Lower Part Of Canopy Research Articles

Effect of Daytime and Tree Canopy Height on Sampling of Cacopsylla melanoneura, a 'Candidatus Phytoplasma mali' Vector.

The psyllids Cacopsylla melanoneura and Cacopsylla picta reproduce on apple (Malus × domestica) and transmit the bacterium ‘Candidatus Phytoplasma mali’, the causative agent of apple proliferation. Adult psyllids were collected by the beating-tray method from lower and upper parts of the apple tree canopy in the morning and in the afternoon. There was a trend of catching more emigrant adults of C. melanoneura in the morning and in the lower part of the canopy. For C. melanoneura remigrants, no differences were observed. The findings regarding the distribution of adults were reflected by the number of nymphs collected by wash-down sampling. The density of C. picta was too low for a statistical analysis. The vector monitoring and how it is commonly performed, is suitable for estimating densities of C. melanoneura. Nevertheless, above a certain temperature threshold, prediction of C. melanoneura density might be skewed. No evidence was found that other relatively abundant psyllid species in the orchard, viz. Baeopelma colorata, Cacopsylla breviantennata, Cacopsylla brunneipennis, Cacopsylla pruni and Trioza urticae, were involved in ‘Candidatus Phytoplasma mali’ transmission. The results of our study contribute to an advanced understanding of insect vector behavior and thus have a practical impact for an improved field monitoring.

Vertical distribution of the greenhouse whitefly, Trialeurodes vaporariorum Westwood, within potato plant canopy

The greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae) is one of the most important pests of horticultural crops worldwide. The presence of the insect in South Sulawesi was first reported in 2016 when it was seriously damaging field grown potato crops in Malino, causing a yield loss of up to 39%. As a new invasive pest in the region, its population and distribution must be continuously monitored. Effective monitoring can only be achieved if it is based on the knowledge of insect bio-ecology and behavior. Therefore, the purpose of this study was to determine the vertical distribution of T. vaporariorum within the plant canopy. A survey was conducted in a farmer’s potato plantation in Tinggi Moncong, Gowa Regency, South Sulawesi Province, Indonesia. The selected plantation was about 0.2 ha. Ninety plants were randomly selected throughout the field. Each plant canopy was divided into three parts: upper, middle, and lower parts. From each part of the canopy, two leaflets were randomly selected for egg, nymph, and adult counts. The adult number was determined in the field by slowly turning the leaves and all adults found on the lower leaf surface were counted and recorded. The leaves were then picked up and put inside of zip lock bags and brought to the lab for counting the eggs and nymphs under a dissecting microscope (200x). The results showed that about 81, 18, and 1% of the eggs were laid on the upper, middle, and lower parts of the canopy, respectively. Similarly, about 80, 17, and 3% of the adults were found on the upper, middle, and lower parts, respectively. In contrast, no nymphs were found in the upper part of the canopy but about 39 and 61% were found in the middle and lower parts, respectively. This information is very important in monitoring the pest on potato because we now know that for monitoring eggs and adults, the sample should be taken from the upper part of the canopy, whereas for monitoring the nymphs, samples should be taken from the middle and lower parts of the plant canopy.

Multi-scale evapotranspiration of summer maize and the controlling meteorological factors in north China

Evapotranspiration (ET) scale effect influences the understanding of water and energy balance processes at different scales. However, there are fewer studies about the relationships between multi-scale ET and the controlling meteorological factors. In this study, the variations in leaf and plant transpiration and farmland ET of summer maize were systematically analyzed using three-successive-year data from an irrigation experiment station in north China, and the meteorological factors affecting ET at different scales were analyzed based on multivariate regression. The main findings include (1) the transpiration rate (Tr) and stomatal conductance (gs) of sun and shade leaves reduced with the reduction of photosynthetically active radiation (PAR), and the Tr and gs in shade leaves were about half of sun leaves. When the differences in PAR were smaller, leaf Tr and gs at lower part of canopy were slightly lower than those at middle and upper parts of canopy. (2) The sap flow rate (plant transpiration) of summer maize was related to the net radiation but lagged 1h. (3) Diurnal variation in latent heat flux (λET) of summer maize was similar to that in net radiation but lagged slightly. λET, sensible heat flux and ground heat flux accounted for 66.9–70.7, 23.4–26.1 and 4.0–9.2% of net radiation over the whole growing period, respectively. The Bowen ratio ranged from 0.33 to 0.37 over the whole growing period, and peaked at around 10:00 a.m. (4) Leaf transpiration and farmland ET can be characterized by net radiation, air temperature, vapor pressure deficit and wind speed, but plant transpiration cannot be well characterized by them, possibly due to the change of stored water in the stalk.

