 flowers per cluster. Leaf damage was less than??10%, even at the fast rotor speed of 420?rpm, which was associated with negligible wood injury. Mechanical thinning induced firmer and sweeter fruit, i.e. tastier apples with longer shelf life, relative to control fruit from non-thinned apple trees. The greatest efficacy in terms of final fruit quality in the grading/sorting was achieved by a rotor speed of 360?rpm at a tractor speed of 5?km/h: Fruit mass increased by up to 20?g and the proportion of fruit larger than 70–75?mm by 10–30% compared with the fruit from non-thinned trees. Mechanical thinning with this newly constructed device led to a 10–20% reduction in yield, but increased returns due to better fruit size and colouration in apple with the potential to overcome alternate bearing.     

Einfluss der Bestäubung durch die Honigbiene (Apis mellifera) auf Ertragsparameter der Kulturheidelbeere (Vaccinium corymbosum)

The influence of honey-bees’ pollination on parameters of yield of the three highbush blueberry varieties ‘Bluecrop’, ‘Reka’ and ‘Brigitta Blue’ was investigated. Four pollination variants were realized: 1. without cage; 2. cage with bees; 3. cage without bees; 4. fine-meshed bag. Total yield, fruit weight, seed production and phenology of the three varieties were examined. An enormously positive influence of honey-bees on yields of ‘Bluecrop’ and ‘Reka’ was found: total yield was by 500–560% higher in cages with bees compared to cages without bees. The results of fruit weight and seed production were similarly clear. However, ‘Brigitta Blue’ hardly responded to different intensities of pollination: regardless of the variant, total yield was extremely low (in cage with bees only 35% of the ‘Bluecrop’-yield) and couldn’t be improved by intensive pollination. The same applied to number of seeds per fruit. However, the mean fruit weight resembled that of ‘Reka’, but wasn’t influenced by the intensity of pollination, either. ‘Bluecrop’ lived up to its reputation as most profitable standard grade with highest yields in all variants (3.7?kg/m³ bush in cage with bees), highest fruit weight (1.6?g) and maximum number of seeds per fruit (98). A direct correlation between fruit weight and number of seeds per fruit couldn’t be established.     

龙眼葡萄棚架栽培条件下的根系分布

通过对棚架龙眼葡萄根系分布的研究,可以了解龙眼葡萄从种植到结果不同时期的根系水平分布、垂直分布变化,为合理施肥、灌水提供依据。采用改良壕沟法,对棚架栽培的龙眼葡萄定植后3～5年的架下和架后根系分布进行了观察。结果表明,定植后3年内,根系伸展速度快。进入结果期后,延伸速度逐渐变缓。根系集中分布区从定植穴逐年外移,结果后稳定在距离树干1.5m处,并在距离地面0.4～0.6m处分布最多。根系和地上部表现出明显的同侧生长的相关性,葡萄架下根系生长快,根数多,分布范围广。架后的总根数仅为架下的2/3左右,并随着树龄的增加,这个比例有逐年下降的趋势,呈不对称的“∞”型分布。对葡萄施肥时应以架下为主,架后为辅的原则。     

Growth and stability of deep planted red maple and northern red oak trees and the efficacy of root collar excavations

Trees with root systems established well below grade due to deep planting or soil disturbance are common in urban landscapes, yet the long term effects of buried trunks and subsequent remediation strategies, such as root collar excavation are poorly documented. We evaluated the consequences of deep planting over a 10-year period on tree growth and stability, with and without root collar excavation, for red maple [Acer rubrum L. Red Sunset^® (‘Franksred’)] and Northern red oak (Quercus rubra L.) planted at grade or 30-cm below grade. Sleeves to prevent soil-trunk contact were installed around trunks on a subset of deep trees. Root collar excavations were made during the 6th growing season for both species and trees were grown for an additional 4 and 3 growing seasons for red maples and Northern red oaks, respectively. Within two weeks of root collar excavations, pulling tests compared the effect of treatments on stability of red maples. Deep planting generally slowed growth of red maple but had no clear effect on Northern red oak. Root collar excavation had no lasting effect on growth of either species. Approximately 55% of deep red maples and 33% of deep Northern red oaks had roots crossing and in intimate contact with buried trunks, suggesting a potential for future girdling roots. Approximately 25% of deep maples had substantial adventitious rooting. All deep Northern red oaks had new roots emerging just above the first original structural roots but none were clearly adventitious. Trunk sleeves had no effect on growth for either species. Neither deep planting nor root collar excavation resulted in a loss of tree stability compared to trees planted at grade, although failure patterns varied among treatments. Overall, the biggest long term concern for deep-planted trees is the potential for girdling root formation.     

Quality of Highbush Blueberry (Vaccinium corymbosum L.) and Bilberry (Vaccinium myrtillus L.) Jam

ABSTRACT

Jam from wild bilberries and from the blueberry culti vars ‘Bluecrop’ and ‘Berkeley’ were analyzed by means of sensory profiling and by instrumental measurement of anthocyanins, color, pH and soluble solids. The study shows that bilberry jam has more “bluish black color,” compared to a more “reddish-blue color” and “glossy” surface of the jam from cultivated blueberries. Bilberry jam was less “smooth” and higher in “viscosity” and “berry density” as well as less distinct in “flavor of flowers and fruits,” while the “blueberry flavor and odor” were more distinct in the bilberry jam than that made of highbush blueberries. Analysis of color by means of sensory hue and instrumental a Hunter lab corresponded well, as did saturation measured by the sensory method and chroma instrumentally measured.     

Apfel oder Acai: Brasiliens Obstbau im ökonomischen und klimatischen Wandel

In times of recession with a 7–10% inflation rate, drop in consumption and loss in value of the Real currency, Brazil as the third largest fruit producer with 46 mil t fruit on 2.2 mil ha (2013), exports ca. 3% of its production worth ca. 765 mil (2013) – 807 (2014) US $, of which 80% is destined for Europe – the fruit export target for the future is 1 bil US $. Apple (cv. ‘Gala’ and ‘Fuji’) production under Southern hemisphere conditions (26–31°S) in Brazil rose from 0.6 mil t in 2002, peaked at 1.4 million t on 39,600?ha in 2011/12, declining in 2012/13 to 1.05 mil t due to orchard reductions in Fraiburgo as a result of lack of chilling, 1.16 mil t in both 20131/4 and 2014/15 and then 0.8 mil t in 2015/16 on 36,090?ha, resembling average apple yields in Germany on 31,400?ha.Apple orchards are essentially free of fire blight and codling moth, but with 1700?mm annual precipitation, they are affected by the scab and Glomorella fungi. Climate change affects apple production: Lack of chilling, caused by cold winters, induces vertical vegetative branches, flat speckled fruit with long pedicels (fruit stalks; cv. ‘Gala’), sunburn (cv. ‘Fuji’). Warm autumns result in a lack of fruit colouration in both varieties and prevent the cultivation of high chill apples, pears and plums.Three major fruit, orange (7.5?kg), banana (6.8?kg) and apple (cvs ‘Gala’ and ‘Fuji’; 4.2?kg apples/head/year; 2014) dominate the overall fruit consumption of 31.4?kg fruit/head/year compared with 36?kg beef, 34?kg pork and ca. 10?kg poultry resulting in ca. 80?kg meat/head/year in Brazil.In the last three years, a new range of storable apple varieties like ‘Venice’ and ’Daiane’ as well as ‘M 58/07’ and ‘M 10/09 – these latter two, still without a variety name – have been, like ’Eva’ added to the existing new breeds from EMBRAPA as very early variety (harvest in January; low chill; 150 CH) and to the summer varieties ‘Condessa’, ’Monalisa’ and ’Princesa’ (all 300–450 CH) without storability; red mutants of ‘Gala‘ (‘Gala, Maxi’ from RASIP) and of cv. ‘Fuji’ (‘Fuji Suprema’) both with 500–600 CH have been bred for growing in Brazil’s higher altitudes. The new cultivars provide medium-sized fruit, bright red peel colour and sweet taste with little acid and a sugar: acid ratio of 25–55:1, as required by Brazil’s domestic market, but so far lack market acceptance and a marketing concept.     