English

Studies on the quality of applications of plant protection products on coffee crops are lacking. Thus, we studied spray deposition on coffee leaves and losses to the soil from hydropneumatic spraying at different spray volumes and with and without an electrostatic charge. The experiment was set up using randomized blocks in a factorial design (4 x 2 + 1). Spray deposition on the upper, middle and lower parts of the canopy and losses to the soil were evaluated using Brilliant Blue tracer. Applications were made at 200, 300, 400 and 500 L ha -1 with a conventional airblast sprayer (axial fan type) and an airblast sprayer with directed air jets. Applications were also made with an electrostatic sprayer at 130 L ha -1 . Electrostatic spraying resulted in greater spray deposition on the lower part of the coffee canopy compared to non-electrostatic spraying. On the lower and middle parts of the plants, the sprayer equipped with directed air ducts performed better than the sprayer with nozzles arranged along the lateral arcs (axial). The spray volume of the airblast sprayers without electrostatic charge (200 to 500 L ha -1 ) did not influence spray deposition on the plant leaves and losses to the soil, which were lower with the electrostatic sprayer.

A new nonlinear analytical model for canopy flow over a forested hill

A new nonlinear analytical model for canopy flow over gentle hills is presented. This model is established based on the assumption that three major forces (pressure gradient, Reynolds stress gradient, and nonlinear canopy drag) within canopy are in balance for gentle hills under neutral conditions. The momentum governing equation is closed by the velocity-squared law. This new model has many advantages over the model developed by Finnigan and Belcher (Quart J Roy Meteorol Soc 130: 1–29 2004, hereafter referred to as FB04) in predicting canopy wind velocity profiles in forested hills in that: (1) predictions from the new model are more realistic because surface drag effects can be taken into account by boundary conditions, while surface drag effects cannot be accounted for in the algebraic equation used in the lower canopy layer in the FB04 model; (2) the mixing length theory is not necessarily used because it leads to a theoretical inconsistency that a constant mixing length assumption leads to a nonconstant mixing length prediction as in the FB04 model; and (3) the effects of height-dependent leaf area density (a(z)) and drag coefficient (Cd) on wind velocity can be predicted, while both a(z) and Cd must be treated as constants in FB04 model. The nonlinear algebraic equation for momentum transfer in the lower part of canopy used in FB04 model is height independent, actually serving as a bottom boundary condition for the linear differential momentum equation in the upper canopy layer. The predicting ability of the FB04 model is largely restricted by using the height-independent algebraic equation in the bottom canopy layer. This study has demonstrated the success of using the velocity-squared law as a closure scheme for momentum transfer in forested hills in comparison with the mixing length theory used in FB04 model thus enhancing the predicting ability of canopy flows, keeping the theory consistent and simple, and shining a new light into land-surface parameterization schemes in numerical weather and climate models.

Two-Season Study of the Influence of Regulated Deficit Irrigation and Reflective Mulch on Individual and Total Phenolic Compounds of Nectarines at Harvest and during Storage

The influence of deficit irrigation (Deficit) and reflective mulch (Reflective) of Caldesi 2000 nectarines on the content of individual phenolic compounds was studied at harvest and during storage for 2, 4, and 6 weeks at 2 °C during two consecutive years (2007 and 2008). Individual phenolic groups in the edible fruit part consisted mainly of proanthocyanidins (200 mg/100 g fw), lower content of phenolic acids (17 mg/100 g fw), and minor content of flavonols (5 mg/100 g fw) and anthocyanins (1.2 mg/100 g fw). Deficit irrigation increased the content of total phenolics, including proanthocyanidins and phenolic acids, reaching similar amounts in both years. Sun-exposed fruit (upper part of canopy) showed higher content than shaded fruit (lower part of canopy). However, Reflective significantly increased the content of total phenolics, particularly phenolic acids and proanthocyanidins, of fruit located in the lower part of the canopy. During storage, Deficit and Reflective did not affect the content of phenolic acids, flavonols, and proanthocyanidins when compared to the content at harvest. Optimizing cultural practices can be a way to increase the phenolic content of nectarines.

Effects of water stress and pod position on the seed quality of chickpea (Cicer arietinum L.) cultivars.

A field experiment was carried out in 2008 to evaluate the effects of different irrigation treatments (I1, I2 and I3: irrigation after 70, 120 and 170 mm evaporation from class A pan, respectively), and pod positions (upper, lower and middle parts of canopy) on the seed quality of four chickpea cultivars (Jam, Hashem, Arman and ILC from Kabuli type). Seed quality as determined by electrical conductivity of seed leachates, germination percentage, germination rate and seedling dry weight were not significantly affected by water stress, but mean seed weight decreased with increasing irrigation intervals. The largest seeds with the highest quality were obtained from the lower parts of canopy. No significant interaction of irrigation versus seed position indicated that seeds of lower position had high quality under both adequate and limited irrigations. ILC had larger and more vigorous seeds compared to other cultivars. Mean seed weight, germination percentage, germination rate and seedling dry weight had positive and significant correlation with each other. It was concluded that sorting chickpea seeds for large and uniform size after harvest could be a practical way of improving seed lot quality.