高丛蓝莓对干旱胁迫的生理响应及其抗旱性综合评价

 为研究高丛蓝莓对干旱胁迫的生理响应并筛选具有较强抗旱能力的品种,同时确定基于生理指标的隶属函数分析对于筛选蓝莓抗干旱品种的可行性,分别以北高丛蓝莓中的‘布里吉塔’、‘斯巴坦’以及南高丛蓝莓中的‘夏普蓝’、‘奥尼尔’4 个品种为材料,在人工控水模拟水分胁迫条件下,测定叶片相对含水量、电导率、丙二醛含量、H₂O₂ 含量与　产生速率、F_v/F_m 以及叶片气孔特性等生理生化指标的变化,并采用隶属函数法进行综合评价。结果表明,随着干旱胁迫程度的加深,4 个蓝莓品种叶片的相对含水量、Fv/Fm、气孔开放率和气孔大小均呈下降趋势,而相对电导率、丙二醛含量、H₂O₂ 含量与产生速率以及气孔密度则呈上升趋势。4 个高丛蓝莓品种的抗旱性强弱顺序为奥尼尔 > 夏普蓝 > 布里吉塔 > 斯巴坦,大田干旱试验验证了基于生理指标的隶属函数分析对于蓝莓抗旱品种的筛选的准确性及可靠性。     

Einfluss der Schnittintensität auf Ertrag, Fruchtgröße und Pflückleistung bei Kulturheidelbeeren

From 1999 til 2003, the influence of pruning intensity on yield, fruit size, and picking efficiency was tested for the ‘Bluecrop’, ‘Bluetta’, ‘Patriot’, and ‘Spartan’ highbush blueberry varieties. The following procedures were compared: no pruning (control), little annual pruning in the late winter, little pruning every 2 years in the late winter, intensive annual pruning in the late winter, intensive pruning every 2 years in the late winter, and complete pruning down to the ground in the late winter before the first vegetation period of the trial. Each kind of pruning led to a decline in yield. Therefore the highest yield was produced by controls, and the lowest yield (40% of the control level) was shown with intensive annual pruning. Pruning also increased the size of the fruits. The smallest size was found for controls, the biggest with little annual pruning. Picking efficiency increased along with fruit size. Little annual pruning seems to be the best pruning method for highbush blueberries. This method indeed leads to a visible decrease in yield, but the positive effects on fruit size and picking efficiency compensate this inevitable disadvantage. So, from the economical point of view, there is a clear advantage for this variant. Both nonpruning and regular intensive pruning have to be avoided.     

Weinanbau – Viticulture

Data mining is used as a popular technique in several scientific researches. In agriculture, application of data mining is a relatively new approach. One of the most popular data mining approaches is to find prediction rules from experimental data sets. The present study was conducted in two stages to find out a rule for estimation of width of stalk cavity, depth of stalk cavity, width of eye basin and depth of eye basin of different apple varieties (‘Amasya’, ‘Starking’, ‘Granny Smith’, ‘Pink Lady’, ‘Golden Delicious’ and ‘Arapk?z?’) based on physical properties and to propose an equation for calculating these parameters. In the first stage, data processing was performed and in the second stage, Find Laws was used for prediction of apple properties. Current results revealed that data mining technique had a superior performance and could reliably be used in estimation of physical characteristics of agricultural products. Further research is recommended for possible use of datamining in other agricultural application.     

Einfluss schwach wachsender Apfelunterlagen auf Wachstum,Ertrag und Fruchtgröße verschiedener Sorten – Teil IV: Abschließende Bewertung

From 2001 to 2005 the influence of the dwarfed apple rootstocks M?9 (clone: Burgmer 984), Fleuren 56, Supporter 1, P?16, P?22, J-TE-F, J-TE-E and M?27 on growth, yield and fruit size of the apple varieties ‘Elstar, Elshof’, ‘Boskoop, Herr’ and ‘Jonagored’ was investigated on the locations Auweiler, Dresden-Pillnitz, Osnabrück and Wurzen in Germany.All rootstocks induced a less vegetative growth as the rootstock M?9. In comparison with M?9 the crown volume of the trees ranged from 92% (Supporter 1) to 52% (M?27). The highest yield potential showed the rootstock P?16. Her specific yield (kg/m³) was 17% higher than the specific yield of M?9. All rootstocks produced a lower individual fruit size as M?9. J-TE-E and J-TE-F produced the lowest specific yield.     

Vergleich von Anbausystemen bei der Birne in Abhängigkeit von Sorte und Unterlage: Schlanke Spindel und Güttinger-V-System

To the tenth leaf the influence of two planting systems on yield and fruit size of pear cultivars ‘Conference, 202’ and ‘Alexander Lucas’ grafted on the rootstocks Quince A (MA) and Quince C (MC) was investigated. The planting systems “Slender Spindle” (3.25?×?1.25 m) and “Güttinger-V-System” (3.50?×?0.60 m) were compared. The “Güttinger-V-System” led to higher yields than the planting system “Slender Spindle”. In average of both cultivars and rootstocks the difference between the planting systems amounted to 75.9 t/ha from the third to the tenth leaf. To the additional yield of the “Güttinger-V-System” face additional costs for the installation of the orchard and for the formation of crown. Thus the decision for this planting system will be influenced in a high measure from the producer price.     

Growth and establishment of container-grown London planetrees in response to mulch,root-ball treatment and fertilization

We conducted two experiments to evaluate the impact of cultural treatments on growth and establishment of container-grown London planetrees (Platanus × acerifolia’ Bloodgood’). In both experiments, 48 trees grown in 100 l (#25) black plastic containers were assigned at random to one of three root-ball treatments prior to planting; no treatment (Control), outer 3 cm of roots removed around entire root-ball (Shave), or outer circling roots disentangled from the root-ball (Tease). In Experiment 1, half of the trees were fertilized with 400 g of controlled release fertilizer (15-9-12; N-P₂O₅-K₂O) at planting and the remainder of the trees were not fertilized. In Experiment 2, half of the trees were mulched with an 8 cm deep × 2 m diameter ring of coarse ground pine bark at planting and the remainder of the trees were not mulched. In Experiment 1, fertilization at planting increased SPAD chlorophyll content on two of four measurement dates but did not affect cumulative height or caliper growth after two years. After two growing seasons, root-ball treatments (shaving or teasing) increased root growth outside the original root-ball compared to control trees. Both root-ball treatments also reduced circling roots. In Experiment 2, mulching at planting increased soil moisture and cumulative tree height and diameter growth. Shaving increased new root growth and both root-ball treatments improved root architecture and reduced circling roots. Overall, the study demonstrates that root-ball manipulations can stimulate new root growth and reduce circling roots. Mulch is a valuable aid to conserve soil moisture and increase tree growth. Fertilization at planting provided little benefit in this experiment, which may have been related to a high level of soil fertility at the site or nutrient loading of the trees from nursery culture prior to transplanting.     

Grundlagen der Reaktion von Apfelbäumen auf Wurzelschnitt – eine Übersicht

Root pruning in order to reduce shoot growth is characterized by inconsistent results and has unavoidable side effects. The theoretical basis for reliable predictions of apple tree's responses to root pruning is still largely missing. Here it is proposed that root pruning primarily interferes with the plant's mechanism of growth control: Reduced provision of cytokinins by the roots → reduced activity of shoot gibberellins → limited shoot growth and reduced auxin formation by the shoots → less inhibition of root growth and less shoot competition for carbohydrates → renewed root formation, cytokinin supply by the roots and shoot gibberellin activity → probably renewed shoot growth. Obviously, the initially reduced activity of gibberellins is crucial for the reduction of shoot growth and the various side-effects of root pruning. It depends – next to the extent and timing of root pruning – on the endogenous and external growing conditions. If these are optimal, the effect of root pruning is very limited as renewed root formation and vigorous root growth subsequently soon abolish the reduction of gibberellin activity. For a general recommendation of root pruning as part of a strategy of growth control, the prerequisites are missing.     

三种类型越橘根系垂直分布特征研究

调查了7 a生北高丛越橘、半高丛越橘、矮丛越橘在辽南地区棕壤条件下根系垂直分布特征。结果表明:根系生物量以高丛越橘、半高丛越橘较大,矮丛越橘较小;不同径级根系生物量占总生物量的比例以1～3 mm的根系最大,其次为≤1 mm的根系,大于3 mm的根系所占比例较小;根长密度以北村、斯卫克、康维尔较大,北陆、美登较小;不同径级根系根长密度占总根长密度的比例以≤1 mm根系最大,其次为1～3 mm的根系,大于3 mm的根系所占比例较小;5个越橘品种根系生物量和根长密度垂直分布深度在30～40 cm以内,主要分布在0～20 cm土层中,其中康维尔和北村集中分布在0～10 cm土层中,美登集中分布在10～20 cm土层中,北陆和斯卫克在0～20 cm土层内分布相对较为均匀。