PEACH PLANTING SYSTEMS IN SOUTHERN ITALY: ECOPHYSIOLOGICAL ASPECTS AND TECHNICAL DEVELOPMENTS

PEACH PLANTING SYSTEMS IN SOUTHERN ITALY: ECOPHYSIOLOGICAL ASPECTS AND TECHNICAL DEVELOPMENTS

Irradiation on teak and pine agroforestry system and the effect on growth of soybean

Teak and pines are the largest tree forests in Central of Java so that they are very potential to be developed as an argoforestry system. The average Relative Irradiation Fraction (RIF)’s in the teak and pines trees are 50% and 14% respectively. Meanwhile, soybean is sunloving crop potentially to be cultivated in the agroforestry system. The aim of the research was to study the response of the soybean (Glyicine soya) varieties to the tree canopy pruning. The experiment was conducted at teak and pines forest area (vertisol and ultisol soil type respectively) arranged in split plot design. The main plot factor was pruning (no pruning and pruning) and the sub plot factor was variety (Wilis, Pangrango and Brawijaya). The teak and pines canopy pruning (50% lower part of canopy) increases the incident irradiation among the trees by 70%-89% or equal to 600-1000 μ mol m-2 s-1 and 80% or 840 μ mol m-2 s-1 respectively. The increase in the irradiation among the trees enhances the photosynthetic rate of soybean. The response of the soybean to the enhancing irradiation is higher in specific leaf area (SLA). Biomass production and seed yield of the soybean increases due to the canopy pruning. The seed yield of soybean increase respectively from 0.12 to 0.57 tons ha-1 and from 0.78 to 1.74 tons ha-1 in no pruning and pruning teak and pines agroforest. The Pangrango variety produces the highest yields of seed, thus it is potential to be cultivated as intercrops in a teak and pines agroforestry system.© 2006 Jurusan Biologi FMIPA UNS SurakartaKey words: soybean, teak, pines, agroforestry

Irradiation on teak and pine agroforestry system and the effect on growth of soybean

Teak and pines are the largest tree forests in Central of Java so that they are very potential to be developed as an argoforestry system. The average Relative Irradiation Fraction (RIF)’s in the teak and pines trees are 50% and 14% respectively. Meanwhile, soybean is sunloving crop potentially to be cultivated in the agroforestry system. The aim of the research was to study the response of the soybean (Glyicine soya) varieties to the tree canopy pruning. The experiment was conducted at teak and pines forest area (vertisol and ultisol soil type respectively) arranged in split plot design. The main plot factor was pruning (no pruning and pruning) and the sub plot factor was variety (Wilis, Pangrango and Brawijaya). The teak and pines canopy pruning (50% lower part of canopy) increases the incident irradiation among the trees by 70%-89% or equal to 600-1000 μ mol m-2 s-1 and 80% or 840 μ mol m-2 s-1 respectively. The increase in the irradiation among the trees enhances the photosynthetic rate of soybean. The response of the soybean to the enhancing irradiation is higher in specific leaf area (SLA). Biomass production and seed yield of the soybean increases due to the canopy pruning. The seed yield of soybean increase respectively from 0.12 to 0.57 tons ha-1 and from 0.78 to 1.74 tons ha-1 in no pruning and pruning teak and pines agroforest. The Pangrango variety produces the highest yields of seed, thus it is potential to be cultivated as intercrops in a teak and pines agroforestry system.© 2006 Jurusan Biologi FMIPA UNS SurakartaKey words: soybean, teak, pines, agroforestry.

(318) Influence of Orchard Site Parameters and Fruit Distribution within Canopy on Fruit Quality of `Fuji' Apple

Canopies of `Fuji' apple trees, grafted on M.9 rootstock, planted in 1998 on two orchard sites at 2.8 × 0.7 m and trained as super spindles, were subdivided in Spring 2003 into upper and lower parts. In each part, the number of fruits, yield per tree, external (fruit size classes, and fruit coloring), and internal (total sugar content, titratable acid content, and flesh firmness) fruit quality attributes were determined. The orchard site parameters affected growth, yield, and fruit quality in different ways. The less suitable orchard site had less growth, lower yield per tree, and a lower percentage of first class fruits, but most fruits had good color (86% in top and 75% in lower part of canopy). The favorable orchard site produced higher growth and yield, and a higher percentage of first class fruits, but fruits had poorer color. In the lower part of the canopy, fruits were of a good size, but had poor color. Fruits of the best quality were obtained from the top part of the tree.